Women taking oral contraceptives need vitamin supplements

This is probably false. The transport of some vitamins in blood and the metabolism of some vitamins can be changed by the oral contraceptive pill. Lower dose pills have a lesser effect. This does not necessarily mean that one needs to alter one's vitamin intake. Studies of vitamin supplementation in this situation have been conflicting. The vast numbers of women who take the oral contraceptive pill do so without any convincing evidence of functional abnormality arising from vitamin deficiency.