Omega-3 fatty acid supplements slow cognitive
decline in early Alzheimer’s disease
In research published in the October, 2006 issue of the American Medical Association
journal Archives of Neurology Yvonne Freund-Levi, MD, of the Karolinska Institutet
in Stockholm, Sweden, and colleagues found that omega-3 fatty acid supplementation
could slow cognitive decline in patients with very mild Alzheimer's disease.
The team divided 204 patients with Alzheimer’s disease to receive 600
milligrams eicosapentaenoic acid (EPA) and 1.7 grams of docosahexaenoic acid
(DHA), or a placebo for six months, followed by a six month period during which
both groups received the omega-3 fatty acids. Physical examinations that included
blood testing, blood pressure assessment and cognitive function testing were
conducted at the beginning of the study, and at six and twelve months.
One hundred seventy-four participants completed the study. While there was no
difference in the rate of cognitive decline at the six month mark in the majority
of participants, a subgroup of 32 patients with very mild cognitive impairment
experienced no change in cognitive function test scores while receiving omega-3
fatty acids, while those who received the placebo experienced a significant
decline. This decline was halted when the placebo group received the omega-3-containing
supplements during the second half of the study. The group that received omega-3
fatty acids during the first six months experienced no further change during
the second six months of the study.
The results support other findings that suggest that a high intake of fish,
which is a source of omega-3 fatty acids, is helpful for the prevention but
not the treatment of Alzheimer’s disease. As the anti-inflammatory effect
of omega-3 fatty acids is a well known property of fish oil, it may play a role
in Alzheimer’s disease prevention. Research indicates that there may be
a critical period at least two years before the development of dementia in which
inflammation is elevated, and is potentially treatable.
“The mechanisms by which omega-3 fatty acids could interfere in Alzheimer's
disease pathophysiologic features are not clear, but since anti-inflammatory
effects are an important part of the profile of fish oils, they are conceivable
also for Alzheimer's disease,” the authors write. “It is possible
that when the disease is clinically apparent, the neuropathologic involvement
is too advanced to be substantially attenuated by anti-inflammatory treatment."
“Studies in larger cohorts with mild cognitive impairment, including those
at risk for Alzheimer's disease, are needed to further explore the possibility
that omega-3 fatty acids might be beneficial in halting initial progression
of the disease," they conclude.