Anorexia nervosa is a serious eating disorder marked by severe restriction of food intake, an intense fear of gaining weight, and a distorted body image, leading to a low body weight. Despite severe calorie deprivation and malnutrition, individuals with anorexia often present with elevated levels of cholesterol in their blood. This finding often puzzles those unfamiliar with its physiological impacts.
The Counterintuitive Connection
High cholesterol is commonly linked to diets rich in saturated and trans fats, a lack of physical activity, or genetic predispositions, often seen in individuals who are overweight or obese. This makes the observation of high cholesterol in people with anorexia nervosa perplexing, as they consume limited calories and are significantly underweight. The body, adapting to prolonged starvation, initiates metabolic adjustments that lead to this rise in cholesterol levels. This represents a physiological response rather than a direct consequence of dietary fat intake.
Physiological Mechanisms Behind Elevated Cholesterol
Severe calorie restriction elevates cholesterol levels. Prolonged starvation causes the metabolic rate to slow down to conserve energy, impacting various bodily functions, including lipid processing. This reduction in metabolic activity contributes to an altered handling of fats.
Changes in thyroid hormone function also contribute to this. Anorexia nervosa can lead to a suppression of thyroid hormone production, particularly triiodothyronine (T3), the active form of thyroid hormone. Thyroid hormones are important regulators of cholesterol metabolism, influencing both its synthesis and its removal from the blood by the liver. Reduced T3 levels can impair the liver’s ability to clear cholesterol, allowing it to accumulate.
The liver’s metabolism undergoes adjustments in response to starvation. Despite limited dietary intake, the liver may increase its production of cholesterol. This upregulation of cholesterol synthesis, combined with an impaired ability to excrete cholesterol or convert it into bile acids, leads to higher circulating levels. Both total cholesterol and low-density lipoprotein (LDL) cholesterol, often referred to as “bad” cholesterol, are found to be elevated in individuals with anorexia.
Health Implications and Recovery
Elevated cholesterol levels in anorexia nervosa, while less immediately life-threatening than other complications of severe malnourishment like cardiac arrhythmias or electrolyte imbalances, pose health implications. Persistently high cholesterol can increase the risk of developing cardiovascular issues over time, including atherosclerosis, a condition where plaque builds up in the arteries. However, these longer-term risks are overshadowed by the acute medical dangers associated with severe malnutrition itself.
Fortunately, cholesterol levels normalize as individuals recover from anorexia nervosa. With proper re-feeding, gradual weight restoration, and the return of normal metabolic and hormonal functions, lipid processing improves. As thyroid hormone levels normalize and the liver’s metabolic functions stabilize, the synthesis and clearance of cholesterol return to healthy ranges. This normalization is an indicator of physiological recovery.