What is Lipoic Acid?
Lipoic acid (LA), a compound synthesized in the body and obtained from food, is derived from a short-chain fatty acid. LA primarily serves as a critical cofactor, or assistant, in mitochondrial energy metabolism. At high concentrations, LA functions as an antioxidant, a metal-chelator, and in glucose metabolism.
The antioxidant and metal-binding activities of LA may be particularly beneficial for diseases affected by oxidative stress and free-radical damage. Chief among such diseases is cardiovascular disease (CVD), referring to any abnormal condition affecting the heart and blood vessels that can progress to heart attack and stroke. CVD is the leading cause of death for both men and women in the U.S.
Damage to blood vessels that supply the heart and brain with vital nutrients and oxygen is a common early event in CVD. Depending on the balance between injury and repair, these lesions can accumulate further damage, become constricted, and eventually result in a stroke or heart attack.
In cell culture and animal studies, LA exerts several positive effects on cardiovascular health. One benefit is LA’s metal-chelating capacity. By binding reactive iron and copper, LA interferes with the recruitment of immune cells to sites of injury in blood vessel walls, a crucial initiating event in atherosclerosis. LA can also influence blood lipid profiles in animal models. For example, feeding LA to rats prevented diet-induced abnormalities in triglycerides and HDL, thereby significantly modifying known risk factors for CVD. Very limited research in humans suggests that LA supplementation improves blood vessel function in high-risk CVD patients.
The levels of LA needed to exert metabolic effects are not commonly achieved dietarily because LA from food is not readily absorbed. Supplemental LA is absorbed with higher efficiency; on an empty stomach, 30-40% of doses over 50 mg are absorbed.
Because it is not considered an essential nutrient, there are no formal dietary requirements for LA. Scientists at the Linus Pauling Institute at Oregon State University (LPI) are investigating the mechanisms underlying the observed benefits of LA and conducting clinical studies to evaluate the effects of LA in humans. In the meantime, the LPI Rx for Health suggests that healthy adults over age 50 may consider taking a daily LA supplement of 200-400 mg, doses that appear to be safe and without serious side effects. For more detailed information on lipoic acid, please visit the LPI Micronutrient Information Center at: http://lpi.oregonstate.edu/infocenter/othernuts/la.