It's not too late to start a brain-healthy diet, a large study shows

NBC News

3 days ago

New evidence finds that the MIND diet lives up to its name, even when it is started later in life.
Middle-aged and older participants in a large, long-term study were less likely to develop Alzheimer's disease or other types of dementia if they followed a diet filled with green, leafy vegetables, olive oil, whole grains and lots of berries, according to a report presented Monday at the annual meeting of the American Society for Nutrition.
Researchers from University of Hawaii at Mānoa and the University of Southern California discovered that adhering to the MIND diet, which combines the Mediterranean diet with the blood-pressure-lowering DASH diet, results in a stronger and more consistent reduction in dementia risk than what is seen with other healthy diets.
The new findings suggest it's never too late to switch to a healthy diet, said the study's lead author, Song-Yi Park, an associate professor at the University of Hawaii at Mānoa. 'It shows that sticking to a healthy diet, as well as improving the health of the person's diet over time, is very important for older adults who want to prevent dementia.'
While all the Mediterranean-related diets appear to be good for the brain, the MIND dietary pattern was specifically designed for brain health.
'One important difference is that MIND includes berries, which have been linked to brain health,' Park said.
The MIND diet, or Mediterranean-DASH Intervention for Neurodegenerative Delay, scores individual foods based on how protective they are and how much is eaten. Berries — especially strawberries and blueberries — for example, get a score of 1 if two or more servings are consumed per week. The score drops to 0.5 if just one serving per week is consumed and a score of 0 if none are.
A person's individual diet gets an overall rating by adding up the scores for individual foods. The higher the overall score, the better it's for the person's brain.
Park and her colleagues turned to data from nearly 93,000 U.S. adults who had provided information about what they ate as part of a research project known as The Multiethnic Cohort to get a closer look at how diet influenced the risk of developing dementia.
The Multiethnic Cohort was started in the early 1990s through a joint effort of the University of Hawaii Cancer Center and the USC Norris Comprehensive Cancer Center. The men and women enrolled in the study came from five ethnic/racial populations: Japanese Americans, Native Hawaiians, Black Americans, Latinos and whites.
At the outset, the 215,000 participants were ages 45 to 75. When data for the new study was analyzed, more than 21,000 participants had developed Alzheimer's or a related dementia.
At the beginning of the study, people who scored higher for adherence to MIND had a 9% lower risk of developing dementia.
The amount of reduction varied among the racial groups in the new analysis. Greater risk reduction, 13%, was seen in participants who identified as Black, Latino or white.
Participants who improved their adherence to MIND over the 10-year period had a 25% lower risk of dementia compared with those whose adherence declined, and that trend was seen across all age and racial groups.
How to follow the MIND diet
Some suggestions for reaching the optimal score for the MIND diet, according to a 2015 study:
Leafy green vegetables, such as kale, spinach, broccoli, bok choy and mustard: six or more servings per week
Other vegetables: one serving per day
Nuts, such as almonds, walnuts or pistachios: five or more servings per week
Cheese: less than one per week
Whole grains: three or more per day
Fish (not fried): one or more servings per week
Red meat: less than one serving per week
Fast fried foods: less than one per week
Pastries and sweets: less than five servings per week
Park cautioned that like all observational studies, the new research reports an association and doesn't prove that the diet prevents dementia.
It is a high-quality study, Dr. Walter Willett, a professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health and a professor of medicine at the Harvard Medical School, said in an email.
'It adds to the evidence that a Mediterranean-type diet has important benefits for reducing the risk of dementia,' said Willett, who wasn't involved in the research. 'The differences between groups defined by race/ethnicity may well be due to random variation, so at this time it's reasonable to assume that this healthy dietary pattern has benefits for all groups."
When it comes to leafy green vegetables, it's probably best to consume a variety rather than a single type, Willett said.
'In particular, spinach is good in many ways, but has high oxalate content and high intake of spinach can cause kidney stones,' he said.
In general, the MIND diet is in line with the principles of the two diets it's built from, said Dr. Yian Gu, an associate professor of neurological sciences at the Columbia University Irving Medical Center. 'Each of those diets has unique characteristics,' she said.
The Mediterranean diet emphasizes multiple daily servings of fruits and vegetables, along with whole grains, legumes, olive oil, seafood, and nuts and seeds, such as chia, flax, pumpkin and sesame.
DASH, or Dietary Approaches to Stop Hypertension, is meant to prevent hypertension, so it emphasizes low salt, which isn't a major component in the Mediterranean diet.
The MIND diet is easy to follow, Gu said, encouraging people to pick the green, leafy vegetables they prefer. What's important is to increase the diversity of vegetables.