Humans are discovering the benefits of adding supplements to their diets to support good health. If the majority of the food you eat is commercially grown and processed, you should be concerned. Growing evidence suggests that modern farming techniques, based largely on synthetic fertilizers and single-crop fields, have stripped much of the mineral content from the soil and thus from the foods we eat. Processing also destroys many vital nutrients.

If you have plenty of grazing land for your horses to forage on, you are fortunate, but you are also in the minority. Most horse owners must keep their animals confined to smaller acreage with limited year-round access to the grasses that could supply their needs. For at least part of the year, they must supplement those needs with commercial feeds and hay purchased elsewhere.

When you leave iron tools out in the weather, they oxidize, which produces rust. A similar degenerative process happens in cells. In the metabolic process, the body produces oxides, which are known as free radicals. Antioxidants are key components in the free radical defense system. Familiar examples of antioxidants are vitamins A, C, and E. When all is going well, the balance between free radicals and antioxidants keeps cellular damage manageable. However, in times of illness and other stresses — including exposure to pollution, heavy metals, and chemicals — free radicals can overwhelm the body's immune system, leaving the body vulnerable to infections and illness, perhaps even cancer. The theory is that supplemental antioxidants can help return stressed bodies to health or prevent stress exposure from negatively impacting health. The body will use and store only the antioxidants it requires and eliminate excess levels.

Horses that compete on the show circuit endure a great deal of extra stress. Frequent trailering, disruption of routine, and the added athletic demands placed on them during show season all can take their toll. If you feel your horse may benefit from an antioxidant supplement, talk to your veterinarian. Ideally, your veterinarian can help you determine the need and the best strategy for supplementation.

Methylsulfonylmethane (MSM) is an organic sulfur used by the body to produce enzymes for digestion and antibodies to fight infection and to build connective tissue (e.g., cartilage, skin, and hooves). MSM, used in conjunction with glucosamine, is often recommended for arthritic symptoms to help rebuild the cartilage that cushions the bones. It also reduces allergic reactions.

Osteoarthritis seems to go hand in hand with an athletic life. When the cartilage that lines the joints to keep bones from rubbing together deteriorates because of wear and tear or age, crippling pain can result. Proponents claim that glucosamine can actually rebuild damaged cartilage, in contrast to anti-inflammatory drugs that mask the pain and, therefore, speed up the deterioration process from overuse. If you and your veterinarian suspect arthritis, try a joint supplement containing glucosamine, additional vitamin C, and MSM. (It is worth noting that there is evidence that glucosamine HC1 is more absorbable than glucosamine sulfate.)

The supplier will provide a recommended dosage frequency and amounts based on your horse's weight. You may see some change in about a month, but it often takes several months before the full benefit of the supplement begins to kick in. If it's effective, you can keep your horse on glucosamine for the rest of his life if you can afford it. Although prices have come down a bit, joint supplements can still be quite an expensive addition to your feed bill.

Be aware that feeding an excess of certain nutrients and supplements can sometimes backfire and cause unintended problems. For example, you can undermine your efforts to improve your horse's health by creating an imbalance of phosphorus and calcium through over supplementation. Too much sulfur may actually inhibit hoof growth. That's why it's important to know exactly what's already going into the feed bucket and the hay bin, as well as the quality of your pastures, before you start adding supplements willy-nilly. If your horse maintains good health and body condition without them, save your money.

As an owner, your horse's digestive health is a primary concern. Colic (abdominal pain that can be mild or severe) is the number one killer of horses, and a variety of things can cause it, including: