Mediterranean Diet Can Reduce Risk of Alzheimer’s by 40%

Mediterranean Diet Can Reduce Risk of Alzheimer's by 40%

Do you want to improve your mind tonight? Consider what you eat for dinner. Our chef suggests the Brain Food Special–a tender fillet of wild caught salmon in curry sauce over a pilaf of brown rice and lentils, accompanied by a baby spinach salad lightly dressed in olive oil and topped with slivered almonds. For dessert, enjoy a melange of orange slices and blueberries. Complement your meal with a crisp glass of wine if you choose.

Mediterranean Diet Can Reduce Risk of Alzheimer's by 40%
In addition to tickling your senses and satiating your hunger, our chef’s creation will pump your body full of the nutrients researchers believe might be pivotal in maintaining brain health. The menu is built on the pillars of the Mediterranean diet–lean protein (especially fish), leafy green vegetables, whole grains and legumes, nuts, antioxidant-rich fruit, monounsaturated oils such as olive oil, and moderate alcohol consumption. This nutritional lineup has long been heralded as the gold standard for heart-healthy eating. Evidence is mounting that it’s good for your brain, as well.

Protecting Brain Blood Vessels

Research from Columbia University that looked at the eating habits of 2,258 older adults found that individuals whose eating habits closely matched the traditional Mediterranean diet were 40 percent less likely to get Alzheimer’s disease than those whose diets were least like the Mediterranean style of eating. Other researchers from Harvard and Columbia have found a link between the Mediterranean diet and protection from Parkinson’s disease and an early stage of brain impairment known as cognitive decline.

Mediterranean-style eating may benefit the brain for the same reason it benefits the heart and the rest of the circulatory system: it supplies the body with substances that fend off damage to the blood vessels. As part of a population based study on stroke risk, researchers performed brain MRIs on a multiethnic group of 1,000 older adults to look for markers of vascular injury known as white matter hyperintensities (WMHs). They also assigned a point level, based on how closely a person’s eating habits followed important elements of a Mediterranean diet.

The subjects with lower Mediterranean diet scores tended to have a higher volume of WMHs. Other research has linked cardiovascular risks such as high blood pressure and smoking to a higher volume of WMHs and greater cognitive decline later in life.

Omega-3s: The ‘Smart’ Fats

To further understand how your diet can go to your head, let’s take a minute to deconstruct the Brain Food Special. The main course, salmon, is a major source of omega-3 fats. In addition to protecting against clogged arteries throughout the body, omega-3s provide building material for brain cells. Researchers have identified a correlation between lower intake of fatty fish, such as salmon, and increased risk of dementia.

In a study published earlier this year in Neurology, scientists compared blood levels of omega-3s with data from MRIs and cognitive tests and found that people with the lowest blood concentration of these nutrients performed worse on assessments of thinking skills such as memory and problem-solving.

Brain scans also revealed that these individuals had more brain shrinkage and other signs of early aging. Some research suggests that omega-3 fatty acids may aid the brain by reducing the production of beta-amyloid protein, a marker of Alzheimer’s disease.

If the brain benefits of omega-3 fatty acids are not enough to entice you, salmon is also a good natural source of choline. This little-known nutrient speeds up the creation and release of acetylcholine, a protein that carries signals among brain cells. The brains of people with Alzheimer’s disease have lower levels of acetylcholine than those of people without the disease. Also, some studies have shown that people who consumed a lot of choline performed better on tests of memory and other cognitive abilities.

Our chef’s signature curry sauce may also be a brain booster. Curcumin, the not so-secret ingredient that gives curry powder its bright yellow color, has a long history as a traditional remedy in China and India. Sure, the results are from small experimental studies, but researchers have reported that curcumin may have the power to inhibit the formation of beta-amyloid plaques in the brain. This effect has yet to be confirmed in well-controlled clinical trials, but it doesn’t hurt to spice things up in the meantime.

Nuts for the Noggin

Olive oil is the undisputed heavy-hitter of Mediterranean-style eating, but the nuts in your salad may pack a punch that goes beyond crunch. A study of 243 older adults in Spain compared a control diet with two versions of the Mediterranean diet, one with additional olive oil and the other with nuts.

At the end of a three-year follow-up period, the individuals who ate nuts were 78 percent less likely than those on the control diet to have low blood levels of a protein called brain-derived neurotrophic factor (BDNF), which promotes cell growth and signaling in the brain. A deficit of BDNF has been linked with neurological and mood disorders. Interestingly, the largest improvement in BDNF levels was seen in the nut-eating subjects who were depressed at the outset of the trial.

Though delicious, typical dessert foods are laden with sugar and saturated fats that are very likely detrimental to brain health. Our colorful orange and blueberry plate, on the other hand, contains substances that help protect your brain.

An analysis of the eating habits of 69,000 women in Harvard’s Nurses’ Health Study, published earlier this year, showed that individuals who consumed the highest daily amounts of flavanones, compounds found in citrus fruits, had a 19 percent lower risk of having a stroke from a blocked artery (an ischemic stroke). Other research has shown that anthocyanins, the family of antioxidants that gives blueberries their indigo hue, may help prevent high blood pressure, a major risk factor for stroke.

Some Wine is Wise

Finally, you can rest assured as you savor a glass of wine with your meal that moderate alcohol consumption, too, has a place in a brain-healthy eating style. A study published in The Journal of the American Medical Association (JAMA) several years ago showed that people over age 65 who consumed one drink a day had about half the risk of Alzheimer’s disease as nondrinkers.

Other research indicates that moderate drinking may lower the risk of stroke and perhaps other vascular damage in the brain. Earlier this year, results from the Nurses’ Health Study showed that daily consumption of the amount of alcohol in a 4-ounce glass of wine or a 12-ounce beer is protective against ischemic and bleeding (hemorrhagic) stroke. Too much alcohol, however, is dangerous. Heavy drinkers in the JAMA study had a 22 percent higher Alzheimer’s risk than the nondrinkers.

So, if you do drink, limit your imbibing to two drinks a day if you are a man or one drink if you are a woman.

Bon appetit!

– Harvard Health Letter


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