Cat & Dog - High-Dose Vitamin Therapy (Orthomolecular Medicine)

What is orthomolecular therapy?

vitamins_72Much of the research into nutrition has focused on minimum requirements of nutrients to avoid deficiency problems. Orthomolecular therapy (from 'ortho' meaning 'right') focuses on providing optimal levels of nutrients and substances that are normally present in the body in order to prevent development of disease or to treat disease once it has occurred. Orthomolecular medicine becomes necessary because of variability in food quality due to soil depletion or contamination. Also, individual patients have unique nutritional needs depending on heredity (genes), health status and lifestyle.

Orthomolecular therapy may involve the use of single substances or combinations. Essential fatty acids, minerals and vitamins may be administered in higher doses than normally recommended when a pharmacological effect is sought. Thus a common form of orthomolecular therapy is known as megavitamin therapy. This involves administering doses of certain vitamins at a much higher level than is generally recognised as the minimum daily requirement. Often up to three or four vitamins are combined e.g. vitamins A, C, and E etc.

What conditions are most often treated with Orthomolecular Therapy?

Inflammatory conditions and immune-mediated diseases can respond to increased doses of essential fatty acids, especially omega 3 fatty acids. Vitamin A can increase a patient's resistance to infection and may enhance immune function. Vitamin E can be useful in the treatment of feline steatitis (inflammation of fat cells) and some forms of liver disease. Vitamin C can be useful in the treatment of some cases of hip dysplasia, especially in the early stages. Vitamin E and C have antioxidant and anti-inflammatory effects; these effects appear to be synergistic when they are used together.

Combination megavitamin therapy may be useful in the treatment of skin allergies, inflammatory bowel disease, feline gingivitis (gum disease) and feline leukemia. Megadoses of vitamin A and D3 may be helpful for short periods in the treatment of cancer. Vitamin B12, given by injection, appears to stimulate the appetite of weakened animals. Zinc may be useful in the management of recurrent infectious skin disease. Injectable magnesium appears extremely useful in the treatment of cardiomyopathy (heart muscle diesease) and congestive heart failure. Vanadium can help in some cases of diabetes.

How successful is orthomolecular therapy?

The use of vitamin C and vitamin E supplementation for treatment of certain skin conditions has become accepted in orthodox medicine. Anecdotal reports of the success of orthomolecular therapy for other conditions such as cancer are encouraging. Cardiac muscle weakness appears dramatically responsive to magnesium. However, there are currently no controlled studies to demonstrate the efficacy or success of orthomolecular medicine in small animals.

How safe is orthomolecular therapy?

It is possible to produce toxicity if excessive amounts of some nutrients are administered. Toxicity problems are more common with fat-soluble vitamins, especially vitamin A and D, and possibly vitamin E.

pets_appealdogtt8_72Because vitamin C is water-soluble and readily excreted, toxicity is not generally an issue, although excessive levels of vitamin C given orally will cause diarrhoea. Excessive levels of any nutrient may interfere with levels of other related nutrients in individual patients.

Can orthomolecular therapy be combined with other types of veterinary medicine?

Because of the potential for toxicity and other adverse nutritional effects, only vets should prescribe orthomolecular therapy for animals. It is often safe to combine orthomolecular treatment with other types of veterinary medicine, but it is best overseen by a professional.

Please ask one of the vets here if you would like to discuss orthomolecular medicine treatment with your pet.

© Copyright 2025 LifeLearn Inc. Used and/or modified with permission under license. This content written by LifeLearn Animal Health (LifeLearn Inc.) is licensed to this practice for the personal use of our clients. Any copying, printing or further distribution is prohibited without the express written consent of LifeLearn. This content does not contain all available information for any referenced medications and has not been reviewed by the FDA Center for Veterinary Medicine, or Health Canada Veterinary Drugs Directorate. This content may help answer commonly asked questions, but is not a substitute for medical advice, or a proper consultation and/or clinical examination of your pet by a veterinarian. Please contact your veterinarian if you have any questions or concerns about your pet’s health. Created on Jun 24, 2008.

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