Fat Imbalance Drives Depression and Inflammation

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Fat Imbalance Drives Depression and Inflammation

Depression increases inflammation; Imbalanced omega-3/omega-6 ratio

typical of American diets fuels both problems further

by Craig Weatherby

 

We were intrigued by the findings of a study published last month, which

suggest a sinister synergy between imbalanced fat intake and the degree

of depression and inflammation in older adults.

 

This prompted us to search the literature for similar investigations.

And our hunt uncovered a Dutch study conducted in college students,

which produced parallel results.

 

Aside from the direct evils of depression, this debilitating mood

disorder damages memory and mental acuity and promotes inflammation.

 

In turn, depression-induced inflammation drives a variety of serious

health problems, from heart disease, arthritis, and cancer to diabetes

and Alzheimer's disease.

 

This is why both teams thought it important to detail the degree to

which imbalances in dietary fat intake might interact with depression

and its insidiously unhealthful handmaiden, inflammation.

 

Depression, inflammation and dietary fats in older adults

Thanks to prior research, we know that depression activates the body's

inflammatory response system, which yields higher blood levels of the

pro-inflammatory immune-system proteins called cytokines.

 

As the authors of a French review said at the turn of the century, " It

has been shown that a dietary increase of polyunsaturated omega-3 fatty

acids reduced strongly the production of [pro-inflammatory cytokines].

In contrast, diets with a higher supply of omega-6 linoleic acid [from

vegetables oils] increased significantly the production of

pro-inflammatory cytokines … " . (Colin A et al 2003)

 

Last month, researchers at Ohio State University set out to examine

whether diets high in omega-6 fatty acids and low in omega-3s - in other

words, high omega-6/omega-3 intake ratios -- add to depression-induced

increases in pro-inflammatory cytokines (Kiecolt-Glaser JK et al 2007).

 

The Ohio group wanted to know whether the excessive intake of omega-6

fatty acids typical of the American diet - which is usually accompanied

by inadequate intake of omega-3s -- fuels high, depression-driven levels

of inflammation even higher.

 

The three pro-inflammatory cytokines they measured were tumor necrosis

factor (TNF)-alpha, interleukin (IL)-6, and IL-6 soluble receptor

(sIL-6r) … elevated levels of which serve as markers of increased

inflammation in the body and are also associated with diverse health

problems.

 

The Ohio State team took blood samples from 43 older adults (average age

67), and the participants' depressive symptoms - or lack thereof -- were

assessed by means of a standard test (Kiecolt-Glaser JK et al 2007).

 

They found that symptoms of depression and high omega-6/omega-3 ratios

worked together to drive blood levels of pro-inflammatory IL-6 and

TNF-alpha higher than the levels produced by depression or a high

omega-6/omega-3 ratio alone.

 

In addition, while blood levels of TNF-alpha and IL-6 rose in tandem

with worsening depression, higher omega-6/omega-3 ratios increased the

levels of these cytokines even more.

 

Study participants who met the test criteria for major depression had

higher omega-6/omega-3 ratios and higher blood levels of the three

pro-inflammatory cytokines, compared with those who did not suffer from

major depression.

 

As the Ohio researchers said, " Diets with high … [omega-6/omega-3

ratios] … may enhance the risk for both depression and inflammatory

diseases. " (Kiecolt-Glaser JK et al 2007)

 

Dutch study extends concerns to college-age people

Just as depression does, psychological stress induces increased

production of pro-inflammatory cytokines. And, like most Americans, most

people in Western Europe eat diets too high in omega-6 fatty acids and

too low in omega-3 fatty acids from fish.

 

Seven years ago, a Dutch team from the University of Maastricht decided

to test whether this imbalanced omega-6/omega-3 intake ratio causes the

body to produce more pro-inflammatory cytokines than usual in response

to psychological stress (Maes M et al 2000).

 

They recruited 27 university students, and took blood samples a few

weeks before a difficult oral examination, one day before the exam, and

a few weeks afterwards.

 

The stress of the exam increased the students' blood levels of

pro-inflammatory cytokines, significantly.

 

What's more, blood levels of pro-inflammatory cytokines were highest in

the students with the lowest blood levels of omega-3s and in the

students with the highest omega-6/omega-3 ratios.

 

The Dutch scientists came to the obvious conclusion: " The results

suggest that increased omega-3 levels may attenuate [reduce] the

pro-inflammatory response to psychologic stress. " (Maes M et al 2000)

 

 

Sources

Kiecolt-Glaser JK, Belury MA, Porter K, Beversdorf DQ, Lemeshow S,

Glaser R. Depressive Symptoms, omega-6:omega-3 Fatty Acids, and

Inflammation in Older Adults. Psychosom Med. 2007 Mar 30; [Epub ahead of

print]

Colin A, Reggers J, Castronovo V, Ansseau M. [Lipids, depression and

suicide] Encephale. 2003 Jan-Feb;29(1):49-58. Review. French.

Maes M, Christophe A, Bosmans E, Lin A, Neels H. In humans, serum

polyunsaturated fatty acid levels predict the response of

proinflammatory cytokines to psychologic stress. Biol Psychiatry. 2000

May 15;47(10):910-20.