Dietary Supplements: Are They Necessary?

Good nutrition is vital to good health. Ideally, everything we need comes from our daily diet, but many of us pop vitamins just in case. Should we give our cats supplements too? Not according to Francis Kallfelz, DVM, nutrition professor at the Cornell University College of Veterinary Medicine. Dogs and cats are fed completely differently from people, explains Kallfelz. They eat total mixed rations, where every bite of food has the right balance of all essential nutrients, while we eat various items to provide various nutrients – e.g., milk for calcium, meat for protein, carrots for vitamin A, etc. However, not all feline diets are created equal, and some owners feel supplements provide security.

What are supplements?
Its a very broad category that has expanded in recent years, says Kathryn Michel, DVM, assistant professor of nutrition at the University of Pennylvanias veterinary hospital. Dietary supplements are often driven by trends. People read about something like chromium, and they want to feed it to their cats, comments Michel. Theres limited research on this in people, and even less in cats. Some recent fads encourage the use of essential fatty acids to promote coat health and brewers yeast to combat fleas. Michel says there has been little research on the effect of either of these on feline health, and what research exists is largely borrowed from other species. Regarding herbs and botanicals, adds Kallfelz, I am unaware of any of them having a proven benefit in cats.

When to supplement
Supplementation has two purposes, says Michel. Are we giving it to an animal to correct a deficiency? Or are we using it in super physiological amounts for its pharmacological (drug-like) effects?

Nutrients given in amounts far higher than normal daily requirements can be therapeutic in specific situations. For instance, says Michel, vitamin A is known to help skin wounds heal in people. However, she cautions pet owners, benefits are higher in potential than fact. Very few of these supplements – even those used in people – have had good clinical trials to establish efficacy.

But as health status changes in your cat, so do nutrient needs. Maintenance diets arent sufficient during pregnancy or lactation, but a growth diet makes supplementation unnecessary. Its better to feed a good quality diet, Michel explains, than to try and patch up a poor diet with supplements.

No veggie plates; were carnivores
Complicated feline physiology requires nutrients only found in animal tissue. But when cat owners insist on their cats becoming vegetarian or vegan, supplements are essential. Basically you make a trade-off, says Michel. If youre going to make your cat a vegan or vegetarian and a cat needs nutrients only found in meat – such as vitamin A – you have to use a synthetic substitute.

There are legitimate formulas for such diets but they must be followed meticulously. But, notes Michel, people have to recognize that while its theoretically possible for a cat to be vegan or vegetarian, its not natural. Its something even expert feline nutritionists are very loathe to do.

When NOT to supplement
If you feed your cat a diet that meets the criteria established by the Association of American Feed Control Officials for complete and balanced nutrition, supplements are not only unnecessary, they may be harmful. Nutrient imbalances create havoc in the body. If calcium/phosphorus ratios are disturbed, for example, the results can be devastating for growing kittens.

Fat-soluble vitamins, such as vitamins A, D, and E are accumulated in the body and if given in excess, can be toxic. Everyone loves vitamin E, comments Michel, but beware: even vitamin E can reach toxic amounts. Excessive vitamin E intake may interfere with vitamin K metabolism and result in bleeding problems.

Special treats?
Any additions to cat food can potentially disrupt dietary balance, even table scraps. Its a matter of magnitude, says Michel. Keep it to less than 20 percent of the animals total intake. Adding meat, such as canned tuna fish, can also become a problem if the animal starts to eat the treat preferentially because
heat-processed meat is deficient in vitamin B1. And beware of liver and cod-liver oil. Both are rich sources of vitamin A and when over-fed, can cause vitamin A toxicosis.

According to Kallfelz and Michel, who are both board certified by the American College of Veterinary Nutrition, its simple: If you feed a well-balanced diet, you dont need to supplement. But if supplementation provides peace-of-mind, be safe: ask your veterinarian before top-dressing your cats dinner. Most pet vitamins are formulated to provide safe amounts without hurting an animal, adds Michel. Its reassurance when you cant take the label information on faith.