Like your stash of leftover Halloween candy and your reserve of willpower for the day, there are a few things in life you really don't want to run out of.
Also at the top of that list: your gray (and white) matter. Obviously, your capacity to remember things and process information—abilities bestowed upon us by the robustness of our physical brains—holds a prize spot way higher up than those fun-size Snickers (at least, let's hope).
For a while now, researchers have known that following a Mediterranean diet—one heavy on whole grains, fresh produce, and fatty fish and low in red meat and dairy—seems to ward off signs of looming cognitive decline. But in a new study published in the journal Neurology, researchers examined the effect of the diet "on the brain itself," says lead author Yian Gu, PhD, assistant professor of neuropsychology at Columbia University, "rather than clinical symptoms." (Boost your memory and age-proof your mind with these natural solutions.)
Gu and her colleagues wanted to find out how the Mediterranean diet confers its cognitive benefits, and their research showed that the eating plan seems to be linked with a physically bigger brain. So much bigger, in fact, that sticking to the diet prevents the amount of decline researchers would expect to see naturally occur with 5 years of aging. (Here are 5 foods that are hurting your brain.)
The researchers analyzed food questionnaires from 674 adults, ages 65 and older, without dementia who were part of ongoing aging research. Each person was scored on their intake of these components of the Mediterranean diet: veggies, legumes, whole grains, fish, fruit, nuts, monounsaturated fats, little red meat, little dairy, and moderate alcohol consumption. They were awarded 1 point for each component if they ate more of the good stuff or less of the bad stuff than the average person.
Brain MRIs showed that the 304 people who scored from 5 to 9 on the questionnaire had more brain volume than the 370 who scored from 0 to 4. Those Mediterranean eaters had on average 13.11 milliliter larger total brain volume, 5 milliliter larger volume of gray matter (the part of our brains that contains all our synapses), and 6.41 milliliter larger volume of white matter (which connects different areas of gray matter).
"Age so far is the most important factor contributing to brain shrinkage in older people," Gu says. "The difference between the high- and low-scoring Mediterranean diet groups is similar to the brain size difference between a 70-year-old and a 75-year-old."
Even just eating 3 to 5 ounces of fish a week (choose from one of these 10 healthiest fish on the planet) and lowering red meat intake to 100 grams (roughly a quarter-pounder) a day or less offered a protective effect to the tune of 3 to 4 years of aging. "When gray and white matter shrinks, you basically can't process information, you get more forgetful, memory starts to become impaired," says cardiologist Michael Ozner, author of The Complete Mediterranean Diet. "As a result, your risk of Alzheimer's disease increases."
The Mediterranean way of eating is in stark contrast to the more traditional American diet. "I call it the 'toxic American diet'—highly processed, calorie-dense, and nutrient-depleted," Ozner says. While red meat's not completely off the table in Mediterranean eating, he says, it should probably be reserved for special occasions. (Here are healthy ways to eat red meat.) The traditional Mediterranean diet was low in red meat not because our ancestors knew one day it would be added to the World Health Organization's list of carcinogens, but simply because they couldn't afford it. "They'd have veal or lamb on birthdays or at weddings," he says.
We don't entirely understand how the Mediterranean diet might stop this kind of brain shrinkage, Gu says, but it's probably a melting pot of anti-inflammatory and antioxidant superpowers from the wide range of nutrients you'll get by eating more fish and more produce. (Here's how to pick perfect produce every shopping trip.) We also can't definitively say that the Mediterranean diet caused these larger brain sizes, according to the study authors. But the ever-growing wealth of scientific evidence favoring the Mediterranean diet makes it pretty much a, er, no-brainer, Ozner says. "We should be shouting this from the rooftops." Emphasizing nonprocessed meats, nonrefined carbohydrates, and unsaturated fats could not only keep our minds sharp, but could also help many of us avoid interventions like cardiac stents and bypass surgeries and meds like statins, he says. "Leave these things for people who absolutely need it. Everybody shouldn't have to have them."