The microbiome was first defined in 1958. It was identified as the collective genome of the microorganisms that share body space. These microorganisms include bacteria, archaea, virus, and fungi. It is believed that 90% of human cells are not of human origin; hence the saying we are only 10% human. Microorganisms of the microbiome therefore provide an important genetic variation. Bacterial genes provide diversity and functions that human cells do not have. This similarly applies to our pets. The microbiome is an important modifier of disease and an essential component of immunity. Dysbiosis of the many microbiomes have been associated with a range of disorders and each day we are learning more about more about the community inside and on top of us, and our pets. Whilst our research is still getting a handle on things, and there are many things we still don’t know much about, we know that certain things can skew the microbiome to result in dysbiosis, and there are somethings than can help it sort itself out. Let’s take a look. The intestinal microbiota is the collection of all microorganisms in the gastrointestinal tract. The microbiome is the collective genome of these microorganisms. Bacteria make up most microbial cells, showing an increase in abundance from the stomach to the colon. The predominant phyla in the GIT of healthy dogs are: Firmicutes, Bacteroidetes, Actinobacteria, and Fusobacteria But each individual animal will have their own personal profile. A note on testing… it would stand to reason, that if we know the bugs that contribute to healthy microbiomes and those that can start to run amok, if we could test for them, then we could tailor a microbiome for health? This is a great concept and one that is gaining traction in the human world, but we still haven’t established a perfect microbiome or microbiota. As it stands, we need to learn more – and acknowledge that our microbiomes are unique – what may be perfect for your dog, may not be perfect for mine. We know that certain bacterial groups have consequences – both beneficial and potentially deleterious. For example, certain dietary carbohydrates can be fermented by the microbes in the gut – in this process, they produce short-chain-fatty-acids. These are known as butyrate, acetate and propionate. On the plus side, these compounds are anti-inflammatory, they maintain intestinal barrier function, regulate motility (the movement of the digestive system) and also provide energy for epithelial cells. On the downside, they can activate virulence factors of enteropathogens. In addition, bile acids also seem to be a major regulator of the gut microbiota. Liver health is therefore implicated in microbiome composition as reduced bile levels are associated with bacterial overgrowth and inflammation. Secondary bile acids have been seen to inhibit the growth of clostridum difficile, Escherichia coli and more. They are also seen to modulate glucose/insulin secretion from the pancreas. Bacteria in the gut produce these secondary bile acids and so if they aren’t present, their antimicrobial function is missed! Dogs with exocrine pancreatic insufficiency have significantly reduced bacterial diversity, with lactic acid bacteria Bifidobacteriaceae, Enterococcaceae, and Lactobacillaceae increased, likely because of overgrowth associated with maldigestion. As we know, the pancreas produces enzymes that help digestion, so if this isn’t occurring upstream in the digestive process, it can cause problems further down. If you would like to know more about the digestive process that occurs in the dog, check out our blog: The Digestive System of the Dog Many studies have highlighted the alterations in bacterial diversity in a range of conditions in the dog. So, what can result in these alterations in bacterial diversity? Generally, the major types of dysbiosis fall under 4 categories. Abnormal substrates in digestive tract Loss of beneficial commensal bacteria Increase in total bacterial load Increased pathogenic bacteria Abnormal Substrates in Digestive Tract The most common here are undigested nutrients – if there is low stomach acid, digestion is impaired resulting in undigested nutrients moving through the digestive tract. If the pancreas isn’t fully functioning and releasing those helpful digestive enzymes, the same applies. The other abnormal substrate includes medications – which may result in changes in the microbiome. Loss of Beneficial Commensal Bacteria The most common cause of loss of commensal bacteria is the administration of broad-spectrum antibiotics (BSA) – BSAs aren’t fussy – they’ll do their job perfectly, taking all bugs with them – this includes those beneficial commensal bacteria that keep the bad guys in check, and which help produce metabolites for optimal functioning. Of interest here is the mechanism by which antibiotics can affect the chemical transformation of pesticides. Antibiotics, through their bug killing capacity, have been seen to suppress enzymes required in hepatic metabolism and also increase intestinal absorption leading to improved bioavailability of pesticides and therefore skyrocketing their risk factor. Findings Here Increase in Total Bacterial Load This is more relevant in cases of small intestinal bacterial overgrowth. When we reference the microbiome, we are considering the microbial community found in the whole of the digestive tract. Generally, the further down we go, the more bugs we find. For this reason, we would expect the majority of the bugs to be found in the colon. SIBO is when there are higher numbers found in the small intestine. Low stomach acid can contribute to the development of SIBO – and the administration of proton pump inhibitors and antihistamines can both suppress gastric acid secretion. Poor motility can also contribute to the development of SIBO, and stress can be a huge factor that contributes to motility issues. In short, if the digestive system isn’t moving, food particles sit where they shouldn’t. Increased bacterial load is what occurs in yeast issues for example. Candida is harmless when kept in check, but for a number of reasons it can overgrow. If you would like to learn more about yeast, check out our blog: Is your Dog a Yeasty Beast? Increased Pathogenic Bacteria No-one will knowingly ingest pathogenic bacteria – we can’t speak for
Vomiting is one of the most common reasons owners take their dog to the vet. Here at My Pet Nutritionist it is a common symptom too, but it is often misperceived for regurgitation. There are a number of reasons for both, and they are very different mechanisms. So, let’s first establish the difference between vomiting and regurgitation, and focus specifically on reasons why your dog may be regurgitating. What’s the difference between vomiting and regurgitating? Vomiting is an active process, where the dog is forcefully ejecting the contents of their stomach or intestines. It is often preceded by sound. Food is usually at least partially digested, or it may be bile that comes up. In vomiting you will notice signs of nausea, like drooling or lip licking. Regurgitation is more passive and usually happens while a dog is eating or shortly afterward. There is usually no sound beforehand. Regurgitation is often just water or undigested food. Regurgitation can be common if a dog eats something that is too large – think large bones or chews. Some dogs will attempt to re-ingest it as soon as they’ve regurgitated it. But there are also some other reasons for regurgitation. 1) Stress Stress is a response in the body –and it is similar across humans and dogs. When exposed to a stressful trigger, the sympathetic nervous system fires up. During this process, resources are directed away from the digestive system and so digestive function is compromised. This can lead to the development of acid reflux which is one of the more common reasons for regurgitation. Stress has also been seen to affect oesophageal sensitivity. During stress, corticotropin releasing hormone plays a key role. This hormone is regularly implicated in hypersensitivity (which is why conditions like IBS are more common in those who are anxious or stressed). But what it means is that the oesophagus is more sensitive to mechanical distension, chemical stimuli and more, which may lead to regurgitation. 2) Reduced Mucosal Integrity In the same strand, mucosal integrity also influences oesophageal hypersensitivity. Just like we have a barrier in the skin and gut, we also have an oesophageal one. It too is made up of tight junctions and has its own plethora of defence mechanisms, including a mucosal barrier. But the presence of acid, in cases of acid reflux can injure the oesophageal epithelium and so, in turn, it damages the mucosal barrier, along with the tight junction formation. During attempts to repair, the inflammatory response is called to action, and animal studies into oesophageal damage have suggested it is a double-edged sword. This inflammatory response has been seen to lower oesophageal pressure through its action on smooth muscle which, not only allows for further reflux of acid,but also then delays acid clearance. Findings Here. The take home here is to restore mucosal integrity as soon as possible and modulate inflammation with ingredients such as l-glutamine, slipper elm, deglycerised and marshmallow root. Gut Guardian 3) Good Stress You may notice that your dog is more likely to regurgitate if they eat too soon after exercise. There is such a thing as good stress, but the response in the body will be the same. When your dog is running, chasing and playing, they are asking their body to move away from homeostasis. Their body will need compounds at a higher rate than what they are needed at rest. It therefore places their body under stress and so, resources are redirected. Digestion is no longer a required function and energy conversion is more important. The sympathetic nervous system is the functional stress response, the parasympathetic nervous system is the commande rthat walks into a room and states, “as you were!” But this command can take time to be heard, and so, if your dog eats too soon after exercise, the entirety of the parasympathetic nervous system hasn’t yet got the message. Without a fully functioning digestive system,it propels the food back out again. Always be mindful of when you choose to offer meals to your dog. 4) The Food Being Fed Regurgitation immediately after eating is in fact relatively common in dogs – but this doesn’t mean its normal. From experience, we often link it to the type of food being fed, as often in many cases, when the food is changed,the regurgitation stops. This can be for a number of reasons,but in short, the body isn’t liking what is going in. The enteric nervous system (ENS) is a subset of the autonomous nervous system and can function independently of the central nervous system. The enteric nervous system innervates the entirety of the digestive system and ENS neurons become hyperexcitable in the presence of toxins, bacteria, inflammatory and immune mediators. Animal studies have demonstrated hyperexcitability of ENS neurons after sensitization withmilk ingestion, leading to mast cell degranulation and histamine release. What caused the sensitisation in this study isn’t relevant, the note to make is that hyperexcitability can occur after sensitization, leading to aberrant enteric function. And so, it pays to consider an inflammatory/immune component in cases of chronic regurgitation. An elimination diet may be useful in this case. Check out our blog for more information. Here Equally, an easily digestible recipe such as white fish, can help, if fish is well tolerated. Low Fat Fish Of interest here is the crosstalk between the microbiome and the enteric nervous system. ENS nerves are thought to detect microbial products because germ-free animals exhibit significantly altered enteric function. A healthy microbiome is therefore crucial for the correct digestive messages to get where they need to go. To support your dog’s microbiome, check out our blog: Here 5) Structure There are cases where the structure of the oesophagus can result in frequent regurgitation. This can be a developmental abnormality or blockage. A thorough exam would be necessary to establish the severity of any structural issue. Summary In many acute cases of regurgitation, acid reflux often comes intoplay. If you would like to learn more then check out
Here at My Pet Nutritionist, we often track many health concerns back to the administration of flea and tick treatments. Whilst correlation is not causation, there is still a correlation. So let’s take a look at how they work and see if we can understand why we don’t recommend them. Grab a cuppa, and sit tight! Permethrin, discovered in 1973, is predominantly administered as a spot-on formulation but has also been formulated in collars. A bit wordy but, permethrin works after contact with the arthropod and absorption into the arthropod either directly through the outer cuticle or through ingestion during feeding on the host. Permethrin is distributed throughout the arthropod nervous system. As this occurs, it interferes with the voltage-gated sodium channels of neurons by slowing down the activation and inactivation process of the sodium channel gates and significantly prolonging sodium ion influx. What this means is that it causes continuous nerve charges, resulting in restlessness, incoordination, tremor, paralysis, respiratory failure, and eventually arthropod death. It acts on the nervous system of the flea to kill it. Permethrin is touted for its fast metabolism in dogs – but cats lack the same enzyme necessary for this process, so any cats that are in contact with dogs who have been treated often show signs of toxicity – hypersalivation, motility disorders, lameness and in some cases death. Check out our article on cat detoxification here. Flea repellence is difficult to appropriately define and measure because fleas attack and bite so rapidly after arriving on the host – for this reason, it is claimed that products like this are designed to reduce flea numbers in the household, rather than to prevent new fleas from taking a bite. Fluralaner is a novel, recently developed chewable tablet, and a molecule of the isoxazoline class. Isoxazolines block the ligand-gated chloride channels of both GABA and glutamate receptors (and as we know these are chemical messengers in the nervous system). After oral administration and absorption int he digestive tract or topical administration and transdermal absorption, fluralaner is rapidly distributed by the circulatory system and maximum plasma levels are on average reached within 24 h after oral or approximately 7 days after topical administration in dogs. This compound has a slow-clearance rate in the body. Fluralaner is a systemically distributed anti-parasitic agent and, by definition, is not a repellent. The reason these products are used is to mitigate the risk of tick-borne disease is to disable the critter when they have latched on to your dog but a review carried out on the efficacy of flea and tick products concluded that there are no currently available acaricidal treatment that can completely prevent transmission of tick-borne diseases. Findings here The other reason these products are used is often if there are known allergies to fleas. But as these products don’t repel, you still run the risk of contact whilst the flea is being killed from ingesting the toxic compound. So, if these products don’t repel, is there anything we can do that can? 1) Start in the Garden! Plant pots of lemon balm, sage, rosemary, lemongrass, basil, and mint! These aromas are great for repelling those pesky fleas! Lemon balm, or Melissa officinalis L., grows natively in West Asia,North Africa, and parts of Europe. As the name suggests, lemon balm has a lemony scent and flavour. And whilst you’re growing some, you may as well note the additional benefits: Antiviral Antispasmodic Improve cognitive function Promote digestion and mitigate griping pains Antioxidant Hepatoprotective Immunomodulatory Findings here 2) Apple Cider Vinegar! ACV can be added to water to support gut health in the dog, but it can also be used as a coat rinse – the smell is particularly repellent, to most! Never use neat, always dilute with filtered water. 3) Neem! Neem has a range of functions including: Fungicide – effective in cases of ringworm, yeast overgrowth and many more fungi species Antibacterial – neem has effectively suppressed several species of pathogenic bacteria Antiviral Insecticidal Controlling intestinal worms Findings here 4) Mint! Not just a breath freshener, it also repels pesky visitors. However, peppermint has been seen to possess the following benefits too: Antibacterial: Peppermint has demonstrated antimicrobial effects against a range of nasties, including:e.coli, salmonella, streptococcus, staphylococcus, Enterobacter and more! Attention is being paid to its role against multi drug resistance bacteria. Antifungal: Peppermint ha sbeen seen to have good fungicidal action against candida, and dermatophytic fungi. Findings here The reason we have considered additional benefits of these herbs is because worse outcomes are usually associated with a poorly functioning system – and so, in repelling nasties, and mitigating the risk of a burden, it is essential to take a whole health approach to parasite control. Ironically, the very administration of some of these treatments is often associated with a subsequently poorly functioning system. Reviews have even concluded that there is strong evidence that products not only target fleas and ticks but they compromise the health of the non-target species, in this case, the dog. Findings here And so, the single best thing we can do to support the overall health of our pets is provide a fresh, whole-food diet, use natural repellants, to find out more, click here. The body has cells, which have jobs to do. To do those jobs, they need nutrients, and whilst some nutrients can be synthesised in the body, many are ingested through the diet. Ensure the diet is full of bioavailable protein, fat, and a range of micronutrients. In order to fight any nasties that appear, a strong immune system is key, check out our article here to learn more about the function of the immune system here and for some top foods to help support it here. If you are concerned that any treatment you have administered has compromised your dog’s system, as the above review highlights, then check out our article on detoxification here and also ensure you are supporting their gut health here. If you would like any support with your dog’s health,
Here at My Pet Nutritionist, we are often presented with a range of tests, that seemingly identify what your pet is allergic to. These tests will often even highlight how severe the allergy is. But do you want to know a secret? They often don’t help. We realise that this may a bold statement, so we’ll explore the mechanism behind allergies in a little more detail, and why there are better tools to establish what’s going on in your pet. An allergy is an unnecessary immune response to an innocuous substance, but a true allergy can be fatal. Immune Responses The innate immune system provides the first line of defence; broadly divided into physical/chemical barriers and nonspecific response. The physical barriers include the skin and mucosa of the digestive and respiratory tracts. Saliva, tears, and mucous all help to provide a barrier, as does the microbiome of the skin and gut and of course stomach acid. Hair inside the nasal capacity also traps pathogens and environmental pollutants. Pathogens that sneakily get past these first defences are next welcomed by the nonspecific innate response. Here cells recognise and bind to pathogens and engulf them. White blood cells are recruited to the site of infection, leading to the well-known inflammatory response. The inflammatory response, whilst often on the receiving end of bad press, is a vital response to injury, infection,trauma, and other insults. Mast cells release histamine, and histamine causes blood vessels to widen, there by increasing blood flow to the area and so, we have the usual signs like redness, heat, swelling and pain associated with inflammation. Mast cells are particularly numerous at potential sites of injury like the nose, mouth, feet, internal body surfaces and blood vessels. Histamine is also stored and released from cells in the stomach. Histamine is involved in stomach acid secretion, but it also has effects on smooth muscle which is why it is thought to be involved in increased peristalsis (movement of food through the digestive system) in food allergies. This is why antihistamine use can be implicated in poor digestive function. The inflammatory response is also a key player in the third line of defence, adaptive immunity. This system is likewise activated by exposure to pathogens, but it uses an immunological memory to learn about the threat and adjust its response accordingly. The adaptive immune response is much slower to respond to threats and it relies on fewer types of cells to carry out its work. Some of these cells manufacture immunoglobulins which are proteins that circulate in the blood stream and bind to antigens (allergens). Immunoglobulins also known as antibodies, abbreviated as Ig, are involved in our dog’s systems when they fight off infections, but they are also involved in sensitivities or allergic reactions to things in the environment or food. A food allergy or other allergic response is caused by an IgE antibody reacting towards that allergen. IgE binds to mast cells to promote histamine release. IgA is an antibody that lives in mucous membranes, inside nasal cavities, and lungs. It helps to protect the respiratory tract as a first line of defence. IgM is the first immunoglobulin that is encountered in an infection, or vaccines for the first time. IgG is the work horse antibody; it is the soldier, the memory antibody. This is what gets drafted when your dog is exposed to something they have already figured out a response to. Here in lies the problem – many allergy tests claim to test IgG. IgG is the memory antibody – so all this is really indicating is exposure. Tests Available Blood – this test is where a sample of blood is taken. It has been noted to measure total IgE antibodies found in the blood, but there are also specificIgE tests which measure the level of antibodies in response to particular allergens. Other blood tests measure IgG antibodies. There are many test providers to be found online – so what they measure is usually very individual. Fur – these tests are usually carried out using bio resonance technology which measures the frequencies emitted from the hair sample. It is based on the idea that unhealthy cells or organs emit altered electromagnetic waves due to DNA damage. Saliva – these tests generally measure IgM, IgA and IgG. It is thought that the same immunoglobulins that are generally found in the blood, are found in the saliva, but this way is less invasive. That said, there are food sensitivities that are deemed non-IgE, meaning they don’t recruit IgE antibodies, which would suggest a blood test would be inconclusive, despite showing symptoms like vomiting, bloating and diarrhoea. What the Data Shows: Testing often show positive results for apparently healthy dogs (not demonstrating any symptoms of discomfort). Findings here There are often no clear differences in positive reactions between allergic dogs and healthy dogs. Findings here There is no clear difference in total IgE and IgG before starting an elimination diet, and completing an elimination diet, despite there being symptomatic improvement when re-challenged. Findings here When comparing saliva and fur samples from healthy and allergic dogs, the distribution of positive and negative results was no different to that expected by random chance. This sample also include fake fur. Findings here This doesn’t mean the reaction doesn’t occur – what this means is that that testing is inconclusive. For that reason, elimination diets remain the gold standard for diagnosing adverse food reactions in dogs. Findings here A true allergy can be fatal, but true allergies are less common than you would think. In our pets, we are generally tackling sensitivities, and this often starts with a poorly functioning digestive system. In normal conditions, the digestive tract should be impermeable to antigens. When it is damaged, antigens can boldly go where no antigen has gone before, resulting in the immune response we discussed earlier. The inflammatory response, if prolonged, can result in further damage, permeating other antigens, and so the cycle continues. Therefore, gut healing is so
Everyday, ours and our pet’s bodies are exposed to toxins. They are produced internally in the body, like lactic acid and consist of waste products from gut microbes, hormones, and neurotransmitters. But the largest threat is possibly those external toxins, like air pollution, chemicals from cleaning products and volatile organic compounds from the plug-in air diffuser in your lounge. Here at My Pet Nutritionists, when considering your pet’s well-being, detoxification is largely looked at as part of the health picture. It is thought that in the 25 years between 1970 and 1995, the volume of synthetic organic chemicals produced tripled from about 50 million tonnes to approximately 150 million tons, and this number has grown year on year since. Findings here These toxins can disrupt essential biological structures in the body. A toxin is defined as any substance that must be neutralised and eliminated to avoid its promotion of ill-health if left to accumulate. What surprises most people is that the body produces waste products every second of every day in the form of used hormones, neurotransmitters, or oxidised lipids. For this reason, even if we manage ours and our pet’s environments well, we still need to support our detoxification system, simply to eliminate the exhaust fumes of daily life. So, what is detoxification? Detoxification is carried out by a range of mechanisms and this comes in particularly handy if one pathway is overwhelmed, another can pick up the slack. We can think of it like a waterfall, water will always find a way down. In a healthy system, toxins will be able to find a way out. Initially, the body will attempt to detoxify at source. These locations include the intestinal mucosa, the respiratory mucosa, the microbiome,and the skin epidermis. Whilst these also provide a physical barrier to prevent toxin penetration, they also express a range of enzymes which are essential in sweeping toxins away. Detoxification falls into three phases. The first two phases are concerned with breaking down the toxin in the body, and phase three is concerned with excreting it. For us to manage ours and our dog’s toxic load, all three phases need to be working optimally. Liver Guard Phase I PhaseI is primarily undertaken by a superfamily of enzymes and they are predominantly concentrated in the liver (but are found in the oral and nasal cavity). t also includes enzymes like MAOs or monoamine oxidases to deal with neurotransmitters (those chemical messengers involved in mood and behaviour ) and PON1 or paraoxonase 1 dealing with pesticides and oxidised lipids. The names aren’t important, but the point is that at this stage the body needs to be efficiently producing these enzymes to metabolise the toxins. So, it stands to reason that this stage is particularly nutrient demanding and sufficient levels of key vitamins and minerals like vitamin A, C, E, B1, B2, B3 and iron, along with cysteine, are essential. This phase also generates high numbers of reactive oxygen species, or ROS leading to oxidative stress (there is also evidence of poor antioxidant capacity in obesity). These enzymes are also highly polymorphic – which means they are prone to altered gene expression. If you would like to know how gene expression can alter detoxification in the cat, then check out our blog here. But, whether the expression starts to cause problems can often depend on the nature and exposure to toxins. Once toxins have been passed through phase I, they are not finished with. Intermediate metabolites are produced, and they sit in the body. t’s almost like putting your rubbish in the outside bin, but missing collection day. The rubbish remains. Welcome to phase II Within phase II there are number of pathways and they are all responsible for detoxifying different compounds. Methylation The process of methylation deals with heavy metals, plastics, medications, mould,histamine, hormones, and neurotransmitters. This process requires nutrients like folate, vitamin B6, zinc and magnesium. Many environmental factors can limit methylation capacity including low dietary intake of co-factors, use of proton pump inhibitor medication, stress, use of anti-depressant medication, gut dysbiosis, high exposure to toxins and a high histamine diet. This can then become more of an issue in those with genetic SNPs in the genes that code for the enzymes involved. Poor methylation can also impair bile synthesis, which then impacts on cholesterol maintenance and glucose metabolism. Sulphation The process of sulphation deals with heavy metals, heavy smoke, hormones, neurotransmitters, plastics, phenols, and medications including antibiotics. Efficient sulphation requires an adequate supply of sulphur (included in cruciferous vegetables for example), but also iron, molybdenum and vitamin B12. Deficiency in any of these can result in an accumulation of sulphites and then an increased sensitivity to sulphite containing foods or supplements (MSM for example). Since this pathway modulates catecholamine levels, poor function can result in higher circulating levels too. Glutathione conjugation This deals with heavy metals, plastics, mycotoxins, mould, heavy smoke, pesticides, and medications like steroids. Glutathione is a master antioxidant so is also important in neutralising the reactive oxygen species produced in phase I. Steady supply of the enzymes in this pathway relies on vitamin B2. But what is also of interest is that the more the glutathione pathway becomes overloaded with long-term paracetamol use, the more depleted glutathione stores become, which places increased pressures on other Phase II pathways and Phase I processes. Low selenium also contributes to poorer enzyme function here. Glucuronidation Glucuronidation is involved in managing heavy metals, sex hormones, neurotransmitters, plastics, mould, alcohol, smoke, medications including paracetamol,non-steroidal anti-inflammatories, warfarin and immunosuppressants. Important nutrients in this process include vitamin B3, B6 and iron. The glucuronidation pathway is particularly affected by digestive health. Anything that promotes gut dysbiosis, like antibiotics, high sugar intake or the use of certain medications which later digestive function can result in toxins being recirculated throughout the body. This then results in increased oxidative stress, which has its own ramifications throughout the body. Acetylation Acetylation supports the detoxification of smoke, halides, tyramine, caffeine, neurotransmitters, histamine, and
An elimination diet – the wand of all wands. Or at least we would like to think so. Here at My Pet Nutritionist, we regularly utilise elimination diets in our healing plans. But there is often some confusion over their purpose and how best to use them. So, we thought we’d cover, what they are, what they hope to do, and what they can’t do. What is an elimination diet? An elimination diet, also known as exclusion diet, is a diagnostic procedure used to identify foods that an individual/animal cannot consume without adverse effects. Adverse effects may be due to food allergy (IGE), food intolerance (IGG), other physiological mechanisms, or a combination of all of the above. The point to note here is that it is a diagnostic tool – not a long-term lifestyle and in some cases, a means to give the immune system a welcomed break. People often look at certain foods being the culprit or the saviour. But what’s really happening is the bodies inability to deal with certain antigens effectively. As we know, the immune system functions like a radar – always on the lookout for potentially harmful compounds. But, through regular activation it can become hypersensitive and seemingly forget that it does have a tolerance capacity too. Immune Tolerance In the body, there are two types of immune tolerance, one is self-tolerance, and this prevents the development of autoimmune disease. The body accepts its own cells and doesn’t try to kill them (so kind!). But there is also this idea of induced tolerance. Induced Tolerance Induced tolerance occurs when the immune system actively avoids responding to an external antigen. This tolerance is induced by previous encounters with that antigen. An example of induced tolerance is a deliberate manipulation of the immune system to avoid the rejection of transplanted organs or to provide protection from allergic reactions. But induced immunity needs a fully functioning immune system to make the right calls at the right time – this is the basic premise of why we want to carry out an elimination diet. To see what foods might elicit a reaction. Through the removal of antigenic compounds (the foods potentially wreaking havoc), you remove the adverse responses pulling on resources and you can then spend time supporting the various systems in the body, including the immune system, to get your ducks in a row. Why would you do an elimination diet? An elimination diet is often the first port of call for dogs suffering with allergies, intolerances, inflammatory conditions and also behavioural issues. This last point often raises a few eyebrows –but as we know, immune responses are intricately linked with the brain and subsequently behaviour. We not only have sickness behaviour, which makes us hunker down and prevent the spread of virus (evolutionary purpose for survival), but pain simply makes us, and our dogs, miserable. In cases of irritable bowel syndrome, there is a noted visceral hypersensitivity too, which in a nutshell means an even higher sensitivity to pain (and sadly an increased propensity to be miserable). The take home? Allergies, intolerances and inflammatory conditions are all an immune response. So, the point is to lighten the load on the immune system. But we can’t forget there are differences between allergies and intolerances. A food allergy or other allergic response is caused by an IgE antibody reacting towards that allergen. IgE binds to mast cells to promote histamine release. This is an immediate response and in some to certain food allergens can be fatal (anaphylaxis). Hives or instant rashes and swelling can be seen. IgA is an antibody that lives in mucous membranes, inside nasal cavities, and lungs. It helps to protect the respiratory tract as a first line of defence. IgM is the first immunoglobulin that is encountered in an infection, or vaccines for the first time. IgG is the work horse antibody; it is the soldier, the memory antibody. This is what gets drafted when your dog is exposed to something they have already figured out a response to. When you have a food intolerance, we tend to discuss it in terms of IgG. Symptoms usually begin within a few hours of eating the food that you are intolerant to. Yet, symptoms can be delayed by up to 48 hours and last for hours or even days, making the offending food especially difficult to pinpoint. IgG’s are mostly raised from the barrier mucosa in the digestive system. After a meal, there are both antibodies and complexes of food antigens bound to specific IgG’s. These complexes are quickly cleared by the reticuloendothelial system. Clinical observations suggest that due to gut inflammation and permeability (leaky gut), the digestive system is unable to digest the proteins effectively which subsequently raises IgG response to certain foods. We know that chronic intestinal inflammations and permeability are related to and possibly responsible for food IgG sensitivity. 90% of food reactivity comes from IgG’s. Just to confirm, intolerances can be changeable but allergies tend to be for life and only account for around 10% of food reactivity. IgG’s come in different categories but to keep it simple, they are generally defined as cyclic or fixed. A common IgG reaction is cyclic and can take around 3 months to disappear/change. A fixed Intolerance tends to linger for longer and can take around 6 months to disappear/change. So how do we move forward? We prime and reset the digestive system, and this includes starting with an elimination diet but also gut healing and immune balancing protocols. We follow the 4 R’s. – Remove – carry out an elimination diet. Remove offending foods, one at a time and note changes in symptoms. Quite often, even offending foods can be reintroduced at a later stage. – Repair – support immunity and gut healing with ingredients like slippery elm, de-glycerised liquorice, glutamine, andN-acetyl-glucosamine. It is also important to consider how existing medications are affecting gut healing for example, steroid use impairs intestinal absorption which is linked to several gastrointestinal dysfunctions. But, because of their anti-inflammatory and immunosuppressive activities,
Would you believe that around 70% of the consultations we carry out here at My Pet Nutritionist are surrounding allergies? The reasons for this are largely multi-factorial and bigger than the scope of one blog article, but as in the words of someone much smarter than us – you’ve got to start somewhere – so we thought we’d explore histamine in a little more detail. What it is, what it does, if indeed it is found in foods and whether there is anything, we can do to reduce the load. So, let’s get cracking. What is histamine? Histamine is a transmitter in the nervous system and a signalling molecule in the gut, skin, and immune system. It is synthesised from the amino acid histidine which is in fact an essential amino acid for humans and dogs. Before we knew better (and in some labs we still don’t), animal studies established that histidine deplete diets result in dog death! Findings here Histamine is primarily associated with the functioning of the immune system. During an immune reaction, histamine is released and contributes to the physical changes necessary for the immune system to fight the pathogen, including the increase in blood pressure, temperature, swelling, and constriction in the lungs. Like all things in the body, histamine needs receptors for it to do its job and there are especially high concentrations of histamine receptors found in the lungs, skin, blood vessels, and gastrointestinal tract. Histamine is stored in granules in mast cells throughout the body and as we know mast cells mediate inflammatory responses such as hypersensitivity and allergic reactions. The granule protects the histamine; if histamine could float freely it would degrade very quickly. Histamine is released from those granules in response to tissue injury resulting from cold, heat, toxins, and trauma. As noted, there are numerous histamine receptors throughout the body. H1 and H2 receptors are of most interest in the hypersensitivity and allergic response (but there are H3 and H4 too). H1 receptor binding results in a range of actions. Peripheral sensory neurons are acted upon which causes itching and sometimes pain. Intestinal smooth muscle is affected causing constriction, cramps and possibly diarrhoea. H1 receptor binding can result in secretory mucosa causing bronchi and nasal mucus. Lastly the pulmonary smooth muscle can be affected resulting in constriction. There are some tissues that have both H1 and H2 receptor binding sites. This includes the cardiovascular system. Histamine binding here drops blood pressure by widening the blood vessels. It also increases heart rate. There are also dermatological effects resulting in increased permeability. This is often described as the triple response resulting in the reddening of the skin, wheal formation and an irregular “halo” flare, also known as hives. H2 receptor binding sites are more commonly seen in the stomach itself. Histamine can bind to parietal cells stimulating the secretion of gastric acid. This is why antihistamine medication is sometimes implicated in digestive dysfunction due to the lower secretion of gastric acid – which is ironic, when partially digested proteins can then become antigenic. H1 receptors are involved in type 1 hypersensitivity reactions (involves immunoglobulin E – IgE – mediated release of antibodies), H2 are involved in Th1 lymphocyte cytokine production, H3 are involved in blood-brain barrier function and H4 are also expressed on mast cells exacerbating histamine and cytokine generation. The long and the short of it, histamine stimulates inflammation and is a prominent contributor to hyper sensitivities and allergic disease (but it is only one of many mediators of allergic disease). Histamine kick starts the processes to get rid of the offending particle/s – whether this is to sneeze pollen from your nose, or to expel food allergens from the gut, but it also plays a role in wakefulness, appetite, and endocrine homeostasis. So, histamine is in fact necessary to maintain homeostasis (balance in the body). But there can be too much of a good thing. Histamine is released to carry out a function and then it is removed by a few different pathways. The enzymes we are particularly interested in are diamine oxidase (DAO) along with histamine-N-methyltransferase (HNMT). DAO inhibition or disruption can result in disproportionate amounts of histamine in the body which can result in a range of GI symptoms along with cardiovascular, respiratory, and skin complaints. Disruption of HNMT function, on the other hand, tends to affect the nervous system. HNMT inactivates histamine by transferring a methyl group, so methylation is a key process in maintaining HNMT activity. Methylation is a relatively simple process, but it occurs billions of times every second! It underlies the proper function of virtually every body system. It is dependent on certain key nutrients like folate in its active form, methyl folate, B12 and B6. There are a number of factors that can affect methylation, from nutrition to genes, but stress and vaccination is a major drain on it. The stress response is a sequence of processes that relies on methylation, depleting key nutrients as it goes. Therefore, if methylation isn’t efficient, HNMT isn’t efficient, and histamine can become imbalanced affecting behaviour, sleep, appetite, immune function and digestion. A range of factors can increase histamine in the body such as infections, B12/folate deficiency, magnesium deficiency, stress, inflammation, trauma and exercise. Not only that but certain gut bacteria produce histamine. DAO and HNMT can become flooded when there is a high histamine load, subsequently affecting breakdown. Histamine load can be increased by the ingestion of high-histamine foods too, but the release of it can also be promoted in the body, by foods we know as liberators. The following list is of foods to avoid if opting for a low-histamine approach to hypersensitivity, whilst getting to the bottom of things. Fermented foods (kefir, sauerkraut etc, prebiotics) Tripe Vinegars (including ACV) Long-stored nuts Beans and pulses Canned foods Citrus fruits Banana Wheat germ Spinach Canned fish (salmon can contain more histamine than most) There is also discussion around yeast behaving as a histamine generating catalyst, so the general rule
The Universe inside your Puppy Here at My Pet Nutritionist we always focus on microbrial health, so we delve into it’s importance for your puppy to hopefully set them up for life. Microbes have been around for billions of years, humans – less than a million and we all know there is much disagreement over the domestication of our faithful furry friends. Microbes can multiply in minutes, survive and thrive in every habitat on earth, and technically, they’ve killed more people than all wars combined. But, without them, we actually couldn’t survive. Microbes are like a bad version of Ed Sheeran, you need me, I don’t need you. The body is in fact like a mini ecosystem. It has many different microbial communities throughout the body. They live inside; in the lungs, nose, urinary tract, and digestive tract, but they also live on; they are all over the skin! Because you sadly have jobs that need to get done today, we’re just going to do a whistle stop tour of the three main microbial communities and how we can support them in the puppy. First up, the skin microbiota. Not surprisingly, the skin microbiota plays a role in skin conditions like atopic dermatitis and even some skin cancers. Check out our blog on atopic dermatitis in pets here. In the dog, there are different communities found in different areas of the skin; there are also clear differences in diversity between healthy and allergic dogs. The skin provides one of the first lines of defence in the immune system, but in two ways. Not only does it have its physical structure to keep things in, and things out, but the community of microbes on the skin also protect against potentially harmful pathogens. The good guys can engulf the bad guys before they gain entry into the body, but they can also compete for nutrients and resources, to prevent the bad guys from thriving. In utero, foetal skin is thought to be sterile. But colonisation of microbes occurs during and immediately after birth. As the newborn puppy moves through the birth canal, he is exposed to a variety of bacteria from Mum. Once puppy is born and grooming begins, Mum passes even more over to her offspring. Mum health is therefore imperative – not only for the diversity she possesses but also her emotional health. Stressed Mum’s are less likely to engage in grooming behaviour, so if she isn’t grooming her offspring, she’s not passing her microbes to them. The environment greatly influences the microbiome of the skin. There are noted variations in skin microbial communities between those living rurally and those in urban areas. There is also an increase in chemical use associated with urban living, which also influences the composition of the microbiome. Diversity is significantly reduced with the use of detergents and antibacterial cleaning products. Potentially pathogenic taxa are also increased as there are fewer good guys to keep the bad guys in check. This is why skin issues like acne or dermatitis are deemed western diseases; they simply just aren’t found on the skin of indigenous tribes or on that of individuals from non-industrialised societies. What is also interesting is that there is also a clear distinction between male and female microbiome, therefore suggesting hormonal influences. This poses food for thought in the neutered pet and how their microbiome is subsequently affected. Unnecessary use of antibiotics also affects the skin microbiome, along with excessive use of grooming products and of course nutrition. The Oral Microbiota There is a collection of microbes found in the mouth; these are the ones that result in bad breath or dental issues. Again, they pose a first line of defence against ingested potentially harmful pathogens. But they also play a role in metabolising certain nutrients. It is clear that the oral microbiota found in dogs differs significantly from humans – some researchers have even gone as far as saying that a human bite would be more dangerous than a dog bite in terms of wound infection potential. Findings here The oral microbiota is gaining more attention and for good reason – there are associations between oral microbiota composition and weight gain, much like we have with the gut microbiota. So, caring for the mouth cavity is just as important as caring for the gut, and colonisation, like in the skin occurs at and shortly after birth – and certainly within the teething period! Data is relatively new, but in human realms, to support oral health, the guidelines regularly include avoiding ultra-processed foods along with high-sugar foods (think high-fructose corn syrup found in many dog treats and processed foods). Guidelines also promote dental hygiene –for our puppies and dogs, raw, meaty bones are a great opportunity to support dental health. Remember to choose appropriately sized bones for puppies – soft bones like chicken necks or wings. They must always be raw – cooked bones pose a splinter risk! The Gut Microbiota/Microbiome When we reference the microbiome, we are considering the microbial community found in the whole of the digestive tract. Generally, the further down we go, the more bugs we find. SIBO or small intestinal bacterial overgrow this when there are too many bugs in the small intestine. We want the majority of them in the large intestine. Each puppy and dog have a unique microbiome – just as we do. It’s like a fingerprint. How cool is that? But it just goes to show that if there is dysbiosis (imbalance of good to bad guys) – there is no one silver bullet. For our puppy, we are in a great position to support optimal gut health from the beginning (not withstanding gene interactions). When we talk about the microbiota or microbiome, we are not just talking about bacteria, but fungi and viruses which live inside the gut too. This is totally normal – the good guys with the right tools can keep the bad guys in check. This community can metabolise nutrients (ruminant
Well, the sun is shining, and the buds are on some of the trees. Whilst it is a great time of year and you feel like anything is possible, it is also the time that seasonal allergies start to rear their ugly head! Whilst many dogs simply have a sensitivity to grass sap and keeping them off the freshly mown lawn for a couple of days can help keep pesky irritation at bay, some allergies are a little more complicated. As always, we are available to help you manage any chronic irritation suffered by your dog, but we thought we would give you some of our top tips that can come in handy when managing seasonal allergies. We love Spring here at My Pet Nutritionist, however we don’t love all of the poor itchy dogs we see due to seasonal allergies. What is an allergy? An allergy is a hypersensitivity with a basis in immune mechanisms. Seasonal allergies tend to manifest as dermatological and respiratory symptoms. Sadly, secondary to dermatological symptoms, dogs can often develop chronic infection from repeated trauma in the form of licking, scratching, or rubbing. Flea allergies are also often deemed as seasonal allergies, and it is the saliva from the flea that causes the irritation. Flea allergies affects animals of all ages, irrespective of sex or breed and there is new data to suggest that puppies given flea protection treatments too early are more susceptible to this disease. It is argued that this is because the young puppy will not be able to acquire immunity to the antigens contained in flea saliva. Findings here For this reason, our first tip is: 1) Avoid the overuse of pharmaceutical flea and worm treatments Whilst there is sometimes a place for the use of pharmaceutical products in high burdens of parasites, we would always advocate the use of worm count kits to establish any burden of worms before treatment and also the use of natural flea repellent products over any spot-on or tablet flea treatment. The overuse of certain pharmaceutical products can place an unusual burden on many pathways in the dog’s body. 2) Support the Gut! As you will know if you read our articles on the immune system and the lymphatic system, in the gut you will find GALT, or gut-associated lymphoid tissue. The digestive tract is heavily laden with lymphocytes, macrophages and other cells that participate in immune responses. As we mentioned, an allergy is an immune response gone bad, so we need to support immune function. In a poor functioning digestive system, rogue particles can end up leaking through the barriers; this can be in cases of periodontal disease (bacteria getting into the blood stream from plaque formation), to damage in the tight junctions in the intestinal tract. But when this happens, the immune response is called to the area of the rogue particle to get rid of it. These systemic responses can lead to hypersensitivity, leaving the immune system a little too eager to do its job on a body wide level. It is essential to support the barriers in the mouth; ensuring good dental hygiene but also to support the barrier of the gut. Bone broth can be a great addition to support gut health. Glutamine is an amino acid that maintains gut barrier integrity and it can be found in bone broth. Read more about gut health here. 3) Limit Stress Mast cells have a key role in allergic response; when they detect a substance that triggers an allergic reaction, they release histamine and other chemicals into the bloodstream. Histamine makes the blood vessels expand and the surrounding skin itchy and swollen. This is known as degranulation and we know that stress can induce mast cell degranulation. Findings here If you are working to tackle allergies in your dog, then it is important to remove as many stress triggers as possible. There is also this idea of co-regulation of species, that dogs can pick up when we are stressed too. We know that seeing our canine companions suffer is worrying, so this is where it can be particularly useful to get a qualified professional on board to help develop a plan of action to move forward. Learn more about how to possibly support stress here. 4) Rinse your dog, but not wash! If you suspect your dog may have sensitivities to certain grasses or pollen, rinse their paws, undercarriage,and chest after walks. You can also wipe their muzzle, ears, and face with a damp microfibre cloth when you get home too. But avoid over-shampooing your dog. Whilst you may opt for non-toxic products, washing can skew the microbiome found on the skin of your dog and this provides a first line of defence for the immune response. The skin has its own community of microbes that can engulf and destroy pesky ones before they have chance to cause problems; frequent bathing can alter this community. 5) Fill up on Fat! As we know, allergies are an immune response and inflammation is the hallmark of an immune response. Therefore, it can help to fill up on foods to down-regulate inflammation. Omega-3 is a fatty acid that has regularly been linked to reduced levels of inflammation. In turn it is often associated with reduced perception of pain (win win!). Omega-3 is found in fatty fish like salmon, mackerel, sprats, and sardines. Fresh or tinned are a great addition to the diet (although be mindful of how much tinned due to mercury content). You will find some content in beef and lamb– just opt for grass fed. There are many fish oil supplements available, just be mindful that as the level of polyunsaturated fatty acids are increased in the diet, the need for Vitamin E also increases. To learn more about your fatty acid options, read here. For some dogs, they can manage seasonal allergies well, with some simple lifestyle changes like: Ensure a fresh diet to give optimal support to your dog’s immunity
If you spotted our My Pet Nutritionist blog last week, then you’ll notice that we didn’t really discuss the lymphatic system with the immune system, despite them being intricately linked. It’s because this system deserves a blog all of its own. So, let’s take a look at what it is and what it does! The lymphatic system is a network of tissues and organs which help the body eliminate toxins, waste, and other unwanted compounds. It is like the sewer system for the body. But it also plays a role in immune function. Like the blood system, the lymphatic system is made up of many vessels that branch all around the body. It is a subset of both the circulatory and immune system. Without it, neither of them would function. The lymphatic system includes: Lymph – a fluid that moves all around the lymph system. It contains a type of white blood cell known as lymphocytes. Lymphocytes – these are white blood cells that fight infection and disease. Lymph vessels – these are tiny tubes that carry lymph fluid around the body. Lymph nodes – these are small, bean-shaped organs. They act as filters for the lymph fluid as it travels all over the body. Lymph nodes are found in the underarms, groin, neck, chest, and belly (abdomen). During infection, lymph nodes swell because of the multiplication of lymphocytes multiplying inside. Function of the Lymphatic System A major function of the lymphatic system is to drain body fluids and return them to the bloodstream. Blood pressure causes leakage of fluid from the capillaries, resulting in the accumulation of fluid in the interstitial space—that is, spaces between individual cells in the tissues. This is where the lymphatic system comes into play. It drains the excess fluid and empties it back into the bloodstream via a series of vessels, trunks, and ducts. But as we mentioned, it also plays a role in the immune function of the host. The lymphatic system is a sort of immune surveillance system. It protects us against pathogens. Our dogs are constantly being invaded by bacteria and viruses; they take them up through food, they breathe them in, and they get in through wounds in our skin.These pathogens must be removed by the immune system. Because the lymphatic system is constantly filtering the contents of the body it collects these micro-organisms which have been engulfed by immune cells and carries them to the lymph nodes. Within the lymph nodes there are T cells and B cells which recognise these pathogens and which multiple in response. So, the lymphatic system acts as a collecting system and therefore an integral part of the immune system. Another role of the lymphatic system is the absorption of fats and fat-soluble vitamins from the digestive system and the subsequent transport of these substances into circulation. The mucosa that lines the small intestine is covered with finger like projections called villi. There are blood capillaries and special lymph capillaries, called lacteals, in the centre of each villus. The blood capillaries absorb most nutrients, but the fats and fat-soluble vitamins are absorbed by the lacteals. The lymph in the lacteals has a milky appearance due to its high fat content and is called chyle. Organs and Tissues of Interest The primary lymphoid organs are the bone marrow, spleen, and thymus gland. Tonsils are known as lymphoid nodules. The lymphoid organs are where lymphocytes mature, proliferate, and are selected, which enables them to attack pathogens without harming the cells of the body. As we explored in the guide to the immune system, lymphocytes are the primary cells of adaptive immune responses. The two basic types are B and T cells – B cells maturing in the bone marrow, and T cells maturing in the thymus. Bone marrow is the spongy tissue in the middle of the bigger bones in the body. The bone marrow makes blood cells from stem cells. These are undeveloped cells that can divide and grow into different types of blood cells needed by the body including red blood cells, platelets, and white blood cells. This is where lymphocytes are made. The thymus is in the thoracic cavity, just under the neck. It’s made up of two lobes of lymphoid tissue. Each lobe has a medulla surrounded by a cortex. The cortex is where immature lymphocytes first go to become T cells, but their maturation finishes in the medulla. The spleen is in the upper-left part of the abdomen. It is tucked up under the ribs. The spleen’s main function is to filter the blood. It removes old or damaged red blood cells, which are phagocytised by macrophages. The spleen also detects viruses and bacteria and triggers the release of lymphocytes. But as the main entry for microbes into the body is through mucosal surfaces, most of the lymphoid tissue is located within the lining of the respiratory, digestive, and genitourinary tracts. These are known as MALT and GALT. MALT is mucosa associated lymphoid tissues, and GALT is gut-associated lymphoid tissue. Tonsils are an example of MALT. The tonsils are masses of lymphoid tissue found in the back of the throat and nasal cavity. Tonsillitis is when they become swollen and typically a sign of infection. Peyer Patches within the small intestine are also MALT. They are like the tonsils for the digestive system. The function of Peyer’s Patches is to analyse and respond to pathogenic microbes in the ileum. They trap foreign particles survey them and then destroy. What can go wrong with the lymphatic system? Enlarged (swollen) lymph nodes (lymphadenopathy): Enlarged lymph nodes are caused by infection, inflammation, or cancer. Swelling or accumulation of fluid (lymphedema): Lymphedema can result from a blockage in the lymphatic system caused by scar tissue from damaged lymph vessels or nodes. Cancers of the lymphatic system: Lymphoma is cancer of the lymph nodes and occurs when lymphocytes grow and multiply uncontrollably. For dogs, lymphoma can arise in the skin. Summary The lymphatic system is an extensive drainage network that helps keep bodily fluid levels in balance and defends the body against infections. It is made up
Here at My Pet Nutritionist, we often find that in many cases, immune function in some pets has gone a little awry. Being the thing that quite literally keeps us alive, you can see, how optimal immune function is kind of important. So, we thought we’d give you a run through on its function. What is the Immune System? When the body is invaded by bacteria, a virus or parasites, an immune alarm goes off, setting off a chain reaction of cellular activity in the immune system. Specific cells are deployed to help attack the invading pathogen. Those cells often do the job, and the invader is destroyed. But sometimes, when the body needs a more sophisticated attack, it turns to a more specialised set of cells. These cells are like the special ops of the immune system—a line of defence that uses past behaviours and interactions to tell it exactly how to deal with the threat. The immune system is responsible for all of this, and not surprisingly is has many systems to mobilise action. We tend to explore the immune system in terms of innate immunity and adaptive or acquired immunity. Innate immunity is what everyone is born with – it’s a type of general protection. The innate immune system provides the first line of defence; broadly divided into physical and chemical barriers and nonspecific responses. The physical barriers include the skin and mucosa (a membrane that lines cavities in the body) of the digestive and respiratory tracts. Saliva, tears, and mucous (that sticky material) all help to provide a barrier, as does the microbiome of the skin and gut. In the gut, stomach acid also provides a first line of defence as its acidity level can kill off potentially harmful pathogens. Hair inside the nose also traps pathogens and environmental pollutants. This is where you’ll recognise the age old having something stuck up your nose when you are viciously sneezing! Pathogens that sneakily get past these first defences are then tackled by the next row of soldiers in the innate immune system. There area number of white blood cells involved in innate immunity: Monocytes which develop into macrophages Neutrophils Eosinophils Basophils Natural Killer Cells But there are also other participants: Mast Cells The Complement System Cytokines Macrophages develop from a type of white blood cell called monocytes. Monocytes become macrophages when they move from the bloodstream to the tissues. They ingest bacteria, foreign cells, damaged and dead cells. This process is called phagocytosis, and cells that do the ingesting are called phagocytes. Macrophages secrete substances that attract other white blood cells to the site of the infection. They also help T cells recognise invaders and therefore also participate in acquired immunity (which we’ll come to later). Neutrophils are among the first immune cells to defend against infection. They are phagocytes, which ingest bacteria and other foreign cells. Neutrophils contain granules that release enzymes to help kill and digest. Neutrophils also release substances that may trap bacteria, preventing them from spreading and making them easier to destroy. Eosinophils can ingest bacteria, but they also target foreign cells that are too big to ingest. Eosinophils contain granules that release enzymes and other toxic substances when non-self-cells are encountered which make holes in the target cell’s membranes. They also produce substances involved in inflammation and allergic reactions. We know this because those suffering with allergies, parasitic infections, or asthma tend to have more eosinophils in the bloodstream than those not suffering with the conditions. Natural killer cells are ready to kill as soon as they are formed. They attach to infected cells or cancer cells, they then release enzymes and other substances that damage the outer membranes of these cells. NK cells play a role in the initial defence against viral infections, and they produce cytokines that regulate some of the functions of T cells, B cells, and macrophages too! We’ll look at T and B cells later. Also involved in the inflammatory response, mast cell function resembles that of basophils in the blood. When they encounter an allergen, they release histamine. Histamine causes blood vessels to widen, thereby increasing blood flow to the area and so, we have the usual signs like redness, heat, swelling and pain associated with inflammation. The complement system consists several proteins that function in a sequence. One protein activates another,which activates another, and so on to defend against infection. This is known as the complement cascade. Complement proteins play a role in both innate and acquired immunity. They kill bacteria directly,help destroy bacteria by attaching to them, they attract macrophages and neutrophils, neutralise viruses, help immune cells remember invaders, promote antibody formation, and help the body eliminate dead cells and immune complexes. Cytokines are the messengers of the immune system. White blood cells and other cells of the immune system produce cytokines when an antigen is detected. There are many different cytokines, which affect different parts of the immune system. Some cytokines stimulate activity – asking the white blood cells to become more efficient killers, some cytokines inhibit activity, signalling an end to an immune response and some are known as interferons, which interfere with the reproduction of viruses. Cytokines also participate in acquired immunity. Acquired (adaptive or specific) immunity is not present at birth. It is learned. Its job is to learn, adapt and remember. It’s almost like a cheesy advert for a local school! Acquired immunity does take time to develop after exposure to a new antigen, but afterwards, the response is quicker and more effective! Key Definitions Antibody – Antibodies are specialised, Y-shaped proteins that bind like a lock-and-key to the body’s foreign invaders — whether they are viruses, bacteria, fungi, or parasites Antigen – An antigen is any substance that causes the immune system to produce antibodies against it. The white blood cells responsible for acquired immunity are Lymphocytes which include T and B cells. There is also a role for others in acquired immunity which include dendritic cells, cytokines, and the complement
The primary two functions of the skin is to act as a protective barrier and an immune barrier, between the body and its external environment, it keeps everything in, and prevents the entry of pathogens and allergens. Here at My Pet Nutritionist, we have heavily focussed on the skin function and allergies so let’s take a look. A defective skin barrier is a key feature of the chronic inflammatory skin disease, atopic dermatitis and it has been noted that the protein filaggrin has a pivotal role in skin barrier function. Mutations with the FLG gene, which encodes filaggrin, strongly predisposes to conditions including atopic dermatitis and secondary allergic diseases. Whilst we always find these revelations in human literature, we have found that this also applies to dogs. So, let’s take a look at filaggrin in a little more detail and how there is a possibility that the skin issues faced by your dog may have a genetic origin. What is Filaggrin The term filaggrin, derived from filament-aggregating protein, was first coined in 1981 to describe a class of structural protein that had been isolated from the stratum corneum (the outermost layer of the epidermis of the skin). Filaggrin is formed from the breakdown of profilaggrin, a protein contained in the granular layer of the upper epidermis. Filaggrin is vital for skin cells to mature properly into the tough, flat corneocytes that form the outermost protective layer of our skin known as the cornified cell envelope (CCE). It does this by binding together the rigid keratin filaments that form a structural skeleton within the cells. As a result, the cells collapse and become flattened. The CCE is constantly renewed by new cells formed in the basal layer of the epidermis. These gradually work their way to the top of the skin layers where they become corneocytes. They will then shed. Surrounding the corneocytes you will find a layer of lipids, which coat the CCE, keeping the skin waterproof, protected and supple. This also provides a protective layer, keeping out irritants and allergens. Without filaggrin, the CCE does not form correctly. Corneocytes dry out, and the lipid layer is lost. This results in dry, cracked skin and a permeability to the skin. Atopic dermatitis is characterised by these symptoms, and data has revealed an association between loss of functions of the filaggrin coding gene and this condition. In short, these conditions are more commonly noted in those with a mutant gene, than those without a mutant gene. What is particularly interesting is that the environment plays a role, not only in developing atopic disease, but also directly in FLG expression. It is regularly noted that exposure to irritants can reduce epidermal FLG levels and lead to an acquired filaggrin deficiency. The FLG deficiency, be it genetically determined or acquired, causes an altered epidermal structure and an impaired barrier function. Sadly, this allows penetration of environmental allergens into the skin, including house dust mites, pollen, bacteria, irritants, and toxicants but it also results in sensitisation of the host. The resultant alteration of the epidermis by way of increased pH, altered lipid secretion, modification of keratinocytes and reduction of antimicrobial peptides also then paves the way for the perfect environment for other bacteria and fungi to thrive, leading to recurrent skin infections, which you’ll have likely observed in cases of canine atopic dermatitis. Environmental and Inflammatory Factors known to alter the amount of Filaggrin: Humidity It seems there is a correlation between indoor humidity and disease severity. In human studies, in those children with atopic dermatitis and FLG mutations, their skin lesions are more often located in air-exposed skin areas. Interestingly, children with atopic disease experience a reduction in disease severity after one month spent in a humid climate. It seems that filaggrin and more filaggrin proteolysis is required in a dryer environment and for that reason, it is often concluded that children predisposed to atopic dermatitis should be encouraged to increase their indoor humidity. Findings here Mechanical damage Mechanical damage includes stretching, compression, and friction on skin cells. It not only affects the barrier function of the skin but also induces various immune responses, triggering inflammation at the site of the stress on the skin. For example, scratching of itchy lesions exacerbates the skin inflammation in atopic dermatitis. This increase in inflammatory mediators has been seen to down regulate filaggrin expression. Skin Irritants Studies have demonstrated that profilaggrin expression can be down regulated after application of experimental sodium lauryl sulphate (SLS). In the 6 hours post exposure, it was noted that SLS in fact induced skin barrier defects. Findings here SLS is what’s known as a surfactant. This means it lowers the surface tension between ingredients, which is why it’s used as a cleansing and foaming agent. You will find SLS in a range of human products and may find it in some dog grooming products. It is generally what makes them foam. Human Products: Hand sanitiser Makeup remover Liquid hand soap Shampoo Conditioner Styling gel Bubble baths Dental care products like toothpaste Anti-itch creams Sunscreen You may also find it as a food additive in certain products, it is used to mix acids with other liquids, or as an emulsifier or thickener. Dog Grooming Products: Shampoo Conditioner Detangler Conditioning balms Deodorising sprays Cologne It is also worth noting that some shampoos specifically prescribed or advertised for use in atopic disease also contain SLS, amongst other ingredients. The issue is that when products reduce filaggrin expression, it disrupts the skin barrier, making it permeable to other toxicants and irritants, creating a vicious cycle. What you choose to apply to your dog’s coat and skin is just as important as what you put into their body through their diet. Not only that, but whilst you may not be applying human products directly to your dog, they may come into contact with them through exposure to soft furnishings or you. In the hopes to create a mechanical barrier, without harsh chemicals being used, there are certain topical products
