The belief that wine — in particular red wine — contributes to longevity is not a new one. Jars of 5,000 year old wine have been found in Egypt, 4,000 year old hieroglyphs and Sumerian tablets document wine as one of humanity’s oldest medicines, and wide social belief in the drink’s health benefits persist to this day.

Over the past year, however, the World Health Organization (WHO) and the National Institute on Alcohol Abuse and Alcoholism (NIAAA) have released statements warning that, contrary to popular belief, drinking a glass of wine daily may not be healthy. Alcohol, they say, is a carcinogen that can cause a variety of cancers — and may outweigh the potential benefits of antioxidant-rich wine on the heart or blood sugar levels.

But what about the grapes — without the alcohol? At the Annual Meeting of the Society of Nuclear Medicine and Molecular Imaging (SNMMI) in June, the results of a years-long study of the effects of grape consumption on cognitive decline were presented by a group of researchers with the University of California – Los Angeles.

During a year-long, double-blind placebo-controlled study, twenty subjects with mild cognitive decline, mostly in their 70s, were monitored. Half were given 36 grams of a grape powder formulation twice per day, while the rest were given a placebo.

Grapes are known for their high antioxidant content — polyphenols and resveratrol in particular — which fight free radicals. Free radicals are atoms with at least one unpaired electron, making them unstable, highly reactive, and therefore damaging to the cells around them.

Though free radicals only last for a split second, their nature is to damage everything around them, and can cause damage to DNA, including mutations that cause premature aging and can increase the risk of cancer, heart disease, diabetes, poor vision, dementia and Alzheimer’s, and degenerative diseases like Parkinson’s. Our bodies create free radicals all the time, including during metabolic processes, after eating or exercise, and in response to inflammation or toxins from external sources from sun damage, smoking, infections, alcohol, and more.

Antioxidants, found in abundance in fruits and vegetables, stabilize free radicals by resolving the unpaired electrons, by either donating or accepting an electron. Many studies have demonstrated how diets rich in antioxidants can counteract oxidative stress — an imbalance of free radicals and antioxidants — which has been closely associated with metabolic syndrome linked to myriad heart ailments.

But what about the brain? Our brains, though making up just two percent of our body weight, use up to 25 percent of our body’s energy during its metabolic processes. Over 33 percent of women and 20 percent of men will develop dementia during their lifetime, and more will experience milder decline in cognition.

The team from UCLA sought to explore just that, departing from studies that typically focus on heart health, and instead observing effects of antioxidants on metabolism in the brain. The active formula group’s intake of grape powder was the equivalent of just over one cup of grapes, twice per day, for a year. Metabolic brain function was evaluated in 47 regions of the brain via PET scan at the beginning and end of the 12-month period, then again two to three years later.

Daniel Silverman, M.D., Ph.D. — one of the UCLA researchers who presented their findings at the 2024 SNMMI Annual Meeting — says that using PET scans to observe metabolic brain function allowed the study to take place with a smaller group of subjects than if they’d used self-reported questionnaires or other forms of subjective monitoring, which he explained would require hundreds of participants to collect sufficient data to draw conclusions. “PET allows less variability.”

The results were more significant than the team expected. “In the placebo arm, 20 of 47 [monitored brain regions] saw significant decline” in brain metabolism, said Dr. Silverman, “with the grape group it was zero out of 47.” The most significant metabolic declines monitored in the placebo group were in areas of the brain correlating with neuropsychologic decline, but the group consuming the grape formulation saw no significant decline in any monitored regions.

Two to three years after the study ended, PET scans showed sustained protection in the group that consumed the grape formulation compared to the placebo group.

Though grapes were used for this study, Dr. Silverman says that similar benefits would likely come from substituting other foods rich in polyphenols, especially dark red and brightly colored fruits such as strawberries, raspberries, and blueberries.