If you're stressed, overweight and depressed, it may not be all in your head. In fact, it's probable that the high levels of blood fats (triglycerides) associated with obesity or with prediabetic insulin resistance in older persons are actually contributing to your depression.
A 2007 study conducted by the National Institutes of Health found links between depression and high levels of the stress-induced hormone cortisol. And there is evidence that depression may cause cardiovascular disease and diabetes.
Researchers at VU University in Amsterdam, The Netherlands; National Institute on Aging in Baltimore, Maryland; Geriatric Rehabilitation ASF in Florence, Italy; National Institute on Aging in Bethesda, Maryland and Geneva University Hospitals in Geneva, Switzerland, collaborated on the NIH study, which involved 867 participants.
The Metabolic Syndrome
Researchers found that elevated levels of urinary cortisol were linked to depression and to the metabolic syndrome. The metabolic syndrome describes abdominal obesity (pot belly) , high levels of blood fats (triglycerides), low levels of HDL ("good: cholesterol), high blood pressure and a high level of fasting glucose (blood sugar).
High levels of triglycerides (blood fats) are found in people who suffer from the metabolic syndrome and in those with cortisol-related depression.
The NIH study examined 867 persons 65 years and older (with a mean age of 74) and found evidence of a vicious cycle involving depression, high triglycerides and cortisol levels, and the onset of the metabolic syndrome. In a paper published in "Psychoneuroendocrinology," in February 2007, the researchers identified a "synergistic relationship" between these factors.
Stress and Cortisol
Chronic stress can disturb areas of the brain that regulate levels of blood cortisol. There is also a link between depression and high cortisol levels. And there is a connection between abnormally high levels of cortisol and signs of the metabolic syndrome, including abdominal obesity and glucose intolerance.
The NIH researchers concluded that people with depression caused or exaggerated by elevated cortisol levels are at increased risk not only for the metabolic syndrome but for cardiovascular disease and diabetes as well. Moreover, the study identified an interaction between depression and urinary cortisol as predictors of metabolic syndrome.
Other Effects on Mood
Besides depression, high levels of triglycerides are also correlated with other affective disorders including bipolar disorder (manic depression), schizoaffective disorders, aggression and hostility. In fact, the poor nutritional status of many depressed persons, who often have diets high in fats, can be improved to lessen the depression, according to Charles Glueck, MD, medical director of the Cholesterol Center of Jewish Hospital in Cincinnati.
"We have shown that in patients with high triglycerides who were in a depressive state, the more you lower the triglycerides, the more you alleviate the depression," Glueck wrote in a 1993 article in Biological Psychiatry.
According to the U.S. Centers for Disease Control and Prevention (CDC), most Americans aren't aware of the role triglycerides play in physical and mental health. A five-year study of more than 5,000 Americans found that 33 percent of them had borderline high triglyceride levels.
Treatment
Treatment for high triglyceride levels is the same as for high cholesterol: Lose weight, exercise regularly, eat a low-fat diet and quit smoking, according to the CDC. The effectiveness of treatment with drugs is unproven, according to Dr. Earl Ford with the CDC. Thus, it is unclear whether taking drugs to lower triglycerides can reduce the risk of cardiovascular disease or have any effect on mood, he said.
Summary
Although many Americans are not aware of their triglyceride (blood fats) level, it is an important number to watch, because of its potential to cause cardiovascular disease and depression. Triglyceride levels are linked to both mood as well as the metabolic syndrome through blood cortisol levels. Regular exercise, a low-fat diet, losing weight and stopping smoking are important to breaking this negative feedback loop between brain and body.
Tags: metabolic syndrome, blood fats, cardiovascular disease, cortisol levels, depression high, between depression, high levels