In a study of 106 healthy volunteers, researchers found that participants who had lower blood levels of omega-3 polyunsaturated fatty acids were more likely to report mild or moderate symptoms of depression, a more negative outlook and be more impulsive. Conversely, those with higher blood levels of omega-3s were found to be more agreeable.

"A number of previous studies have linked low levels of omega-3 to clinically significant conditions such as major depressive disorder, bipolar disorder, schizophrenia, substance abuse and attention deficit disorder," said Sarah Conklin, Ph.D., a postdoctoral scholar with the Cardiovascular Behavioral Medicine Program in the department of psychiatry at the University of Pittsburgh School of Medicine. "However, few studies have shown that these relationships also occur in healthy adults. This study opens the door for future research looking at what effect increasing omega-3 intake, whether by eating omega-3 rich foods like salmon, or taking fish-oil supplements, has on people's mood."

The American Heart Association recommends that all Americans consume fish, which is high in omega-3 fatty acids, twice per week. This recommendation is based upon evidence that a diet high in fish s associated with improved heart health and reduced risk for heart-related problems. While the cardiovascular benefit of increasing omega-3 intake is well recognized, relatively little is known of the potential mental health effects among the general public.

Comparisons were made by analyzing levels of omega-3 fatty acids in participants' blood and comparing that data to the participants' scores on three accepted tests for depression, impulsiveness and personality. The amount of omega-3 circulating in blood reflects dietary intake of the fatty acid. The study did not require participants to make changes in their normal diet habits.

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Still, some nutritional supplement companies make and sell gamma-tocopherol supplements, promoting this version of vitamin E as a good antioxidant source. In theory, taking a vitamin supplement - a concentrated form of the vitamin - increases the amount of that substance in the body.

Using laboratory techniques that allowed them to detect the activity of the quinones inside the cells, the researchers found that the gamma-tocopherol quinone formed a compound which destroyed that cell. It did so by preventing proper protein folding in the cells, which causes a cellular response that is involved in a variety of human diseases, including diabetes and Parkinson's disease.

However, the alpha-tocopherol quinone did not kill cells, nor did it interfere with protein folding. The researchers repeated their experiments on kidney cells cultured from monkeys and on skin cells cultured from mice and found similar results.

"We think that gamma-tocopherol may have this kind of damaging effect on nearly every type of cell in the body," Ma said.

While the study doesn't get into the possible effects on health, the researchers raise the point that there is still a great deal that isn't known about how antioxidants act in the body. In order to get to that point, scientists must study how antioxidants and cells interact on their most fundamental levels.

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