• Belmont Avenue Veterinary Hospital
  • 304 Belmont Avenue,
  • Kewdale ,
  • Western Australia,
  • 6104
  • Phone: +61892774966
  • Website: http://belmontavevet.com.au/


E and C supplementsWhat are antioxidants?

An antioxidant is any substance that protects the body from free radical damage. Free radicals are very reactive chemicals that can cause damage to living tissue via a process called oxidation. When you cut an apple and it turns brown, that’s oxidation. Free radicals can come from the environment in the form of pollution and UV radiation, but they are also produced naturally in the body with normal metabolism, exercise and stress. There are natural antioxidants produced in the body to counter these free radicals, but antioxidant food supplements can also be administered to neutralize their damaging effects.

Well known antioxidants include Vitamin C (ascorbic acid), Vitamin E (alpha-tocopherol) and Vitamin A (Beta-carotene) which are found in carrots and other fruit and vegetables. Other antioxidants are also listed below.

Why should I give antioxidants to my pet?

Damaging free radicals are produced all the time. They are mopped up by antioxidants produced in the body and from eating a healthy diet. Under certain circumstances free radicals can build up when the body uses up its own antioxidants, such as in chronic inflammation, hard exercise, undergoing general anaesthetics or when the diet is low in antioxidants. Free radical damage can contribute to ongoing disease, to aging and to cancer. This is why diets high in antioxidants are considered to contribute to good health and help prevent age related problems.

How much veterinary experience is there with antioxidants?

Allergies and arthritis have been extensively studied in animals. Other work is being pursued enthusiastically. Dogs, cats and horses have been treated extensively using antioxidants.

How much research has been conducted on these supplements?

Massive amounts of work have been done on the effects of antioxidants in people and animals. Results of clinical data also show benefits to pets with allergies and/or arthritis, for example. Generally, the work suggests antioxidants are safe to use. To prevent toxicity, balanced and broad spectrum vitamin and mineral supplementation should be used rather than selecting individual nutrients in isolation. Remember that in nature, antioxidants combine in different ratios in different foods; a balanced diet provides blanket cover with them all. Veterinary supervision is recommended when using antioxidants in the treatment of cancer as some can inhibit chemotherapy and radiotherapy, while some can enhance these therapies.

How successful are antioxidants?

They are very successful when used appropriately. In themselves they may not be curative but can form part of a broad approach to treating a range of diseases from allergic dermatitis and irritable bowel problems to cancer prevention/support.


Vitamins A and E are fat soluble. They can accumulate in the body over time if given in excess can cause problems such as spinal problems for vitamin A and bleeding problems for vitamin E.

Vitamins B and C are water soluble. Any excess given will just be passed from the body. Very high doses of vitamin C can cause diarrhoea. This clears up if the high dosing is discontinued.

When used appropriately and at the right doses, antioxidants are considered safe to use.

Vitamin C – Ascorbic acid

Probably the best known of all antioxidant nutrients for people. Cats and dogs have the ability to make their own Vitamin C, but supplementation can be helpful in older animals or those with long term inflammation problems such as arthritis, skin or bowel disease. Ascorbic acid is essential to the healing process by having an anti-inflammatory action. It promotes healthy immunity, hormone function, iron absorption from food, is active against cancer cells and reduces ageing effects. Vitamin C is found in fresh vegetables and especially in fresh fruit. It is present in some processed pet foods. Ester-C and sodium ascorbate are the best forms for pet supplementation, ascorbic acid and calcium ascorbate are other forms, and a mixed supplement with all forms can be used..

Vitamin E – Tocopherol

This vitamin is present in meat, nuts, vegetables and in fruit. It has a protective effect on tissues by protecting the membranes surrounding cells, especially, heart, liver, muscle, fat and red blood cells carrying oxygen. Supplementation can help with circulation, improve immunity, improve liver health, protect the heart and helps with ageing. Your vet will be able to guide you on dose rates for your pet.

SAMe – S-adenosyl-L-methionine

SAMe is a naturally occurring antioxidant that has particular use for liver problems. In people it is used as an anti-depressant and for the treatment of arthritis. A veterinary form suitable for cats and dogs is available in Australia from your veterinarian.

Coenzyme Q10 - Ubiquinone

Coenzyme Q-10 (CoQ10) is abundant naturally in cells of the body. It is a vital component of the mitochondria, the powerhouses of the cell. Organs with a high demand for oxygen, including the heart and the brain have a high requirement. Coenzyme Q-10 is being studied as a treatment for heart disease and Parkinson’s disease in humans. Coenzyme Q-10 has a natural affinity for oxygen and acts as a powerful antioxidant. It is found in meat but is usually given as a supplement in capsule form. It may be helpful for pets with elevated blood pressure due to heart disease, diabetes, immune problems, dental disease and decreased energy.

Beta-carotene (Vitamin A)

Beta-carotene is converted in the dog’s body into Vitamin A, another fat soluble vitamin. Talk to your vet about the best way to add a supplement to your pet’s diet as it is possible to overdose over long periods of time. It is found in most vegetables, is high in broccoli and carrots, liver, kidneys and some fruits. As well as being antioxidant, it is very nutritive to the eyes and skin and boosts immunity. Cats cannot convert beta-carotene to Vitamin A and so must be given foods containing organ meats or vitamin A.


Copper, Manganese, Selenium and Zinc are minerals used by antioxidant pathways in the body’s metabolism. They are present in a balanced raw food or good quality processed food. An excess of these minerals can be toxic.

free radical damageBlack and Green Tea

Black tea is well known, it is the stuff we all drink on a daily basis e.g. Liptons or Tetley tea. Green tea is produced from the same tea plant, but higher on the bush from more tender and green leaves. It is less oxidised and so contains more constituents called catechins and polyphenols, the active antioxidant components. Adding dried green tea, or brewed green tea to the diet of any sick or old animal can be beneficial. Toxicity is rare. For more information, see our handout on ‘Black and Green Tea’.


N-acetylcysteine (NAC, a potent anti-oxidant) is used in veterinary medicine for the treatment of paracetamol toxicity in cats and dogs. Other potential applications for NAC include the treatment of degenerative myelopathy in dogs (DM), respiratory and hepatic disease, chronic renal failure and feline immune deficiency virus (FIV), FIP, FeLV. See our handout on NAC.

Where can I find Antioxidants?

Please talk to the practice about a supply of antioxidants. We can guide you on products we have and products we recommend. Prescriptions are not needed.

Adapted by Barbara Fougere BSc BVMS (Hons) BHSc (Comp Med) MODT MHSc (Herb Med) CVA CVBM CVCP © Copyright 2015 LifeLearn Inc. Used and/or modified with permission under license.