With similar names and sometimes even the same abbreviation -- ALA -- alpha-lipoic acid and alpha-linolenic acid also play important roles in human health. They are, however, quite different. Alpha-lipoic acid, an antioxidant that neutralizes free radicals created when the body turns food into energy, occurs throughout the body and can be synthesized within the cells. Alpha-linolenic acid, an omega-3 fatty acid, is more concentrated in brain tissues. Unlike alpha-lipoic acid, it cannot be made by the human body and must be obtained in the diet, making it an essential fatty acid.
Alpha-lipoic acid is an antioxidant which -- like vitamins E and C -- scavenges free radicals to prevent them from damaging cells. In addition to neutralizing free radicals, this molecule recharges other antioxidants so they can once again attack free radicals. Alpha-lipoic acid also works alongside enzymes in the mitochondria -- powerhouses -- of cells to convert glucose into energy. Alpha-linolenic acid, on the other hand, plays a role in reducing inflammation in the body -- and diseases related to that -- as well as forming part of cell membranes.
The human body produces alpha-lipoic acid, but the molecule also occurs naturally in red meat, organ meats such as liver, and yeast, especially brewer’s yeast. Supplemental alpha-lipoic acid is available as capsules or through injection by a health care provider. Alpha-linolenic acid, however, cannot be made by the human body, so it must be obtained in the diet. Flaxseeds provide the highest concentration of alpha-linolenic acid -- both as the seeds and the oil. Other plants contain this molecule, as well, including canola, soybeans, perilla and walnut oils.
Disease and Health
Alpha-lipoic acid plays a role in lowering blood sugar levels in people with diabetes, and it may also help with pain and burning in the limbs -- peripheral neuropathies -- associated with that disease. In animals, this molecule protects the brain and nerve tissues after a stroke, although it is not certain that the effect is the same in people. Alpha-linolenic acid, like other omega-3 fatty acids, may fight heart disease and high blood pressure, and reduce inflammation -- as with arthritis and asthma. It may also play a role in brain health -- such as reducing depression -- as well as be involved in growth and development.
Both compounds may interact with prescription and over-the-counter medications, so it is important to consult with a health care provider before taking supplements. Few risks are associated with alpha-lipoic acid, although because it lowers blood glucose levels, it may interact with insulin to cause hypoglycemia -- a dangerously low blood glucose level. Alpha-linolenic acid may cause increased bleeding and can interact with blood thinner medications. It may also increase the risk of prostate cancer in men, and macular degeneration -- an eye disorder.