Coenzyme NAD Brain Benefits Unproven, Further Research Needed

Any substance in the body that decreases with age is bound to become the subject of scientific research — and a place for the public to pin its collective hopes and dreams — about aging. “What if we increase this substance?” “Could it stop or reverse the aging process? “Could it keep the brain healthy forever?” Scientists — and the public — have been asking. 

Coenzyme NAD+ is one of those substances that dwindles with age. The nutrient nicotinamide riboside, which is a form of niacin, or vitamin B3, is converted into this coenzyme in the body. You can get trace amounts of nicotinamide riboside — let’s call it NR for short — from milk, yeast and a few other common foods. 

When research in mice showed that this form of niacin may offer benefits that might be useful to older adults — such as blood sugar control, improved exercise abilities, counteracting the consequences of a high-fat diet and possible brain cell protection — researchers began to test the nutrient’s effects on humans.

The results of the first human clinical trial of the potential health benefits of daily NR supplements were published in 2016. Since then, two dozen more trials have been published. It can take time to accumulate enough study volunteers and enough data to draw final conclusions about the health effects of any substance, but so far, the results of this research have been a bit underwhelming.

In a 2023 review in Science Advances, researchers analyzed the results of all 25 clinical trials that had been published up to that point. Some of these studies seem to suggest that NR supplements may reduce markers of inflammation in the blood. Less inflammation could mean lower risk for chronic diseases of old age, such as Alzheimer’s, heart disease, diabetes and cancer. But no studies have proven that the supplements have those kinds of direct effects on disease risk. A few studies have found that there could be a role for NR supplements in heart failure, Parkinson’s disease and ataxia (loss of muscle control caused by damage to the brain, spinal cord or nerves). The published studies have included relatively few people who were only followed for a few hours to a few months. Larger, longer-term studies are needed to confirm any clinical benefits of these supplements.

For now, there’s not enough evidence to support taking NR supplements with the expectation of brain or any other health benefits, a stance taken by AARP’s Global Council on Brain Health in a report on brain health supplements in 2019, which remains unchanged. But researchers continue to be interested in this nutrient, so stay tuned.