Galactosemia
Digestion of lactose in the intestine, and fermentation of milk gives increased concentrations of galactose. Galactose is catabolized by the Leloir pathway by phosphorylation at position 1, and then converted to UDP-galactose
and glucose-1-phosphate. Defects in enzymes in this pathway may result in galactosemia in humans, and early onset cataract. In young women ovarian failure at a very early age has been observed following galactose accumulation. Cramer et al. studied the relation between age-specific fertility rates, the prevalence of adult
hypolactasia and per capita milk consumption. They found that fertility at high ages is lower with high per capita consumption of milk and greater ability to digest its
lactose component. These demographic data thus add to existing evidence that dietary galactose may deleteriously affect ovarian function.