The Anorexia Nervosa-Osteoporosis Link
From the National Institutes of Health's Osteoporosis and Related Bone Diseases - National Resource Center
Anorexia nervosa has significant physical consequences. Affected individuals can experience nutritional and hormonal problems that negatively impact bone density. Low body weight in females causes the body to stop producing estrogen, resulting in a condition known as amenorrhea, or absent menstrual periods. Low estrogen levels contribute to significant losses in bone density.
In addition, individuals with anorexia often produce excessive amounts of the adrenal hormone cortisol, which is known to trigger bone loss. Other problems — such as a decrease in the production of growth hormone and other growth factors, low body weight (apart from the estrogen loss it causes), calcium deficiency, and malnutrition — contribute to bone loss in girls and women with anorexia. Weight loss, restricted dietary intake, and testosterone deficiency may be responsible for the low bone density found in males with the disorder.
Studies suggest that low bone mass (osteopenia) is common in people with anorexia and that it occurs early in the course of the disease. Girls with anorexia are less likely to reach their peak bone density and therefore may be at increased risk for osteoporosis and fracture throughout life.
Osteoporosis Management Strategies
Up to one-third of peak bone density is achieved during puberty. Anorexia is typically identified during mid to late adolescence, a critical period for bone development. The longer the duration of the disorder, the greater the bone loss and the less likely it is that bone mineral density will ever return to normal.
The primary goal of medical therapy for individuals with anorexia is weight gain and, in females, the return of normal menstrual periods. However, attention to other aspects of bone health is also important.
Nutrition: A well-balanced diet rich in calcium and vitamin D is important for healthy bones. Good sources of calcium include low-fat dairy products; dark green, leafy vegetables; and calcium-fortified foods and beverages. Supplements can help ensure that people get adequate amounts of calcium each day, especially in people with a proven milk allergy. The Institute of Medicine recommends a daily calcium intake of 1,000 mg (milligrams) for men and women, increasing to 1,200 mg for those age 50 and older.
Vitamin D plays an important role in calcium absorption and bone health. It is synthesized in the skin through exposure to sunlight. Food sources of vitamin D include egg yolks, saltwater fish, and liver. Many people obtain enough vitamin D by getting about 15 minutes of sunlight each day; others may need vitamin D supplements to achieve the recommended intake of 400 to 600 International Units (IU) each day.
Exercise: Like muscle, bone is living tissue that responds to exercise by becoming stronger. The best exercise for bones is weight-bearing exercise that forces you to work against gravity. Some examples include walking, climbing stairs, weight lifting, and dancing.
While walking and other types of regular exercise can help prevent bone loss and provide many other potential health benefits, these potential benefits need to be weighed against the risk of fractures, delayed weight gain, and exercise-induced amenorrhea in people with anorexia and those recovering from the disorder.
Healthy lifestyle: Smoking is bad for bones as well as the heart and lungs. In addition, smokers may absorb less calcium from their diets. Alcohol can also negatively affect bone health. Those who drink heavily are more prone to bone loss and fracture, because of both poor nutrition as well as increased risk of falling.
Bone density test: A bone mineral density (BMD) test measures bone density in various parts of the body. This safe and painless test can detect osteoporosis before a fracture occurs and can predict one's chances of fracturing in the future. The BMD test can help determine whether medication should be considered.
Medication: There is no cure for osteoporosis. However, there are medications available to prevent and treat the disease in postmenopausal women; men; and both women and men taking glucocorticoid medication. Some studies suggest that there may be a role for estrogen preparations among girls and young women with anorexia. However, experts agree that estrogen should not be a substitute for nutritional support.