Following up briefly on yesterday’s post regarding dietary fat and its effect on mental health, I have found a few articles to share with you.

The first is ‘The Risks of Low Fat Diets’ from Psychology Today dated April 29, 2003 (reviewed in 2012).

The article by Hara Estroff Marano reveals (emphases mine):

The first clue that low-fat diets might have anything to do with depression or self-directed violence turned up a few decades ago, quite by surprise. Large community-based studies of heart disease prevention strategies showed that among persons with the lowest cholesterol levels, there was a increased incidence of death not caused by illness, primarily to suicide, accidents, and violence.

the link between cholesterol lowering and suicide may run directly through brain serotonin pathways, with side stops to depression, irritability, impulsiveness, and aggression. Or it may run more indirectly through metabolic pathways of brain serotonin, the neurotransmitter most associated with depression. Whatever the link is, it’s complex, because it hasn’t been easy to pin down.

The article says that researchers are reluctant to delve too closely into this possible correlation because of the push for everyone to adopt a low-fat diet. No one wants to upset the apple cart.


Several studies have shown that low cholesterol is linked to depressed mood and to impulsivity, although it isn’t clear whether the link to depression is as true for people whose cholesterol levels are lowered by diet as in people with naturally occurring low cholesterol levels

But some problem in serotonin function seems always to be at the center of the story.

In nonhuman primates, high cholesterol levels enhance serotonin function. They lower levels of overt aggression. And they promote social behavior.

The article concludes that low-fat diets alter serotonin function. It is thought that lower fat levels in nerve-cell membranes could inhibit serotonin receptors.

Serotonin receptors help us function in society by regulating our moods and reactions. Low-fat diets could well have knock-on effects on all of us, directly or indirectly.

I seem to be acquainted with a number of bipolar people in the offline world. I’d never met any until a few years ago. Some of them were diagnosed in middle age.

It makes one wonder whether these people have been following low-fat diets for a long time. It also raises the question of whether adding a small amount of animal fat and/or omega-3 and omega-6 to their daily diets would help alleviate their symptoms.

More on low-fat diets and their effect on the body next week.