Q. My dogs get a dietary supplement made from dessicated liver, kelp, and yeast cultures. Do you think this is what they should be on?

A. Even natural dietary supplements can be inappropriate for some animals. Here are three important guidelines for using nutritional supplements in small animals:

1. No supplement is ideal for life-long use. Age and diet limitations necessitate some flexibility in choosing supplements. For example, brewer's yeast is a common allergen in dogs though many canine supplements have this ingredient.

Adding yeast, kelp, and other food concentrates to the diet every day with no break simply increases the risk for sensitizing the pet to these ingredients. I do not recommend a dietary supplement for more than 12 months to avoid development of an allergy or negative response. At a minimum, monitor the pet's blood and urine before starting a supplement, and have a realistic end-point such as three months, to evaluate its effect. Before investing in a dietary supplement, consult with an independent party who has knowledge and experience with nutritional therapies.

2. There is significant individuality among animals even in the same home, eating the same food. The best way to know what a pet needs is to periodically measure their nutritional status through a chemistry profile, blood cell count, thyroid level, and urinalysis. This should be done every year as a way to anticipate problems (excesses, deficiencies, imbalances) and get the dog or cat back on a good trajectory (prevention of disease).

3. Check the potency of the formula, per serving. Supplements may contain wholesome, natural ingredients but one should ask if the pet has a need for more kelp, garlic, yeast, etc. every day for many months or years. I rarely see such a need in clinical practice and find some nutrients in the product such as iodine, sodium and potassium may be too high for some pets and some diets at some stages of their life.

For example, the level of iodine on the product label at 300mcg was high if that is per serving (unclear from the web site). The combined amount of sodium + potassium was 637mg, significantly higher than the calcium + magnesium at 429mg. If the client's two dogs need more magnesium but not more sodium, this supplement is not for them! A blood test will accurately show the dog's electrolyte or mineral balance.   

Overall the product my client was feeding is probably fine for a few weeks or months in apparently healthy dogs, but why guess? Some people will administer a supplement on a trial basis and find a favorable effect but others could see no improvement or even a worsening of their animal's health. If you have no idea about the internal condition and nutritional status of your cat or dog, limit a supplement to a low/conservative dose and finish it in three months. Otherwise have blood work done so there are clear indications for the supplement, a safe dose is determined for that individual, and a safe termination date is set at which time the pet's needs should be re-evaluated. These cautions will help avoid nutritional errors and potentially some undesirable effects on our animals.

- William K. Kruesi, D.V.M.