Supplementation with docosahexaenoic acid may not be useful in reducing cognitive decline in Alzheimer’s disease, says a new US study.
In the randomized controlled trial, 402 individuals with mild to moderate Alzheimer’s disease were randomly assigned to receive algal docosahexaenoic acid (DHA) at a dose of 2 grams per day or placebo for 18 months (1). The results showed that supplementation with DHA compared with placebo did not slow the rate of cognitive and functional decline in the Alzheimer patients. Furthermore, the rate of brain shrinking (atrophy) was no different between the groups.
The researchers said that it is still possible that an intervention with DHA might be more effective if initiated earlier in the course of the disease in patients who do not have overt dementia.
Experts commented that several observational studies reported on diets rich in fish or supplements with omega-3 fatty acids, which were associated with reduced risk of developing Alzheimer’s disease (AD). However, most randomized clinical trials for treatment of AD or mild cognitive impairment have not found a beneficial effect. Effective treatment strategies to prevent progression of AD would likely need to be initiated earlier in the course of AD in order to be more efficacious (2). Given the accumulating evidence that the process of developing AD begins years, if not decades, prior to the diagnosis of clinical dementia, treatment of mild to moderate AD could come too late.
Whether in their diet or through the use of dietary supplements, individuals should ensure they are receiving adequate amounts of DHA and eicosapentaenoic acid (EPA); they should not wait until they begin to experience symptoms of a health concern, according to the experts. Supplements would not be a cure or treatment for any disease but, when incorporated into a healthy lifestyle, they could play an important role in disease prevention.