Docosahexaenoic acid, or DHA, is a long chain omega 3 fatty acid naturally found in oily fish such as mackerel, trout, sardines and salmon. The brain contains a high proportion of DHA and, as you will see from my past blog posts, omega 3 fats have been linked to brain benefits including protection from depression and dementia and better mental function, or cognition. It is known that DHA plays an important role in neural function and that decreases in blood plasma levels of DHA are associated with cognitive decline in healthy elderly adults and in those with Alzheimer’s disease. Until now there has been very little investigation into the potential benefits of DHA supplementation in age-related cognitive decline.
A recently study (1) published in the Journal of the Alzheimer’s Association has found that taking DHA supplements in older age may improve memory and learning (improve cognition) in those individuals with mild cognitive impairments. The study was a well designed randomised, double-blind, placebo-controlled study which looked to evaluate the effects of DHA supplementation on cognitive function in healthy older adults with mild age-related cognitive decline. The study included over 450 individuals aged 55 or over, they received either 900mg of DHA daily or a placebo supplement for 24weeks. Various tests were used to evaluate cognitive function.
The researchers found that after 24weeks those individuals given the DHA had better cognitive function test scores compared to those taking the placebo and DHA supplementation was also associated with improved immediate and delayed Verbal Recognition Memory scores. In the supplemented group the blood plasma DHA levels doubled and were correlated with improved test scores. DHA was well tolerated with no reported treatment-related serious adverse events. The authors of the study conclude that “Twenty-four week supplementation with 900 mg/d DHA improved learning and memory function in ARCD [age-related cognitive decline] and is a beneficial supplement that supports cognitive health with aging”
In a press release (2) Duffy MacKay, N.D., vice president, scientific & regulatory affairs, for the Council for Responsible Nutrition (CRN) said “The results of this study are very encouraging for those consumers concerned about maintaining memory. We know that lower DHA levels are associated with cognitive decline in healthy elderly and Alzheimer’s patients, and higher DHA levels help reduce the risk of Alzheimer’s disease,” “Memory loss, dementia and the development of Alzheimer’s disease are prominent health concerns for older individuals. The more we learn about the valuable role DHA plays in supporting brain function, the more options aging Americans have towards managing cognitive decline.”
The findings of this study show how important early intervention with omega 3 supplements is. This study (1) found that DHA supplementation was beneficial to the population being tested who were suffering with mild age-related cognitive decline but who were free of Alzheimer’s disease. Another recent study (3) published in the Journal of the American Medical Association (JAMA) was conducted with individuals who were diagnosed with mild-to-moderate Alzheimer’s disease. In this study DHA supplementation did not provide a statistically significant benefit to cognitive function. The authors of the JAMA study write “In summary, these results indicate that DHA supplementation is not useful for the population of individuals with mild to moderate Alzheimer disease,” but also add that “it remains 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.”
In the study mentioned earlier (1) it was found that DHA was useful as an early intervention in order to PREVENT cognitive decline. In a press release Dr MacKay said “This study reinforces the principle that consumers will reap the most benefit from their DHA supplements — and many supplements — when they are taken over time and before a health concern is imminent,” “When included as a part of a proactive health regimen that includes a well-balanced diet, regular physical activity and routine visits with a healthcare professional, dietary supplements offer an important tool to help support many systems in the body, including memory and cognitive function.”
If you feel you would like to take omega 3 fish oil supplements then it is always best to check with your medical doctor first but they may well be worth considering, especially if you do not eat at least two portions of oily fish weekly. Omega 3 fatty acids are important for the health of the brain, heart and circulatory system and have many other health benefits in addition.
(1)Yurko-Mauro K et al. Beneficial effects of docosahexaenoic acid on cognition in age-related cognitive decline. Alzheimer’s and Dementia. 6 (6): 456 DOI: 10.1016/j.jalz.2010.01.013
(2)Press release. Council for Responsible Nutrition (2010, November 8). DHA improves memory and cognitive function in older adults, study suggests. ScienceDaily. Retrieved November 9, 2010, from http://www.sciencedaily.com /releases/2010/11/101108151346.htm
(3) Quinn JF, et al. Docosahexaenoic Acid Supplementation and Cognitive Decline in Alzheimer Disease: A Randomized Trial. JAMA: The Journal of the American Medical Association. 304 (17):1903
Written by Ani Kowal