Experts estimate that over 24 million people worldwide suffer from dementia, and many of these people live in low- and middle-income countries. Recently, there has been growing interest in whether dietary factors, particularly oily fish and meat, might influence the onset and/or severity of dementia. Oily fish are rich in omega-3 long-chain polyunsaturated fatty acids, which some studies suggest are positively related to cognitive function in later life. Conversely, there is a suggestion from some studies that increased meat consumption may be related to cognitive decline. To examine this, a group of international researchers studied older people in 7 middle- to low-income countries. You can read the results of their study in the August 2009 issue of the American Journal of Clinical Nutrition.

Data from 14,960 participants (≥65 y of age) living in China, India, Cuba, the Dominican Republic, Venezuela, Mexico, and Peru were analyzed. Dietary habits were assessed by using standard, culturally appropriate face-to-face interviews, and dementia was diagnosed by using validated culturally and educationally fair criteria.

In each of the study countries, except India, there was an inverse association between fish consumption and dementia prevalence. These data extend to low- and middle-income countries previous conclusions from industrialized countries that increased fish consumption is associated with lower dementia prevalence in later life. The authors propose that this relation is not due to poor overall nutritional status in those with dementia, because meat consumption tended to be higher in this group. The relation between meat consumption and dementia remains unclear.

(Eurekalert.org July 18, 2009)