Fish oil is sometimes used to fight Alzheimer's disease, an aging-related condition that impairs your memory and mental functioning. Preliminary research suggests that docosahexaenoic acid (or DHA, an omega-3 found in fish oil) may help prevent the formation of brain plaques associated with Alzheimer's. But while there's some evidence that regular intake of fish oil may reduce your Alzheimer's risk, fish oil doesn't appear to benefit people already struggling with Alzheimer's disease.
The Science Behind Fish Oil and Alzheimer's Disease
Following a diet rich in fish oil may protect against Alzheimer's disease, according to a 2004 study from Archives of Neurology. For the study, scientists gathered data on 815 older adults (all of whom were Alzheimer's-free at the start of the study). After an average of 3.9 years, 131 participants had developed Alzheimer's. Analyzing the participants' eating habits, the study's authors found that those who consumed fish once per week or more had a 60 percent lower risk of Alzheimer's compared to those who rarely or never ate fish. In addition, intake of DHA was strongly associated with a reduced risk of Alzheimer's.
In studies testing fish oil's effects on the development of Alzheimer's, researchers have found less positive results. For instance, a 2010 clinical trial involving 402 people with mild to moderate Alzheimer's found that fish oil supplements failed to slow the disease's progression. Published in the Journal of the American Medical Association, the study found that participants given two grams of DHA daily for 18 months did not experience a slower rate of cognitive decline (compared to those given a placebo).
Using Fish to Fight Alzheimer's Disease
Adding oily fish like salmon, mackerel, and herring to your diet may offer some protection against Alzheimer's disease (as well as enhance your heart health). However, given the lack of supporting research, use of fish oil in treatment of Alzheimer's is not advised. What's more, using fish oil in place of standard treatment for Alzheimer's may have health consequences.
Although fish oil is generally considered safe, there's some evidence that high doses of fish oil may keep blood from clotting, suppress the immune system, and increase levels of LDL cholesterol. Fish oil may also cause a number of mild side effects, such as temporary breath odor, nausea, and heartburn. If you're considering the use of fish oil supplements in prevention or treatment of Alzheimer's disease, talk to your doctor before you begin taking the supplements.
Sources
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National Institutes of Health. "Fish oil: MedlinePlus Supplements". January 2011.
Quinn JF, Raman R, Thomas RG, Yurko-Mauro K, Nelson EB, Van Dyck C, Galvin JE, Emond J, Jack CR Jr, Weiner M, Shinto L, Aisen PS. "Docosahexaenoic acid supplementation and cognitive decline in Alzheimer disease: a randomized trial." JAMA. 2010 Nov 3;304(17):1903-11.
