The Mediterranean diet has earned a reputation for promoting heart health, as we discuss below. A Harvard study suggested it might also be good for the brain, especially for people with type 2 diabetes (Diabetes Care, online May 23, 2019). How did researchers measure the Mediterranean diet benefit? Could it have been due to the anti-inflammatory effects of a diet rich in vegetables and olive oil, with very little processed foods?
Dietary Inflammation and Brain Health:
Scientists have been considering how inflammation might affect the brain. They have looked for ways to determine how dietary choices change the inflammation in our bodies. One approach is to examine the diet and then see how people respond.
Research on the Framingham Heart Study Offspring cohort measured the dietary inflammation index in nearly 1,500 individuals, who are now at least 60 years old (Alzheimer’s & Dementia, Dec. 6, 2024). They had filled out the Harvard food frequency questionnaire at least three times over the last ten years, allowing the investigators to calculate whether their diets were predominantly pro- or anti-inflammatory. On average, diets were somewhat anti-inflammatory.
The mean follow-up time on these volunteers was more than 12 years, with a maximum follow-up of 22 years. During that time, 246 participants developed dementia. Those with the highest dietary inflammation scores were most likely to have a dementia diagnosis.
Observational studies like this can’t show cause and effect, but this finding might help convince us to follow an anti-inflammatory eating pattern. Keep reading to learn more about the Mediterranean diet benefit.
The Study on Cognitive Effects of the Mediterranean Diet:
Harvard investigators collected information on the eating habits, blood sugar control and cognitive function from over 900 volunteers during the two-year study. The volunteers were part of a multi-ethnic study, the Boston Puerto Rican Health Study. Two-fifths of the participants had type 2 diabetes. The scientists scored the dietary information according to how closely it resembled a Mediterranean style diet. They also considered the Healthy Eating Index, the Alternate Healthy Eating Index and the score for Dietary Approaches to Stop Hypertension (the DASH diet).
People without diabetes scored higher on memory tests when they followed a diet that resembled the Mediterranean pattern more closely. The real rewards were to people with type 2 diabetes. Those who followed diets that most resembled Mediterranean standards scored better on a range of cognitive function tests. Only the Mediterranean diet scores correlated to cognitive outcomes, however. In addition, the Mediterranean benefit was apparent only for those who maintained good blood sugar control.
How Can a Mediterranean Diet Benefit Your Heart Health?
Previous randomized controlled trials, such as the Lyon Diet Heart Study and the PREDIMED study were conducted in Mediterranean countries. Dietary habits are different in the US. Is it possible for Americans to benefit by following a Mediterranean-style eating pattern?
Results from the Women’s Health Study published in JAMA Network Open show that American women who emphasize veggies and fruits, nuts and fish and downplay meats and sweets get a significant cardiovascular edge (JAMA Network Open, Dec. 7, 2018). The study included nearly 26,000 women over 45 years old. They answered detailed questionnaires about their diets and gave blood to be analyzed for cholesterol and other markers.
Harvard researchers scored the dietary data on a scale from one to nine for adherence to a Mediterranean style eating pattern. The categories included vegetables, fruits, nuts, whole grains, legumes, fish and olive oil, as well as moderate alcohol intake. Over about two decades, women with scores in the upper third were 28 percent less likely than those in the lowest third to suffer cardiovascular complications. These included heart attack, stroke, hospitalization for a coronary or death from cardiovascular causes.
How Would a Mediterranean Diet Protect Your Heart?
Following a more Mediterranean eating plan might not work by lowering cholesterol. Oddly, women following diets closest to the Mediterranean pattern had higher total cholesterol overall than those in the lower group. However, their markers for inflammation were lower. They also had lower glucose levels and less insulin resistance. Although this was not a randomized controlled trial, it strongly suggests that American women can help their hearts with a Mediterranean eating style.
The Many Benefits of a Mediterranean Diet:
Earlier studies already indicated that people who eat more vegetables, fruits, fish and olive reap health benefits. An analysis of 56 studies of the Mediterranean diet found that people following this eating pattern have a lower likelihood of developing diabetes, heart attacks, strokes and breast cancer (Annals of Internal Medicine, Oct. 4, 2016). To be included in the research, a study had to have at least 100 participants. Each study lasted at least a year. Volunteers needed to adhere to at least two of the following seven components:
- more monounsaturated fat (usually from olive oil or nuts, with little if any animal fat like butter);
- lots of vegetables and fruits;
- plenty of legumes such as peas, beans and lentils;
- mostly whole grains;
- moderate amounts of red wine;
- limited dairy products;
- and reduced consumption of meat, with fish as a substitute.
Importantly, the diets were not restricted in fat. Many physicians and nutrition experts have thought that avoiding red meat and dairy products would be beneficial primarily because people eat less fat. That was not necessarily true for these study diets.
The Envelope:
The research can’t demonstrate cause and effect. But by now the consensus is that you can get a Mediterranean diet benefit for the heart, the brain and various other organs. Significantly, that seems to be true even for a relatively high-fat diet. People following a Mediterranean pattern lowered their chance of a heart attack or stroke by 29 percent. They were 57 percent less likely to be diagnosed with breast cancer. The risk of diabetes was 30 percent lower. The scientists didn’t detect any difference in overall death rate, however.
Myths About the Mediterranean Diet:
With more than 700 entries in the PubMed index regarding Mediterranean diet benefit, we should consider some myths that can be confusing (Nutrients, Nov. 8, 2017). Although the Mediterranean diet is plant-based, it is not a strictly vegetarian diet. Even more important, pizza is not a food that fits well in the Mediterranean dietary framework. Third, although this traditional dietary pattern includes moderate amounts of wine, people drink it at meals, in the presence of friends and family. They do not consume any appreciable amount of other spirits.
Avocado, soy and oils such as corn, peanut or sunflower oil do not belong in the Mediterranean diet, whether or not we consider them healthful. Perhaps most challenging for Americans, following a traditional Mediterranean diet means cutting out processed foods, fast foods, soda pop and sweet desserts, at least for the most part.
Do Try This at Home:
You might try to get your Mediterranean diet benefit at home by using olive oil rather than other fats and focusing on plant foods, especially vegetables, beans and seeds. Mediterranean-style menus from Italy, Spain, France, Turkey, Lebanon and Israel are delicious, so adopting such a plan shouldn’t mean sacrificing flavor. If you would like guidance on following a Mediterranean diet, you will find it in our book, The People’s Pharmacy Quick & Handy Home Remedies.
