We have talked before about the associations between inflammation and psychiatric illnesses.
There is yet more evidence in the shape of a study just published in the journal Psychosomatic Medicine. by Janice K. Kiecolt-Glaser and her colleagues from Ohio State University College of Medicine in Columbus.
The study involved 43 older adults with a mean age of 66.67 years, and the results suggests that the imbalance of omega-6 and omega-3 fatty acids in the typical American diet could be associated with the sharp increase in heart disease and depression seen over the past century. The more omega-6 fatty acids people had in their blood compared with omega-3 fatty acid levels, the higher their levels of the inflammatory mediators tumor necrosis factor-alpha and interleukin-6, and the greater the chance that they would suffer from depression. These are the same inflammatory mediators associated with insulin resistance, type 2 diabetes and coronary artery disease, all of which are more common in depression. And depression is more common in diabetes, arthritis and coronary artery disease than expected.
Our hunter-gatherer ancestors consumed two or three times as much omega-6 as omega-3, but today the average Western diet contains 15- to 17-times more omega-6 than omega-3. There were 6 individuals in the study who had been diagnosed with major depression, and they had nearly 18 times as much omega-6 as omega-3 in their blood, compared with about 13 times as much for subjects who didn't meet the criteria for major depression.
Depressed patients also had higher levels of tumor necrosis factor alpha, interleukin-6, and other inflammatory compounds. And as levels of depressive symptoms rose, so did the omega 6 and omega 3 ratio. So it seems as if the effects of diet and depression enhance each other. People who had few depressive symptoms and/or were on a well-balanced diet had low levels of inflammation in their blood. But when they became more depressed and their diets became worse – which is very common when people are depressed – then the inflammatory mediators in the blood surged.
Omega-3 fatty acids are found in foods such as fish, flax seed oil and walnuts, while omega-6 fatty acids are found in refined vegetable oils used to make everything from margarine to baked goods and snack foods. The amount of omega-6 fatty acids in the Western diet increased sharply once refined vegetable oils became part of the average diet in the early 20th century.
Depression alone is known to increase inflammation, the researchers note in their report, while a number of studies have found omega-3 supplements prevent depression.
So this more evidence for the value of eating fatty fish like salmon, mackerel or sardines two or three times a week, but be sure to avoid fish that may contain a lot of mercury. If you add more fruits and vegetables to your diet, you will also reduce your levels of omega-6 fatty acids.
I have just finished analyzing all the new literature on using fish oils for the prevention and treatment of psychological and psychiatric problems, and I am going to post my findings in the next couple of days.