Failure to taste zinc sulphate solution does not predict zinc deficiency in pregnancy

As part of a double-blind randomised controlled trial to test the efficacy of 20 mg of zinc supplementation during pregnancy, 494 mothers were enrolled at booking. After giving informed consent they were asked to taste a dilute solution of zinc sulphate. Of the 489 mothers who were given the solution, 44 (9%) were unable to taste it. Mothers who failed this test did not differ significantly from the rest of the population in background factors such as social class, ethnic group, maternal age or parity. Significantly more non-tasting mothers had had a previous growth-retarded infant. Their diets did not differ in any way from those of the tasters. Zinc supplementation did not affect their taste as assessed at the end of pregnancy. Of the possible outcome measures considered, the zinc taste test did predict whether the mother was to develop diastolic hypertension (23% of non-tasters, 8% of tasters), but the mean birthweight, preterm delivery rate and other outcomes were identical.