Can nutritional supplements improve cognition in the elderly?

22 Jun

A review, just published, in Current Directions in Psychological Science:

“With increasing life expectancies in most Western populations, the number of people experiencing age-associated cognitive impairment is increasing. Research is needed to identify factors that may help the elderly maintain or even improve cognitive function in the face of advancing age. This review evaluates whether dietary supplementation with natural pharmaceuticals can be used as a means to improve cognitive function or limit cognitive decline. The evidence surrounding popular supplements such as Ginkgo biloba, fish oils, Bacopa monnieri, polyphenol extracts, and vitamins is reviewed briefly. Potential mechanisms of action are also highlighted. This review also discusses challenges surrounding cognitive testing in psychopharmacological research, highlighting discrepancies between the domains of human cognition as described by contemporary models and as measured in clinical trials.”

Here is the paper’s concluding paragraph:

“The results of the clinical trials reviewed here are an admixture of hopeful findings, often leavened by studies of small duration and sample size. Although difficult and costly to conduct, trials of longer duration are needed to ascertain which dietary supplements, if any, afford protection against cognitive decline and cognitive impairment. Differences between existing studies also make it hard to draw overall conclusions about any particular supplement. In our own work, standardized herbal extracts of bacopa and pine bark have shown promise in terms of their ability to improve cognitive function, with a larger trial of longer duration currently underway to validate these preliminary findings (Stough et al., 2012). Meta-analyses have shown that multivitamins, fish oils, and ginkgo can all enhance specific aspects of cognitive function. To minimize differences in cognitive outcomes between studies, we suggest cooperation between different groups working in the area to develop a set of freely available cognitive tasks validated against the CHC model.”

This is paper, published in a highly regarded journal, is very optimistic about the prospect of nutritional supplementation. I am open minded about this, but note that research in this area tends to follow cycle: initial poorly designed studies raises hopes, while the effect tends to disappear with later better designed studies. I am particularly skeptical about claims made about fish oil.

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