DHA for Brain Fitness? Mixed Results

A paper in last week’s JAMA reports on a clinical trial of docosahexaenoic acid (DHA) in preventing cognitive decline in patients with Alzheimer’s disease. DHA is a component of fish oil supplements that have been recommended for the prevention of heart disease and, possibly, to prevent aging-related cognitive decline.

Results of the overall study were negative – DHA at a dose of 2 grams a day didn’t slow how much patients’ cognitive abilities declined over 18 months.

One finding of the study has been largely ignored in media reports. In a planned subgroup analysis, though, patients treated with DHA and who did not have the ApoE 4 allele had slower cognitive decline. ApoE 4 is a gene that has been associated with greater risk for having Alzheimer’s disease. It may be related to how fatty substances in the body are used by the body.

Although the findings of the main trial are negative, one subgroup may have benefited from DHA treatment.

This study thus adds to a series of studies based on observations that people who take vitamins, nonsteroidal anti-inflammatory drugs, and fish oil supplements have lower risks for Alzheimer’s disease. The logic of the trials has been to evaluate things associated with lower risk as treatments, but none has turned out to be effective.

Click here to read the full article.

Reference:

Quinn JF et al (2010). Docosahexaenoic acid supplementation and cognitive decline in Alzheimer disease. JAMA, 304, 1903-1911.

Smoking and Brain Fitness

As though there wasn’t already enough evidence that smoking tobacco is bad for you, a new study shows a significant relation between smoking in your late 50’s and the chance of developing dementia about 20 years later. Smoking has multiple effects on your body, especially your heart, and this study again supports the idea that things that are bad for your heart are also bad for brain fitness.

The study published online in the Archives of Internal Medicine used data from more than 20,000 members of a health care organization. They completed surveys in the late 1970s to the early 1980s. The authors of the study looked at how many of them were later diagnosed with dementia.

Results showed that the risk of getting dementia (either Alzheimer’s disease or vascular dementia) increased steadily the more people reported smoking. For less than a pack a day, the increase was small and not statistically significant. But for larger amounts of smoking, the increased risk was significant, and for people smoking more than two packs per day, the risk was doubled.

This study once again shows that brain fitness is also cardiovascular fitness. The same things that cause clogged arteries around your heart may very well result in clogged arteries in your brain.

One good note: people who described themselves as former smokers had the same risk as those who never smoked. So quitting now may help reduce your risk later.

Reference:

Rusanen M et al (2010). Heavy smoking in midlife and long-term risk of Alzheimer disease and vascular dementia. Archives of Internal Medicine. Published online October 25, 2010. View the abstract here.