Using diet as a treatment for conditions like cardiovascular disease and diabetes has been widely accepted for many years. For cardiovascular disease specifically, the use of the Dietary Approaches to Stop Hypertension diet (DASH) has been popular. Another diet that has gained publicity for its potential health effects is the Mediterranean Diet, which focuses heavily on a plant based diet, including lots of leafy green vegetables, olive oil, nuts, berries, and fish. As the rate of Alzheimer’s disease climbs across the globe, researchers have been evaluating whether lifestyle changes similar to those found to be effective for cardiovascular disease and diabetes may be effective for the prevention and treatment of Alzheimer’s disease as well. This study specifically evaluated the comparison between the Mediterranean diet, DASH diet, and a hybrid called the Mediterranean-DASH Intervention for Neurodegenerative Delay diet (MIND).1
Older adults with moderate or high adherence to the MIND diet had lower rates of Alzheimer’s disease compared to participants with low adherence of the MIND diet. Meanwhile, only individuals with high adherence of the DASH and Mediterranean diets were associated with lower Alzheimer’s disease rates. Researchers concluded that high adherence to all three diets may reduce the risk for Alzheimer’s disease, while moderate adherence of only the MIND diet may also reduce Alzheimer’s disease risk. Given that the rate of high adherence to most dietary protocols is typically low in the general population, the MIND diet is likely to be a better recommendation for the general population because the brain health benefits of the MIND diet are still found at only the moderate adherence rate.
Study participants were part of the Rush Memory and Aging Project (MAP) that began in 1997 and included 1,545 volunteers living in retirement communities and senior public housing in the greater Chicago area. In 2004 an addition to the initial MAP study was made with the add-on of a food frequency questionnaire. A subset of 923 participants who completed the food frequency questionnaires and follow-up tests which identified that they did not have Alzheimer’s at baseline were followed from 2004 to February 2013.
Study participants reported their usual frequency of food intake over the previous 12 months of 144 food items. The MIND diet score included 15 dietary components evaluated using the food frequency data. The 15 components included 10 food groups that were deemed to include brain healthy foods based on previous studies, including green leafy vegetables, other vegetables, nuts, berries, beans, whole grains, fish, poultry, olive oil and wine; as well as 5 unhealthy food groups including red meats, butter and stick margarine, cheese, pastries and sweets, and fried or fast food. The DASH diet score included 7 food groups and 3 dietary components of total fat, saturated fat and sodium. The Mediterranean diet score was based on 11 dietary components of the traditional Mediterranean diet.
At the study conclusion, 144 cases of Alzheimer’s disease had developed in the 923 participants. The average MIND diet score for those who developed Alzheimer’s disease was 7.4 (15 possible) and ranged from 2.5 to 12.5. The MIND diet participants with the lowest scores also had lower education, reported fewer hours of physical activity, were more likely to be obese and to have diabetes, and experienced more depressive symptoms. The MIND diet score was statistically significantly associated with a lower risk of developing Alzheimer’s disease. When the MIND diet model was adjusted for age, sex, education, APOE-ε4, total energy intake, physical activity and participation in cognitively stimulating activities, participants with the highest adherence to the MIND diet (scores in the top tertile range of 8.5 – 12.5) had a 53% reduction in the rate of developing Alzheimer’s compared with participants in the low adherence MIND diet group (lowest tertile score range of 2.5 – 6.5). The participants in the moderate adherence group of the MIND diet (middle tertile diet scores) also had a statistically significant 35% reduction in Alzheimer’s disease rates compared with those in the low adherence group. Meanwhile, only the high compliance group (highest tertile) of the DASH and MedDiet diet scores when compared to their low compliance scores (lowest tertile) were significantly associated with Alzheimer’s disease rates. High adherence with the Mediterranean diet showed a 54% reduction in Alzheimer’s disease compared to low adherence, while high adherence of the DASH diet resulted in a 39% reduction in Alzheimer’s disease. However, neither the Mediterranean diet nor the DASH diet showed a significant relationship for reduced risk of Alzheimer’s disease at the moderate compliance level.
Researchers found no statistical evidence that the MIND diet and the development of Alzheimer’s disease risk was modified by age, sex, education, physical activity, obesity, low body mass index, or histories of stroke, diabetes, or hypertension. There was suggestion that the MIND diet was less protective for APOE-ε4 positive participants and more protective in participants with a history of myocardial infarction, although this did not reach statistical significance (p-value for interaction=0.06 for both).
Overall, the DASH, Mediterranean, and MIND diets all demonstrated a significant reduction in the rate of Alzheimer’s development when strictly followed. However, only the effects of MIND diet were still significant when followed moderately. Knowing that strict dietary adherence is difficult for most individuals, recommending the MIND diet is the most likely to result in a favorable reduction of Alzheimer’s disease risk in the general population. Furthermore, the MIND diet should especially be considered for individuals with a previous history of myocardial infarction.
1. Morris MC, Tangney CC, Wang Y, et al. MIND Diet Associated with Reduced Incidence of Alzheimer’s disease. Alzheimers & Dementia. September 2015; 11(9): 1007-1014.