[Methods and their evaluation in estimating the vitamin B6-status in humans. 4. 4-PA: reliability of the parameters].

Effects of physiological factors on 4-PA-excretion of more than 400 industrial workers and students were examined. Borderline values are discussed. With increasing age men as well as women showed significant higher 4-PA-values. After optimizing the vitamin B6-uptake by means of vitamin administration the differences disappear. Age-depending variations in the ability forming 4-PA are not likely. The higher 4-PA-excretion of men is probably due to better dietary supply rather than to sex differences in metabolising the vitamin. There are no considerable influences on the parameter by oral contraceptives Short-term variations of dietary vitamin B6-supply have striking effects on the 4-PA-excretion and restrict the reliability of this parameter. An insufficient vitamin B2-supply can stimulate a marginal vitamin B6-status. Alcohol consumption the day before does not change the 4-PA-excretion.