Omega-3 Fatty Acids Affect Risk Of Depression, Inflammation

[Guest guest]

Source:

Ohio State University

Date:

March 29, 2007

Omega-3

Fatty Acids Affect Risk Of Depression, Inflammation

A new study suggests

that people whose diets contain dramatically more of one kind of

polyunsaturated fatty acid than another may be at greater risk for both

clinical depression and certain inflammatory diseases.

The

report, published online in the journal Psychosomatic Medicine, suggests that

we need to balance out our intake of omega-6 and omega-3 fatty acids. The current typical American diet contains 20 times more

omega-6 than omega-3, a ratio that researchers say

should be lowered to 4-to-1, or even 2-to-1.

This is

the most recent in a long series of experiments Ohio

State University

researchers have conducted on the links between psychological stress and

immunity. The addition of dietary questions to studies

that have previously focused solely on emotional and biochemical markers may

yield important new clues about the immune system.

" In this study, we're looking at the intersection of

behavior, immune function and diet. In past

experiments, we concentrated only on the first two, " explained Jan Kiecolt-Glaser, professor of psychiatry and psychology at Ohio

State and lead author on the paper.

" It

now appears that diet is a very important variable in the equation as to how

people respond to depression and stress. "

The

study, conducted in OSU's Institute for Behavioral

Medicine Research, focused on a

group of 43 middle-aged to elderly men and women, nearly half of which were the

caregiver spouses of people with Alzheimer's or other dementias. By including caregivers who typically report greater

stress and more depression than similar adults who are not care giving, the

researchers could look at how depression and diet might interact to affect

inflammation.

Blood

samples were drawn from each person in the study and tested for interleukin-6

(IL-6), tumor necrosis factor -alpha (TNF-alpha ) and the receptor molecule for

IL-6. Participants also completed a survey

questionnaire that gauged their level of depression.

The analysis showed that participants who had much more omega-6 --

compared to omega-3 -- fatty acids, and who also were reporting more symptoms

of depression, had much higher levels of IL-6 and TNF-alpha, two cytokines

which enhance inflammation.

" The data suggest that higher depression and a poorer diet in

terms of omega-3 can work together to promote inflammation. Other

researchers have shown that clinically depressed people -- those with more

severe depression -- often have lower omega-3 levels in their blood, and

several studies have shown that supplementing diets with omega-3 improves

depression, " Kiecolt-Glaser said,

although the reason isn't clear.

" People

who are depressed don't eat well, or it might be that there is something about

depression that affects how well people process such foods. "

In recent years, research has shown that an

increase in omega-3 fatty acids in the diet has specific health benefits,

especially in patients with depression, cardiovascular disease

and inflammatory and autoimmune diseases.

Martha Belury, an associate professor of human nutrition,

endocrinology, diabetes & metabolism at Ohio

State and co-author of the study,

said the design of the study was important.

" We

looked at people who were experiencing real depression, not those whose

depression arose as a part of some experiment, and we could clearly see a

relationship between lower omega-3 fatty acids and certain markers of

depression and inflammation. "

Belury said that current

recommendations allow up to two servings each week of cold-water fish -- the

best source of omega-3 -- such as salmon or trout. This

would not apply to pregnant women, she said, where concerns are greater about

the heavy metal contamination such fish might contain. Omega-3

is also available as nutritional supplements

" This

study has shown that even in people who did not take supplements, maybe just a

little bit more omega-3, could help reduce their markers for both stress and

depression, " Belury said.

" The

important message for consumers is that they don't have to take mega-doses of

omega-3 to have some impact. It might not take a whole

lot to have a significant clinical impact, " Belury

said.

The researchers are now starting a larger, more comprehensive

randomized and controlled trial of omega-3 in adults between the ages of 50 and

80 in hopes of testing the questions raised in this pilot study.

Ron

Glaser, professor of internal medicine, molecular virology, immunology and

medical genetics; Beversdorf, an assistant

professor of neurology; Stanley Lemeshow, dean of the

College of Public Health, and Porter, a statistician in the Center for

Biostatistics, were also part of the project. The research

was supported in part by the National Institutes of Health.

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