The DCM and diet connection?

What with all of the concern recently on the dogs who have developed heart disease, I've gotten a lot of questions on whether we know the cause and what to do about it.  There are a couple of great summaries that I will refer you to, but the short answer from me is this - the problems seem to be associated solely with small companies or homemade diets.  From what I can tell, none of the larger, very well established companies are involved.  So that's the answer for now - I would try to stick with large, well established companies and not just one of them. I've always said that it's safer to rotate between a few different companies and this is a good example of why I recommend that.

That's not what this is about though - there has recently been some kerfuffle claiming that the reason for this crisis is plant lectins.  I was curious and did some research myself.  This is what I've come up with.

Lectins in Pet foods

Susan G. Wynn, DVM, DACVN

Antinutritional factors appear, as a whole, to benefit plants by deterring predators and microbes. The varying degrees of toxicity to animals, insects and microbes have been exploited in studies that explore medical applications.

Plant defenses include low molecular weight compounds (alkaloids, terpenoids, tannins, and glycosides), and proteins (lectins, ribosome-inactivating proteins (RIPs), protease inhibitors, a-amylase inhibitors, ureases, arcelins, canatoxins, antimicrobial peptides and pore-forming toxins). The proteins tend to accumulate in vulnerable (i.e. edible) parts of the plants - seeds and storage tissues.

The first toxic carbohydrate-binding protein - a lectin called ricin - was discovered in the seeds of castor beans in 1888. Lectins have been reported in bean, tomato, potato, banana and garlic. Lectins are ubiquitous among plants and to date, several hundred have been identified. In addition to plants, animals, insects, viruses, fungi and bacteria also synthesize lectins.

Lectins are globular proteins of non-immune origin that have specific CHO-binding activity and have at least one non-catalytic domain that binds reversibly with specific mono- or oligosaccharides without altering the substrate. Binding is specific but diverse, with some lectins recognizing monosaccharides (such as mannose, glucose, galactose, and fucose). However most plant lectins preferentially bind oligosaccharides like N- and O-linked glycans. Thus far, 12 lectin families have been described, based on sequence similarities and evolutionary relationships.

Toxicity is, in part, determined by resistance to proteolysis by gut enzymes. Lectin toxicity varies widely, from antinutritional activity to lethal effects. Common beans (Phaseolus vulgaris) contain phytohemagglutinin (PHA) which is highly toxic. In the gastrointestinal tract, lectins can act as toxic allergens and hemagglutinins. If lectins bind epithelial cells in the animal digestive tract, the activity at these receptors may have adverse effects on the cellular morphology and metabolism of the stomach and/or the small intestine, and can alter permeability and activate signaling cascades that alter intermediary metabolism (Vasconcelos, 2004).

Most of our knowledge about the anti-nutritional effects of lectin is derived from animal experiments, using purified lectins, with very few clinical studies in humans. Short term experiments in rats have shown that purified lectins from beans or soybeans damaged the epithelial cells. led to enlargement of the small intestine, stimulated hypertrophy and hyperplasia of the pancreas, and impaired the growth of rats in the studies. In addition to disrupting the cell membrane, lectins can inhibit the activity of brush border enzymes. If the activity of lectins is marked enough and not modulated by the intraluminal food matrix, the potential toxicity is primarily  interference with protein and carbohydrate digestion and absorption. It does appear that lectins must bind to the gut epithelium to cause damage, and any that pass through the gut are harmless.

Phytohemagglutinins (PHA) from Phaseolus vulgaris, the common bean including black turtle bean, string bean, flageolet bean, kidney bean, pea bean, pink bean, pinto bean, white bean, yellow bean, cranberry and borlotti bean, and so on, have been studied extensively. PHA is a mitogen and has been used in laboratory studies to stimulate cellular activity. PHA binds strongly to the brush border of the small intestine, and disrupts normal development of intestinal microvilli (in rats). Since lectins remain attached to the epithelial surface, they may also inhibit plasma membrane repair resulting in a net loss of cells.

Even endogenous lectins have been implicated in GI damage - several galectins appear to be involved in the development and progression of inflammatory bowel disease and intestinal tumors. Galectins are a group of mammalian lectins which are involved in cell-to-cell adhesion, growth regulation, signalling and cytokine secretion.

A potential secondary toxic effect of undigested lectin in the small intestine is to lead to overgrowth of coliform bacteria, possibly due to the intraluminal changes in nutrient content induced by increased mucus secretion, epithelial cell loss, serum protein leakage and reduced digestion of dietary protein.

As additional adverse effect is stimulation of an allergic response.  When systemically absorbed intact, PHA can lead to a Th2 response and a Type I (IgE-mediated) allergy, at least in rat studies.

What isn’t understood is the physiologic and nutritional significance of low level, chronic ingestion of lectins and other anti-nutritional factors when taken in as part of the natural diet, cooked or raw, or even whether beans can be considered a natural part of the canine or feline diet. Soy products, for instance, retain 5-20% of the trypsin inhibitory activity originally present in raw soybeans. While some have theorized that the amounts of trypsin and chymotrypsin produced by a human could be completely inhibited by ingestion of raw soybeans or 200 g of other raw legume containing 2 grams of inhibitors, humans do not routinely eat raw beans.

Lectins have been subjected to industrial and experimental processing methods such as steam heating, autoclaving, extrusion and dry roasting in order to study their antinutritional effects.  Although lectins are in general considered heat-resistant, it has been well established that they can be inactivated after cooking (around 100C or 212 farenheit) for short periods of time (up to about 15 minutes), with an improvement of the accessibility of the protein to enzymatic attack(Coffey et al., 1992) (He 2018 p78). He (2018) reports that the navy bean (Phaseolus vulgaris) hemagglutinin (HA) lectin “could be fully eliminated at 121C for 5 minutes after the autoclaving treatment, and white bean (Phaseolus vulgaris) lectin could be fully inactivated after steam treatment of 100C for 15 minutes; extrusion treatment of 145C for 16 minutes resulted in 98% reduction in the HA of small red bean (Phaseolus vulgaris) lectin, as well as 99% reduction in the HA of navy bean (Phaseolus vulgaris) lectin observed with the dry roasting treatment at 200C for minutes (Van der Poel, 1990; Shimelis and Rakshit, 2007)." Purified PHA was subjected to high pressure pasteurization (HPP) and while low pressure (150 mPA) did not change the hemagglutinin activity, high pressure (450 mPA) led to a ‘noticeable decrease in the hemagglutinin activity”.  To summarize, normal cooking temperatures for 15 minutes appear to inactivate most of the undesirable activity, as does high pressure pasteurization.

Lectins may have biomedical applications and are being investigated for potential anti-tumor activity. The antiviral, antifungal and insecticidal properties of some toxic plant proteins has given them potential use in agriculture. Lectins have been used to target malignant cells for specific drug delivery, especially Concanavalin A and BSA. Some PHAs may bind human tumor cells and elicit production of inducible NO synthasae which is anticarcinogenic.  PHA has also been shown to inhibit HIV replication. PHAs have also been shown to enhance the immune response against infections in general as it stimulates lymphocyte replication.

Extracts of beans are marketed for weight loss with the premise that PHA inhibit carbohydrate absorption and metabolism. These effects are seen using isolated, uncooked plant lectin - obviously a plate of cooked beans would not have the same benefit!

Summary

While lectins do have adverse effects on the Gi tract of rats when administered as an isolated treatment, similar damage has not been demonstrated when lectin-containing foods are ingested as a normal part of the diet in humans. Reviewers have concluded that when properly cooked, lectin-containing foods are unlikely to pose any risk to humans. While beans in significant amounts are not a natural component of the feline diet, they may or may not be a natural part of the canine diet. In pet foods, lectin-containing foods are extruded or canned, which should destroy most of the antinutritional activity. In addition, these foods are only one component in a recipe containing other ingredients, which are usually meats. Vegan diets containing no animal protein may have enough residual lectin activity to be of concern, especially if they have been subjected to dry heat only, as wet heat is more effective. The recent crisis in dogs who develop dilated cardiomyopathy is unlikely to be related to the lectin content of bean- or lentil- containing foods because many kinds of foods have been implicated, including some that contain no beans or other  foods high in lectins. Further, if lectins were causing mucosal damage, why would the metabolism or absorption of taurine in particular be targeted? Damage from lectins appears to have a much broader effect, resulting in a leaky gut that should theoretically have much more systemic results. But probably only if you are a rat, eating pure lectin.

The “Myth” Of Complete And Balanced Nutrition

A common theme heard from those who believe in paleolithic feeding claim that the “complete and balanced diet” is unnecessary. Their reasoning goes like this –

• ·         Humans don’t eat a complete and balanced food every day. We even raise children without a daily complete and balanced, all-in-one food like pets eat, and they do just fine, don’t they?
• ·         Wolves and wild cats don’t eat complete and balanced foods every day.  Not only does their native diet supply all they need, but the foods that they can hunt or forage varies on a day to day or week to week basis – this variety in the diet leads to a complete/balanced nutrient profile over time.
• ·         Complete and balanced nutrition has not resulted in pets living longer lives – my childhood dog lived to be 20 years old!
• ·         ONE complete and balanced food is not, by itself, able to provide complete and balanced nutrition over months to years.

Let’s look at these claims one by one.

Humans don’t eat a complete and balanced food every day. We even raise children without bothering to balance every meal, and they do just fine, don’t they?

Actually, no.  Both young and aging humans experience different kinds of illnesses than dogs and cats, particularly atherosclerosis, hypertension and metabolic syndrome, which are rampant in developed countries.  And humans could be considered a sentinel population for the increasing problem of obesity, childhood diabetes, and preventable cancers.  No, humans are not doing just fine.

Wolves and wild cats don’t eat complete and balanced foods every day.  Not only does their native diet supply all they need, but the foods that they can hunt or forage varies on a day to day or week to week basis – this variety in the diet leads to a complete/balanced nutrient profile over time.

The natural diet of wolves and African wild cats are perfect for repeated reproduction, not longevity.  Wild animals eat diets that are high in protein and energy to support repeated production of offspring - as many and as much as possible. Repeated reproduction is associated with shorter life expectancy, and the body is worn out from optimal reproduction, there is no further use for that individual in the population, so they die from exhaustion and inability to fend for themselves. 

We have different plans for our pets - we want them around for 15 or more years, and we know that neutering them and keeping them thin adds many years to their lives in comparison to their wild ancestors We also know that preventing nutrient deficiencies through development of complete and balanced diets has been associated with an increase in life expectancy. Paleolithic diets are too high in fat for many of our pets whose most intense exercise is a few 30 minute walks or play sessions a day.  In order to achieve our goals for our pets, we may not always be able to feed a paleolithic diet, and balancing that diet appears to optimize an animal’s life expectancy..

Complete and balanced nutrition has not resulted in pets living longer lives – my childhood dog lived to be 20 years old!

If you don’t believe that pets are living longer, just look at the surge in old age diseases in the last 50 years. Veterinarians now treat more degenerative issues like osteoarthritis and kidney disease than ever before.  And cancer!  Yes, it’s possible cancer is on the rise due to environmental or other exposure issues, but pets are also living long enough to contract cancer.  We just did not see as much cancer to treat 50 years ago.

In addition, we now have evidence for certain interventions that increase life expectancy – a great example is that of keeping dogs and cats thin -the increase in lifespan is up to 2 years.

There is evidence that life expectancy is greater in pet or domesticated dogs and cats than in feral or ‘wild’ dog and cat populations. The average life expectancy in pet cats (12–14 years) is considerably higher than the reported median lifespan in feral cats (4·7 years). It is not known what factors contribute to this difference between feral and pet cat populations, however, accidents, diseases, parasites, food availability and stress due multiple and frequent pregnancies may contribute. 

A study from Banfield showed that, over the past decade, average lifespan has increased by 1 and 0·5 years in cats and dogs. 

Results from a yearly survey of UK households over a 34 year period, totaling 233,461 households, showed that the average age of dogs and cats increased by about 13% from 1960 - 1994. The percentage of both dogs and cats over the age of 8 years also increased. During this same time period, the feeding of "prepared pet food" increased from 49 - 69% for dogs, and from 64 - 90% for cats.  Veterinary databases from academic sources also show greater longevity in dogs

And those 20 year old beloved family pets?  These are the pets who made it past deadly infectious diseases (for which there were no vaccines) and traumas (such as fights, vehicular accidents, etc). Those pets that died early were not remembered later in the owners’ lives, but the few who did lived on as beloved memories.

ONE complete and balanced food is not, by itself, able to provide complete and balanced nutrition  over months to years.

I don’t completely disagree with point 4 – feeding a single brand of complete and balanced food may indeed reveal some shortcomings of that diet over months to years.  Or more precisely, reveal that the pet eating the diet has requirements that the diet cannot fulfill.  These diets are formulated to supply complete nutrition for 99% of normal animals.  However, even normal animals have individual nutrient requirements that may vary widely from “average”.  Pet owners and veterinarians frequently note how a pet’s haircoat declines on one diet over time, and immediately improves after a switch to another over the counter diet.  That pet just received missing nutrients of some sort, or conversely, got relief from an overdose of a nutrient that he or she couldn’t tolerate well.  There might well be a perfect diet out there for every individual pet, but with thousands of brands available, finding that one diet is challenging if it exists at all!

There is another aspect to this observation that pets may respond very decisively to diet changes.  Depending on how the food is formulated, there may be ingredients and nutrients present which are not considered essential but that do confer some benefit. Phytonutrients from fruits and vegetables are one example.  Nutritionists formulate complete and balanced foods to supply optimal (not minimal) amounts of all the essential nutrients, but a food containing more biochemical complexity may benefit an animal’s metabolism in ways that are not obvious or easy to study.

One of the most common areas for a nutrient deficiency or imbalance to show up is in the skin.  I see sparse hair growth and flaky or greasy skin pretty commonly in animals that are eating deficient diets. However, we generally do not see classical nutrient deficiencies if a pet is eating a diet that is deficient in 1 or 2 micronutrients but contains plenty of protein, fat, calcium, etc.  What we see instead is that if the pet becomes ill with another problem, that illness may be worse, or require more treatment or hospitalization than if the pet had been eating a complete and balanced diet. Those subclinical nutrient deficiencies leaves the patient wanting and without metabolic reserves when the system is stressed. The other relatively common situation is the sudden “appearance” of a nutrient deficiency that was developing for months to years while the animal seemed perfectly healthy.  A particularly dangerous example is taurine deficiency in dogs* – a dog can motor along seeming perfectly healthy, but behind the scenes, the heart is proceeding into heart failure, and the owner doesn’t notice anything wrong until failure has occurred.

Can you measure blood levels to determine whether a vitamin or mineral deficiency is present? In many cases, the test is either not very accurate or difficult to run so we don't typically do those tests unless special circumstances exist.  On the other hand, if a pet is chronically malnourished or has been starved, we do see indirect indicators such as w protein and other laboratory values.  But the physical condition often tells us what we need to know. 

To summarize, there are many good reasons to feed a complete and balanced diet, and no good reasons to avoid doing so.  It’s easy to find foods of all types – complete/balanced homemade recipes, raw foods, grain-free foods, paleo foods, kibbles, cans, prescription diets -why take chances when it just isn’t necessary?

*Taurine is not considered an essential nutrient in dogs, and yet some dogs develop heart failure due to taurine deficiency from certain diet formulations, including diets very high in fiber (we believe), or those composed of meats that are low in taurine. 

References

Watson D.  Longevity and diet (letter). Vet Rec 1996 (138) 3: 71

Butterwick RF. Impact of nutrition on ageing the process. Bridging the gap: the animal perspective. The British journal of nutrition. , 2015, Vol.113 Suppl, p.S23-S

 EJ Taylor , C Adams & R Neville (1995) Some nutritional aspects of ageing in dogs and cats. Proc Nutr Soc 54, 645–656.

 Banfield Pet Hospital (2013) State of pet health 2013 report. http://www.stateofpethealth.com/Content/pdf/Banfield-State-of-Pet-Health-Report_2013.pdf.

J Levy , D Gale & L Gale (2003) Evaluation of a long-term trap-neuter-return and adoption program on a free-roaming cat population. J Am Vet Med Assoc 222, 42–46.

Paleo for all?

Recently many pet owners have become interested in the idea of paleolithic feeding - that is, feeding the paleolithic diet of cat or dog's ancestor. Paleolithic feeding does not mean the same thing to everyone, so some definitions are in order:

·         Paleolithic diets are high in meat and fat, and low in starches and sugars - they theoretically mimic the ancestral diet of dogs (the wolf) and cats (the African wild cat).

·         Low carb diets are theoretically low in *digestible* carbohydrates such as starches and sugars, and high in meats.  They should also be low in another type of carbohydrate - fiber - but this varies diet to diet.

·        Grain-free diets contain no grains (such as wheat, corn, oats, rice, millet, amaranth, quinoa, barley, etc).  Grain-free diets are not necessarily low in carbohydrates, which are instead found as potato, tapioca, or pulses in these diet formulations.

Raw diets contain raw meat, and are typically high in protein and fat.  They may or may not contain starches, sugars, fiber from vegetables and fruits, nutraceutical additives, or vitamins and minerals.

In general, the increasingly popular trend is to feed a paleolithic diet.  These high meat, high fat diets usually consist of muscle and organ meat, ground bone, and may or may not contain vegetables, or be complete and balanced.  It is important to note that these homemade and commercial combinations are not really paleolithic at all, as wolves and feral cats would typically eat almost all parts of their prey including the toughest, least digestible parts containing primarily connective tissue*, nervous system; organs not available for consumer purchase like trachea, lymph nodes, spleen, etc; GI tract contents, etc.  Commercially available meat has also been exsanguinated - blood was drained at slaughter, and blood is a very rich source of nutrients. 

Also, prey animals have generally eaten wild foods, which give their flesh a very different nutrient profile than that of store-bought meats. Wild grains (and therefore wild prey animals) contain higher levels of healthy omega-3 fatty acids and other types of plant compounds as well. Conventional meat used in raw diets come from intensively raised cattle and chickens with unhealthy fat (that causes atherosclerosis and heart disease in people!).

(*These poorly digestible, high connective tissue parts are known as by-products when found on a pet food label.  Note that many pet owners consider “by-products” unhealthy, when they are, in fact, part of the natural diet.)

More important is the question of whether domestic dogs and cats should eat a paleolithic diet at all.  First, domestic pets are genetically different from their wild ancestors.  Even the tiny amount of DNA that   differs between dogs and wolves, or domestic and wild cats accounts for major variations in some visible traits, like the differences in size between a Great Dane and a Chihuahua, or the leg length of a munchkin cat, the ears of a Scottish fold, or the nose and haircoat of a Persian cat.  The traits we cannot see, such as those regulating metabolic enzymes, differ just as greatly from those of wild animals.

Next, evolution has different plans for wild animals than we do for our pets. Wild animals eat diets that are high in protein and energy to support repeated production of offspring - as many and as much as possible. Repeated reproduction is associated with shorter life expectancy, and when the body is worn out from optimal reproduction, there is no further use for that individual in the population, so they die from exhaustion and inability to fend for themselves. 

We have different plans for our pets - we want them around for 15 or more years, and we know that neutering them and keeping them thin adds many years to their lives in comparison to their wild ancestors We also know that preventing nutrient deficiencies through development of complete and balanced diets has been associated with an increase in life expectancy. Paleolithic diets are too high in fat for many of our pets whose most intense exercise is a few 30 minute walks or play sessions a day.  In order to achieve our goals for our pets, we may not always be able to feed a paleolithic diet.

Formulated diets that are lower in fat may be appropriate, and they may contain sources of carbohydrates (such as corn, lentils, rice, sweet potato, etc).  These are not just fillers -  they can contain low-fat sources of protein, as well as vitamins, minerals and good fiber types.

Finally, while raw and paleolithic diets can occasionally be used to feed sick animals, this is just as often not true, as we need to intensively manage some nutrients such as phosphorus or copper or fat.  These ill animals have progressive illness that, without nutritional management, would kill them.  In fact, in the wild, animals with these conditions indeed die an early death.  We are able to keep our sick pets happy and well for much longer with controlled nutrition, whereas in the wild, they wouldn't have a chance, even if they were well enough to find food. Geriatric, ill pets who live for months to years happily represent a very, very artificial situation, and a natural diet is likely the worst thing that could happen to some of them!

Raw and homemade fresh diets can be formulated to provide just about any nutrient profile required by your pet, and pets are individuals – some will do well on raw and paleolithic diets, and some will not.  The ideal diet for your dog or cat is the one that produces the best long term (not just short term) results.  I recommend that your pet's diet be balanced in calories, protein and other nutrients to maintain your pet's optimum condition, rather than conform to some standard that doesn't apply to his or her lifestyle.

What is a Novel Protein Anyway, Or, Why is Chicken Bad for My Pet?

 Recently I've had a spate of owners claiming that they've been told that chicken is bad for their dog or cat. Well……yes and no.

Like the game we played in grade school – Rumor – the real story has been lost in the re-telling, such that when it reaches me from the owner in my hospital, chicken has become the enemy.

It is not.  So let’s talk about food allergy.

Food allergy is believed by many to be a common cause of allergic skin disease.  It is not – environmental  allergies are by far the most cause of skin allergy.  However, changing dietary ingredients may help  improve the itching from environmental allergy.

Food allergy is more likely to cause GI problems – intermittent or persistent loose stool, diarrhea, reflux, vomiting, gas, and noisy stomach.  And just to return to skin allergy for a second, I usually expect that GI signs will accompany skin signs if food allergy is the cause.

Food allergy is a problem for animals who are genetically predisposed to it, or for animals who have had an insult to the gut resulting in inflammation.  That inflammation can lead to a breakdown in the normal gut barrier, leading to absorption of substances into the body that would otherwise be kept safely inside the gut ultimately to be eliminated. This situation has a name – Leaky Gut.

When a leaky gut is present, the immune system gains abnormal access to food molecules, bacteria, and other protein-containing substances that lead to the development of immune response to “fight” this “foreign invader” that the immune system has never  seen before.

The good news is that leaky gut is often treatable using a combination of diet changes, probiotics, and anti-inflammatory herbs, nutraceuticals or drugs. For even more good news, some of these food allergy cases turn out not to be permanent.

Food allergy, if the conditions are right, develops because of exposure to that particular food ingredient.  Chicken just happens to be the most common meat ingredient in the pet food industry, so…..

So, if an animal does in fact develop a sensitivity* to chicken, a change in dietary ingredients is certainly warranted, but that doesn’t mean that chicken is forbidden forever.  In fact, it is not possible to definitively diagnose a food allergy in any way except for elimination and then challenging with that food ingredient.  If a challenge test using chicken meat results in a reaction (GI OR skin), well, food allergy is usually the answer.  But what we usually find is that on challenge testing, chicken is no longer a problem (or never was).

By the way, this reminds me of the whole corn story from 10 or 15 years ago.  Many dog owners were claiming that their pets were allergic to corn simply because they changed from corn-containing diets to diets that had none. There are many great reasons for significant clinical improvements to occur when we change diets, so I believed these owners. However, a true allergy to corn is even less rare than a true allergy to chicken.  There was something else at work there.    

Bottom line – if your pet is itchy or has ear problems, it’s usually fair to try and change the dietary ingredients.  But if your pet improves, we just can’t conclude that food allergy was the reason.  Food changes are powerful for many reasons.

When a Vitamin isn't a Vitamin At All

Pet owners ask me every day about supplementing a nutraceutical* for their pet's chronic condition.  Some common examples are:

Heart disease - magnesium, Vitamin E, B vitamins, taurine, thiamin

Wound healing - zinc 

Immunedeficiency - Vitamin A

Anemia - Vitamins B2, B6,  iron, etc

Oxalate bladder stones - Vitamin B6

Asthma - Vitamin B6

Diabetes - magnesium

Immune-mediated diseases - Vitamin D

The difference between most people and most pets is that most pets are eating complete and balanced diets, and people do not.  In fact, the majority of chronic problems experienced in the human population are likely due to some form of malnutrition, which may be why humans have a different set of common disorders than dogs and cats (such as atherosclerosis, diabetes, and hypertension). Every one of the conditions with suggested nutraceuticals listed above are used in people to correct a dietary deficiency. 

Generally, supplementing dogs and cats with nutrients doesn't make much sense if they are eating a complete and balanced diet - at least if that nutrient is used in the human conditions to treat a deficiency.  Yes, you need to know a bit of physiology to evaluate these compounds for use as medication.

On the other hand, I've seen a rise in the number of people feeding unbalanced homemade diets, so perhaps veterinarians should give these kinds of supplements a closer look in pets eating unbalanced diets.  Or just encourage the owner to get them properly balanced.

But nutrients can have other effects, activities that show up only when pharmaceutical doses are used.  When nutrients are used at doses beyond what is necessary for nutritional maintenance, they are being used as nutraceuticals. And some do have interesting potential. One well known example is the use of Vitamins A, E, C, and pyridoxine as antioxidants.  Another is the use of fish oil in higher than nutritional doses to suppress chronic inflammation.

Moral of the story - it's hard to decide if a nutraceutical will help a pet with a chronic problem without direct evidence, like a study involving that nutrient, for that condition, in a group of similar patients, compared to patients taking a placebo.  But studies are expernsive, and we can't usually count on getting all of the studies we need.  If the scientific support is lacking but the supplement seems safe and the mechanism makes sense, a veterinarian may choose to use a nutraceutical. But it's just not as simple as searching the web and picking the most common recommendations that can be found. 

*A nutraceutical is a nutrient used at supra-nutritional doses. Herbs are not nutraceuticals. 

Inflammatory Bowel Disease and Plant Medicines

A variety of plants, plant extracts,  and complex herbal formulas have  been studied in the treatment of IBD.  Central to the problem of studying this condition  is the lack of understanding about the cause.  Bowel inflammation is believed to involve the following: ¹

• ·         multiple genetic variations
• ·         alterations in the composition of the intestinal microbiota
• ·         changes in the surrounding environment
• ·         overreactivity of the intestinal mucosal immune response

Herbal treatments have been identified based on ancient traditional treatments for chronic diarrhea, vomiting and other GI complaints, while more scientifically based testing has been done based on the content of anti-inflammatory compounds contained in plants.

Experimental animal studies have indicated that a variety of herbs and herbal formulas may quell gut mucosal inflammation. These are established models for the human diseases known as IBD, irritable bowel disease, ulcerative colitis, and Crohn's disease.   Most recently, cannabidiol from the hemp plant has been shown to suppress mucosal inflammation as well as hypermotility.²  A very small sampling of other plants shown in recent experimental animal studies  to have benefit include:

• ·         Zanthoxylum myriacanthum var. pubescens 3
• ·         A formula of Quebracho, Conker tree and M. balsamea Willd extracts 4
• ·         Zataria multiflora Boiss 5
• ·         Daucus carota (carrot)  6
• ·         Boswellia serrata (conflicting results) 7,8
• ·         Zingiber officinale (ginger)  9
• ·         Cordia dichotoma 10
• ·         Patrinia scabiosaefolia 11
• ·         Vitex negundo 12
• ·         Pistacia lentiscus 13
• ·         Mastic 14,15,16
• ·         Plantago ovata (psyllium) 17

Human clinical trials are naturally fewer, and there were virtually no clinical trials found in dogs and cats at the time of this review.  A systematic review ¹ from 2015 highlighted the following herbs.  In all cases where adverse effects of treatment were tracked,  herbs were deemed very safe.

• ·         Aloe vera (1 trial) - significant maintenance of remission as compared to placebo
• ·         Andrographis paniculata (1 trial) - clinical efficancy similar to mesalamine though recurrence rate was higher
• ·         Artemisia absinthum (2 trials) significant improvement over placebo in 1 trial but not anotherj smaller trial
• ·         Boswellia serrata (3 trials) - treatment efficacy similar to sulfasalazine in 2 trials but not different  from  placebo in a third trial
• ·         Cannabis sativa (THC extract, 2 trials, one not controlled)  - significantly better results over  placebo 
• ·         Curcuma longa (turmeric, 3 trials, only 1 controlled) - reduced clinical signs and relapses as compared to placebo group.

A modern Chinese herbal formula significantly improved symptoms of irritable bowel syndrome in a randomized controlled trial in human patients 18. This trial compared patients given placebo, individualized Chinese herbal prescriptions, and standard formula. Initially, both treatment groups improved significantly compared to the placebo group; at follow-up 14 weeks later, only those receiving individualized prescriptions maintained improvement.

Standard Chinese herbal formula in Bensoussan trial

Dang Shen            Codonopsis pilosulae               7gm

Huo Xiang             Agastaches seu pogostemi      4.5gm

Fang Feng            Ledebouriella sesiloidis            3gm

Yi Yi Ren              Coicis lacryma-jobi                      7gm

Chai Hu                 Bupleurum Chinense                4.5gm

Yin Chen               Artemisia capillaris                    13gm

Bai zhu                 Atractylodes macrocephalae    9gm

Hou Po                 Magnolia officinalis                    4.5gm

Chen Pi                 Citrus reticulata                          3gm

Pao Jiang             Zingiber officinalis                     4.5gm

Qin Pi                   Fraxinus rhynchophylla             4.5gm

Fu Ling                 Poria cocos                                 4.5gm

Bai Zhi                  Angelica daihurica                    2gm

Che Qian Zi           Plantago asiatica                     4.5gm

Huang Bai             Phellodendron amurense      4.5gm

Zhi Gan Cao          Glycyrrhiza uralensis             4.5gm

Bai Shao               Paeonia lactiflora                     3gm

Mu Xiang              Aucklandia lappa                     3gm

Huang Lian            Coptis sinensis                       3gm

Wu Wei Zi             Schisandra chinensis              7gm

How might herbal medicines work to improve the clinical signs of, or even resolve, IBD?  There are a variety of potential active compound classes contained in herbs, including proteins, carbohydrates, lipids, alkaloids, glycosides, flavonoids, saponins, terpenoids, tannins and essential oils. Importantly to the practice of herbal medicine, it may be the combination of components that is most effective as opposed the singular effect of one compound.  Herbal medicines may exert anti-inflammatory, antiphlogistic, astringent, and mucosal protective effects, and may also alter the microbiome.  Botanical medicines have also been used in IBD for their psychological effects, as the pain secondary to inflammation of the bowel may alter circulation and other functions of the gut.19

Veterinarians who use integrative therapies will choose from a variety of approaches to treat this potentially deadly disease.  A change in diet is a reasonable first step, and herbal therapies often come next, sometimes along with acupuncture. Many veterinary herbalists are consulted after conventional therapies including steroids  (prednisone, budesonide) or stronger immunesuppressive therapies (cyclosporine, azathioprine, chlorambucil and even mycophenylate, leflunomide, etc ) are already on board and see an improvement when natural therapies are instituted. Patients can die of this disease, and herbal therapies are a reasonable addition at any stage in order to mitigate side effects and perhaps increase the chance of a remission.

References

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