People who stuck most closely to a Mediterranean diet — rich in seafood and plant-based foods — had an up to 23 percent lower risk for dementia than those who had a lower adherence to the diet, said the latest study, published Monday in the journal BMC Medicine by an international team of researchers. In absolute terms, the research found sticking closely to a Mediterranean diet was equivalent to a 0.55% reduction in risk of developing dementia.
The latest research involved 60,298 people who were part of the UK Biobank study and tracked for a period of just over nine years. During the study period, there were 882 cases of dementia among the group. The individuals were between the ages of 40 and 69 years and were White British or Irish. How closely they followed the Mediterranean diet was assessed using two different questionnaires that have been widely used in prior studies on the diet, the researchers said.
“There is a wealth of evidence that eating a healthy, balanced diet can help reduce the risk of cognitive decline. But evidence for specific diets is much less clear cut,” Susan Mitchell, head of policy at Alzheimer's Research UK, said in a statement. She was not involved in the research.
“This new, large study adds to this overall picture, but it only drew on data from people with White, British, or Irish ancestry,” she said. “More research is needed to build on its intriguing findings, and uncover whether these reported benefits also translate to minority communities, where historically dementia has often been misunderstood and highly stigmatized, and where awareness of how people can reduce their risk is low.”
There is currently no magic bullet to stop dementia in its tracks, but eating plenty of vegetables and fruits, regular physical activity and not smoking are behaviors that contribute to heart health, which helps protect the brain from diseases associated with dementia, she added.
A study published on March 8 revealed people who consumed foods from the Mediterranean and brain-focused MIND diets had fewer of the hallmark signs of Alzheimer’s — sticky beta-amyloid plaques and tau tangles in the brain — when autopsied. Alzheimer’s is a form of dementia. The MIND diet, short for Mediterranean-DASH Diet Intervention for Neurodegenerative Delay.
The Mediterranean diet focuses on plant-based cooking. The majority of each meal should be fruits and vegetables, whole grains, beans and seeds, along with a few nuts. There is a heavy emphasis on extra-virgin olive oil. Butter and other fats are consumed rarely, if at all. Sweets and goods made from refined sugar or flour are rare.
Meat can make a rare appearance but usually only to flavor a dish. Instead, meals may include eggs, dairy, and poultry, but in much smaller portions than in the traditional Western diet. However, fish, which is full of brain-boosting omega-3s, is a staple.
Study participants who stuck most closely to the diet were more likely to be female, have a BMI within the healthy range, have a higher educational level, and be more physically active than those with lower adherence to the diet.
David Curtis, an honorary professor at UCL Genetics Institute in London, who was not involved in the research, noted that the latest study was observational and did not uncover cause and effect. The finding could reflect a generally more healthy lifestyle, he said.
“It is not clear that such a diet itself reduces dementia risk, although it is plausible that it might do so. It is important to note that the study concerns all forms of dementia, not specifically Alzheimer’s disease. In my opinion, if there is an effect of diet then it is more likely to be on cardiovascular health in general and hence to impact dementia due to vascular disease rather than Alzheimer’s disease.”
Mediterranean diet has a social component
Duane Mellor, a registered dietitian and senior lecturer at Aston University in Birmingham, U.K., said the benefits of a Mediterranean diet were not confined to the nutrients provided by the food.
“The Mediterranean way of eating is not just about food on plates, it’s about the social interactions linked to food, and people who socialize more have lower risk of dementia and other conditions,” Mellor, who was not involved in the research, noted in a statement.
“We need to consider how a Mediterranean-type diet can be adapted to foods available and eaten in the U.K., so that inclusive messages about eating healthily can be developed, which include the importance of the social aspects of sharing and eating food with others.”
The study tentatively suggested adhering to a Mediterranean diet was linked with a reduced risk of dementia even when an individual had an existing genetic risk for the disease.