How can you protect cognitive function as you age? Several studies suggest that a Mediterranean-style diet plan can help. What does that entail? Lots of veggies, fruits and whole grains like farro, not much meat or sweets, and olive oil as the primary fat. Oh, and nuts! The famous PREDIMED study found that a daily ounce of nuts could be as health-promoting as extra-virgin olive oil. Now a new study supports nut consumption.
Why Munching on Nuts Could Protect Your Brain:
New research offers a wonderful excuse to eat nuts (GeroScience, Sep. 30, 2024). Scientists studied more than 50,000 volunteers in the UK Biobank who filled out detailed dietary questionnaires when the study began. These people were between 40 and 70 years old and free of cognitive problems at that time. The investigators followed up between six and 10 years later to find out how the participants had fared.
Those who ate nuts every day were 12% less likely to develop dementia during that time. Overall, 2.8% of the volunteers had a dementia diagnosis by the end of the study. Unsalted almonds and cashews appeared to be more helpful than salted or processed nuts. Women, older people, and those with healthy lifestyles seemed to benefit the most. As the authors note, an observational study of this sort cannot establish cause and effect, but the antioxidant capacity of nuts might contribute to their apparent neuroprotective activity.
Previous studies have considered the benefits of nuts as part of a larger eating pattern. In countries like Spain and Greece, people who follow a traditional Mediterranean diet appear less likely to develop dementia. Research from Europe suggests that older people at risk of cognitive decline do much better if they follow a Mediterranean-style eating pattern. Here are the details.
Checking Out Mediterranean Diet Metabolites:
A group of researchers wanted a better way to determine what people have been eating than simply asking them to remember and write it down on a questionnaire. Instead, they utilized unusually rich data from the Three Cities study (Molecular Nutrition & Food Research, Oct. 24, 2023). To accomplish this, they analyzed the participants’ blood samples for metabolites related to the major components of a Mediterranean diet: vegetables, legumes, fruits, cereals, dairy, olive oil and fish.
The study included more than 400 senior citizens of Bordeaux and another 400 plus from the city of Dijon. None of these people had cognitive problems at the beginning of the study, and all took tests throughout the 12 years the research lasted. The findings were encouraging: People who followed a Mediterranean diet more closely were less likely to experience cognitive decline.
France is arguably within the Mediterranean geographic area. However, not everyone lives in this region. What about older adults who live elsewhere?
British People Do Better with Mediterranean-Style Diet:
Finally, a UK study showed that a Mediterranean dietary pattern could help even where it is not traditional. An analysis of data from the European Prospective Investigation into Cancer and Nutrition in Norfolk, England, demonstrated that people who consume more fruits and vegetables and fewer meats and sweets scored better on cognitive tests (American Journal of Clinical Nutrition, online, June 17, 2019). This dietary pattern also featured olive oil as its primary fat, along with beans, legumes and seafood as the main protein sources. People following this type of diet also consumed moderate amounts of eggs and dairy products such as yogurt. They might have drunk some wine with meals, and they used traditional spices such as thyme and rosemary.
What the Study Shows:
The researchers analyzed data on over 8,000 older individuals and classified their food habits on how closely they resembled a Mediterranean pattern. Those at higher risk for cardiovascular disease were less likely to perform poorly on cognitive tests if they followed a traditional Mediterranean dietary program. Perhaps this is because a Mediterranean diet has been shown to protect the heart. Older people eating like this are also less likely to become frail.
Understanding the Benefits of a Mediterranean Diet:
Health professionals and patients alike may doubt that diet can be as powerful as pills. When it comes to important benefits such as preventing heart attacks and strokes, reducing the risk of diabetes or delaying dementia, doctors like medication. Strong evidence shows, however, that a traditional Mediterranean diet rivals medications when it comes to these important health conditions.
Studying the Mediterranean Diet:
Spanish scientists made an impressive contribution when they published the first results of their PREDIMED study (New England Journal of Medicine, Apr. 4, 2013). PREDIMED stands for Prevencion con Dieta Mediterranea, which means about what you might guess.
This was a randomized, controlled trial, a rarity in dietary studies. It included almost 7,500 people who did not have heart disease at the start of the study but were at high risk for it. (They were overweight or had diabetes or high blood pressure.) They were randomly assigned to follow a Mediterranean diet with additional extra-virgin olive oil; a Mediterranean diet with additional nuts; or a prudent low-fat diet of the type usually recommended by the American Heart Association.
Sticking with the Mediterranean Style of Eating for a Healthy Heart:
The researchers had no trouble getting the Spanish study subjects to stick with the Mediterranean diet plans. The investigators supplied the extra olive oil and nuts, which made following the diet even easier. The volunteers gravitated toward a diet rich in vegetables, fruit and fish, with little milk, meat or sweets. People had more difficulty following a really low-fat diet.
Still, the differences were significant. After less than five years, people in the Mediterranean diet groups had suffered approximately 30 percent fewer heart attacks, strokes and deaths due to cardiovascular causes than those in the low-fat diet control group. That compares quite well to the use of statins. These cholesterol-lowering drugs reduce the possibility of such an event by about 25 percent (JAMA Cardiology, June 1, 2016). (This is relative risk in both cases; absolute risk reduction is much lower.)
Can You Help Your Brain by Eating Like a Spaniard or an Italian?
Heart disease is not the only chronic health problem that might be forestalled with a tasty menu full of vegetables, fruits, fish, nuts and olive oil. PREDIMED data also demonstrated that those on an olive oil based Mediterranean diet are less likely to develop dementia or cognitive problems (Journal of Neurology, Neurosurgery and Psychiatry, Dec., 2013). Perhaps that is because those in the Mediterranean diet groups were less likely to suffer a stroke (Diabetes Care, Aug., 2013) A stroke results from damage to the circulatory system in the brain. Such damage can also lead to cognitive decline.
Counteracting Genetic Susceptibility:
Eating Mediterranean-style was able to blunt the impact of genetic variants that put some people at greater risk for diabetes and for stroke. A recently published study shows that people with diabetes are only about half as likely to develop diabetic retinopathy if they follow a Mediterranean diet with at least two servings a week of fish and seafood (JAMA Ophthalmology, online Aug. 18, 2016). This complication of diabetes is one of the leading causes of blindness among working age people. (You can learn more about protecting your vision from our interview with Dr. Peter McDonnell, director of the Wilmer Eye Institute at Johns Hopkins Medical Center.)
How to Eat Mediterranean-Style:
So how can you get these benefits for yourself? A meta-analysis of studies on Mediterranean-type diets used seven criteria (Annals of Internal Medicine, July 19, 2016):
- Most of the fat in the diet is monounsaturated, from olive oil or nuts.
- The basis of the diet is vegetables and fruits.
- The diet provides plenty of beans, peas and lentils.
- Breads or cereal products in the diet are whole grain, mostly.
- Dairy products are limited.
- Meat is rare, but fish is more common as a menu item.
- Wine, especially red wine, is permitted in moderation.
The meta-analysis shows that people following a Mediterranean diet based on these principles are less likely to suffer heart attacks, strokes, diabetes, breast cancer and colorectal cancer. That seems to us like a lot of benefit to be gained from eating delicious food with friends.
Learn More:
You may be interested in reading other posts on this topic, such as this one. If you’d like more guidance on how to follow this healthful way of eating, you’ll find it in our book, The People’s Pharmacy Quick & Handy Home Remedies.
