by Richard Podell, M.D., MPH
Dr. Richard Podell is Clinical Professor in the Department of Family Medicine at Rutgers-Robert Wood Johnson Medical School. His website is DrPodell.org
What is the Mediterranean Diet?
The Mediterranean Diet emphasizes eating “good fats”—mainly from olive oil and/or nuts. It encourages fruits, vegetables, whole grain cereals and moderate portions of wine. Red meat (high in saturated fat) and high sugar junk foods are kept to a minimum. (See specific recommendations below.) There are two studies of note that focus on cognitive improvement and the Mediterranean diet: PREDIMED and MIND studies.
The PREDIMED Study
In 2013, Spanish researchers recruited 7,000 middle aged and older men and women for a long-term diet study called the PREDIMED study. Each volunteer agreed to be randomly assigned to either a high fat Mediterranean style diet with the main fat source being from either olive oil or nuts or to a diet modeled after the American Heart Association’s low fat recommendations. After five years, the rate of heart attacks was about 25% lower among those on the Mediterranean diet compared to those eating the American Heart Association style relatively low fat diet.
Among the several PREDIMED study centers, the research group in Barcelona selected 447 participants who were given a battery of cognitive skill tests at the start of the study. Most, but not all of these volunteers returned for repeat cognitive testing after about four years on their assigned diets.
The initial scores on nine detailed cognitive tests were about the same for both groups. But at follow-up, the Mediterranean Diet group scored significantly higher than the low-fat-diet group for four of the nine cognitive tests—including two that were the most challenging and complex. The Mediterranean Diet group also outperformed the low-fat-diet group on the other five test scores, though these differences were not statistically significant. This suggests that the Mediterranean Diet might also prevent mild cognitive impairment (MC1).
Strengths of the recent study: The cognitive arm of the PREDIMED study was well designed. Its four-year-long follow up is also a plus.
Weaknesses: 447 patients are “small potatoes” compared to the 7,000 followed by all the PREDIMED study sites. Also about 100 of the original 447 subjects were not willing to come back for repeat cognitive testing after four years. So, the best we can say for now is that these results are encouraging and it seems fairly likely but not certain, that the high fat olive oil/nut Mediterranean style diet improves cognition among people as they age.
Caution: The Barcelona PREDIMED report is the only well designed long term controlled study where formal cognitive testing was done both before and after adopting the Mediterranean Diet. So, clearly, we need additional controlled trials before firmly accepting any conclusions.
The MIND Diet Study
Dr. Martha Morris and her team at Chicago’s Rush University Medical Center monitored the diet and cognitive testing of 960 people in their 70s and 80s for about 4.5 years. Based on their dietary history, the research team scored how closely the individual’s self-chosen eating tended to match the Mediterranean Diet and also a very similar diet-style she calls the “MIND diet.”
Over about 4.5 years persons whose diets most closely matched the Mediterranean and MIND-style diets had substantially less cognitive decline compared to those whose dietary choices tended away from the Mediterranean/MIND way of eating. Impressively, those who most closely followed the MIND/Mediterranean pattern had on only about half the risk of developing full-blown Alzheimer’s dementia compared those whose diets least reflected a Mediterranean/Mind diet style.
Practical Issues: How to Start a Mediterranean Style Diet
The Mediterranean Diet as used in the PREDIMED study recommended what most Americans would view as enormous intakes of olive oil—four tablespoons each day either added to food or taken down straight. Nor do we know for sure which elements of the Mediterranean Diet are most important for health: Olive oil versus whole grains vs. wine vs. low red meat vs. drastic reduction in sugary junk.
Specific Diet Recommendations Used by the PREDIMED Study
|Food Type:||Recommended Amounts|
|Olive Oil||>4 Tbs./day|
|Tree nuts and peanuts||>3 servings/week|
|Fresh Fruit||>3 servings/day|
|Fish (especially fatty fish)||>3 servings/week|
|Sofrito sauce (blend of tomato, onion, garlic, aromatic herbs
and olive oil
|White meat||Instead of red meat|
|Wine with meals||>7 glasses/week|
|Foods Not to Eat Much:|
|Commercial bakery goods, sweets and pastries||<3 servings/week|
|Spread fats||<1 serving/day|
|Red and processed meats||<1 serving/day|
These Mediterranean Diet Books Have Good Reviews on Amazon:
Richard Podell, M.D., MPH, is a graduate of Harvard Medical School and the Harvard School of Public Health. He has been treating patients with ME-CFS and Fibromyalgia for more than 20 years.
A clinical professor at New Jersey’s Robert Wood Johnson Medical School, Dr. Podell see patients at his Summit, NJ and Somerset, NJ offices. His website is DrPodell.org