To Your Health
May, 2011 (Vol. 05, Issue 05)
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For example, Harvard University researchers have found that omega-3 fatty acid deficiency kills an estimated 72,000-96,000 Americans annually, potentially ranking as the sixth biggest killer of Americans.

This is more deadly than excess trans fat intake, which claimed an estimated 63,000-97,000 American lives the same year. The researchers drew on 2005 data from the National Center for Health Statistics, assessing 12 dietary, lifestyle and metabolic risk factors; and created a mathematical model to determine how many deaths could have been prevented if people had followed better dietary practices.

Major Health Benefits

Depression: Daily supplements of omega-3 fatty acids may improve measures of depression in seniors with mild to moderate depression. Yaser Tajalizadekhoob, from Tehran University of Medical Sciences (Iran), and colleagues have elucidated on the biological basis supporting this association. The team enrolled 66 men  and women, ages 65 years and older, in a six-month study. Each subject received either an omega-3 supplement containing one gram of fish oil per day, providing 300 mg of both EPA and DHA, or placebo. The researchers reported: "After adjusting for cholesterol, [body mass index], and history of thyroid dysfunctions, a statistically significant difference was seen in scores [on a standardized depression test for seniors] between both groups. Furthermore, treatment with [omega-3 fatty acids] was clinically more effective in treating depression in comparison with the placebo."

Heart Function: Among patients with heart failure, omega-3 fatty acid supplements improve heart function and exercise capacity. Northwestern University researchers report that omega-3 fatty acid supplements improve heart function and exercise capacity among patients with heart failure whose condition has been controlled. Mihai Gheorghiade and colleagues studied a group of 130 patients with chronic heart failure who were on standard therapy, assigning them to receive either omega-3 supplements (2 grams daily) or placebo. The team assessed left ventricular function and functional capacity at the study's start and 12 months later.

After a year, those patients receiving the omega-3 supplement showed a 10.4 percent increase in heart function, compared with a 5 percent decrease among those taking placebo. In addition, blood oxygen levels increased 6.2 percent in the omega-3 patients and decreased 4.5 percent in the placebo patients. Moreover, the team observed that exercise time went up 7.5 percent in those receiving supplements, while it went down 4.8 percent in those receiving placebo. Finally, among those taking the supplement, the hospitalization rate was 6 percent during the year, compared with 30 percent for those not taking the omega-3 supplement.

Vision: Age-related macular degeneration (AMD) is the leading cause of blindness in Caucasian Americans. High concentrations of omega-3s have been found in the eye's retina, and evidence is mounting that the nutrient may be essential to eye health. Sheila West, from Johns Hopkins School of Medicine, and colleagues studied 2,520 Maryland residents, ages 65 to 84 years, assessing the role of a diet rich in fish and seafood on AMD onset and progression. The team surveyed study subjects for fish and shellfish consumption over a one-year period, and assessed participants for AMD. Those with no AMD were classified as controls (1,942 people), while 227 had early AMD, 153 had intermediate-stage disease, and 68 had advanced AMD.

In the advanced AMD group, the macular area of the retina exhibited either neovascularization (abnormal blood vessel growth and bleeding) or a condition called geographic atrophy. Both conditions can result in blindness or severe vision loss. The team found that while participants in all groups, including controls, averaged at least one serving of fish or shellfish per week, those who had advanced AMD were significantly less likely to consume large quantities of omega-3 fish and seafood.

Brain Function: Healthy, middle-aged men and women with higher blood levels of DHA (docosahexaenonic acid), a type of omega-3 fatty acid, perform better on tests of reasoning, memory, and vocabulary. Matthew Muldoon, from the University of Pittsburgh, and colleagues pursued the mechanisms underlying this association. The researchers assessed data collected on 280 community-dwelling men and women, ages 35 to 54 years, who were free of major neuropsychiatric disorders and not taking fish-oil supplements. The team monitored dietary biomarkers of specific types of omega-3 fatty acids, and found that alpha-lipoic acid (ALA), eicosapentaenoic acid (EPA), and DHA correlated to five major aspects of cognitive performance. While neither ALA nor EPA was associated with improvements in tests of reasoning, memory or vocabulary, higher DHA did correspond to better performance on those cognitive parameters.