Twelve Weeks of Additional Fish Intake Improves the Cognition of Cognitively Intact, Resource-Limited Elderly People:...

Dietary omega 3 polyunsaturated fatty acids (PUFA) may reduce the risk of dementia. Many studies have investigated PUFA supplementation in high-income countries, yet food-based randomized control trials using omega 3 PUFA rich fish in lower to middle income countries, are lacking.

To determine the effect on cognition of adding either fish or non-fish foods for twelve weeks to an enhanced diet of cognitively intact, independently living, resource-limited elderly people.

Randomized control trial (National Health Trial register: DOH-27-061-6026).

Retirement center in urban South Africa.

Fifty-seven (74% female, mean age: 72±7 years) elderly participants with cognitive function exceeding 22 on the Mini Mental State Examination were randomized into an intervention (n=31) and control (n=26) group.

The usual diets of both groups were enhanced with context-appropriate foods to mimic elements of the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet. The intervention group additionally received canned pilchards and fish spread every week amounting to an additional (theoretical) intake of 2.2g omega 3 PUFA daily. The control group received canned meatballs and texturized soya every week.

Cognition was measured twice before and once after the intervention phase using the Cognitive Abilities Screening Instrument (CASI). Adherence was assessed by a study-specific food frequency questionnaire and red blood cell (RBC) PUFA biomarkers. Data were analyzed using a non-parametric analysis of covariance (ANCOVA) with, and without, bootstrap imputation.

Participants in the intervention group had a significantly higher post intervention (P=0.036) CASI score than the control group, when the model was fitted with imputation and controlled for baseline scores. Participants in the intervention group also had a significantly higher intake of calculated dietary omega 3 PUFA and higher levels of RBC eicosapentaenoic acid and docosapentaenoic acid content than the control group (P < 0.05).

Twelve weeks of fish intake in the context of a modified MIND diet may improve the cognition of cognitively intact, resource-limited elderly people.