Anorexia nervosa is the classic eating disorder associated with a distorted sense of one’s own body weight and body shape, as well as a dangerous associated drop in weight levels. Doctors have known for some time that people affected by anorexia often have unusually high levels of cholesterol in their bloodstreams, even though they heavily restrict their food intake. According to the results of a new study published in September 2013 in the journal Molecular Psychiatry, anorexic individuals commonly have a genetic mutation that alters their ability to process cholesterol. In turn, poor cholesterol processing may play a critical role in the eating disorder’s manifestations in those individuals.
Cholesterol is the commonly used name for a group of wax-like substances called lipoproteins, which contain both fat molecules (lipids) and protein molecules. The two most prominent forms of these substances in the human body are low-density lipoprotein (LDL cholesterol; also known as “bad” cholesterol) and high-density lipoprotein (HDL cholesterol; also known as “good” cholesterol). Despite its notorious reputation, LDL cholesterol plays a critical role in human health by doing such things as supplying some of the building blocks needed to create the body’s cells, helping the body digest food, helping manufacture hormones and helping manufacture the body’s internally generated supply of vitamin D. Unfortunately, when it accumulates in the bloodstream in excessive amounts, LDL cholesterol can also seriously endanger human health by clogging arteries and disrupting the normal rate of blood flow. HDL cholesterol plays a critical role in health by removing unneeded LDL cholesterol from the bloodstream.
Anorexia and High Cholesterol
People with anorexia commonly go to great lengths to avoid eating foods that contain large amounts of calories. Since foods high in cholesterol also frequently contain significant amounts of weight-gain promoting fat calories, anorexics typically have unusually low levels of cholesterol consumption when compared to the rest of the teen and adult population. Despite this fact, anorexic individuals commonly have higher-than-average levels of cholesterol in their bloodstreams. In a study published in 2006 in the International Journal of Psychiatric Nursing Research, researchers from King’s College London examined this issue in anorexic women from Argentina, a group known internationally for their unusual susceptibility to heart disease. These researchers concluded that the women in their study had elevated levels of both LDL and HDL cholesterol; they also concluded that the affected women have clearly increased risks for heart attacks and other forms of cardiovascular disease.
In the study published in Molecular Psychiatry, researchers from more than 24 U.S. and international institutions conducted an extensive series of gene-mapping experiments designed to uncover the hereditary factors that may play a role in the onset of anorexia. In the initial stages of these experiments, the researchers identified over 150 genes that might be linked to the disorder in some way. Gradually, they narrowed this number down until only a few potential candidates remained. Unexpectedly, one of the most prominent candidates turned out to be a mutation in one of the genes that the body relies on to properly process both internally produced cholesterol and dietary cholesterol. To eliminate the random effects of chance, the researchers repeated their genetic analyses in several groups of anorexic individuals. In each of these analyses, the same cholesterol-processing genetic mutation appeared as a common link among people affected by the eating disorder.
Significance and Considerations
The genetic mutation for cholesterol processing appears in people with anorexia far too often to be the result of chance. However, no one knows precisely why this mutation is so closely associated with the eating disorder, the authors of the study in Molecular Psychiatry note. Despite the lack of sure conclusions, several potential explanations exist for a connection between cholesterol processing and anorexia. For instance, some research findings indicate that high levels of cholesterol in the body help improve a person’s mood and also increase the durability of the body’s cells. In people affected by anorexia, the cholesterol-related genetic mutation may produce mood improvements while simultaneously making it easier to withstand the severe malnutrition classically associated with longstanding anorexic eating behaviors. Conversely, genetic problems with cholesterol processing may actually help trigger mood- and eating-related problems that lead to the onset of anorexia. Further research is needed to clarify these issues and uncover the true relationship between anorexia and genetically altered cholesterol processing.