Maida’s cognition showed additional improvement, however, after she completed a total of 40 weeks of intensive lifestyle changes, said principal investigator Dr. Dean Ornish, a clinical professor of medicine at the University of California, San Francisco, and creator of the Ornish diet and lifestyle medicine program.

Ornish gave a study update on Tuesday at the 2025 Alzheimer’s Association International Conference in Toronto.

While not everyone in the 26-person interventional group benefited, 46% showed improvement in three of four standardized tests, he said, including one that measures changes in memory, judgment and problem-solving as well as the ability to function at home, practice hobbies and practice personal hygiene.

“An additional 37.5% of people showed no decline in cognition during those 40 weeks,” Ornish said. “Thus, over 83% of patients improved or maintained their cognition during the five-month program.”

The new findings mirrored those of other studies on lifestyle interventions, he said, including the recent US POINTER study, the largest clinical trial in the United States to test moderate lifestyle interventions over two years in people who are at risk but do not yet have Alzheimer’s disease.

“Our study complements these findings by showing, for the first time, that more intensive lifestyle changes may often stop or even begin to reverse the decline in cognition in many of those who already have Alzheimer’s disease, and these improvements often continue over a longer period of time,” Ornish told CNN.

And unlike available medications for Alzheimer’s, he added, lifestyle changes have no side effects, such as bleeding and swelling in the brain that may occur with the newest class of drugs.

EmblemHealth, a New York-based insurance company, announced Tuesday that it will be the first health insurer to cover the Ornish lifestyle medicine program for patients who have early-stage Alzheimer’s disease.

‘Eat well, move more, stress less and love more’

The lifestyle intervention Ornish created — which he calls “eat well, move more, stress less and love more” — has been tested before. In 1990, Ornish showed for the first time in a randomized clinical trial that coronary artery disease could often be reversed with nothing more than diet, exercise, stress reduction and social support.

The US Centers for Medicare and Medicaid Services, or CMS, declared in 2010 that Ornish’s program for reversing heart disease was an “intensive cardiac rehabilitation” and that it would be eligible for reimbursement under Medicare.

Additional research has shown the same four-part program can lower blood sugars and heart disease risk in patients with diabetes, reduce prostate cancer cell growth, improve depression and even lengthen telomeres, the protective caps of chromosomes that are worn away by aging.

During the Ornish intervention, one group of people consumed a strict vegan diet, did daily aerobic exercise, practiced stress reduction and engaged in online support groups. The rest of the participants were in a control group and were asked to not make any changes in their daily habits.

Therapists led hour-long group sessions three times a week in which participants were encouraged to share their feelings and ask for support. Meditation, deep breathing, yoga and other ways to reduce stress took up another hour every day. The program also encouraged participants to prioritize good-quality sleep.

Supplements were provided to everyone in the intervention group, including a daily multivitamin, omega-3 fatty acids with curcumin, coenzyme Q10, vitamin C and B12, magnesium, a probiotic, and Lion’s mane mushroom.

In addition to online strength training led by a physical trainer, people in the intervention attended hour-long video classes on vegan nutrition hosted by a dietitian. Then, to ensure a vegan diet was followed, all meals and snacks for both participants and their partners were delivered to their homes.

Complex carbs found in whole grains, vegetables, fruits, tofu, nuts and seeds made up most of the diet. Sugar, alcohol and refined carbs found in processed and ultraprocessed foods were taboo. While calories were unrestricted, protein and total fat made up only some 18% of the daily caloric intake — far less than the typical protein intake by the average American, Ornish said.

Working harder pays off

People in the intervention group who put the most effort into changing their lifestyle have the most improvement in their cognition, said Ornish, founder and president of the nonprofit Preventive Medicine Research Institute and coauthor of “Undo It! How Simple Lifestyle Changes Can Reverse Most Chronic Diseases.”

“There was a statistically significant dose-response relationship between the degree of adherence to our lifestyle changes and the degree of improvement we saw on measures of cognition,” Ornish said.

The 25 people in the study’s original 20-week control group — who did not receive the intervention — had shown further cognitive decline during the program. They were later allowed to join the intervention for 40 weeks and significantly improved their cognitive scores during that time, Ornish said.

It all makes sense, said co-senior study author Rudy Tanzi, an Alzheimer’s researcher and professor of neurology at Harvard Medical School in Boston.

“If you picture a brain full of damage as a sink full of water, when you just turn off the tap, it takes a long time for that sink to slowly drain, right?” Tanzi told CNN in 2024. “If you want the amyloid to go down in 20 weeks, as we found on one blood test, you’re going to need a Roto-Rooter.”

Additional blood testing may offer insights

In the 2024 study, a blood test called plasma Aβ42/40 showed a significant improvement in the original intervention group. Aβ42/40 measures the level of amyloid in the blood, a key symptom of Alzheimer’s.

Tests that measure amyloid in different ways, however, did not show improvement, Dr. Suzanne Schindler, an associate professor of neurology at Washington University School of Medicine in St. Louis who specializes in blood biomarkers told CNN at the time.

There was no significant change in a test for amyloid called p-tau 181, considered to be a superior measure of Alzheimer’s risk, said Schindler, who was not involved in the study. Nor was there any change in glial fibrillary acidic protein, or GFAP, another blood biomarker that seems to correlate reasonably well with Alzheimer’s disease.

“If one of these markers improves, you typically see all of them improve, so the fact they did not makes me wonder whether this effect is real,” Schindler said. “If they were to repeat the study with a much larger population for a longer period of time, perhaps more change could be seen.”

Over the complete 40-week program, however, a number of people in the intervention group did continue to improve their Aβ42/40 scores, according to the study update.

“Changes in amyloid — as measured as the plasma Aβ42/40 ratio — occur before changes in tau markers such as p-tau 218, so this is not surprising after only 40 weeks,” Ornish said.

For Ornish, who has watched members of his family die from Alzheimer’s disease, the study’s results are important for one key reason — hope.

“So often when people get a diagnosis of dementia or Alzheimer’s, they are told by their doctors that there is no future, ‘It’s only going to get worse, get your affairs in order.’ That’s horrible news and is almost self-fulfilling,” Ornish said.

“Our new findings empower patients who have early-stage Alzheimer’s disease with the knowledge that if they make and maintain these intensive lifestyle changes, there is a reasonably good chance that they may slow the progression of the disease and often even improve it,” he said.

“Our study needs to be replicated with larger, more diverse groups of patients to make it more generalizable,” Ornish said. “But the findings we reported today are giving many people new hope and new choices — and the only side effects are good ones.”