Individual variability in homocysteine response to folate depletion: an unusual case

Research within the past decade has shown that even moderately elevated plasma homocysteine concentrations are associated with increased risk of vascular disease. A variety of genetic and nutritional factors can affect homocysteine concentrations, with folate nutriture being one of the most influential. Plasma homocysteine responses of healthy adults to folate depletion and repletion vary substantially, even when many nutritional and lifestyle factors are normalized in a metabolic unit. The case of a woman with a highly exaggerated homocysteine response to moderate folate depletion is presented. A variety of possible factors relating to homocystine metabolism are discussed, yet no convincing explanation for the unusual pattern is apparent. The case demonstrates that the homocysteine response to folate can be highly variable between individuals, and suggests that further research on the genetic determinants of the human folate requirement is warranted.