Sticking to the MIND diet for 10 years produced a small but significant decrease in the risk of developing thinking, concentration and memory problems, a recent study found. It also suggested that black people and women appeared to benefit more from following the diet.
The Mediterranean-DASH Intervention for Neurodegenerative Delay diet combines elements from the traditional Mediterranean diet and the Dietary Approaches to Stop Hypertension, or DASH diet, which focuses on reducing blood pressure.
The MIND diet was specifically designed to combat cognitive decline, said lead study author Dr Russell Sawyer, an assistant professor of clinical neurology and rehabilitation medicine at the University of Cincinnati Gardner Neuroscience Institute.
“Among the MIND diet components are 10 brain healthy food groups: green leafy vegetables, other vegetables, nuts, berries, beans, whole grains, seafood, poultry, olive oil and wine,” he told CNN.
Five unhealthy food groups – red meats, butter and stick margarine, cheese, fried and fast foods, and pastries and sweets – are limited in the MIND diet, which helps reduce the intake of trans and saturated fats, he added.
“The MIND diet has all of the key features – notably an emphasis on real food, mostly plants – required to reduce systemic inflammation, facilitate weight loss, improve the health of the microbiome, ameliorate insulin resistance, lower elevated blood lipids (fats), and slow atherogenesis (clogging of arteries),” said Dr David Katz, a specialist in preventive and lifestyle medicine who founded the non-profit True Health Initiative, a global coalition of experts dedicated to evidence-based lifestyle medicine. He was not involved in the study.
“That such effects would translate into protection of the brain is anything but a surprise,” he said. “This study of association does not, by itself, prove that the MIND diet protects cognitive health, but given the clear mechanisms in play, it certainly suggests it does.”
Larger benefit for women and black people
The study, published in Neurology, the journal of the American Academy of Neurology, is part of an ongoing study called REGARDS, or Reasons for Geographic and Racial Differences in Stroke.
Sponsored by the National Institutes of Health, REGARDS was created to examine why Southern American and black American people have a higher incidence of stroke. It has been following about 30 000 adults age 45 and older since 2003.
Of the more than 14 000 people in the study, 70% were white and 30% were black. At the start of the study, and again at 10 years, participants were asked about their dietary intake and underwent electrocardiograms, blood pressure measurements and blood work.
Researchers then scored the diets on higher adherence to MIND diet parameters: eating more than three servings of whole grains per day, consuming more than six servings of green leafy vegetables each week, eating at least one other vegetable each day, eating more than two servings of berries each week, having a fish meal more than once and poultry more than twice a week, and eating beans more than three times per week.
Eating nuts and using primarily olive oil were also scored more highly.
People who ate red or processed meats less than four times a week, fried or fast food less than once a week, and less than a tablespoon of butter or margarine a day were also scored higher.
People who followed the MIND diet more closely were 4% less likely to develop memory and thinking problems than those who did not adhere to the diet, the study found. The finding remained even after mitigating factors such as exercise, education, smoking, body mass index, medical conditions, age, and anxiety or depression were factored out.
For women, the risk was even less. They were 6% less likely to develop cognitive impairment. Men, however, saw no such benefit, the study found.
When it came to how quickly those with such memory and thinking issues declined, the study found that people who closely followed the MIND Diet regressed more slowly than those who did not. That association was stronger in black participants than in white participants, Sawyer said.
“These were surprising findings,” Sawyer said. “The benefits of the MIND diet may have a differential impact in women and blacks and this is an area for future research.”
Dr Jacqui Hanley, head of research at Alzheimer’s Research UK, said: “There is a wealth of evidence that eating a healthy, balanced diet can help protect our brain health. But the benefits of specific diets is less clear.
“This study adds more evidence that the MIND diet may delay cognitive decline, including memory issues,” she told The Independent.
“However, without a detailed picture of what’s going on in the brain, we don’t know whether there is a direct link between this diet and a reduced risk of cognitive impairment. Larger and longer-term studies will be needed to understand this effect more and this should be carried out in a more diverse group of people.”
More research needed
A previous, 2023 randomised controlled clinical trial, found the MIND diet no better than the control diet in reducing signs of cognitive decline in the brain. However, experts were concerned the trial was not long enough to fully capture results.
“The three years’ follow up, while admirable for a randomised clinical trial provides less insights about the long-term benefits of diet compared with the 10+ years of follow up in our study,” Sawyer said.
In addition, only 66 people in the clinical trial were black, which limits “the generalisability of this randomised control study compared with our cohort study, though both offer important information”, he said.
Study 1 details
Association of Adherence to a MIND-Style Diet With the Risk of Cognitive Impairment and Decline in the REGARDS Cohort
Russell Sawyer, Jessica Blair, Rhonna Shatz, Jennifer. Manly and Suzanne Judd.
Published in Neurology on 18 September 2024
Abstract
Background and Objectives
Diet may influence the development of cognitive impairment and affect cognitive decline, but whether this relationship varies between black Americans and white Americans is unclear. This study examined the association of Mediterranean-Dietary Approaches to Stop Hypertension Intervention for Neurodegenerative Delay (MIND) and incident cognitive impairment and cognitive trajectories in a biracial prospective cohort study.
Methods
Using data derived from the Food Frequency Questionnaire in the REasons for Geographic and Racial Differences in Stroke study, we compared MIND diet adherence with incident cognitive impairment and cognitive trajectory in black participants and white participants. Logistic regression was used to model MIND diet score (continuous variable and using tertiles) and incident cognitive impairment after adjusting for age, sex, race, region, education, income, total energy, hypertension history, dyslipidemia, diabetes, estimated glomerular filtration rate, ischemic heart conditions, atrial fibrillation, and lifestyle factors including sedentary, obesity, and smoking. Mixed-effects models were used to examine the association between cognitive trajectory and MIND diet adherence.
Results
Dietary data to calculate the MIND diet score and cognitive data were available on 14,145 participants with a mean age of 64 years (SD 9.0 years) that was 56.7% female. Greater MIND diet adherence was associated with a decreased incidence of cognitive impairment (odds ratio [OR] 0.96, 95% CI 0.93–0.99, p = 0.02) after adjusting for all covariates. In the fully adjusted model, greater MIND diet adherence was associated with decreased risk of cognitive impairment in female participants (OR 0.92, 95% CI 0.89–0.96, p < 0.001) but not in male participants (OR 1.01, 95% CI 0.97–1.06, p = 0.64). In all models, greater MIND diet adherence was associated with decreased risk of cognitive decline. MIND diet adherence was a better predictor of cognitive decline in black participants (β = 0.04, SE = 0.007, p < 0.001) than in White participants (β = 0.03, SE = 0.004, p < 0.001).
Discussion
Greater MIND diet adherence was associated with decreased risk of cognitive impairment in female participants but not male participants, with no difference between black and white participants. However, MIND diet adherence was a better predictor of cognitive trajectory in black participants than in white participants.
Study 2 details
Trial of the MIND Diet for Prevention of Cognitive Decline in Older Persons
Lisa Barnes, Klodian Dhana, Xiaoran Liu et al.
Published in NEJM on 18 July 2023
Abstract
Background
Findings from observational studies suggest that dietary patterns may offer protective benefits against cognitive decline, but data from clinical trials are limited. The Mediterranean–DASH Intervention for Neurodegenerative Delay, known as the MIND diet, is a hybrid of the Mediterranean diet and the DASH (Dietary Approaches to Stop Hypertension) diet, with modifications to include foods that have been putatively associated with a decreased risk of dementia.
Methods
We performed a two-site, randomised, controlled trial involving older adults without cognitive impairment but with a family history of dementia, a body-mass index (the weight in kilograms divided by the square of the height in metres) greater than 25, and a suboptimal diet, as determined by means of a 14-item questionnaire, to test the cognitive effects of the MIND diet with mild caloric restriction as compared with a control diet with mild caloric restriction. We assigned the participants in a 1:1 ratio to follow the intervention or the control diet for 3 years. All the participants received counselling regarding adherence to their assigned diet plus support to promote weight loss. The primary end point was the change from baseline in a global cognition score and four cognitive domain scores, all of which were derived from a 12-test battery. The raw scores from each test were converted to z scores, which were averaged across all tests to create the global cognition score and across component tests to create the four domain scores; higher scores indicate better cognitive performance. The secondary outcome was the change from baseline in magnetic resonance imaging (MRI)–derived measures of brain characteristics in a non-random sample of participants.
Results
A total of 1929 persons underwent screening, and 604 were enrolled; 301 were assigned to the MIND-diet group and 303 to the control-diet group. The trial was completed by 93.4% of the participants. From baseline to year 3, improvements in global cognition scores were observed in both groups, with increases of 0.205 standardised units in the MIND-diet group and 0.170 standardised units in the control-diet group (mean difference, 0.035 standardised units; 95% confidence interval, −0.022 to 0.092; P=0.23). Changes in white-matter hyperintensities, hippocampal volumes, and total grey- and white-matter volumes on MRI were similar in the two groups.
Conclusions
Among cognitively unimpaired participants with a family history of dementia, changes in cognition and brain MRI outcomes from baseline to year three did not differ significantly between those who followed the MIND diet and those who followed the control diet with mild caloric restriction.
See more from MedicalBrief archives:
MIND diet slows cognitive decline in stroke survivors
Daily multivitamins linked to slower cognitive ageing — COSMOS-Mind study
Plant-based diet lessens risk of cognitive impairment — 12-year European study
Mediterranean diet + oil and nuts = better memory