Depression has been found to be caused by a number of conditions, including osteoporosis, stroke, and type 2 diabetes. It effects an estimated 18 million Americans. While supplements like St. John’s Wort reduce minor to moderate depression, the fact that depression’s root causes reside in the brain leaves omega-3 fatty acids as perhaps the best way to help promote mental health.
Previous research has shown that omega-3 fatty acids found in fish oil (called EPA and DHA), promote mental health by helping decrease inflammatory proteins called PGE27 and interleukins. This new study published in the August 2006 European Journal of Clinical Nutrition has found that long-term intake of omega-3 fatty acids are effective in helping promote mental health.
In the study, researchers studied depression in 124 Greek elderly males with an average age of 84 years. In addition to measuring depression through the Geriatric Depression Scale, they measured omega-3 fatty acid intake in both blood and fat tissue. These measurements were used to identify which methods were better predictors of short-term and long-term omega-3 intake for helping improve mental health.
The researchers found that depressed males had significantly lower levels of DHA and EPA in fat tissue than non-depressed males while no significant differences were seen in the blood measurements. The fact that researchers found measuring fat tissue levels to be better predictors of depression than blood levels is thought to be due to the slow rate of deposition of omega-e fatty acids in the brain. They also found that this effect on depression may lie in the ability of the omega-3's to help keep PGE2 levels low, confirming previous research. Finally, keeping PGE2 levels low is thought to help protect an area of the brain called the hippocampus which controls emotion.
The researchers concluded, “a reduced long-term [omega-3 fatty acid] intake is associated with an elevated risk for depression in the elderly.” There are a number of good fish oils on the market, but one of the best new ways to get omega-3 polyunsaturated fats is from krill oil.
Mamalakis G. Depression and adipose and serum cholesteryl ester polyunsaturated fatty acids in the survivors of the seven countries study population of Crete. Eur J Clin Nutr 60: 1016-1023