Written by Tatjana Djakovic, Staff Writer. A cross-sectional study of 8,035 participating adults (aged 50 years and older) demonstrated that high adherence to the Med and MIND diets was associated with better cognitive function.
Cognitive decline leading to dementia is a major cause of disability and death in older Americans 1, leading to a significant interest in lifestyle factors for prevention of cognitive decline with aging 2. The Mediterranean diet (MedDiet), an anti-inflammatory diet rich in fruit, vegetables, whole grains, nuts, olive oil and fish, has been used for prevention of many health issues such as heart disease, diabetes and depression 3. The use of MedDiet for cognitive function has shown encouraging results, however the studies were conducted in a limited population. 4
A recent, large cross-sectional study consisting of 8,035 participants was conducted using data from the Health and Retirement Study (HRS), a national survey consisting of 30,000 U.S. adults aged 50 and older. This large survey was initiated in 1992 to collect data from U.S. retired adults and is collected biennially. The number of participants analyzed for the cross sectional study was 5, 907, aged on average 68.7 years, after exclusion for parameters such as dementia, stroke and extreme caloric intake (> 6,000 kcal/day) or (<600 kcal/day) 5.
The scores for each dietary pattern were calculated using data from food frequency questionnaires. The MedDiet scores (range from 0-55) were based on consumption of foods such as non-refined grains, fruits, vegetables, legumes, olive oil), with higher scores indicting better adherence to the traditional Mediterranean diet 5. Additionally, the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) 6 diet score (range 0-15) was based on consumption of brain healthy food groups including: leafy vegetables, nuts, berries, beans, whole grains, seafood, poultry, olives and wine. Lower scores were given for consumption of red meats, butter and stick margarine, cheese, pastries and sweets, fried and fast food. Scores increased with higher consumption in both MedDiet and MIND diet.
Cognitive performance was measured using a composite test score of global cognitive function (range 0-27), with higher scores indicating higher cognitive function. The parameters tested included: immediate and delayed recall of 10 words, backward counting and serial subtraction. 7
The results of the study indicate that a greater adherence to the MedDiet and MIND diet was associated with better cognitive function. In fact, those with the highest scores in both diets had 30- 35% lower odds of having poor cognitive performance than those with the lowest score (p<0.001). In addition, the cognition score was 14.8 in participants with low MedDiet Scores and 15.7 in those with high MedDiet Scores (p<0.001). Similarly, the cognition score was 14.9 in those with low MIND diet and 15.6 in those with high MIND diet scores (p<0.001). The scores were calculated after adjusting for outside factors such as smoking, total wealth, obesity, hypertension, diabetes, physical inactivity, depression and total energy intake 5.
The results of the study show a large risk reduction of cognitive decline in a well-represented sample of older adults with high adherence to the Med and MIND diet. Even though the increase in cognition scores was small, it is not as significant as maintaining and reducing the risk of cognitive function decline with increasing age. The major limitation of the study is its use of a cross sectional design as opposed to a clinical trial which meant that researchers were not able to establish a causal relationship between diet and mental decline.
Source: McEvoy, Claire T., Heidi Guyer, Kenneth M. Langa, and Kristine Yaffe. “Neuroprotective Diets Are Associated with Better Cognitive Function: The Health and Retirement Study.” Journal of the American Geriatrics Society (2017).
© 2017, Copyright the Authors Journal compilation © 2017, The American Geriatrics Society
Posted August 3, 2017.
References:
- Association As. 2016 Alzheimer’s disease facts and figures. Alzheimer’s & Dementia. 2016;12(4):459-509.
- Barnes DE, Yaffe K. The projected effect of risk factor reduction on Alzheimer’s disease prevalence. The Lancet Neurology. 2011;10(9):819-828.
- Estruch R. Anti-inflammatory effects of the Mediterranean diet: the experience of the PREDIMED study. Proceedings of the Nutrition Society. 2010;69(3):333-340.
- Morris MC, Tangney CC, Wang Y, Sacks FM, Bennett DA, Aggarwal NT. MIND diet associated with reduced incidence of Alzheimer’s disease. Alzheimer’s & Dementia. 2015;11(9):1007-1014.
- McEvoy CT, Guyer H, Langa KM, Yaffe K. Neuroprotective Diets Are Associated with Better Cognitive Function: The Health and Retirement Study. Journal of the American Geriatrics Society. 2017.
- Morris MC, Tangney CC, Wang Y, et al. MIND diet slows cognitive decline with aging. Alzheimer’s & dementia. 2015;11(9):1015-1022.
- Herzog AR, Wallace RB. Measures of cognitive functioning in the AHEAD Study. The Journals of Gerontology Series B: Psychological Sciences and Social Sciences. 1997;52(Special_Issue):37-48.
