Equine Antioxidants 

Antioxidants are important for many reasons.  Antioxidant help protect horses from the destructive effects of environmental free radicals.  Free radicals are caused by ultra-violet rays from the sun, x-rays, exposure to pesticides, insecticides, herbicides, competitive training and stress.

When horses are competitively trained, the stress of exercise can damage red blood cells. Antioxidants help prevent this damage.  It also increases the strength and stamina of horses, yet at the same time, it reduces stress and anxiety in horses. 

Antioxidants also boost the immune system, which aids in preventing disease.  Antioxidants help prevent disease in a number of ways. For one, it reduces the oxidative damage to cells that make them more susceptible to disease and strengthens the cell walls to make it more difficult for invaders to penetrate and enter the cell. Antioxidants also help reduce stress and anxiety in horses and we know that stress contributes to the onset of disease - in both horses and humans. 

The overall benefits of antioxidants in helping to reduce the oxidative damage to cells when horses exercise is well described in this paper on vitamin E and selenium . 

Vitamin C	Vitamin C particularly binds to nitrates, which play a role in the development of some cancers. It is also called ascorbic acid or sodium ascorbate.
Vitamin E	Vitamin E is fat soluble and protects the lipid (fat) parts of the cells such as cell walls and cell membranes. Also called alpha-tocopherol. The Vitamin E requirements for performance and endurance horses are higher than those horses getting less exercise.
Vitamin A	It is one of the most effective and efficient scavengers of a free radical called 'singlet oxygen.'
Zinc	Zinc is a mineral that helps to maintain the health of cell membranes, protecting them from injury from free radicals.
Selenium	Selenium is a mineral needed by the body to synthesize sufficient amounts of glutathione peroxidase, which is an important antioxidant enzyme that protects against free radical damage. Works synergistically with Vitamin E. In many areas, selenium is deficient in the soil and in plants. Selenium can be toxic at high levels, however, so be aware of all sources of selenium in your horse's diet. Consult your veterinarian if there is concern about selenium deficiency or toxicity.
Grape seed extract	Grape seed extract contains proanthocyanidins, which are a type of flavonoid. They are not only antioxidants, but also appear to protect the heart, liver, and capillaries. It is especially helpful in preventing the oxidation of fats, including fatty acids.