You already know that diet plays a key role in health, quality of life and longevity. But if you ever considered that the quality of your diet may play a role in mental illness, you may be more motivated to clean up your eating habits. That's the conclusion of some disquieting research that found that trans fats and saturated fats --- long demonized for their effects on heart health --- are also linked to the development of depression.
Fat Consumption in the United States
The type of fat and amount Americans typically eat can be detrimental to health. Although most recommendations about fat in your diet are based on lowering your risk for heart disease, there's growing evidence that cardiovascular disease and depression share some of the same risk factors. In addition, although some foods naturally contain some fat, fat is also deliberately added to other foods. It's these added fats that Americans consume too much of and that are worsening the rates of chronic diseases, possibly including depression. Solid fats comprise about 19 percent of the average American diet, according to the Dietary Guidelines for Americans 2010.
Depression
Depression is more than feeling sad for a few days. It is a serious and common illness that requires the attention and care of a medical professional. The Centers for Disease Control and Prevention reports that one in every 10 American adults has depression. Depression is influenced by genetic, hormonal, immunological, biochemical and neurological factors, but your diet can affect each of these factors, according to the "American Journal of Psychiatry." The CDC says depression can also negatively affect other chronic diseases such as asthma, arthritis, heart disease, certain cancers and diabetes.
Dietary Fat and Depression
In the January 2011 "PLos One," Spanish public health researchers reported a rising trend in depressive disorders that paralleled increased consumption of fats found in the Western diet. Chiefly, the increased use of saturated and trans fat was replacing the use of monounsaturated and polyunsaturated fats typically found in the Mediterranean diet. Their study, believed to be the first of its kind, showed that trans fat, and to a lesser degree, saturated fat, was a strong risk factor for depression. They also noted the depressed people in their study also had low-grade inflammation, which may interfere with the metabolism of neurotransmitters and impair nerve cell function.
Good Fats
The Spanish researchers also noted that monounsaturated and polyunsaturated fats had an inverse association with depression, although it wasn't very strong. There's some evidence that fats found in olive oil, nuts and seeds may provide some protection of your mental health. Their findings dovetail with research reported by Rosemary Wander, a former nutrition professor and researcher at Oregon State's Linus Pauling Institute. She said those same fats in your bloodstream are indicative of how much serotonin you have. Serotonin is a neurotransmitter and major biomarker for depression and aggression.
References
- "PLoS One"; Dietary Fat Intake and the Risk of Depression: The SUN Project; Almudena Sánchez-Villegas et al.; January 2011
- Linus Pauling Institute; A Primer on Dietary Fat: The Good, the Bad and the Unknown; Rosemary Wander; November 1998
- "American Journal of Psychiatry"; Association of Western and Traditional Diets With Depression and Anxiety in Women; Felice N. Jacka et al.; March 2010
- Centers for Disease Control and Prevention: Depression
- "British Journal of Psychiatry"; Dietary Pattern and Depressive Symptoms in Middle Age; Tasnime N. Akbaraly et al.; November 2009
