Feeding Dogs with Hepatic Encephalopathy

Fri, 17 May 2013 11:00:00 +0000

One of the complications commonly seen with advanced liver disease in dogs is hepatic encephalopathy. The liver acts as a giant filter for the gastrointestinal tract (among other roles). After a meal, the circulatory system absorbs all sorts of things from the gut. Many of these substances, especially ammonia, can adversely affect the brain after reaching excessively high levels in the blood.

When liver function decreases to approximately 70% of normal, the signs of hepatic encephalopathy begin to emerge, including:

mental dullness

staring

unsteadiness

circling

head pressing

blindness

drooling

coma

These symptoms are usually observed in combination with the typical sings of liver failure including loss of appetite and weight, increased thirst and urination, vomiting, diarrhea, a yellowing of the skin and mucous membranes, and accumulation of fluid in the abdomen.

The symptoms of hepatic encephalopathy typically wax and wane throughout the day, often worsening after meals. Therefore, it’s not too surprising that dietary manipulation plays a big role in the management of the condition.

Dogs with hepatic encephalopathy should eat a diet with a reduced amount of protein since the byproducts of protein digestion (e.g., ammonia) are responsible for many of the symptoms associated with the disease. Diets should contain just enough protein but no “extra” to ease the liver’s workload. Research also indicates that soy protein may be a better at ameliorating the signs of hepatic encephalopathy in comparison to meat-based sources of protein.1 Dogs with advanced liver disease still need calories, however, which are best supplied by increasing the percentages of high quality carbohydrates and fats in the diet.

Feeding several smaller meals throughout the day rather than just one or two larger meals is also beneficial. This feeding schedule reduces the spikes in deleterious metabolites circulating in the bloodstream thereby reducing clinical signs associated with hepatic encephalopathy.

Medications that reduce the numbers of bacteria within the GI tract also play an important role in the management of this disease. Antibiotics, often amoxicillin or metronidazole, are used because they kill off many of the bacteria in the gut that produce high levels of ammonia. Enemas can be given to physically remove feces and bacteria from the colon. Oral lactulose, a type of indigestible sugar, is also used for it cathartic properties. The goal is to encourage rapid transit of stool through the intestinal tract to reduce the amount of time bacteria have to act upon it. Lactulose also lowers the pH within the gut, which reduces the absorption of ammonia. The dose of lactulose should be titrated to the point where the dog produces two or three soft stools throughout the day.

Sometimes the liver disease responsible for causing hepatic encephalopathy is reversible, sometimes it is not. In either case, dietary management and other forms of treatment for hepatic encephalopathy buy dogs precious time.

Dr. Jennifer Coates

Source

1. Proot S, Biourge V, Teske E, Rothuizen J. Soy protein isolate versus meat-based low-protein diet for dogs with congenital portosystemic shunts. J Vet Intern Med. 2009 Jul-Aug;23(4):794-800.

Image: Hannamariah / via Shutterstock

Microminerals: Tiny Amounts, But Big Effects

Fri, 10 May 2013 11:00:00 +0000

I’ve found that whenever I talk about the nutrients that dogs require in a balanced diet I tend to gloss over the microminerals – minerals that are required in the diet in relatively small amounts. The big players like protein, carbohydrates, and fat get the most attention.

Vitamins also have their spot in the limelight because of their importance as antioxidants and in immune support. Macrominerals (minerals are needed in relatively large amounts) like calcium, phosphorus, sodium, potassium, chloride, and magnesium also get their fair share of press. Microminerals, however, are the Rodney Dangerfield of nutrients. They don’t get much respect.

Let’s fix that today with a brief primer on what roles microminerals play in a dog’s diet.

Copper

Adequate dietary sources of copper are needed if a dog’s bones, connective tissue, collagen, and myelin (the protective covering of nerves) are to form properly. Copper helps the body absorb iron, making it an important part of red blood cell function. It can also act as an antioxidant, is a part of many enzymes, and is necessary for the formation of melanin, the pigment that darkens hair and skin. Copper can be found in meat, liver, fish, whole grains, and legumes, and is typically added as a supplement to commercially prepared foods.

Iodine

Iodine’s primary role in the body is in the manufacture of thyroid hormones that regulate growth and the body’s metabolic rate. Iodine is found in fish and iodized salt. It can also be included in pet foods by adding calcium iodate, potassium iodide, or other supplements.

Iron

Iron is a central component of hemoglobin and myoglobin, the molecules that carry oxygen in blood and muscle respectively. It also is a part of many enzymes, particularly those that are catalysts to energy production in cells. Iron is naturally found in meat, liver, fish, green vegetables, whole grains, and legumes. Supplemental iron may also be added to dog foods.

Manganese

Dogs need manganese to produce energy, metabolize protein and carbohydrates, and to make fatty acids. Manganese is an important part of many enzymes and plays a role in the health and maintenance of bone and cartilage in joints. Meat is not a good source of manganese, but the nutrient can be found in whole grains, legumes, eggs, fruits, and green vegetables. To ensure that dogs get enough manganese in their diets, most manufacturers add it as a supplement to their foods.

Selenium

Selenium is a potent antioxidant that acts in concert with Vitamin E to protect cells from damage caused by free radicals. Selenium is found in high concentrations in plants grown in selenium-rich soils. The meat of animals that eat such plants can also be a source, as can eggs and some types of fish. To ensure that dogs get enough selenium, pet food manufacturers add supplements to their products.

Zinc

Adequate amounts of zinc are essential to the health of a dog’s coat and skin, ability to reproduce, and for the functioning of many enzymes that are essential to normal metabolism. Zinc also plays a role in helping muscles work optimally during high intensity exercise. Zinc is present in relatively large amounts in meat, eggs, and dairy products, but is also added as a supplement to dog foods.

Dr. Jennifer Coates

Image: Little Moon / via Shutterstock

What Your Pet's Lifestyle and Diet Says about You

Fri, 03 May 2013 11:00:00 +0000

I’m sure you’ve heard the adage about how dogs and their owners often look alike. Turns out we also often share diet and lifestyle characteristics, particularly as we get older.

A 2011 study looked at similarities and differences in diet and lifestyle between 155 cat and 318 dog owners and their pets. It came to some interesting conclusions.

Eighteen percent of the dogs were reported to be overweight, which is probably a significant underestimate since owners are notoriously bad at recognizing whether or not their pets are plump. Current, unbiased estimates put the number closer to 55 percent in the United States. Forty-nine percent of the dogs had access to food at all times — an unexpectedly high number, I thought.

Overweight dogs tended to have overweight, older owners. Not surprisingly, these owners and dogs both tended to suffer from poor health. Also, “younger dog owners were more likely to have an overweight dog if they themselves were obese. Similarities were found in owner’s and pets’ diet and lifestyle issues with ageing.” The older dogs got, the less exercise their owners tended to get, the fewer fruits, vegetables, and whole grains they (the owners) ate, the more added fat they (the owners) ate, and the higher the owner’s body mass index tended to be.

Cats and their caregivers didn’t fare much better. Fourteen percent of cats were reported to be overweight (again, almost assuredly a significant underrepresentation since current estimates are around 54 percent in the U.S.), with 87 percent having access to food at all times. Overweight, older owners tended to own overweight cats. The same trend was observed in younger cat owners but was not statistically significant.

All of these findings are correlations; in other words, characteristics that are associated but not necessarily caused by one another. That said, owners do tend to project their own behaviors, likes and dislikes, etc. onto their pets. Sometimes, this can be for the good. For example, a person who enjoys jogging may assume, rightfully so, that their dog likes to accompany them. On a cold or damp morning, when an extra cup of coffee and a donut sounds much more appealing, these owners may drag themselves out the door to avoid disappointing the dog. On the other hand, owners who turn to food for solace or to relieve boredom and don’t put a high priority on a good diet and regular exercise are unlikely to encourage healthier habits in their pets than they practice themselves.

I’m sure all of these factors are part of the reason why it can be so difficult to achieve meaningful weight loss in overweight dogs. Poor nutritional choices and exercise habits are often a family-wide problem. I wonder if there’s a need for veterinary and human nutritionists to team up and address the needs of the entire household. What do you think?

Dr. Jennifer Coates

Source:

Heuberger R, Wakshlag J. Characteristics of ageing pets and their owners: dogs v. cats. Br J Nutr. 2011 Oct; 106 Suppl 1:S150-3.

Image: LovelyColorPhoto / via Shutterstock

Deciphering Diet Pet Foods (Part 1)

Fri, 26 Apr 2013 11:00:00 +0000

Have you ever purchased a so-called “diet” pet food? It may have been labeled as “light,” “lite,” “low calorie,” “reduced calorie,” or something similar, but all of these products infer that by purchasing the food in question, owners can help their pets lose weight.

If you have fed a diet food to your dog or cat per the label instructions but meaningful weight loss remained elusive, you’re in good company. I hear this complaint from clients on an almost daily basis. Why? Once we’ve ruled out caregivers and pets “cheating” on the diet, I am quick to blame the perplexing way these products are labeled.

The Association of American Feed Control Officials (AAFCO) does have standard definitions for some terms. For example, foods labeled as “light,” “lite,” or “low calorie” must not contain more than 3100 kcal/kg for dry dog food and 3250 kcal/kg for dry cat food. On the other hand, foods described as “reduced calorie” don’t have to abide by the same guidelines so long as the label indicates which foods are being compared. Therefore, if the manufacturer uses a food with high caloric density as the baseline, its “reduced calorie” version could still be very fattening.

A study published in 2010 took a look at the variability that exists in “diet” pet foods.

Commercially available diets for cats and dogs that might be purchased for weight loss on the basis of label information were included in the study. Various types of locations were surveyed that reflected common locations at which consumers would be able to obtain diets designed for weight loss of pets, including 2 pet specialty stores, 1 discount mass merchandiser, 1 supermarket, and 1 veterinary hospital. A range of label descriptions implying weight loss was accepted, such as the terms weight loss, weight management, overweight, or calorie reduction and images representative of overweight body condition. Diets were allocated into 2 categories: diets with weight management claims and feeding directions for weight loss and diets with weight management claims on the label but no specific feeding directions for weight loss. Label statements in the second category of diets included obese prone, to maintain healthy weight, avoid unwanted weight gain, lose excess weight, and reduced calorie.

The researchers found the following caloric densities in the foods they examined:

Those are huge ranges, and unfortunately the feeding directions printed on the label weren’t very helpful either. The recommended caloric intake varied between 0.73 to 1.47 times their resting energy requirements (RER) for dogs and 0.67 to 1.55 times RER for cats. A standard recommendation is that dogs needing to lose weight should be fed at their RER and cats at 0.8 times their RER.

It’s no wonder that helping pets lose weight is so frustrating! Pick the wrong food and you may very well be offering more calories than your dog or cat was taking in previously. If you’re interested in some tips on how owners can use these numbers to actually help dogs and cats slim down, check out today’s Nutrition Nuggets for cats.

Dr. Jennifer Coates

Source:

Linder DE, Freeman LM. Evaluation of calorie density and feeding directions for commercially available diets designed for weight loss in dogs and cats. J Am Vet Med Assoc. 2010 Jan 1;236(1):74-7.

Image: WilleeCole / via Shutterstock

The Best of Intentions, Gone Astray

Fri, 19 Apr 2013 11:00:00 +0000

Veterinarians often recommend owners feed dogs that have diarrhea a diet consisting of boiled hamburger and white rice for a few days. This type of bland, easily digested diet gives the intestinal tract a bit of a break while still providing needed calories and nutrients.

The recommendation is appropriate, so long as the dog doesn’t have any other worrisome symptoms such as vomiting, abdominal pain, or weakness, the caregivers understand that if the diarrhea doesn’t resolve quickly, the dog must be brought in for an exam, and the dog soon goes back to eating his normal diet.

Owners sometimes will treat their dog’s diarrhea with a homemade diet without first consulting a veterinarian, which is fine so long as they abide by the provisos mentioned above. However, I recently ran across a case report concerning a dog whose caregivers didn’t, and the outcome was almost disastrous.

An 11-week-old Saint Bernard was picked up from his breeder. His new owners realized he had diarrhea and started feeding him a hamburger and rice diet and dewormed him. His diarrhea resolved but returned whenever they tried to feed a commercially available, chicken-based adult dog food. Presumably being aware that hamburger and rice alone was not a nutritionally complete diet, the owners modified their offerings by adding apple, broccoli, egg (including shells), a vitamin and mineral supplement, and a small amount of the chicken-based adult dog food to the hamburger and rice.

The dog was seen several times by a veterinarian for routine care and appeared to be doing well, until he was evaluated at a veterinary teaching hospital for bilateral forelimb lameness presumably associated with osteochondritis dissecans of both shoulders. While there, the dog developed severe seizures; at one point his body temperature rose to a potentially life-threatening 108 degrees Fahrenheit. Lab work revealed many abnormalities, including a very low blood calcium level that was the cause of his seizures. The attending veterinarians were able to save him after giving him intravenous fluids, valium, propofol, and infusions of calcium gluconate, intubating him and putting him on inhalant anesthetics and oxygen, and performing cold water gastric lavage. The dog was hospitalized for three days.

An analysis of the dog’s homemade diet revealed that it was severely deficient in calcium, phosphorus, and vitamin D, all of which were provided at less than half the minimum levels required for growing dogs. Other deficiencies included sodium, chloride, iron, iodine, choline, copper, folic acid, vitamin A, linoleic acid, and taurine.

Once the dog’s condition was stable, he went home with oral calcium carbonate, calcitriol (a form of Vitamin D that helps the body make use of dietary calcium), taurine supplements, and a commercially available puppy food. A recheck of blood work approximately one month later revealed complete resolution of all abnormalities, and interestingly, the dog was also no longer lame.

I relate this tale not to scare you off from feeding dogs that have diarrhea a hamburger and rice diet, but to emphasize that such a nutritionally incomplete diet only be fed for a few days, and if the diarrhea doesn’t resolve, veterinary attention is essential. The long term feeding of a homemade diet should always be done under the supervision of a veterinary nutritionist.

Dr. Jennifer Coates

Source

Hutchinson D, Freeman LM, McCarthy R, Anastasio J, Shaw SP, Sutherland-Smith J. Seizures and severe nutrient deficiencies in a puppy fed a homemade diet. J Am Vet Med Assoc. 2012 Aug 15;241(4):477-83.

Image: Hisom Silviu / via Shutterstock

Fiber: It's Not Filler (at least not always)

Fri, 12 Apr 2013 11:00:00 +0000

Fiber is an important part of a dog’s diet but does not get the recognition it deserves. The word “fiber” typically refers to “partially digestible or indigestible carbohydrates.” “Indigestibility” has negative connotations, but in reality, a dog’s diet shouldn’t be 100 percent digestible. Fiber has three main benefits: It increases the volume of food a dog can eat without adding much in the way of calories. This can help a dog lose or maintain his weight without feeling hungry. It adds bulk to the feces. As long as it is not taken to extremes, fiber promotes normal defecation and can prevent anal gland impaction. It provides nutrients to the bacteria that reside in the large intestine. I want to focus on this third topic today but need to fine-tune our definition of fiber first. Different types of fiber are described as either insoluble dietary fiber (IDF) or soluble dietary fiber (SDF). Examples of IDF include cellulose, hemicelluloses, and lignins. They pass through the gut essentially unchanged. When included in the diet in appropriate amounts they confer the first two benefits mentioned above. Used to excess, they can be described as “fillers” — cheap ingredients that don’t bring much in the way nutrient value to the diet. Chicory, inulin, fructooligosacharides, pectins, and plant gums are examples of soluble dietary fiber. A dog’s own digestive enzymes and chemicals don’t have much of an effect on SDF, but the bacteria that live in his large intestine can break them down through the process of fermentation. The end products of fermentation — short chain fatty acids in particular — are very important for the health of the cells that line the large intestine and can even be absorbed as an energy source. Unfortunately, there is no easy way to determine how much SDF is included in a dog food. With the exception of some prescription diets, the only measure of fiber included on the label is crude fiber (CF). Measurements of CF can give you an idea of how much IDF is included in the diet, but it does not evaluate SDF at all. The best a consumer can do is select foods that include ingredients that are high in SDF such as psyllium husks, guar gum, pectins, oats, barley, chicory, inulin, beet pulp, and some fruits and legumes, or call pet food manufacturers and ask for this information. Fiber supplements that contain a combination of IDF and SDF are also available. I prefer that my patients get all the fiber they need from a complete and balanced diet, but in cases where additional fiber is beneficial, supplements can be a good option. Talk to your veterinarian if you have any questions about your dog’s nutritional needs. Dr. Jennifer Coates Sources: Coates J. Dictionary of Veterinary Terms: Vet-speak Deciphered for the Non-Veterinarian. Alpine Publications. 2007. Image: mffoto / via Shutterstock

Performance Diets for Detection Dogs

Fri, 05 Apr 2013 11:00:00 +0000

We’ve talked a lot on Nutrition Nuggets about how a properly balanced diet is essential to good canine health and how tweaking nutrient ratios can help with disease prevention and management. Well … here’s something new. A diet that is relatively low in protein and high in fat can help dogs to smell better. Odd but true.

Two thoughts immediately crossed my mind when I first ran across this information:

1. Why should I be concerned about increasing a dog’s sense of smell?

2. How in the world would dietary protein and fat concentrations be associated with a dog’s olfactory capabilities?

New research performed by Joseph Wakshlag, associate professor of clinical studies and chief of nutrition at Cornell's College of Veterinary Medicine, in collaboration with researchers at Auburn University, answered both of these questions. According to the Cornell Chronicle:

Bucking conventional thinking, the group found that less protein and more fat in the dogs' diet helped trained dogs perform better in exercise and detection tests. During an 18-month period, they rotated 17 trained dogs through three diets Wakshlag selected: a high-end performance diet, regular adult dog food, and regular adult dog food diluted with corn oil. Measuring how different diets affected each dog, they found that dogs eating the normal diet enhanced with corn oil returned to normal body temperatures most quickly after exercise and were better able to detect smokeless powder, ammonia nitrate and TNT.

"Corn oil has lots of polyunsaturated fats, similar to what you'd find in a lot of nuts and common grocery store seed oils," said Wakshlag. "Past data from elsewhere suggest that these polyunsaturated fats might enhance the sense of smell, and it looks like that may be true for detection dogs. It could be that fat somehow improves nose-signaling structures or reduces body temperature or both. But lowering protein also played a part in improving olfaction."

Wakshlag designed the high-performance and corn-oil diets to have the same amount of energy from fat (57 percent). But the corn oil diet had less protein: 18 percent compared with 27 percent in the regular and high-performance diets.

"If you're a dog, digesting protein raises body temperature, so the longer your body temperature is up, the longer you keep panting, and the harder it is to smell well," said Wakshlag. "Our study shifts the paradigm of what 'high-performance' diet can mean for dogs. It depends on what you want your dog to do. A sled dog or greyhound may need more protein to keep going. But detection dogs tend to exercise in shorter bursts and need to recover quickly and smell well. For that, less protein and more fat could help."

The study, funded with a $1 million grant from the U.S. Department of Justice, also found that detection dogs are more reliable detectors than previously thought. The study is the first to be conducted in the world's only detection dog research facility designed in conjunction with a military dog trainer. The Alabama facility, which provides expert detection dogs to police and military forces, flushes out fumes between tests, ensuring a fresh field each time.

"Previous studies from other facilities, which lack this feature, had suggested detection dogs signaling for suspect substances are about 70 percent accurate," said Wakshlag. "The lower numbers may have been due to study design flaws which our new study overcame. Dogs tested in the new facility signaled with 90 percent and above accuracy. We also found we can push detection performance even further with the right kind of food."

Pretty neat. Detection dogs perform a great service for society, and now we know that the right diet can help them do the best job possible.

Dr. Jennifer Coates

Source:

Hodes, C. More fat, less protein improves detection dogs’ sniffers. March 21, 2013. Cornell University Chronicle Online.

Image: Robin Williams / via Shutterstock

Don't Think 'Good' or 'Bad' When It Comes to Fats: Part 1

Fri, 29 Mar 2013 11:00:00 +0000

You are probably familiar with the concept of “good” and “bad” fats as it applies to human food. Fats are described as being “bad” when their inclusion in the diet is associated with abnormally high blood cholesterol levels and an increased risk of heart attack or stroke and “good” when this is not the case. Most bad fats are of animal origin (think butter and a marbled steak) while good fats are typically derived from plants (e.g., canola oil).

Does this concept of good and bad fats have relevance when it comes to feeding our dogs and cats? I’ve always told my clients that the answer is “no” because these species are at much lower risk for heart attacks and strokes caused by arthrosclerosis than are we. I just ran across an elegant explanation as to why this is true in an article entitled “Facilitative and functional fats in diets of cats and dogs” written by John Bauer, DVM, PhD, DACVN.

Although the concept of good and bad fats is appropriate for human health, dogs and cats are able to consume both types of fats in their diets without undue risk of coronary artery diseases, heart attacks, or strokes to which humans succumb. The simplified reason for this is that they have more good cholesterol (HDL) than bad cholesterol (LDL) to begin with, no matter what types of fat they consume. Second, in contrast to humans, dogs and cats typically are resistant to the development of hypercholesterolemia and atherosclerosis, even when they consume amounts of dietary fat that would typically turn human blood into sludge.

The fact that good cholesterol concentrations are higher than the concentrations of bad cholesterol is part of the mechanism that protects them from cardiac diseases that may affect humans. In addition, although saturated fats (and possibly trans fats) may cause modest increases in blood cholesterol concentrations in dogs, these dietary components do not appear to impart any increased risk of arterial diseases in dogs, which is in contrast to their effects in humans.

Thus, it is not advantageous to classify the various types of fats as good or bad in dogs or cats, although definitive data for cats (other than the fact that cats have high HDL cholesterol concentrations) have not been obtained. In view of these metabolic differences, it is proposed that the types of dietary fats for dogs and cats should be classified as functional or facilitative, rather than good or bad, respectively.

For more on classifying dietary fats as functional or facilitative, head on over to today’s Nutrition Nuggets for cats.

Dr. Jennifer Coates

Source:

Facilitative and functional fats in diets of cats and dogs. Bauer JE. J Am Vet Med Assoc. 2006 Sep 1;229(5):680-4.

Image: All you can eat bacon / via Chuba & Company

Feeding Canine Athletes

Fri, 22 Mar 2013 11:00:00 +0000

I am on vacation this week. Rather than leave you hanging while I’m catching up on some much needed R & R, I thought I’d channel Linda Richman of Saturday Night Live “Coffee Talk” fame.

“Talk amongst yourselves. I’ll give you a [link to a] topic. Discuss!”

Today’s Link:

The Nutritional Requirements of Exercising Dogs

Do you have experience feeding athletic dogs? What works? What doesn’t?

Dr. Jennifer Coates

Image: Ran Z / via Shutterstock

Treats or By-Products?

Fri, 15 Mar 2013 11:00:00 +0000

I had a funny experience with my six year old daughter at a pet supply store a couple of months ago. We were looking for a “chewie” for our dog. He has severe inflammatory bowel disease so is on a strict, limited antigen diet. All the usual treats are off limits, but he still likes to chew, so we were combing the shelves for something appropriate. After a few minutes, my daughter held up a bully stick and asked, “How about this?”

Now she has an age appropriate grasp of the birds and the bees, but I didn’t think the pet store was the place to go into the details of what, exactly, a bully stick is. I managed to dodge the question by simply saying it was made from cattle and therefore wouldn’t work for our dog.

Do you know what bully sticks are? If you don’t, you are in good company. A study published in the January 2013 issue of the Canadian Veterinary Journal (CVJ) revealed that 44 percent of dog owners could not correctly identify their source and neither could 38 percent of veterinarians. The answer … dried, uncooked bull or steer penises.

Even if my dog could eat a bully stick, based on the findings of the CVJ paper I wouldn’t give him one. Tests showed that these products contain between 9 and 22 calories per inch. According to an article on LiveScience, the researchers “found that the treats contained 9 to 22 calories per inch. That means the average 6-inch bully stick potentially represents 9 percent of the recommended daily calorie count for a larger 50-pound (22-kilogram) dog and 30 percent of the requirements for a smaller 10-pound (4.5-kg) dog — a significant source of calories pet owners might not be aware of.”

I recommend to my clients that calories from treats comprise only about 10 percent of a dog’s caloric intake per day; the rest should come from a nutritionally complete diet made from high quality ingredients. While a single 6-inch bully stick might be okay calorie-wise for a large dog, these treats could quickly lead to obesity in smaller individuals.

The study revealed another potentially serious problem with bully sticks. Many were contaminated with potentially nasty bacteria including Clostridium difficile, methicillin-resistant Staphyloccocus aureus (MRSA), and Escherichia coli. Ingesting these bacteria could cause illness in dogs, and just as importantly handling the products could make people sick. I hope I had my daughter wash her hands after we left the pet store!

Admittedly, this study was a small one, examining only 26 bully sticks purchased in the United States and Canada, but the findings are still worrisome. Bully sticks (as well as the equally popular pig’s ears and cow’s hooves) are by-products of the slaughter industry. Owners and veterinarians often disparage the inclusion of by-products in commercially prepared foods. Why then are we feeding them to our pets as treats?

Dr. Jennifer Coates

Image: Supie Davis / via Shutterstock

Coat and Skin Health as an Indicator of Nutritional Status

Fri, 08 Mar 2013 11:00:00 +0000

The eyes may be the windows to the soul, but the condition of a dog’s coat and skin give a better indication of his overall nutritional status. The skin is the largest organ of the body and when it is not getting the nutrition it needs, problems are readily observed.

Protein plays a big role in maintaining the health of a dog’s coat and skin. Fur consists of around 95 percent protein. Studies have shown that 25-30 percent of the protein that a dog takes in goes to support his skin and fur. When a dog eats protein, his digestive system breaks it down into its basic building blocks, amino acids, which are then absorbed and used to form the types of protein needed at that time. A lack of sufficient amounts of protein in general or specific amino acids in particular can result in the following symptoms:

dull , dry, and rough fur

a coat that is thinner than normal

brittle fur that breaks easily

slow hair regrowth

abnormal shedding cycles

depigmentation of the skin and fur

scaly, crusty, or abnormally thickened skin

poor wound healing

Lipids, especially essential fatty acids (e.g., omega 3 and omega 6 fatty acids), are also extremely important to maintaining healthy skin and fur. A lack of EFAs in the diet or an improper balance between the various types hinders the skin’s ability to act as a barrier to potential allergic triggers and irritants and can promote inflammation. EFAs also moisturize the skin from the inside out. Signs that a dog may need more essential fatty acids in his diet include:

dull , dry, and rough fur

increased scaling (small, dandruff-like flakes of skin)

secondary bacterial or yeast infections

increased shedding

thick, greasy skin

poor wound healing

Appropriate dietary levels of several vitamins and minerals play a role in the health of a dog’s coat and skin as well. Vitamin E is an antioxidant and modulates inflammation. Vitamin A (e.g., retinol and beta-carotene) is necessary for normal cell growth and differentiation and the keratinization (hardening and thickening) of skin cells. The minerals zinc, selenium, copper, iodine, and manganese are essential to the normal growth and turnover of skin cells and fur.

Nutritionally complete diets made from high quality ingredients will supply ample protein, lipids, vitamins, and minerals to maintain healthy skin and fur for the vast majority of dogs. Some individuals, however, need more. For example, dogs with atopy (a genetic predisposition to allergic skin disease) often benefit from receiving essential fatty acid supplements, and Siberian huskies and Alaskan malamutes are at higher than average risk for zinc-responsive dermatosis, the treatment of which is suggested by the condition’s name.

If your dog has a poor quality coat and/or a chronic skin condition, he first needs a dermatological work-up, but if a diagnosis remains elusive, take a look at his diet.

Dr. Jennifer Coates

Image: Eric Isselee / via Shutterstock

What is Large Breed Puppy Food?

Fri, 01 Mar 2013 11:00:00 +0000

Whenever I have an appointment with a large or giant breed puppy, I bring up the subject of large breed puppy foods. Puppies that are going to grow up to be big dogs are predisposed to developmental orthopedic diseases (DOD) like osteochondritis dissecans and hip and elbow dysplasia. (I use an adult weight of 55 pounds as my somewhat arbitrary division between medium and large dogs.) Nutrition, or to be precise, over-nutrition, is an important risk factor of DOD.

The physiological details can be a bit overwhelming, but I summarize the situation like this: Dogs are not supposed to be all that big (40 to 45 pounds is what tends to result when dogs mate without human intervention). Breeding for increased size forces them into an unnaturally rapid rate of growth, which pushes the ability of the skeletal system to mature normally over its limits. Developmental orthopedic diseases are the result.

The number one goal when it comes to feeding large breed puppies is to avoid overfeeding, particularly when it comes to calories. By restricting caloric intake slightly, we can slow the puppy’s rate of growth. They still get as big as they would otherwise; it just takes them a little longer to get there. Puppies fed in this way are also slim, which decreases the load that their maturing frames need to carry. Large breed puppy foods achieve these results by having a reduced fat content, and since fat is the most calorie-dense nutrient category in food, the diet is therefore somewhat restricted in calories.

In general, foods designed for large breed puppies have a fat content of between 8% and 12% on a dry matter basis while standard puppy foods often contain between 10% and 25% fat. Of course, the benefits of fat and calorie restriction can be completely undone if a dog eats too much of the food. Large breed puppies should almost invariably be fed several measured meals throughout the day rather than being allowed to eat free choice.

Getting too much calcium in the diet and eating foods with a high calcium to phosphorus ratio also increases the risk of DOD in these dogs. Therefore, large breed puppy foods typically contain less calcium than do “regular” puppy foods and the manufacturers keep the ratio of calcium and phosphorus within fairly narrow limits. Veterinary nutritionists don’t agree as to what the exact levels of these nutrients should be, but the following recommendations are fairly typical.

While feeding a large breed puppy food does not completely eliminate a dog’s risk for DOD (genetics plays a big part as well), offering the right amount of the right diet is very important.

Dr. Jennifer Coates

Image: Eric Isselee / via Shutterstock

The "Owner Effect" in Canine Weight Loss

Fri, 22 Feb 2013 11:00:00 +0000

Helping dogs lose weight is not easy, but sometimes it seems harder than it ought to be. I’ve designed many a weight loss plan for overweight pets. I try to be very specific — feed "X" number of calories, which equates to so many cups of a specific food per day.

I outline how many of which treats are acceptable, what our expectations for exercise are, and what our weight loss goal is for the next month. All too often, the dog’s weight barely budges between appointments.

It’s not the dog’s fault. I can only think of one occasion where my patient was actually eating meals that its owner was not aware of (turns out a neighbor was sneaking him hotdogs, lots of hotdogs). For the most part, dogs can only eat the food their owners give them. So why do doggy diets rarely go as planned?

A German study tried to answer that by questioning 60 owners of obese dogs and 60 owners of slim dogs. They found that the human-animal bond was equivalent between the two groups, but that there were significant differences in how the owners interacted with their dogs. Here are some of what I think are the study’s more relevant findings:

The owners of obese dogs were more likely to

rate exercise, work, or protection by their dogs as less important

spend more time watching their dogs eat

feed their dogs a greater number of meals, snacks, and table scraps

allow the dog to be present when they were eating

rate low cost of food as being important

buy food at the local supermarket

have less interest in balanced dog nutrition

And most importantly, "Owners of obese dogs were often obese themselves and they took only a rather limited interest in their own preventive health behavior as well as that of their dogs."

Client education is crucial, but that’s an awful lot to overcome in one (or several) 15 or 20 minute appointment(s).

I have to admit that I’ve occasionally skirted around the "your pet really needs to lose some weight" talk with overweight owners. I’ll mention the pet’s body condition just in case it’s not obvious and maybe hand over some literature about the benefits of weight loss, but a frank discussion about the risks of obesity when the owners haven’t brought the topic up themselves tends to make everyone in the room uncomfortable.

Spineless of me, I know. I’ll try to do better.

Dr. Jennifer Coates

Source:

Kienzle E, Bergler R, Mandernach A. Comparison of the feeding behaviour of the man-animal relationship in owners of normal and obese dogs. J Nutr.1998;128:2779S–82.

Image: Lesley Rigg / via Shutterstock

When Dogs Eat May be Important for Weight Loss

Fri, 15 Feb 2013 11:00:00 +0000

Have you heard of the term "circadian metabolism?"

I just ran across it skimming through a study that looked into whether or not the timing of a mouse’s meals had an effect on its body weight (more on this later). Essentially, animals have an endogenous clock within their bodies that responds to environmental light-dark cycles. This "clock" is not just a part of our brains (which is how I always thought about circadian rhythms in general), it is also a part of the peripheral tissues (e.g., liver, intestines, and fat) that determine how animals use the nutrients and energy they (we) take in. The clock exerts its effect by modulating the expression and activity of enzymes that are involved in metabolic processes.

This concept has led researchers to ask whether when animals eat affects what eventually happens to what they eat. It’s a reasonable question since different metabolic pathways are most active at different times of the day.

Back to the paper on mice. Scientists had found that feeding an ad libitum (i.e., free feeding), high fat diet to mice "disrupted the circadian expression of metabolic factors" and led to obesity. In this study, the researchers determined that timing the feedings of a high-fat (HF) diet more or less eliminated its harmful effects:

Although timed HF-diet-fed& mice consumed the same amount of calories as ad libitum low-fat diet-fed mice, they showed 12% reduced body weight, 21% reduced cholesterol levels, and 1.4-fold increased insulin sensitivity. Compared with the HF diet ad libitum, the timed HF diet led to 18% lower body weight, 30% decreased cholesterol levels … and 3.7-fold improved insulin sensitivity … Taken together, our findings suggest that timing can prevent obesity and rectify the harmful effects of a HF diet.

This correlates well with a study in people that received wide-spread attention in January of this year. Paraphrasing the paper’s abstract:

Participants were grouped in early eaters and late eaters, according to the timing of the main meal (lunch in this Mediterranean population). 51% of the subjects were early eaters and 49% were late eaters (lunch time before and after 1500 hours [3 p.m.], respectively). Late lunch eaters lost less weight and displayed a slower weight-loss rate during the 20 weeks of treatment than early eaters. Surprisingly, energy intake, dietary composition, estimated energy expenditure, appetite hormones and sleep duration was similar between both groups. Nevertheless, late eaters were more evening types, had less energetic breakfasts and skipped breakfast more frequently that early eaters (all; P<0.05). Eating late may influence the success of weight-loss therapy.

Neither of these papers directly addresses the question of whether when a dog eats could improve his chances of losing weight. (That would be a fantastic study … any takers out there?) But, if you are feeding your overweight dog an appropriate number of calories and are not seeing the expected results, changing when you feed would certainly be worth a try. Start by feeding most of the calories early in the day, and if an evening meal is necessary for behavioral reasons, keep it as small as possible.

Dr. Jennifer Coates

Sources

Timed high-fat diet resets circadian metabolism and prevents obesity. Sherman H, Genzer Y, Cohen R, Chapnik N, Madar Z, Froy O. FASEB J. 2012 Aug;26(8):3493-502.

Timing of food intake predicts weight loss effectiveness. Garaulet M, Gómez-Abellán P, Alburquerque-Béjar JJ, Lee YC, Ordovás JM, Scheer FA. Int J Obes (Lond). 2013 Jan 29.

Image: Suslik1983 / via Shutterstock

Dogs are Not Wolves

Fri, 08 Feb 2013 11:00:00 +0000

I know, it seems obvious … dogs are not wolves. Dogs have evolved and been bred for over ten thousand years to make them distinct from their wolf ancestors. It’s visible in their anatomy and in their behavior.

Now, research is uncovering the differences in their genetic make-up. According to a study that was published on January 23 in the journal Nature, a surprisingly large part of the variation deals with nutrition.

Scientists in Sweden sequenced DNA from 12 wolves and 60 dogs from 14 breeds. They identified "36 genomic regions that probably represent targets for selection during dog domestication. Nineteen of these regions contain genes important in brain function, eight of which belong to nervous system development pathways and potentially underlie behavioural changes central to dog domestication."

That’s to be expected. The boxer curled at my feet has few behaviors that I would call wolf-like. I don’t think he’d last a week if he were forced to fend for himself in the wild.

What I found most fascinating in this study was the following:

Ten genes with key roles in starch digestion and fat metabolism also show signals of selection. We identify candidate mutations in key genes and provide functional support for an increased starch digestion in dogs relative to wolves. Our results indicate that novel adaptations allowing the early ancestors of modern dogs to thrive on a diet rich in starch, relative to the carnivorous diet of wolves, constituted a crucial step in the early domestication of dogs.

This makes sense when you put it in the context of one of the more popular theories of how dogs became domesticated. The hypothesis goes something like this:

Around the time when many of our ancestors were making the change from a hunter-gatherer lifestyle to agricultural living, wolves sensed an opportunity. Food was abundant around our early farms. Livestock was present and so were rodents and other "vermin." Some enterprising wolves that could stand living in relatively close proximity to people were able to make use of this available food source. Over time, the behavioral and anatomic features that were suited to living near people were selected for, which initiated the transition from wolf to dog.

Meat wasn’t the only type of food available around these farms, however. There was also a lot of grain being produced. The wolf-dogs that could also make good nutritional use of the chunk of bread that was available would be at a competitive advantage over those that couldn’t.

Not only did living in close proximity with and eventually being bred by people alter the appearance and behavior of dogs, it also fundamentally changed their physiologic ability to make effective use of the foods we produce for ourselves.

Dr. Jennifer Coates

Source:

The genomic signature of dog domestication reveals adaptation to a starch-rich diet. Axelsson E, Ratnakumar A, Arendt ML, Maqbool K, Webster MT, Perloski M, Liberg O, Arnemo JM, Hedhammar A, Lindblad-Toh K. Nature. 2013 Jan 23.

Image: Doggy Heaven (mashed potatoes) by Laura / via Flickr

Can Diet be Used to Help Anxious Dogs?

Fri, 01 Feb 2013 11:00:00 +0000

I had to deal with an extremely anxious patient a few weeks ago. Chico is a tiny Chihuahua who seemingly views all the world as a threat (a not unreasonable outlook when you weigh only four pounds). He trusts his owners — up to a point — but even they become suspect when they start giving off the wrong vibes.

Needless to say, this made giving the medication that Chico needed challenging. Thankfully, he still had an appetite, so hiding his meds in irresistible tidbits did the trick and he’s feeling much better now.

Chico’s case got me to thinking about treating canine anxiety. The one thing that even the most anxious dogs eventually have to do is eat. I did a quick literature search to see if altering a dog’s diet could be helpful in the treatment of canine anxiety and found this interesting study.

Forty-four privately owned dogs that were determined to have anxiety-related behavioral problems were first fed a control diet for eight weeks. Then, they were then transitioned to another diet that was supplemented with L-tryptophan and alpha-casozepine. L-tryptophan is the amino acid that is credited with the relaxed feelings many report after over-indulging on the Thanksgiving turkey, and alpha-casozepine is a component of milk with activity similar to that of Valium and related drugs. (I wonder if alpha-casozepine was responsible for the smiley "milk coma" my daughter used to fall into after nursing.)

Owners evaluated their dogs’ behavior after seven weeks of eating both the control and the study diet and reported fewer anxiety-related problems after their dogs ate the supplemented diet. However, I take this finding with a big grain of salt since the placebo effect could have played a major role in owners perceiving an improvement in their dog’s anxiety.

The second part of the study is much more interesting. Two urine samples were collected from each dog after they had been eating the control diet for seven weeks and again after eating the study diet for seven weeks.

The first of the urine samples in each pair was collected at home (prestress) and the second after the dogs had their toenails clipped at a veterinary clinic (poststress). The samples were evaluated using a urine cortisol to creatinine ratio (UCCR). High concentrations of urinary cortisol are associated with stress, which was confirmed by statistical analysis revealing that the dogs had higher UCCRs in their poststress urine samples regardless of what diet they were eating.

Here’s the neat bit: The increase in UCCR between the prestress and poststress samples was significantly lower when dogs were eating the L-tryptophan/alpha-casozepine supplemented diet. So, maybe I’m wrong in discounting the owners’ perception that their dogs were less anxious on the study diet.

Diet alone won’t cure dogs of their anxiety, but it looks like it could be used as part of a comprehensive therapeutic plan.

Dr. Jennifer Coates

Source:

Effects of prescription diet on dealing with stressful situations and performance of anxiety-related behaviors in privately owned anxious dogs. Kato M, Miyaji K, Ohtani N, Ohta M. J VET BEHAV 7:21-26, 2012.

Image: Vitaly Titov & Maria Sidelnikova / via Shutterstock

What Happens to Food Once It’s Been Eaten?

Fri, 25 Jan 2013 11:00:00 +0000

I’ve been writing this blog about canine nutrition for quite awhile now and just realized that I haven’t talked about a very relevant subject — what the gastrointestinal system does with all that food our dogs eat. I won’t bore you with excruciating anatomical and physiological detail, but a grasp of the basics of how the GI tract works is essential to understanding nutrition. Here are the basics.

The lips, teeth, and tongue are used to grasp food and bring it into and move it around the mouth. When dogs take the time to chew, the teeth (primarily the molars at the back of the mouth) help break food into smaller pieces that are easier to swallow and make chemical digestion more efficient. The food also mixes with saliva while in the mouth. Saliva acts as a lubricant and also contains enzymes that start to break down large molecules.

The esophagus is the muscular tube that runs through the thoracic (chest) cavity and connects the back of the mouth (oropharynx) to the stomach. Nothing much happens to a bolus of food as it is quickly pushed down the length of the esophagus by the wavelike muscular contraction (peristalsis).

The stomach is a storage area but it is also where the heavy lifting of digestions begins. Glands within the wall of the stomach secrete a number of substances (e.g., hydrochloric acid and enzymes) that break down proteins and other nutrients. Also, strong muscular contractions within the stomach mix food and digestive juices together and liquefy the mixture, preparing it for entry into the small intestine.

In the small intestine, nutrients that are still too large to be absorbed are further broken down by enzymes produced by the pancreas, bile from the liver, and other substances. Once nutrients have been digested into their basic molecular forms (e.g., glucose, amino acids, and fatty acids), they are picked up by cells lining the inner surface of the small intestine and moved into the bloodstream. Water and electrolytes are also primarily absorbed within the small intestine. The surface area of the small intestine is greatly increased by the presence of millions of tiny, finger-like projections called villi. Ingesta is pushed through its length by peristaltic waves of muscular contractions within the organ’s wall.

The large intestine or colon is the last opportunity for the body to remove water and electrolytes from what is soon to be excreted from the body. Also, microbes within the large intestine synthesize molecules (e.g., vitamin K) that are essential to their host’s survival. What is left when all this is done (with the addition of dead intestinal cells, bacteria, and mucus) is feces. Feces is pushed into the rectum usually as a result of something called the gastrocolic reflex. This is the stomach’s way of saying to the colon "more is on the way … better make space." The presence of feces in the rectum results in the urge to defecate.

So there you have it. That’s what happens to your dog’s food after he’s enjoyed his meal.

Dr. Jennifer Coates

Image: Belle by Zane Hollingsworth / via Flickr

Food Dispensing Toys for Bored Dogs

Fri, 18 Jan 2013 11:00:00 +0000

Our dogs are bored. Life as a pet certainly has its advantages (food, shelter, veterinary care, and a doting caretaker to name a few), but as anyone who has been forced to stay home for any length of time will tell you, not having something to do starts to wear on you after awhile.

Dogs express their boredom in different ways. Some are hyperactive when their owners are around. Others find socially unacceptable ways to fill their time (my dog Apollo has a penchant for chewing books when he gets a little stir-crazy). In the worst case scenarios, dogs that don’t receive adequate mental stimulation develop behavioral problems like anxiety and compulsive disorders.

The wild ancestors of domestic dogs spent a lot of time trying to find food. They scavenged and they hunted. If they weren’t immediately successful, they had to keep trying. Compare that to "Fido’s" life. Once or twice a day a bowl of food is plopped down in front of him and he finishes it in a matter of minutes. What’s a dog to do with all that free time between meals?

One potential answer is to extend the amount of time it takes him to eat. Well-designed food dispensing toys do just this. Some are akin to puzzles, where a dog has to rotate a slotted top or slide doors around to reveal small portions of food. Others roll or wobble and when they are in the right position gravity helps them dispense a few kibbles or treats. Others simply make it hard for a dog to reach his meal without a lot of chewing or licking.

I’m not going to make any specific product recommendations because what is right for one pet won’t work for another. A dog may be such as aggressive chewer that all but the toughest toys will fall to pieces under his assault. Some dogs are smart enough to outwit simple devices, while others may be easily frustrated by toys that are too difficult or stingy with the goodies. Product videos (many are available on YouTube) are a great way to see how dogs actually interact with a toy, and then you can determine whether or not it will work for your pet.

Whichever toy you pick, make sure it is safe, easy to clean, and can handle the type of food you want to feed. Kibble, canned (which can be frozen to increase its durability), treats, food from the kitchen (e.g., peanut butter, carrots, or apple slices), and proprietary products are all possibilities. When you first give your dog the "loaded" toy, watch him for awhile. He should not be able to bite down with such force that broken teeth or a broken toy threaten his health.

Food dispensing toys can’t replace the benefits of a long walk or time spent playing or interacting with other pets and people, but they are an added way owners can ensure their dogs get the mental stimulation they need to stay healthy and happy.

Dr. Jennifer Coates

Image: WOAW / via Flickr

There's More to Fat than Meets the Eye

Fri, 11 Jan 2013 11:00:00 +0000

A survey performed by the Association for Pet Obesity Prevention indicates that an estimated 20% of dogs in the United States are obese. We’re not talking "pleasantly plump" here but terribly, dangerously overweight. I wonder, would the owners of these pets work harder to help them lose weight if they truly understood the health risks associated with canine obesity?

Obviously, extra body fat adds to the weight of the body. Lugging around all that extra baggage generates wear and tear on joints, makes the cardiovascular and respiratory systems work harder than they should, and detracts from the joy of being a normal, active dog.

But there’s more to fat than meets the eye. We typically think of adipose tissue (the technical term for fat) as a way for the body to store energy. When dogs eat more calories than they burn off, the extra is stashed away to be used when resources are scarce. It’s a sensible system, but domesticated dogs rarely experience those "lean times" their fat was designed to help them weather.

Adipose tissue does more than store energy, however. It has been described as the largest endocrine (hormone producing) organ in the body. A partial list of hormones produced by fat cells includes leptin, several cytokines, adipsin and acylation-stimulating protein (ASP), angiotensinogen, plasminogen activator inhibitor-1 (PAI-1), adiponectin, steroid hormones, and resistin. 1 These hormones play a role in regulating inflammation, blood pressure, blood clotting, metabolic rates, the function of the immune system, reproduction, and healing.

When a dog is close to its ideal body weight, adipose tissue produces hormones at appropriate levels and in concert with all his other endocrine organs. Obesity throws the whole system out of whack. Is it any wonder then that obese dogs are at excessive risk for:

osteoarthritis

cruciate ligament rupture

intervertebral disk disease

congestive heart failure

respiratory disease

Cushing’s disease

skin disorders

infections

heat exhaustion and heat stroke

complications associated with anesthesia and surgery

many types of cancer

In fact, a 2005 study 2 found that lean dogs lived almost two years longer than their overweight counterparts. Researchers paired up 48 Labrador retrievers. Essentially, one from each pair was allowed to eat as much as he or she wanted and the other was fed 75% of that amount from the time they were 8 weeks old until death. The study determined that the median life span of the restricted-fed dogs was 13 years but only 11.2 years in those individuals allowed free access to food.

Better health and a longer life … isn’t that worth keeping your dog slim?

Dr. Jennifer Coates

Sources:

1. Adipose tissue hormones. Guerre-Millo M. J Endocrinol Invest. 2002 Nov;25(10):855-61. Review.

2. Influence of lifetime food restriction on causes, time, and predictors of death in dogs. Lawler DF, Evans RH, Larson BT, Spitznagel EL, Ellersieck MR, Kealy RD. J Am Vet Med Assoc. 2005 Jan 15;226(2):225-31.

Image: Lesley Rigg / via Shutterstock

Defining Hypoallergenic Dog Foods

Fri, 04 Jan 2013 11:00:00 +0000

Merriam-Webster defines "hypoallergenic" as "having little likelihood of causing an allergic response." Easy enough? Unfortunately, no.

When it comes to dogs, there is great variation between what ingredients are likely to cause an allergic reaction in one individual versus another. For example, lamb has often been thought of as a "hypoallergenic" protein source for dogs, but in a review of 278 cases of canine food allergies, 13 dogs were determined to be allergic to lamb. Thirteen out of 278 (5%) may not sound like a big problem, but to put it in context, fewer dogs were allergic to corn (7), pork (7), fish (6), and rice (5). So, for dogs that are not allergic to lamb, a lamb-based diet is indeed "hypoallergenic," but if yours happens to be a member of the 5%, it is anything but.

Let’s look at the study in another way. The most allergenic ingredient was beef (95 cases), meaning that about one-third of dogs with food allergies are allergic to beef. So, beef can’t be hypoallergenic, can it? Well, for the two-thirds of dogs who are not allergic to beef, that’s exactly what it is.

Most veterinarians now do not recommend feeding potentially food-allergic dogs diets containing such commonly used ingredients as either lamb or beef. Instead, we often rely on limited ingredient diets made from weird protein and carbohydrate sources like duck, venison and sweet potato. I haven’t had the greatest of luck in managing food allergic dogs with these types of diets, however. Most of the time, I suspect treatment failures occur because the dogs are sneaking (or being snuck) small amounts of food that contain ingredients to which they are allergic. I wouldn’t be surprised, however, to find out that some dogs are developing allergies to “novel” ingredients that used to be out of the ordinary but are now becoming an increasingly common component of pet foods.

If any individual dog can, hypothetically speaking, be allergic to any protein source, novel-ingredient foods can’t really be considered nonallergenic, and even those thought to be hypoallergenic may incite an allergic reaction in a particular patient. For these reasons, I don’t refer to novel or limited ingredient foods as hypoallergenic.

I consider other products that take a different approach to be truly hypoallergenic. Several pet food manufacturers produce "hydrolyzed" diets made from proteins that have been split into such tiny pieces that the immune system does not mount an allergic reaction against them. The carbohydrate source and other ingredients that are included are also very unlikely to stimulate the immune system. While nothing in veterinary medicine ever works in all patients, I’ve had much better luck diagnosing and managing food allergies in dogs since I’ve started relying more on hydrolyzed foods and using novel/limited ingredient foods in a backup role.

If you’ve had trouble managing a food-allergic dog, ask your veterinarian if a hydrolyzed diet could be an appropriate option or you.

Dr. Jennifer Coates

Image: chaoss / via Shutterstock