Deficiency of the B-complex vitamin folic acid (also called folate) is linked to birth defects (such as spina bifida), poor hearing, poor cognitive performance, atherosclerosis and osteoporosis. Studies suggest that folic acid supplementation can help prevent birth defects, lower levels of homocysteine (a metabolite that damages blood vessels) and improve blood flow. Now research reports that folic acid supplementation can help prevent age-related hearing loss in older adults.
The randomized, double blind, placebo controlled study, published in the Annals of Internal Medicine, investigated whether folic acid supplementation prevents age-related hearing loss. Researchers at Wageningen University in the Netherlands, administered 800 mcg of folic acid or a placebo daily to 728 Dutch men and women aged 50-70 years for three years. At the beginning of the study, the participants had serum homocysteine levels of at least 13 micromoles per liter and vitamin B12 levels of 200 picomoles per liter, and no ear dysfunctions or hearing loss. Hearing tests measuring the ability to hear low and high frequencies were obtained from the participants at the beginning and end of the study.
The researchers found that the median hearing thresholds were 11.7 decibels for low frequencies and 34.2 decibels for high frequencies at the beginning of the study. Findings revealed that the folic acid group had a 1 decibel increase in low frequencies thresholds, compared with 1.7 increase in the placebo group. However, folic acid supplementation did not affect the decline in hearing high frequencies. The study authors note that the Netherlands did not have folic acid fortification of food during the study. Since the U.S. has folic acid fortification of food, baseline folate levels in Dutch participants were about half of those found in the U.S. Therefore, it is unknown if folic acid's beneficial effect will occur in populations with folic acid fortification of food.
"Folic acid supplementation slowed the decline in hearing of the speech frequencies associated with aging in a population from a country without folic acid fortification of food," the study authors write. "The effect requires confirmation, especially in populations from countries with folic acid fortification programs."
REFERENCES:
1. Durga J et al. Effects of folic acid supplementation on hearing in older adults: a randomized, controlled trial. Ann Intern Med 2007 Jan 2;146(1):1-9.
Posted by Elaine Gavalas on February 26, 2007 03:33 PM
