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People with the early stages of Alzheimer’s disease may be able to slow cognitive decline through diet and exercise, according to a new study.
Participants who combined a daily aerobic exercise with a plant-based diet slowed cognitive decline, while control participants who kept their habits stuck to their roots saw their memory and thinking skills deteriorate, according to a study published Friday in the journal Alzheimer’s Research & Treatment. The study was designed by physician-researcher Dean Ornish, and strict diet and lifestyle recommendations to fight chronic disease have long been controversial among medical researchers.
The researchers cautioned that their results would need to be replicated before drawing any broader conclusions. The study only involved 51 people, a challenge made possible by the COVID-19 pandemic.
But a small, multistate study suggests lifestyle changes may be another way to fight Alzheimer’s, a mind-robbing disease that afflicts 6.9 million Americans and has stymied researchers and drug companies that have poured billions of dollars into developing drugs to target the beta-amyloid protein that builds up in the brains of people with Alzheimer’s.
Despite all this investment, only two drugs, Leqembi and Aduhelm, have been approved by the Food and Drug Administration, and Aduhelm’s maker has stopped selling it and relinquished ownership of the drug. An FDA advisory committee is scheduled to evaluate Eli Lilly’s anti-amyloid drug donanemab next week.
Dr. Rudy Tanzi, director of the Mackens Center for Brain Health at Massachusetts General Hospital and co-author of the diet and exercise study, said the new research suggests that a vegetarian diet and regular exercise can reduce amyloid in patients.
“It’s almost like a mini-Lukembi result,” Tanzi said, referring to the amyloid-clearing drug that received FDA approval last year, “so it’s pretty surprising.”
Researchers not involved in the study said the results were promising but hoped to see larger studies of the effects of diet and exercise in people with Alzheimer’s.
“The sample size was very small,” said Laura Baker, a professor of gerontology and geriatrics at the Wake Forest University School of Medicine, “so we don’t have a definitive answer yet.”
Vegetarian diet, aerobics, supplements
The study involved 51 people with early stages of Alzheimer’s disease who were randomly assigned to either adopt regular exercise and dietary changes or a control group that did not adopt those behaviors. Researchers measured the cognition and functioning of the two groups using several tests commonly used in Alzheimer’s research. The study found that lifestyle changes “may lead to improved cognition and functioning” after 20 weeks. The control group reported worsening disease symptoms.
Participants were sent 21 plant-based meals and snacks each week consisting of fruits, vegetables, whole grains, legumes, soy products, seeds and nuts. They were asked to adhere to the diet and take eight supplements and vitamins. They also took a 30-minute walk every day, did strength training three days a week and tried to manage stress with an hour of meditation, yoga and stretching each day.
To reinforce these behaviors, participants and their spouses or caregivers participated in three four-hour Zoom sessions each week, completing one hour of supervised exercise, one hour of stretching, one hour of support group, and one hour of lectures on lifestyle changes.
People who took part in the diet and exercise regimen reported better scores on four common Alzheimer’s tests compared with those in the control group. Three of the tests produced scores suggesting participants had “improved cognition and function,” and a fourth revealed that participants on the regimen experienced less cognitive decline than the control group.
The study also said measurements of beta-amyloid in the blood were better in the diet and exercise group compared with the control group.
The lifestyle advocate behind the study
Ornish, a physician who has long advocated for lifestyle medicine as a way to fight chronic disease, secured the funding and became the study’s principal investigator. Ornish describes lifestyle medicine as including a plant-based diet, moderate exercise, meditation and support groups to prevent, slow or reverse the effects of heart disease and other chronic diseases. Applying the same principles to Alzheimer’s patients could combat the effects of the disease, he said.
Ornish said decades ago, mainstream medicine believed heart disease was irreversible, but it’s now known that lifestyle changes and drug therapy can often slow or even reverse the progression of heart disease.
He believes the study shows it may be possible to slow the progression of Alzheimer’s disease in a similar way.
Although the number of participants was small, Ornish said the study was rigorous and backed by data.
“There’s a common misconception that if you don’t have 1,000 people, your study isn’t valid,” Ornish says, “but actually the opposite can be made: if you need 1,000 people to show statistical significance, then it’s actually not a very powerful intervention.”
He said measurements of beta-amyloid levels, cognitive scores and other biomarkers led the researchers to conclude that lifestyle interventions are effective.
The study found that two-thirds of patients in the control group worsened over 20 weeks, and none improved, but 17 of 24 patients who completed the diet and lifestyle changes had stable or improved cognitive and functional scores.
“When you look across all these different measures, overall, these patients, on average, are clearly doing better in one group and worse in the other,” Ornish said.
Research lacks racial and ethnic diversity
The study noted limitations, such as a lack of racial and ethnic diversity among study participants. It also means participants knew they were receiving diet and lifestyle treatments, so they may have expected better results. To prevent the placebo effect, researchers told participants they didn’t know if the lifestyle changes would work.
Baker, at Wake Forest, is also studying whether regular exercise, from gentle stretching to vigorous aerobics, can help slow the decline of memory and thinking skills. His team plans to publish the results of a large study of more than 2,000 participants next year.
Baker said his research and Ornish’s work highlight the importance of heart health and the potential benefits to long-term brain health.
But she doesn’t think there’s enough evidence to show that Alzheimer’s disease or other dementias can be improved through diet and exercise. Such claims would need to be backed up by several large studies, and that evidence doesn’t exist yet, she said.
“The idea that you can reverse dementia or cognitive impairment with lifestyle interventions, I don’t think there’s enough evidence,” Baker says, “and I think that’s creating false hope right now.”
Ken Alltucker is @kalltucker at X. Contact him by email at alltuck@usatoday.com..
