ABSTRACT
Chapter 3 discusses the abnormalities of hormones and bone density found in eating disorders. The majority of bone density is laid down during adolescence. During starvation and stress, the hypothalamus in the brain resets to pre-pubertal levels of gonadotropin-releasing hormone, which ultimately results in low testosterone and estrogen production. The cave person brain attempts to reduce sex drive, menstrual period blood loss, and fertility during times of energy scarcity. In response to these changes as well as high cortisol (stress hormone) levels, bone density can fall rapidly. Low bone density (osteopenia or osteoporosis) can increase the risk of stress fracture, other major fracture, and permanent compression fractures in the spine that cause a hunched back, or kyphosis. The diagnosis of low bone density via Dual Energy X-Ray Absorptiometry (DXA or DEXA) scan is reported as a T-score or Z-score. Transdermal estrogen and intermittent progesterone are typically optimal for premenopausal females, while transdermal testosterone may be best for males with low bone density and low hormone levels. Bisphosphonates may be used with caution. Birth control pills do not help bone density or “restart” the period. Elite athletes competing in settings where drug screening is performed may not be allowed to use even therapeutic testosterone. Height, menstrual abnormalities, and the minimal clinical value of the body mass index (BMI) are all covered in detail. The Box at the end reviews compulsive exercise and movement during recovery.
