| An emerging body of evidence has linked high intake of folic acid, common in the Canadian population due to mandatory folic acid fortification and prevalent supplement use, to certain adverse health effects. High intake and blood levels of folic acid were associated with reduced natural killer cell cytotoxicity in a pilot study of post-menopausal women that has not yet been confirmed. As such, we investigated the effects of folic acid supplementation on natural killer cell activity in a mouse model. Folic acid supplementation, plasma folate, and plasma unmetabolized folic acid were associated with reduced NK cell degranulation in response to stimulation with malignant cells. Our data corroborate the previously observed inverse association between folic acid and natural killer cell cytotoxicity and suggests that reduced natural killer cell mediated tumour immunosurveillance may be an additional mechanism behind the purported tumour promoting effect of folic acid supplementation. |
