Folic Acid May Slow Age-Related Hearing Loss

However, the benefit seen in a study isn't significant, experts say.

By Steven Reinberg
HealthDay Reporter
Tuesday, January 9, 2007; 12:00 AM

Copyright © 2007 ScoutNews, LLC. All rights reserved.

WEDNESDAY, Jan. 3 (HealthDay News) -- Age-related hearing loss, a common problem among the elderly, might be related to inadequate levels of folic acid, European researchers report.

The researchers found that people who took a folic acid supplement had less decline in hearing low-frequency sounds over time, compared with people who didn't take the supplement.

Results of the study, led by Jane Durga, of the Cognitive Sciences Group, Nutrition & Health Department at the Nestle Research Center in Lausanne, Switzerland, are published in the Jan. 2 issue of the Annals of Internal Medicine.

The researchers randomly assigned 728 older Dutch men and women, who showed signs of age-related hearing loss and low folate levels, to receive either 800 micrograms of a folic acid supplement or a placebo daily for three years.

Durga's team chose to conduct the study in the Netherlands because, unlike the United States, the Netherlands does not fortify its food with folic acid, a B vitamin also known as folate. Folate levels in study participants were about half those found in Americans. In the United States, many foods contain supplemental folic acid because of its benefits in protecting against birth defects.

At the end of the trial, the researchers found that the ability to hear low-frequency sound did not decrease significantly among those taking folic acid supplements. However, there was no slowing in the decline in hearing high frequencies in either group.

The thresholds of the low frequencies increased by 1.0 decibel in the folic acid group and by 1.7 decibels in the placebo group, the researchers said.

"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 researchers wrote. "The effect requires confirmation, especially in populations from countries with folic acid fortification programs."

But Robert W. Sweetow, director of audiology at the University of California, San Francisco, Medical Center, called the results "clinically insignificant."