Pet Supplement Guide
Essential nutrients for optimal health in cats and dogs of all ages
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The best human diet is a matter of debate. Should it be plant-based? Paleolithic? Mediterranean? For our pets, however, the answer is more obvious.

“For any animal, just think, what would they be eating in the wild?” says Barbara Royal, DVM, president of the American Holistic Veterinary Medical Association, and author of The Royal Treatment: A Natural Approach to Wildly Healthy Pets.
While some animals, such as rabbits and guinea pigs, are naturally vegan, dogs and cats are carnivores, she points out. But that doesn’t mean a steak or chicken breast-which consist only of muscle meat-will provide a complete diet. If they hunted, dogs and cats would naturally eat all of their prey, including fur and feathers for fiber, and organs and stomach contents for vitamins and minerals. And by foraging, they would select food sources of specific nutrients that their bodies need.
“We can’t really provide the perfect diet all the time because they’ve been deprived of their own free choice and their body telling them what they need,” says Royal. “That’s where supplements come in.”
3 Popular Types of Pet Food
The supplements pets need depend largely on the type of food they eat, the most common being kibble, canned food, or ground meat prepared especially for dogs or cats. Pet foods labeled “for supplemental feeding” or “supplementary” don’t contain all the essential nutrients and are not designed to be an animal’s main food. Those described as “complete and balanced” contain a variety of added vitamins and minerals, much like a built-in multivitamin, and are designed to provide adequate nutrition. For insurance, you can add a pet (not human) multi, once a week or more often, depending on your pet’s situation and quality of diet. If in doubt, consult a holistic vet.
No matter which type of food you buy, says Royal, dogs and cats need added fiber and probiotics, and can benefit from coconut oil for healthy digestion and a shiny coat. And cats do well with aloe juice.
For animals that primarily eat kibble and canned food, Royal recommends adding fish oil for omega-3 fats (see “Supplements for Popular Pet Diets,” p. 42), as well as these specifics:
- For a kibble diet: Heat used in producing kibble generates carcinogenic chemical compounds, which turmeric supplements can counteract. To make such a diet more “wild,” replace ¼ to ½ of the kibble with fresh meat, raw or cooked. Your meat leftovers will work, as long as they don’t contain onions, raisins, grapes, wheat, or any raw cruciferous vegetables (when raw, these interfere with absorption of iodine).
- For a canned food diet: BPA (bisphenol A) in the linings of most cans is estrogenic, disrupts hormones, and can contribute to hormonal cancers. Broccoli extract helps to detoxify the chemical. Or, feed your pet some cooked broccoli.
- For pet owners who prepare food from scratch, without using meat labeled “complete and balanced,” Royal recommends adding essential nutrients, such as taurine for cats. Her book includes recipes and meal plans for dogs of all ages and for specific health conditions. For cats, visit catinfo.org.
Pet Supplements
Pet supplements are specially formulated, may be more economical than human versions, are available in forms that are easier for pets to take, and list doses for different sizes of animals. However, many human supplements can also be given to your pets, particularly individual nutrients. Check with a holistic vet before giving your pet any human supplement, but these are Royal’s general guidelines.
- Dogs: ½ the human dose for a 50-lb dog. Adjust proportionally for bigger or smaller dogs. For example, ¼ the human dose for a 25-lb dog.
- Cats: ⅛ the human dose.
Giving a supplement less often than daily will still be beneficial. With cats, which have slower metabolisms, 1-3 times per week is therapeutic. Start with a trace and gradually work up to the full dose.
Because cats are picky eaters, you might be tempted to put a supplement in their food or water. Don’t, says Royal, as it can discourage them from eating and lead to bigger problems. Instead, try:
- Butter, frozen or room temperature
- Thick meat baby food
- Cream cheese
- Liverwurst
Peanut butter caution: Don’t use peanut butter to deliver supplements, as it may contribute to inflammatory conditions from joint pain to skin lesions. Many of Royal’s patients have healed naturally after eliminating peanut butter from their diets.
Food Ingredients to Avoid for Pets
Royal recommends feeding your furry friends organic pet food and treats if possible. Or at least avoiding food coloring and chemical preservatives. The following ingredients also are not naturally part of a dog’s or cat’s diet, can cause digestive and inflammatory problems, and should be avoided:
- Soy
- Corn (and any type of corn syrup)
- Wheat
- Potato (not sweet potato)*
- Peanut butter
- Sugars
- Molasses
- Sugar-free sweeteners
- Alfalfa
- Sorghum
*Potatoes that you cook at home are not toxic, but pet food is typically made with industrial potatoes that contain “eyes” and are green under the skin, concentrating solanine, an inflammatory substance.
Supplements for Popular Pet Diets
To find a holistic vet, the American Holistic Veterinary Medical Association: ahvma.org.