WHAT IT IS Alpha-lipoic acid, also known as lipoic acid, is a nutrient produced naturally by the body that helps cells to metabolize energy and acts as a powerful antioxidant.
HEALING CLAIMS The charged particles known as free radicals are implicated in many health conditions, including heart disease and cancer. Because antioxidants help to neutralize the effects of free radicals, lipoic acid's exceptional antioxidant strength may be useful in treating a wide range of health problems.
And it is especially effective in the treatment of diabetic polyneuropathy-the nerve degeneration that frequently accompanies diabetes-which causes pain tingling, and numbness in the hands and feet.
HOW IT WORKS Unlike vitamin C (which is water soluble and works only on the inside of cells) and vitamin E (which is fat soluble and only works within fatty cell membranes), lipoic acid is both, and so is extraordinarily good at protecting cells from free radical damage. And lipoic acid "recycles" other key antioxidants such as vitamin C, vitamin E, and glutathione. These antioxidants lose electrons when they zap free radicals; lipoic acid replenishes these electrons, restoring their fighting power.
As a treatment for diabetes, lipoic acid not only prevents nerve damage from oxidation, but also lowers blood sugar levels by promoting glucose metabolism.
THE EVIDENCE Lester Packer, Ph.D., a cell biology professor at the University of California at Berkeley, and his colleagues examined more than 150 studies that looked at the antioxidant properties of lipoic acid. Their review article, published in Free Radical Biology & Medicine in 1995, cited one study in which researchers blocked blood flow to the brain in rats, simulating a stroke. (When cells are cut off from their blood supply, they begin to die and trillions of free radicals are produced,) The rats that had been given lipoic acid were four times more likely to survive the stroke than those that were not treated.
In another study, published in Diabetes Care, 73 patients with adult-onset diabetes were given either 800 mg of lipoic acid or a placebo every day for four months. Patients who took the lipoic acid experienced slight nerve regeneration, while patients taking a placebo showed continued deterioration.
Another study tested the effects of lipoic acid in 10 patients suffering from diabetic polyneuropathy. Before treatment, six of the patients reported having moderate pain, while four had severe pain. After 21 days of treatment, five patients reported having no pain, four had moderate pain, and only one had severe pain.
SAFETY In extremely high doses, antioxidants are known to actually cause oxidative damage, warns Teepu Siddique, M.D., a professor of cell and molecular biology at Northwestern University Medical School in Chicago. Although Siddique is currently studying the effects of lipoic acid on Lou Gehrig's disease, he cautions that the long-term effects of lipoic acid and other antioxidant supplements on humans are not yet well understood. "This is a whole large area that hasn't been studied," says Siddique.
In clinical studies over the past three decades, a daffy dosage of 300 to 600 milligrams of lipoic acid has been shown to be safe, with no serious side effects reported. Because the best dose for each individual is different, consult your health care practitioner to determine whether you should take lipoic acid and at what dose.
WHEN TO TAKE According to Burt Berkson. M.D., Ph.D., author of Alpha Lipoic Acid: The Breakthrough Antioxidant (Prima Publishing, 1998), people over age 40 are most likely to benefit from supplementing with lipoic acid because the body produces less lipoic acid as it ages. Vegetarians may also want to consider supplementation since red meat and organ meats (heart and liver) are the richest dietary sources ofalpha-lipoic acid. Lipoic acid is also present-but in very small amounts-in potatoes, carrots, yams, beets: and spinach.