The ratio of omega 6 to omega 3 fatty acids affects the risk of heart disease and depression among others, according to a new study published in the March 30, 2007 issue of Psychosomatic Medicine.

Early studies have already suggested that Americans eat too much of omega 6 fatty acids and too little of omega 3 fatty acids. The imbalance of fatty acids is linked to a variety of diseases.

The study by Dr. Janice K. Kiecolt-Glaser from Ohio State University College of Medicine in Columbus and colleagues found that people who suffer from symptoms of depression had high ratios of omega 6 to omega 3 fatty acids and high levels of inflammation-promoting compounds.

The inflammation-promoting compounds including tumor necrosis factor alpha and interleukin-6 have been associated with heart disease, type 2 diabetes, arthritis and other ailments, Kiecolt-Glaser told Reuters Health.

Omega-6 fatty acids are found in refined vegetable oils and foods with these oils and omega 3 fatty acids, on the other hand, are found in foods such as oily fish, flax seed oil and walnuts.

American men and women use up to 20 times as much omega 6 fatty acids as omega 3 fatty acids.   It is believed that the ratio of omega 6 to omega 3 fatty acids should be maintained at below 4 to 1.

The study involved 43 older men and women.

The researchers found that 6 who were diagnosed with major depression had 18 times as much omega 6 as omega 3 in their blood compared to 13 times as much for people without major depression.

The study also found that depressed people also had higher levels of tumor necrosis factor alpha, interleukin-6, and other inflammatory compounds compared to those who did not have depression.

Levels of depressive symptoms increased as the ratio of omega 6 to omega 3 fatty acids increased.

The association between the ratio of omega 6 to omega 3 and depression is not a causal relationship, meaning that eating more Omega 3 and less omega 6 fatty acids would not necessarily ease or prevent depression.  

But the possibility could not be excluded.   A number of early studies have actually found that omega 3 supplements prevent depression, according to the authors of the current study.