Thursday July 17, 2014 (foodconsumer.org) -- Nutrition scientists from the Linus Pauling Institute at Oregon State University have recently published a study suggesting that lipoic acid a potent antioxidant can rejuvenate circadian rhythms or the biological clock in aging humans and animals.

The study suggests that in aging animals and humans, lipoic acid may help normalize many biological functions caused by age-related dysfunctional circadian rhythms including stress, heart disease, hormonal imbalance, muscle mal-performance, and abnormal glucose metabolism.

In elderly people, circadian rhythms break down and certain enzymes do not work as efficiently as they should as an estimated one thirds of genes are affected by circadian rhythms.  That is in part why elderly people are more susceptible to the development of cancer, heart disease and experience inflammation, hormonal imbalance and many other medical conditions.

In the study, researchers fed lab animals high levels of lipoic acid which a normal diet couldn’t provide and monitored proteins in the liver known to be affected by disruption of the circadian rhythm in old animals.

A dysfunctional circadian clock of the liver which is relevant to lipid metabolism can put millions of people at risk of heart disease, diabetes mellitus and cancer.

The study found animals fed high levels of lipoic acid had some of the liver dysfunctions which are commonly seen in old age restored and the function of circadian rhythms improved.

The dose of lipoic acid used in the study as determined in previous studies was equivalent to 600 milligrams per day for a 150-pound human.  Lipoic acid is found high in organ meats and green leafy vegetables such as spinach and broccoli.   But dietary supplements, but not a normal diet can provide this high amount of lipoic acid.

The study was sponsored by the National Institutes of Health and published in Biochemical and Biophysical Research Communications.

Lipoic acid is not an essential nutrient and humans can naturally synthesize it.  That is, generally, humans are not at risk of lipoic acid deficiency.  However, elderly people may not produce as much as needed and they may benefit from taking alpha-lipoic acid dietary supplements.

Lipoic acid and disease treatment

Lipoic acid has been used to treat a number of chronic diseases including diabetes mellitus, vascular disease, diabetic neuropathy, multiple sclerosis, and cognitive decline and dementia

Lipoic acid and diabetes mellitus

Clinical trials indicated that lipoic acid may help diabetes mellitus by improving insulin sensitivity.   In one trial, patients with type 2 diabetes mellitus receiving a single IV infusion of 1,000 milligrams of lipoic acid improved insulin sensitivity by 50%.  In another trial, IV infusion of 500 mg per day of lipoic acid for ten days improved insulin sensitivity.  

Oral supplementation with lipoic acid also helps diabetics. In one study of 72 patients with type 2 diabetes mellitus, taking supplemental lipoic acid in doses of 600 mg per day, 1200 mg per day or 1800 mg per day for four weeks all improved insulin sensitivity by 25% and the dosage does not make any difference.

Lipoic acid and vascular disease

Lipoic acid can also help diabetes mellitus patients to maintain endothelial function and prevent vascular disease. Intra-arterial infusion of lipoic acid was found effective in improving endothelium dependent vasodilation in diabetic patients, but not healthy controls.

Oral supplementation with 300 mg per day of lipoic acid for four weeks was found to improve flow-mediated vasodilation by 44%.  Taking lipoic acid orally in a dose of 1,200 mg per day for six weeks was found to improve capillary perfusion in the fingers of diabetic patients of peripheral neuropathy.

Lipoic acid and diabetic neuropathy

More than 20 percent of diabetic patients are expected to develop peripheral neuropathy with which patients can experience pain, loss of sensation, and weakness, in most cases in the lower extremities.  The nerve damage is caused by long term exposure to high glucose levels in the blood.

Germany has already approved intravenous and oral lipoic acid as a treatment for diabetic neuropathy.  Clinical trials show that IV infusion of lipoic acid in a dose of 600 mg per day for three weeks reduced the symptoms in patients with diabetic neuropathy.

In one trial, oral supplementation with lipoic acid in doses of 1,800 mg per day for three weeks helped improve peripheral neuropathy. In another trial, 600 mg per day, 1200 mg per day or 1,800 mg per day of lipoic acid taken for five weeks reduced neuropathic symptoms.   A dose of 800 mg per day of lipoic acid may also help patients with cardiovascular autonomic neuropathy.

Lipoic acid and multiple sclerosis

Studies indicated that a dose of 1,200 to 2,400 mg of lipoic acid per day orally taken for two weeks may help patients with multiple sclerosis.  But long term studies are needed to confirm the efficacy and safety.

Lipoic acid and cognitive decline and dementia

Lipoic acid along or in combination with other antioxidants has been found effective in improving memory in aged animals.  That is, lipoic acid can help prevent cognitive decline in elderly people.  Alzheimer's disease patients taking 600 mg of lipoic acid while receiving standard treatment with acetylcholinesterase inhibitors maintained their cognitive function for one year.

Lipoic acid safety

Lipoic acid taken in a moderate dose generally does not cause any serious adverse effect.  Studies show oral lipoic acid in a dose of 1,800 mg per day for six months and 1,200 per day for 2 years does not result in serious side effects in patients with diabetic peripheral neuropathy.

(Edited by David Liu, PHD)