ABSTRACT
Under-eating to reduce body weight appears to be the fundamental cause, leading to a fall in adipose tissue mass. This might appear a good thing, but we now know that adipose tissue has important endocrine functions. In particular, adipose tissue secretes leptin, a polypeptide hormone. If adipose tissue mass falls, so does leptin secretion. Leptin plays an important biological role in control of reproduction and lack of leptin stops reproduction when food is scarce. In female athletes with very low fat mass there is hypothalamic “switch off” of GnRH (gonadotrophin-releasing hormone) and so of reproduction. The consequent fall in oestrogen leads to bone mineral loss, just as it does at the menopause. The relation between mineralisation and menstrual function has been demonstrated many times now – but is still a relatively recent finding – the first studies were only in the mid 1980s.
