Could a Mediterranean-style diet help preserve cognitive function in older individuals? Studies from around the world suggest that people following such a regimen may be able to delay dementia. Based on the evidence, many of us would want to consider eating more vegetables and less meat. Relying on fruit rather than sugar to provide sweetness also makes sense. You don’t have to live in a Mediterranean country to reap the potential benefits.
Don’t Forget the Olive Oil!
A recent analysis shows that people consuming at least half a tablespoon of olive oil daily are 28% less likely to die of dementia (JAMA Network Open, May 6, 2024). The researchers made use of extensive data collected through the Nurses Health Study and the Health Professionals Follow-Up Study over nearly three decades. Previous analysis of these data showed that people consuming half a tablespoon or more of olive oil a day lower their chance of cardiovascular complications.
During the course of the study, 4,751 of the 92,383 volunteers died of dementia. All of the participants answered detailed dietary questionnaires every four years throughout the study. They also provided information about their health status, and after they died, next of kin notified the study investigators.
The investigators also assessed how closely these initially healthy American adults adhered to a Mediterranean type diet. According to the analyses, people consuming the most olive oil were less likely to die of dementia regardless of whether they followed a Mediterranean eating pattern. In addition, each additional 5 gram increment in daily olive oil consumption offered extra protection against dementia-related death. Using olive oil instead of margarine or mayonnaise also appeared to provide protection.
Even though this study did not find that the Mediterranean diet was effective to delay dementia, readers have asked about its benefits.
Trying a Mediterranean-Style Diet to Help Delay Dementia:
Q. My father has Alzheimer disease, and I am doing my best to adopt an eating plan that will help me avoid dementia. I am a 52-year-old pescatarian runner who eats a Mediterranean diet.
Is full-fat yogurt associated with developing dementia or preventing cognitive decline? Nowhere have I found an answer. I eat a cup of full-fat Greek yogurt every other day (I do egg whites and oatmeal the alternate days to keep cholesterol at bay) to ensure I am getting enough protein.
Your articles indicate that full-fat dairy does not seem to be associated with earlier deaths from heart attacks and strokes, notwithstanding cholesterol levels, so I am not afraid of a heart event (especially because I am thin and exercise a lot). However, I can’t find anything in your articles about the association between saturated fats (particularly with whole milk yogurt) and dementia.
Does Greek Yogurt Belong in a Mediterranean Diet?
A. You are a great role model, with your active lifestyle and Mediterranean diet. Both can help reduce your risk for developing dementia (Frontiers in Nutrition, June 29, 2023). Focusing on fish as you do should also help delay dementia, since it is supplies plenty of healthful omega-3 fatty acids in a natural form.
The question of whether full-fat yogurt will be helpful or harmful is a little trickier. Although thick Greek (or Turkish or Syrian) yogurt is clearly part of a Mediterranean diet, scientists don’t seem to have studied it directly. For cardiovascular health, yogurt is beneficial whether it is low fat or full fat (Nutrients, Feb. 16, 2022).
Usually, what is good for the heart is also good for the brain. A recent study of more than 11,000 older Japanese people found that those who ate yogurt were less likely to develop dementia (European Journal of Nutrition, Oct. 2023).
The researchers caution, though, that
“further studies are needed to confirm whether this benefit was from yogurt intake itself or as a part of a healthy dietary pattern.”
Managing a Mediterranean Diet in Minnesota:
Research from Minnesota suggests that a plant-based diet containing olive oil might help delay dementia, even though Rochester, MN, is far from the Mediterranean (Alzheimer’s & Dementia, Feb. 2017).
The Mayo Clinic scientists examined data from 672 older people who were healthy and had no cognitive impairment in 2004, at the start of the study. The volunteers answered extensive questionnaires about their eating habits and took a battery of cognitive tests. The researchers also got multiple MRI images of each participant’s brain so they could evaluate the structure and how that might relate to diet.
Dietary patterns were analyzed to see if they included fish, legumes, nuts, whole grains, vegetables, fruits and healthy fats as the Mediterranean diet does. Those whose diets most resembled the Mediterranean pattern scored higher on the tests and had a thicker cortex in most regions of the brain.
Mayo Researchers Caution Against Inferring Cause and Effect:
Because this is an observational study rather than a randomized controlled trial, the authors don’t claim that there is a causal relationship. They do suggest, though, that elderly people (and maybe the rest of us) might do well to boost their intake of legumes, vegetables and fish and minimize the amount of simple sugars and refined carbohydrates they eat.
Could a Mediterranean Diet Delay Dementia in China?
As we noted, Minnesota is pretty far away from the Mediterranean. So is China! Yet Chinese researchers have studied the nutritional intake of two groups of older Chinese people (Nutrients, Aug. 23, 2023). Some were doing well, while others had mild cognitive impairment.
The volunteers consuming a diet that most closely resembles the MIND (“Mediterranean dietary approaches to stop hypertension intervention for neurodegenerative delay”) diet were least likely to show signs of cognitive impairment in their test results. The scientists are enthusiastic about the prospects of a Mediterranean-style or MIND diet to protect people’s brains. They caution, however, that their study of 40 individuals was too small for firm conclusions and recommend larger (and more rigorous) trials.
Disappointing Results from a Randomized Controlled Trial:
Unfortunately, a randomized controlled trial failed to produce significant benefits for people following a MIND diet for three years (New England Journal of Medicine, Aug. 17. 2023). In this study, 604 volunteers who were overweight and accustomed to a “suboptimal diet” followed an assigned diet for three years. Half ate a MIND diet, “a hybrid of the Mediterranean diet and the DASH (Dietary Approaches to Stop Hypertension) diet,” while the other half continued with their usual fare.
All of the participants had a family history of dementia, but all had normal cognition when the study began. At the end of three years, cognitive test results were not significantly different between the two groups. This might indicate that the MIND diet is ineffective. On the other hand, it might suggest that three years of healthful eating after a lifetime of junk food is not enough to make a dramatic difference. So far as we can tell, though, there are no scary side effects of eating the Mediterranean way.
Learn More:
Promising results from places as far from the Mediterranean as China or Minnesota suggest that following this dietary pattern could help maintain cognitive capacity. If you would like to learn more about how to follow a Mediterranean-style diet yourself, you may be interested in our book, The People’s Pharmacy Quick & Handy Home Remedies, which has a specific description and a number of recipes. To delay dementia and stay sharp as long as possible, you should also get regular exercise and avoid medications that can impair cognitive function.
