Alpha-lipoic Acid

Alpha-lipoic acid is a naturally occurring substance found throughout the human body and in a variety of foods. While alpha-lipoic acid (ALA) performs several vitamin-like functions, scientists do not classify it as a vitamin because the body can manufacture enough for its own needs. Alpha-lipoic acid is a powerful antioxidant that protects cells against damage caused by free radicals, which can bind to and destroy cellular material in the body, including DNA. In addition to its own antioxidant activity, ALA helps to recycle other antioxidants, including vitamin C, vitamin E and glutathione, a substance that is essential for intercellular health. While most bioactive compounds are soluble in either water or fat, alpha-lipoic acid is soluble in both, making it especially useful for protecting against free radical damage both inside and outside the body’s cells.

Because of its impressive antioxidant properties, researchers have investigated alpha-lipoic acid for its role in preventing and treating conditions believed to be related to oxidative stress, including diabetes, diabetic neuropathy, cataracts and radiation injury. Studies have also shown that ALA may help to protect the brain from damage after a stroke and may even be beneficial for people with AIDS.

Because the body’s production of alpha-lipoic acid decreases as we age, some experts believe that a daily ALA supplement may be beneficial for promoting health and preventing disease in middle-aged and elderly adults. Alpha-lipoic acid may also help reverse the decline of mitochondrial energy production that occurs during the normal aging process.

The “Ideal” Antioxidant?

From a therapeutic viewpoint, few natural antioxidants are ideal. An ideal therapeutic antioxidant would fulfill several criteria. These include absorption from the diet, conversion in cells and tissues into usable form, a variety of antioxidant actions (including interactions with other antioxidants) in both membrane and aqueous phases, and low toxicity. Alpha-lipoic acid is unique among natural antioxidants in its ability to fulfill all of these requirements, making it a potentially highly effective therapeutic agent in a number of conditions in which oxidative stress has been implicated.

Diabetes and Diabetic Neuropathy

Alpha-lipoic acid, in conjunction with other antioxidants such as vitamin E and vitamin C, may be doubly helpful for people with diabetes. By promoting the conversion of sugar into energy in the mitochondria (the energy factory in cells), ALA can help remove excess glucose form the bloodstream and improve insulin function, resulting in decreased insulin resistance. Additionally, researchers have found that patients with diabetic neuropathy – ac condition that causes pain, tingling, and numbness in the hands and feet – benefitted significantly from ALA supplementation.

Several research studies support the effectiveness of alpha-lipoic acid in treating diabetic neuropathy. In other double-blind, placebo-controlled trial, scientists assigned 328 participants with type 2 diabetes and diabetic neuropathy to receive either an intravenous infusion of alpha-lipoic acid or a placebo for three weeks. Patients scored their neuropathy symptoms at baseline and throughout the study with the Hamburg Pain Adjective List and the Neuropathy Symptom and Disability Score. The Total Symptom Score was significantly lower in participants taking ALA than in those taking the placebo.

In another study, the SYDNEY trial, 120 participants, with diabetic sensorimotor polyneuropathy were randomly assigned to receive either 600 milligrams of intravenous alpha-lipoic acid or a placebo five days per week for 14 treatments. The ALA group’s Total Symptom Score was significantly reduced compared with those receiving the placebo. Finally, a meta-analysis that combined data from the ALADIN I, ALADIN III, SYDNEY and NATHAN II trials showed that patients who used 600 milligrams of intravenous alpha-lipoic acid for three weeks showed a 24.1 percent reduction in Total Symptom Score and a 16 percent reduction in the Neuropathy Impairment Score.

Please note that the studies cited above used intravenous alpha-lipoic acid supplements. The long-term benefits of oral ALA supplements for diabetic neuropathy have not yet been fully established; however, evidence does suggest that 600 milligrams per day of an oral alpha-lipoic acid supplement may help relieve diabetic neuropathy. Responding to the positive news about ALA’s role in diabetes and its complications, the American Diabetes Association has stated that alpha-lipoic acid and vitamin E supplements may be helpful in some of the health complications associated with diabetes, including kidney disease, vision problems, heart disease and nerve damage. ALA is a potentially vital supplement for the one in 20 Americans who live with diabetes.

Bottom Line

While many antioxidant supplements are available, ALA is unique in its ability to function as both a water- and fat-soluble antioxidant, as well as its role in recycling vitamin C, vitamin E and glutathione. For diabetics, people with other health conditions and even middle aged and elderly adults who want to maintain optimal health, alpha-lipoic acid is showing great promise.