Abstract:
Introduction
The high prevalence and impact of dementia call for preventative measures, including
application of an optimised diet. Omega 3 polyunsaturated fatty acids (PUFA) may influence
the risk for developing dementia by supporting cardiovascular health and by decreasing
inflammation. Research, particularly randomised controlled trials, studying a food-based
approach that uses Omega 3 PUFA intake from foods such as fish to counteract dementia in
low/middle income countries (LMIC), is lacking.
Aim
To determine the effect of supplementing diets of independently living, resource-limited
elderly participants for 12 weeks with fish versus non-fish foods on cognition.
Methods
In a randomised controlled trial the usual diet of independently living elderly persons in a
resource-limited retirement centre in urban South Africa was enhanced with contextappropriate
foods i.e. canned baked beans, canola oil and peanut butter mimicking elements
of the Mediterranean-Dietary Approaches to Stop Hypertension (DASH) Intervention for
Neurodegenerative Delay (MIND) diet. Additionally, the intervention group received canned
pilchards and fish spread (equivalent to a calculated daily intake of 2.2g Omega 3 PUFA)
weekly compared to canned meatballs and texturised soya protein (meat substitute) received
by the control group. Cognition and level of functioning were measured before and after
intervention with the Cognitive Abilities Screening Instrument (CASI) and the Lawton
Instrumental Activities of Daily Living (IADL). Adherence was assessed by determining dietary
intake with a study-specific food frequency questionnaire (FFQ) and red blood cell (RBC)
PUFA biomarkers before and after the intervention. Data were analysed by non-parametric
analysis of covariance (ANCOVA) with, and without, bootstrap imputation.
Results
Fifty seven (74% female, mean age: 72 ±7 years) elderly participants participated in this study.
There was a significant post intervention difference (P=0.036) in the total CASI scores between
the intervention and control groups, when the model was fitted with imputation and controlled
for baseline scores. The predicted total CASI score of the intervention group was higher than the score of the control group. Likewise the calculated dietary Omega 3 PUFA intake and red
blood cell (RBC) Eicosapentaenoic acid (EPA) and Docosapentaenoic acid (DPA) content
differed significantly between the intervention and control group after the intervention phase.
The Lawton IADL presented similar results over the course of the study with limited variance.
Conclusion
Fish intake in the context of the MIND diet may exert a positive effect on cognition as the
current study showed that fish can have a significant effect on the cognition of resource-limited
elderly after 12 weeks of supplementation of an enhanced diet.
