The Supplement Shown to Slow Age-Related Hearing Loss

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Some studies found that higher levels of folate in the blood seem to correlate with better hearing, so researchers decided to put it to the test.

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Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

Healthier diets are associated with a significantly lower risk of hearing loss, and for all three diet quality scoring systems these researchers used, avoidance of meat was most strongly associated with lower risk. The Mabaan from my last video, who preserved their hearing into old age, ate little meat, but also weren’t eating sugary junk––explaining their almost total absence of dental cavities. A high glycemic diet of refined carbs is also associated with developing age-related hearing loss. If it’s the blood sugar spikes, that would explain why diabetics and prediabetics are also at higher risk. Even among whole grains, sorghum, which is the center of the Mabaan diet, has a particularly low glycemic index due to its resistant starch content, causing about a 25 percent lower rise in blood sugar compared to whole wheat.

Impaired blood circulation may also explain how noise damages the inner ear, as loud noises cause constriction of the accompanying blood vessels. This may also help clarify the link between obesity and hearing loss. Excess weight may just be a proxy for unhealthier diets, but the pro-inflammatory state of obesity can itself lead to vascular dysfunction. Measures of systemic inflammation seem to directly correlate with age-related hearing loss, as do measures of oxidative stress.

In my video on brain inflammation, I introduced the antioxidant defense activator Nrf2, called “guardian of healthspan and gatekeeper of species longevity.” Those born with a genetic variant Nrf2 that doesn’t encode as well are significantly more likely to develop impaired hearing, implicating the role of free radicals in the process of hearing loss. You can look in the back of people’s eyes and measure the amount of macular pigment—the lutein and zeaxanthin antioxidants concentrated in greens—and correlate that with superior hearing.

The population data on antioxidant intake and hearing loss is mixed, though. Take vitamin C, for example. Some studies show that higher vitamin C intake is associated with better hearing, but others failed to find any significant connection. The only way to tell if antioxidants help or not—you know the drill—is to put them to the test.

Adding antioxidants to the diets of rats seems to help prevent age-related rat hearing loss, but doing the same thing in mice doesn’t appear to help. The most exciting preclinical data may be a study in which aged rats randomized to added blueberries looked like they had a reversal in hearing deficits–in fact ending up better than the young rats. Wait, I thought hair cells don’t regenerate?

Our ability to hear doesn’t just have to do with our ears, but our brain. As we age, our auditory cortex in the temporal lobe of our brain loses some of its ability to discriminate and understand speech, even in a quiet environment. We don’t just need to sense sounds, but make sense out of them. That’s where blueberries seemed to come in, reversing the age-related cognitive deficits in auditory processing. But what about in people?

There are studies lacking control groups that documented improvements in hearing loss, giving people antioxidant supplements like vitamins A, E, C, and alpha-lipoic acid. But when properly put to the test in a randomized double-blind, placebo-controlled trial of a whole list of antioxidants, the supplements flopped—no effect on any of the measured hearing aspects. Is there any supplement that has been shown to help with hearing in older adults? Yes, folic acid, the supplement form of folate, found concentrated in beans and greens.

Some observational studies had found that higher levels of folate in the blood seem to correlate with better hearing, but maybe that’s just a marker of eating a healthier diet in general. So, Dutch researchers set out on an ambitious three-year double-blind, placebo-controlled trial randomizing more than 700 older men and women to take 800 μg of folic acid a day or an indistinguishable placebo. Excitingly, those who had been taking the folic acid suffered significantly less decline in hearing at speech frequencies. The effect size was rather small, such that one might expect the proportion of men, for example, who would be hearing aid candidates at age 75 might drop from 33 percent to 22 percent with folic acid supplementation. Also note the study was done in the Netherlands, where, at the time, the food supply was not fortified with folic acid. In the U.S., where folic acid fortification has been mandated in refined grain products for decades, it’s unclear how much additional benefit supplements might add. Regardless, the healthiest sources are dark green leafy vegetables and legumes. (A cup of cooked lentils has 90 percent of adult daily needs.)

Please consider volunteering to help out on the site.

Motion graphics by Avo Media

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

Healthier diets are associated with a significantly lower risk of hearing loss, and for all three diet quality scoring systems these researchers used, avoidance of meat was most strongly associated with lower risk. The Mabaan from my last video, who preserved their hearing into old age, ate little meat, but also weren’t eating sugary junk––explaining their almost total absence of dental cavities. A high glycemic diet of refined carbs is also associated with developing age-related hearing loss. If it’s the blood sugar spikes, that would explain why diabetics and prediabetics are also at higher risk. Even among whole grains, sorghum, which is the center of the Mabaan diet, has a particularly low glycemic index due to its resistant starch content, causing about a 25 percent lower rise in blood sugar compared to whole wheat.

Impaired blood circulation may also explain how noise damages the inner ear, as loud noises cause constriction of the accompanying blood vessels. This may also help clarify the link between obesity and hearing loss. Excess weight may just be a proxy for unhealthier diets, but the pro-inflammatory state of obesity can itself lead to vascular dysfunction. Measures of systemic inflammation seem to directly correlate with age-related hearing loss, as do measures of oxidative stress.

In my video on brain inflammation, I introduced the antioxidant defense activator Nrf2, called “guardian of healthspan and gatekeeper of species longevity.” Those born with a genetic variant Nrf2 that doesn’t encode as well are significantly more likely to develop impaired hearing, implicating the role of free radicals in the process of hearing loss. You can look in the back of people’s eyes and measure the amount of macular pigment—the lutein and zeaxanthin antioxidants concentrated in greens—and correlate that with superior hearing.

The population data on antioxidant intake and hearing loss is mixed, though. Take vitamin C, for example. Some studies show that higher vitamin C intake is associated with better hearing, but others failed to find any significant connection. The only way to tell if antioxidants help or not—you know the drill—is to put them to the test.

Adding antioxidants to the diets of rats seems to help prevent age-related rat hearing loss, but doing the same thing in mice doesn’t appear to help. The most exciting preclinical data may be a study in which aged rats randomized to added blueberries looked like they had a reversal in hearing deficits–in fact ending up better than the young rats. Wait, I thought hair cells don’t regenerate?

Our ability to hear doesn’t just have to do with our ears, but our brain. As we age, our auditory cortex in the temporal lobe of our brain loses some of its ability to discriminate and understand speech, even in a quiet environment. We don’t just need to sense sounds, but make sense out of them. That’s where blueberries seemed to come in, reversing the age-related cognitive deficits in auditory processing. But what about in people?

There are studies lacking control groups that documented improvements in hearing loss, giving people antioxidant supplements like vitamins A, E, C, and alpha-lipoic acid. But when properly put to the test in a randomized double-blind, placebo-controlled trial of a whole list of antioxidants, the supplements flopped—no effect on any of the measured hearing aspects. Is there any supplement that has been shown to help with hearing in older adults? Yes, folic acid, the supplement form of folate, found concentrated in beans and greens.

Some observational studies had found that higher levels of folate in the blood seem to correlate with better hearing, but maybe that’s just a marker of eating a healthier diet in general. So, Dutch researchers set out on an ambitious three-year double-blind, placebo-controlled trial randomizing more than 700 older men and women to take 800 μg of folic acid a day or an indistinguishable placebo. Excitingly, those who had been taking the folic acid suffered significantly less decline in hearing at speech frequencies. The effect size was rather small, such that one might expect the proportion of men, for example, who would be hearing aid candidates at age 75 might drop from 33 percent to 22 percent with folic acid supplementation. Also note the study was done in the Netherlands, where, at the time, the food supply was not fortified with folic acid. In the U.S., where folic acid fortification has been mandated in refined grain products for decades, it’s unclear how much additional benefit supplements might add. Regardless, the healthiest sources are dark green leafy vegetables and legumes. (A cup of cooked lentils has 90 percent of adult daily needs.)

Please consider volunteering to help out on the site.

Motion graphics by Avo Media

Doctor's Note

If you missed the first video in this three-part series, see Age-Related Hearing Loss Is Preventable—What Causes It? The next and final one is The Diet Shown to Slow Age-Related Hearing Loss. 

If you’re unfamiliar with sorghum, check out my videos Is Sorghum a Healthy Grain? and The Health Benefits of Sorghum.

The video I mentioned about brain inflammation is Fighting Autism Brain Inflammation with Food. 

For more on how to live your longest, healthiest life, preorder my new book How Not to Age. (As always, all proceeds I receive from all of my books are donated to charity.)

If you haven’t yet, you can subscribe to my videos for free by clicking here. Read our important information about translations here.

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