July 5, 2007
Omega-3 fatty acids, the "good" fats found in salmon and other fatty fish, may ease agitation and depression in some people with Alzheimer's disease, a new study suggests.
Although the study was small and needs further follow-up, results suggest that fish oils may have benefits for the behavioral disturbances that often afflict those with dementia.
The findings came from researchers in Sweden and were published online in the International Journal of Geriatric Psychiatry. Numerous population studies suggest that the heart-healthy fats found in fish have benefits for the brain. A study last year involving some of the same researchers, for example, found that fish oils may benefit those in the earliest stages of Alzheimer's. [See the article, "Omega-3s, the Fats in Fish Oils, May Benefit Very Mild Alzheimer's Disease"]
Animal studies suggest that components of fish oils may also improve cognitive performance, or reduce the build-up in the brain of beta-amyloid, the sticky protein that is thought to underlie Alzheimer's. Other studies suggest that high doses of the fats may also ease depression.
In the current study, researchers at the Karolinska Institute and Uppsala University studied about 200 men and women with mild to moderate Alzheimer's disease. Some received dietary supplements containing omega-3s, while others got a look-alike placebo pill. All were assessed regularly for agitation, depression, and other psychiatric symptoms.
After a year, the researchers did not notice any appreciable differences overall between the two groups. However, when they broke the study participants down into subgroups based on their genetic makeup, they found a notable difference in those who carried the APO-E4 gene, a common gene that predisposes to late-in-life Alzheimer's. Those who carried the APO-E4 gene who were taking the fish oil pills showed less agitation than APO-E4 carriers taking placebo. Those who did not carry the gene, on the other hand, exhibited fewer symptoms of depression than non-carriers taking placebo. In other words, the fish oils seemed to benefit individuals differently, depending on their genetic makeup.
The research team points out that no general therapeutic recommendations can be made from the results until larger trials on individuals with more pronounced behavioral symptoms are conducted. However, the findings suggest that fish oils may provide personalized benefits, depending on the genes an individual inherits.
Fish oils are composed of two key types of omega-3s believed to benefit the heart and, possibly, the brain. One is called DHA, or docosahexaenoic acid the other EPA, or eicosapentaenoic acid. Both are thought to have disease-fighting properties. Researchers speculate that the DHA and EPA in omega-3s may quell inflammation, which is emerging as a possible underlying cause of heart disease and other ills, including Alzheimer's disease.
Omega-3 supplements also appear to be generally safe and well tolerated, producing few undue complaints or side effects. Belching or bloating, however, may be a problem. This might be lessened or prevented by taking "enteric" coated omega-3 supplements. These generally do not break down until they enter the intestine. The researchers point out that more study is needed before fish oils can be recommended for the behavioral disturbances of Alzheimer's.
Yvonne Freund-Levi, Hans Basun, Tommy Cederholm, et al: "Omega-3 supplementation in mild to moderate Alzheimer's disease: effects on neuropsychiatric symptoms." International Journal of Geriatric Psychiatry, doi 10.1002/gps.1857, Published online 21 June 2007