Diet is important to health and well-being, and researchers bring an increasing amount of evidence in support of the saying, “you are what you eat.” So, how does diet affect our brain health in the long run? A new study investigates.
vegetable fruit and nut salad
Brains tend to shrink with age, but could eating healthfully prevent this?

As we age, our brains tend to shrink in volume — “at a rate of around 5 percent per decade after age 40,” to be more precise.

And the more they shrink, the more this seems to affect an individual’s cognitive abilities.

However, there may be ways of maintaining a healthy brain volume, even as we grow older, such as by paying more attention to what we eat on a day-to-day basis.

A study published last year in the journal Nature Ecology & Evolution revealed that non-human primates’ brain size can be predicted by the type of diet they favor. But is the same true in humans?

“People with greater brain volume have been shown […] to have better cognitive abilities,” notes Dr. Meike W. Vernooij, from the Erasmus University Medical Center in Rotterdam, the Netherlands, “so initiatives that help improve diet quality may be a good strategy to maintain thinking skills in older adults.”

But, she adds, “More research is needed to confirm these results and to examine the pathways through which diet can affect the brain.”

Dr. Vernooij and colleagues recently conducted a study on a large Netherlands-based population sample to see if they could observe any associations between dietary preferences and brain size, as well as the existence of any cognitive impairments.

Their findings, published yesterday in the online issue of the journal Neurology, seem to indicate that healthful diets rich in fruit and vegetables may help to protect the brain against age-related shrinkage.

Best diets for health?

The researchers worked with 4,213 participants with an average age of 66, and who did not have a diagnosis of dementia. They were all asked to fill in questionnaires assessing what they typically ate over the course of 1 month.

Among the food groups featured in the questionnaires, there were: vegetables, fruit, whole grain-based foods, legumes, nuts, dairy, fish, tea, unsaturated fats, red meat, processed meat, sugary drinks, alcohol, and salt.

Dr. Vernooij and team evaluated the quality of individual diets based on Dutch dietary guidelines for the public, and they gave each type of diet a score, from zero (least healthful) to 14 (most healthful).

In the researchers’ assessment, the best diets for health were rich in vegetable, fruit, nut, whole grain, dairy, and fish content, and they included very few sugary drinks.

On average, participants’ diets gained a score of seven. MRI scans also revealed that the average total brain volume among this population sample was 932 milliliters.

The researchers also used MRI scans to determine the number of white matter lesions in the brain — which have been associated with cognitive impairments — and non-severe brain bleeds.

Other general health information — which might have a bearing on brain volume shrinkage — was also collected, including instances of hypertension, smoking habits, and levels of physical activity.

‘Complex interactions’ between food groups

Dr. Vernooij and colleagues’ analysis revealed that a higher diet score — corresponding to a more healthful diet — was associated with a greater brain volume, even after adjusting for confounding factors, such as head size variations, age, sex, smoking habits, and exercise.

Specifically, individuals with better dietary habits had 2 extra milliliters, on average, in terms of brain volume, compared with peers who had less healthful diets. But diet did not prove relevant to white matter lesions or the occurrence of brain bleeds.

To ascertain what types of food would be best for brain health, the researchers also adjusted their diet assessment in favor of Mediterranean diet templates, which similarly feature plenty of vegetables, nuts, and fish.

Once more, the investigators found that those participants who adhered to vegetable- and fish-rich diets tended to maintain larger total brain volumes than their counterparts who went for less healthful dietary options.

As a result of this, the researchers concluded that brain volume was maintained by adherence to a healthful diet favoring a combination of the food groups mentioned above.

There are many complex interactions that can occur across different food components and nutrients and according to our research, people who ate a combination of healthier foods had larger brain tissue volumes.”

Dr. Meike W. Vernooij

However, the researchers warn that the new study’s findings do not necessarily imply that eating certain types of food will boost brain volume. Instead, they show an association between more healthful diets and better brain size maintenance.