Racial Differences in Dietary Relations to Cognitive Decline and Alzheimer’s Disease Risk: Do We Know Enough?

Abstract

The elderly population in the US is increasing and projected to be 44% minority by 2060. African Americans and Hispanics are at increased risk of cognitive impairment and Alzheimer’s disease compared to non-Hispanic whites. These conditions are associated with many other adverse health outcomes, lower quality of life, and substantial economic burden. In the past few decades, diet has been identified as an important modifiable risk factor for cognitive decline and Alzheimer’s disease. Some studies report poor diet quality among African American and Hispanic older adult populations compared to their white counterparts. We have a limited understanding of how diet affects brain health in different racial-ethnic groups. One primary reason for our lack of knowledge is that most cohort studies are of majority non-Hispanic white participants. Moreover, those that do include minority participants do not publish their findings stratified by racial-ethnic groups, and likely have a less accurate measurement of dietary intake among minority groups. In this review, we summarize the current, albeit limited, literature on racial/ethnic differences in dietary relations to dementia outcomes. We will also discuss methodological issues in conducting nutrition studies in diverse cultures, and suggestions for future research directions. Overcoming the gaps will make it possible to make dietary recommendations for Alzheimer’s prevention that are more relevant for different racial/ethnic groups and set us on a faster track to reduce health disparities.

Association between healthy eating index-2015 and various cognitive domains in US adults aged 60 years or older: the National Health and Nutrition Examination Survey (NHANES) 2011–2014

“…Notably, our findings are unique in showing that adherence to dietary guidance, as indicated by HEI-2015, was linked to cognitive performance in non-Hispanic White but not other races. Similar race/ethnicity differences have been observed in previous studies investigating associations between diet and cognition [ 36 ]. In the Einstein Aging Study, a healthy diet was related to executive dysfunction specifically in whites [ 37 ].…”

Dementia risk in a diverse population: A single-region nested case-control study in the East End of London

“…There is growing interest in the link between nutritional factors and dementia risk. 38 Dietary patterns vary according to ethnicity and deprivation, and our finding that the association between BMI and dementia risk is dominated by underweight rather than overweight goes some way to suggesting that poor nutrition could be of particular importance in this population, although declining BMI is also recognised as a prodromal feature of dementia. 39 Patterns of risk factor treatment might also alter the effect of risk factors (e.g.…”

A Critical Review of the Study of Neuroprotective Diets to Reduce Cognitive Decline

“…In the recent book published by the National Academy of Sciences, Preventing Cognitive Decline: A Way Forward, the authors identify a lack of consistent cognitive outcome measures across current and recent trials to be a major challenge in understanding the effects of lifestyle interventions such as diet on cognition, making it impossible to pool results across studies [58] (pp. [84][85]. For meaningful outcomes, it is recommended that the measures used to assess cognitive decline reflect the latest diagnostic guidelines for assessing AD.…”

“…All dietary intake tools that involve self-report have inherent limitations which contribute to inaccuracies. For FFQs, used predominantly in large-scale epidemiologic studies, these limitations include inaccuracy related to portion size [ 83 ], lack of generalizability to multi-racial/ethnic cohorts [ 84 ], and the addition of non-standard items unique to the Medi, DASH, or MIND diets which may not exist on the FFQ and contribute to misclassification [ 85 ]. Limitations to 24HRs are the cost and logistics of the data [ 86 ] and the inability to account for day-to-day variation in diet.…”