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
Puppy Nutrition 101 The dog is unique amongst other mammals in that it has the widest range of normal adult body weight within one species. Many breeds will reach 50% of their adult size within 5-6 months. Some breeds will be fully grown by 8-12 months, some 12-18 months, and others 18-24 months. With this incredible range, it’s no surprise that puppyhood is in fact a very sensitive period, and one that we need to get right. Here at My Pet Nutritionist, we are incredibly lucky that we support many owners in choosing the right nutritional plan for their growing puppy. But we thought we’d compile a brief guide to some of the most important things to consider for the growing puppy. Growth and Development After nursing, post-weaning growth is the most nutritionally demanding period in a dog’s life. For large and giant breeds, the length and speed of their growth poses an even higher nutritional demand. By maturity, most dogs will have increased their birth weight by 40-50 times. How amazing is this? But it also poses something to be very conscious of. Physical Growth How are bones formed? Also known as ossification, bone formation is a process where new bone is produced. Look at any large breed and it is clear to see how much new bone needs to be produced from birth to full skeletal maturity. Bone starts as a cartilage model which gets slowly replaced. Osteoblasts are the cells that form new bone. They secrete osteoids. Osteoid tissue is simply unmineralised bone tissue. Soon after the osteoid is laid down,inorganic salts are deposited which forms the hardened material that we know as bone. These inorganic salts include calcium and phosphorus. Bone formation proceeds outwards from ossification centres; short bones tend to have one in the middle whereas long bones typically have three, one at each end and one in the middle. Ossification, or bone formation continues until there is a thin strip of cartilage left at each end of the bone. This is known as the epiphyseal plate, or growth plate in the dog world. When the bone reaches full adult maturity, the cartilage is replaced with bone and“sealed” for want of a better word. It is therefore no surprise that certain minerals are necessary for physical bone growth, along with some vitamins. Calcium is the most abundant mineral in the body; the majority of which is contained in the skeleton. Phosphorus is the next most abundant; also found in bone. Although they have separate functions within the body, being so closely interrelated, they are usually considered together. Calcium is involved in constriction and dilation of blood vessels, nerve impulse transmission, muscle contractions(including the heart), secretion of hormones and blood coagulation. It also plays a role in fluid balance in cells (contributing to homeostasis). A diet grossly inadequate in calcium, results in hypocalcemia. The body will remove calcium from bones to ensure normal cell function in the rest of the body. This leads to weakened bones. Hypercalcemia is a little more uncommon, but it is most often linked with overactive parathyroid gland function. Phosphorus is essential in cell growth and differentiation, energy use and transfer, fatty acid transport and amino acid and protein formation. In general, phosphorus is better absorbed from meat products than plant products. Phosphorus found in meat is mainly in its organic form; in plants it is in the form of phytic acid. Phytic acid impairs the absorption of iron,zinc and calcium and has been linked to mineral deficiencies. It is often referred to as an anti-nutrient. Deficiencies of calcium and phosphorus are unusual, but imbalance is noted. In unbalanced diets, calcium deficiency can develop alongside high levels of phosphorus. Low calcium levels stimulate the release of parathyroid hormone, which increases the production of the active form of Vitamin D. This results in an increased bone reabsorption to restore calcium levels. This eventually leads to bone demineralisation and a loss of bone mass. In dogs, this is more commonly noticed in the mandibles (jaw bones), leading to tooth loss and periodontal disease. Attention is most often paid to the calcium:phosphorus ratio. The note to make is that organic sources of both minerals are slowly and less efficiently absorbed; so, in fresh fed dogs this is less of a concern in terms of excess. Phosphorus found in meat products however is more efficiently absorbed than that found in plants. Findings here Other nutrients relevant to skeletal development include vitamin D, vitamin A, copper, zinc and manganese. Deficiency or excess in these have regularly been linked to abnormal orthopaedic development. But, as we know, it is not just the bones in puppies that grow – it is in fact every part of their body! What do puppies need to grow? Protein Proteins are large, complex molecules composed of hundreds to thousands of amino acids. They are literally the building blocks of the body. Protein is required in the diet to provide a source of amino acids to build, repair and replace body proteins. Proteins in the body have numerous functions. Major structural components of hair, skin, nails, tendons, ligaments and cartilage. Hormones are composed of protein molecules – these include insulin and glucagon which are key to maintaining blood sugar levels. Proteins are found in the blood– for example haemoglobin carries oxygen between the lungs and cells,lipoproteins carry fats throughout the body and transferrin carries iron through the blood. Proteins are also found in the immune system in the form of immunoglobulins to make the antibodies that provide resistance to disease. All proteins are in a constant state of renewal and degradation and during growth (or reproduction) additional protein is needed for the creation of new tissue. High rates of protein synthesis occur in: The production of red and white blood cells Epithelial cells of the skin and those lining the GI tract and pancreas Digestion of Protein Dietary amino acids are absorbed in the gastrointestinal tract, following disruption of their structure. They are then transported
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 know that every cell has a job to do, and it needs certain nutrients to do those jobs. The cells of the immune system have a particularly important job to do and so they too need to be fuelled properly. So, we’ve collated our top foods that you can add to the bowl to support immune function in your dog. The list is not in order of importance, just simple options to pop in! 1) Red Bell Peppers Red bell peppers contain almost three times the amount of Vitamin C that an Orange does! We all know that oranges are touted for their immune supporting functions, but citrus fruits can sometimes cause some digestive discomfort for our furry friends (not all though). Vitamin C contributes to immune defence by supporting various cellular functions of both the innate and adaptive immune system. Vitamin C helps encourage the production of white blood cells known as lymphocytes and phagocytes, which as you know if you read our guide to the immune system, they help protect the body against infection. 2) Broccoli Broccoli is packed full of vitamins and minerals. You will find vitamins A, C and E, fibre and antioxidants in these little green trees! Vitamin A helps maintain structural and functional integrity of mucosal cells in innate barriers (skin, respiratory tract etc). It is also important for the functioning of natural killer cells, macrophages, and neutrophils. In the adaptive immune response, vitamin A is necessary for the functioning of T and B cells and therefore for the generation of antibody responses to an antigen. Vitamin A also supports the Th2 anti-inflammatory response. Broccoli also contains a phytochemical called Indole-3-Carbinol. This compound is formed from a substance called glucobrassicin found in broccoli and other brasscia vegetables such as brussels sprouts, cabbage, collards, cauliflower, kale, mustard greens and turnips. Indole-3-carbinol is formed when these vegetables are cut, chewed or lightly cooked and show some exciting new research on their anti-cancer effect. Findings here The Ultimate Raw Feeding Guide for Dogs Rich in Vitamin C, it is also packed full of antioxidants like beta carotene. Not that you would know it because the chlorophyll hides the yellow-orange pigment. Beta carotene is converted toVitamin A in the body but beta carotene, like all carotenoids is an antioxidant, which protects the body from free radicals. Free radicals are produced by macrophages whilst fighting off invading germs, and these free radicals can then damage healthy cells leading to inflammation, so a diet rich in antioxidants can help mitigate the damage! Best to lightly cook spinach before you offer it to your dog though! 4) Turmeric This bright yellow spice has been used for years as an anti-inflammatory, but it is also known as an immunomodulator. It interacts with dendritic cells, macrophages and both B and T cells. But it also interacts with cytokines and this is why we generally note it’s role in the inflammatory response. The inclusion of turmeric has been seen to increase antibodies to particular antigens and overall, it is seen to improve both innate and adaptive immune function. 5) Poultry There’s a reason why you were always told to eat chicken soup if you felt under the weather! Poultry like chicken and turkey is high in vitamin B6. In the innate immune system, vitamin B6 helps regulate inflammation and has roles in cytokine production and natural killer cell activity. In the adaptive immunity system, vitamin B6 plays a role in the metabolism of amino acids, which are the building blocks of cytokines and antibodies. B6 is also involved in lymphocyte proliferation, differentiation and maturation and it maintains Th1 immune responses. Stock or broth made by boiling chicken bones is also a great option and contains gelatin, chondroitin and other nutrients that are helpful in gut healing in immune function. 6) Shellfish Many types of shellfish are packed full of zinc and this is a particular powerhouse when it comes to immune function. It has antioxidant effects protecting against reactive oxygen species, it helps modulate cytokine release and also helps maintain skin and mucosal membrane integrity (that first line of defence). In the adaptive immune response, zinc has a central role in cellular growth and differentiation of immune cells. It plays a role in T cell development and activation and supports the Th1 response. Cooked mussels are a great addition to your dog’s bowl and are easily picked up in the supermarket. 7) Mushrooms! Not only are mushrooms a great source of B vitamins, but they contain the less talked about mineral selenium. There are such things known as selenium-dependent enzymes which can act as redox regulators and antioxidants; so,selenium can help protect against free radicals too! Not only that but selenium is involved in T cell proliferation and it also has a role in antibody production. Lightly cook mushrooms before offering them to you dog and check out the range of species that have additional health benefits too! 8) Kale One of the leafy greens, kale is rich in folate, or vitamin B9. B vitamins are required to convert food into energy and the demands placed upon the body during sickness can mean more of a demand on this process. Not only that but folate plays a role in maintaining natural killer cells and plays a role in mounting a sufficient antibody response to antigens. Folate also supports Th1 mediated immune responses. In cases of folate deficiency, immune function is often impaired. Low Fat Kangaroo 9) Liver! Whether you opt for cooked or raw, liver is a good source of vitamin D. We find vitamin D receptors throughout the immune system which demonstrates the role it plays in its function. Vitamin D stimulates immune cell proliferation and cytokine production and it helps protect against infection caused by pathogens. It also demonstrates an inhibitory effect in adaptive immunity, suggesting that it is in fact an immune modulator. This is often why we notice increased cases of autoimmunity where there is low vitamin D.
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
What You Need To Know About The Dog’s Digestive System Here at My Pet Nutritionist, most issues that we are faced with involve the need for some form of gut healing. And so, we thought we’d pop a handy guide together, to explain the function of the digestive system, and how it all works. We like to think of it as a journey that food goes on, so, pop on your seatbelt, and come along for the ride. Gut Healt Gut health relates to the whole of the digestive tract, which officially starts in the mouth and ends with, surprisingly, the rear end, or more biologically accurate, the rectum and anus. In humans, digestion begins in the mouth. We physically break down food with our teeth, and salivary enzymes get to work. This is slightly different in the dog. The structure of their teeth means they are equipped for ripping and tearing, and then swallowing larger chunks of foods, whereas us humans have flat surface teeth made for grinding. A dog’s saliva also has a different composition to humans. Studies have demonstrated 2,532 different proteins between human and canine saliva. Canine saliva plays more of a role in protecting against inflammation and functioning as an anti-microbial. Dogs also have lower amounts of amylase than humans and there appears to be no, or very little, salivary amylase present in canine saliva. It is regularly concluded that because a dog is carnivorous, amylase activity in the species is not as dominant. Findings here For this reason, digestion in the dog really starts in the stomach. As food travels down the food pipe (oesophagus), it passes through the lower oesophageal sphincter. These sphincters are important, as they keep parts of the digestive system separate; if they don’t shut or open properly,there may be complaints like acid reflux. The stomach is like a washing machine; it physically churns food around, but it also releases enzymes, acid, and hormones to break it down into a usable form. An enzyme is a protein that speeds up chemical reactions in the body. Digestive enzymes speed up chemical reactions that break down food molecules into something that can be used by the body. Pepsin is an enzyme released in the stomach, from what we call chief cells. It serves to digest protein. The stomach also releases hydrochloric acid, more commonly known as stomach acid from the parietal cells. This highly acid environment causes proteins to lose their characteristic folded structure which exposes the bonds of the protein. Pepsin (having been activated by the stomach acid) can then get to work on these bonds. Stomach acid also inhibits the growth of many microorganisms which is helpful to prevent infection. Digestive hormones are also made in the stomach (and small intestine, but we’ll get there later). The two G’s are released in the stomach, being gastrin and ghrelin. Gastrin stimulates the release of stomach acid when it senses the stomach has been stretched. Ghrelin on the other hand, also produced in the stomach tells the brain that the body needs to be fed; it increases appetite. In the stomach, food is turn into a substance known as chyme, and this moves to the small intestine. The small intestine is full of tiny, carpet like projections called villi and microvilli, which increases the surface area of the organ. These projections allow for nutrient absorption. In short, they allow whatever is in the small intestine to reach circulation. The pancreas feeds into the small intestine and is like the factory of the digestive system; producing enzymes and hormones to further digest the chyme. The pancreas produces: Lipase – think lipid, breaks down fat. Protease – think protein, breaks down protein. Amylase – helps to break down starch. It also produces a range of hormones: Insulin – promotes the absorption of glucose from the blood into the liver, fat and skeletal muscle cells, Glucagon – the messenger which tells the liver to release stored sugar, Gastrin and amylin – whilst most of the G is release in the stomach, some is made in the pancreas too. Amylin helps control appetite and stomach emptying. To further assist with digestion, bile acids are made by the liver, and stored in the gallbladder. Bile is secreted into the small intestine and helps with fat digestion and absorption. To this end, they are also important for the digestion and metabolism of fat-soluble vitamins. As we move through the small intestine, we hit another gateway known as the ileocecal valve. This gateway acts like a watchdog. If it notices under-digested food coming through, it hits what we know as the ileal brake, halting the movement of the upper gut movements. This is a crucial feedback system for nutrient absorption in the small intestine. There is a link between this mechanism and peptideYY, which is produced in the last part of the small intestine known as the ileum. This hormone inhibits intestinal transit (for better absorption of nutrients) and has been associated with higher-fat levels,which is why fat in the diet is associated with higher levels of satiety. Findings here And then we are into the large intestine. The large intestine is responsible for four main things: Hydration The large intestine reabsorbs fluid and electrolytes. Here the contents from the gut turn from liquid to solid (that runny poop – hasn’t spend enough time in the large intestine for some reason). The Microbiome Here resides the microbiome. That community of microbes that is gaining a lot of attention, for good reason. There are microbes found throughout the GI tract, but the majority of them are found here. These guys can make vitamins, amino acids (building blocks of protein), hormones and chemical messengers. They train the immune system, strengthen the gut barrier, communicate with other vital organs including the brain, prevent invasion from the bad bugs, influence gut movement and function and love eating fibre! Nutrient Absorption Whilst most of this occurs in the small intestine, thanks to the
Evolution of the Slowest: The Struggle of the Cat in our Toxic Modern World How many of you have heard that cats are more sensitive to certain things than, dogs for example? If you are using essential oils, that you had to be particularly careful about which oils you used? It turns out there is in fact a biological reason for this sensitivity, and it is all to do with their detoxification pathways. Here at My Pet Nutritionist, we want to explore this fact. We’re not talking about putting your cat on an aloe cleanse programme, but detoxification occurs all by itself, in humans, dogs and of course cats. So, what is detoxification Everyday, ours and our pet’s bodies are exposed to toxins. They are produced internally in the body, like lactic acid and waste products from gut microbes, hormones, and neurotransmitters and externally, like air pollution, chemicals from cleaning products or volatile organic compounds from the plug-in air diffuser in your lounge. 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, and in turn result in chronic health issues. What is a toxin? A toxin is defined as any substance that must be neutralised and eliminated to avoid its promotion of ill-health if left to accumulate. This is what detoxification does. Whilst toxins are generally deemed something in which to avoid, the body is producing waste products every second of every day in the form of used hormones, neurotransmitters, or oxidised lipids. This is why even if we manage our environments well, we still need to support our detoxification system, simply to eliminate the exhaust fumes of daily life. 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 should always 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 transport, they also express a range of enzymes which are essential in sweeping toxins away. Then, 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 cat’s toxic load, all three phases need to be working optimally. Phase I Here we are mostly concerned with a range of enzymes like MAOs or monoamine oxidases dealing with neurotransmitters (those chemical messengers involved in mood and behaviour amongst other things) 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. Once toxins have been passed through phase I, they are not yet finished with. Intermediate metabolites are produced, and they sit in the body. It’s almost like putting your rubbish in the outside bin, but missing collection day. The rubbish remains. Liver Guard Welcome to phase II Within phase II there are number of pathways and they are all responsible for detoxifying different compounds. The pathways include: Methylation deals with heavy metals, plastics, medications, mould, histamine, and hormones, amongst others. This process requires nutrients like folate, vitamin B6, zinc and magnesium. The process of sulphation deals with heavy metals, heavy smoke, hormones, neurotransmitters, plastics, phenols, and medications including antibiotics. Glutathione conjugation deals with heavy metals, plastics, 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. 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 here include vitamin B3, B6 and iron. Acetylation supports the detoxification of smoke, halides, tyramine, neurotransmitters, histamine, and medications including antibiotics. At this point, we move to Phase III Phase III deals with getting rid of them once and for all. This phase is carried out by the gut, skin, liver, and kidneys. All phases need to be working optimally for effective detoxification. Unfortunately, the domestic cat possesses certain genetic mutations which mean these detoxification pathways aren’t as efficient as they need to be. We first started to learn more about this when we realised that cats have a particular sensitivity to phenolic drugs like acetaminoprophen (paracetamol) and aspirin. It turns out that cats demonstrate an inactivation of the gene responsible for the phenol detoxification enzyme and it is thought that their diet played a role. Findings here Phenols are found in plants and as cats are hyper-carnivorous (they get everything they need from animal tissue), there served no evolutionary reason for them to be able to process these compounds. Cats evolved to detoxify environmental threats, not plants they would never choose to eat, nor human-made syntheticones (medications). The problem is, this enzyme is involved in a larger pathway, which deals with things like steroids, hormones, plastics, mould, heavy metals, and other medications like non-steroidal anti-inflammatories. The bottom line? Cats metabolise these compounds at a much slower rate, meaning they are at risk of a build-up. This is why they appear more sensitive and are in fact at a higher risk of
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
Have you ever noticed that the wolves found in Yellowstone are rarely obese? Even the alpha males, who in theory could have access to all the kill they choose, maintain a lean weight. Do they perfectly balance their calories in with their calories out? Whilst not impossible, it’s a slight stretch of their intuition and it demonstrates on a simplistic level, why the CICO model doesn’t really answer enough questions when exploring the concept of obesity. In our last My Pet Nutritionist blog article, we explored a range of ideas that can contribute to obesity in pets, but there are many more schools of thought, so we thought we’d explore another in a separate article. One of them being hormones. All of the fat found in cells is stored in the form of triglycerides. Fatty acids are converted into triglycerides for storage and then for fat to be used as energy, they are freed back into fatty acids. Getting fat is the process where triglycerides are created more quickly than they are broken down. This flow of fatty acids is regulated by a range of enzymes and hormones. This isn’t surprising when we consider the role of growth hormone, it is what drives the growth of children and adolescents. If you are considering bodybuilding, steroid hormones are used to increase bulk and if you take a trip down memory lane, chickens were injected with hormones in the 50’s to increase their size too! Findings here It seems that, on a simplistic level, certain hormones cause fat cells to suck up fatty acids more readily than they otherwise would or slow down the rate at which triglycerides are converted back. Both oestrogen and testosterone have been shown to decrease the rate at which certain cells take up free fatty acids, which results in keeping the fat cells relatively small (and why in humans you will notice differences in fat gain between males and females). This is why after neutering your pet, you are advised to monitor their weight as more often than not, they gain weight. This issue here is demonstrated by a study conducted in the early 1970’s. A professor named George Wade wanted to explore how animals regulated their fat supplies. He had two groups of rats and removed their ovaries. The first group then was given free access to food and they could eat as much as they desired. They subsequently ate more than they had before the surgery and became obese. The second group were restricted to the same number of calories they had eaten before the surgery. Their environment was also kept the same. But this second group too became obese it just occurred through a different mechanism. They simply became less active. With the removal of the hormones, it is thought that the uptake of the free fatty acids was unregulated, resulting in more fatty tissue. With the drop in lipid levels, group one sought to replace the circulating levels with more food, but with the absence of food in the second group, they simply became less active to account for the shortfall. The implication of hormones in fat regulation is also demonstrated when lesions in the brain disrupt the hypothalamus. The ventromedial hypothalamus is one of the most hormonally active areas in the brain, and lesions here have resulted in the development of obesity. Leptin largely exerts its influence in the hypothalamus and leptin has a crucial role in regulating food intake and maintaining metabolic homeostasis (balance). Being another hormone, leptin is secreted mainly by adipocytes. Plasma leptin levels are significantly associated with body mass index and total body fat. It is generally accepted that total fat mass is the strongest predictor of circulating leptin. The discovery of leptin made it clear that adipose tissue (fat tissue) is not only a regulator of body weight but also an endocrine organ with feedback loops between the brain and peripheral tissues. Leptin levels decrease during fasting or energy restriction and increase during refeeding, overfeeding and sometimes during times of stress. Several metabolic and hormonal factors influence the synthesis and secretion of leptin in the body such as cytokines, cortisol, catecholamines, fatty acids, glucose, and insulin. Which brings us to another hormone that is intricately involved in obesity in our pets. Insulin Insulin is deemed an anabolic hormone; it works to accelerate the rate at which nutrients are put together to make new tissues. Insulin is well known for its role in clearing glucose from the bloodstream and regulating blood sugar balance. We’ll use the dry fed dog to explore this a little further. When carbohydrates are digested by the dog, they are broken down into glucose. Carbohydrates can be complex (being longer chains of molecules and taking a little longer to be broken down) or simple (broken down quickly and easily). Ultimately, when they exit the digestive tract and find themselves in the bloodstream, they exist as glucose. When blood sugar levels start to creep up, insulin is called to action. Insulin is like the porter in the hotel; it shuttles glucose out of the bloodstream and opens the doors of where it needs to go. This can be to cells or muscles to be used as energy, but if it isn’t needed there, it can be stored (in adipose tissue). Think of it like when you’ve got an early check out and leave your luggage at reception until you’re due at the airport. But what insulin also does is blocks the conversion of triglycerides back; this makes absolute sense as it wants to prioritise the use of glucose as energy to get it out of the blood stream! But what this means is that insulin is in fact a fat regulator. Now we know glucose can be generated from non-carbohydrate sources through gluconeogenesis, but the issue for the dry fed dog, is that these diets often score incredibly high on their carbohydrate content. Due to the range on the market, it can be anywhere up
