Mediterranean diet lovers have one more reason to celebrate. The diet known to reduce the risk of heart disease also might protect aging brains from dementia.
Those who follow the Mediterranean diet tend to have less brain atrophy - shrinking of the brain caused by the loss of neurons - than those not on the diet. In other words, they have bigger brains.
The Mediterranean diet emphasizes: consuming plant-based foods, such as fruits and vegetables, whole grains, legumes, and nuts, replacing butter with olive oil, using herbs and spices instead of salt, limiting red meat, consuming fish and poultry at least twice a week, and drinking red wine in moderation.
Brain shrinkage is normal, and it does not mean the loss of brain function. The brain begins to shrink in our 30s and continues across the adult life span. However, in cases of dementia, the loss of brain volume is accelerated.
Scientists from Columbia University asked as many as 674 people over the age of 80 who had no signs of dementia about their diet. Then they examined the subjects' brain volume with a scanning method. Results showed that the brains of people who followed the Mediterranean diet were 13.11 milliliters larger on average than those who did not consume that way.
According to World Health Organization (WHO), around 47.5 million people have dementia worldwide, and there are 7.7 million new cases every year. People with dementia experience a deterioration in memory, thinking, behavior and the ability to perform daily activities. Dementia mainly affects older adults, but it is not a normal part of aging. Alzheimer's disease is the most common form of dementia. Dementia is one of the major causes of disability among older people.
For many doctors, the research confirms their beliefs that lifestyle choices can keep the aging brain healthy.
"It's taking the research that was previously done on the Mediterranean diet and taking it to the next level. We've known for years that those who adhere to the Mediterranean diet - which refers to foods that are high in fish and olive oil (and low in saturated fats), plus lots of fruits and vegetables - that these individuals have a lower relative risk of developing dementia of all types later in life," said Dr. Michael Rosenbloom, clinical director of the HealthPartners Center for Memory and Aging in St. Paul, United States.
What the new research reveals, he said, is a connection to brain volumes. Dr. Rosenbloom called the findings "provocative."
The study highlights two important things about the diet that are really good for the brain. One is that a person experiences brain shrinkage with age for lots of reasons. If the blood sugar level is high, that is associated with brain shrinkage or atrophy. One of the advantages of the Mediterranean diet is that it contains foods that help stabilize the blood sugar level. The second thing that the Mediterranean diet is filled with healthy fat, and it's giving the brain the kind of fat it requires.
The study was published in the journal Neurology.
A Cautionary Note From Experts
Dr. David Knopman, a researcher with the Mayo Clinic Study of Aging, opined that the research is solid. But he cautioned against overstating positive effects of the Mediterranean diet on the brain.
"The risk is in over interpreting it. It doesn't say that if somebody who hasn't been eating healthy up until age 65 suddenly becomes a Mediterranean diet devotee that it's necessarily going to help them. But what the study does say is that the folks in this study in New York who had presumably been following the diet for many years, in fact, had better brain volumes than people who followed a diet that was something other than the Mediterranean Diet," said Dr. Knopman.
Moreover, it's slightly difficult to pinpoint exactly what results from other lifestyle factors associated with individuals who typically follow that diet. For example, in Mediterranean countries, meals are eaten over a longer, relaxed period. We cannot also exclude the fact that active lifestyle is also a protective factor for developing dementia later in life. The results may also be because those people on the Mediterranean diet are more health-conscious than others who don't exercise regularly.
Neurology November 17, 2015 vol. 85 no. 20 1744-1751