their results in the paper "Fortification of Orange Juice with Vitamin D: a Novel Approach for Enhancing Vitamin D Nu tritional Health" (American lournal of Clinical Nutrition Vol. 77, pp. 1478-1483). A double-blind experiment was used in which i4 subjects drank 240 mi per day of orange juice fortified with 1000 IU of Vitamin D and 12 subjects drank 240 ml per day of unfortified orange juice. Concentra tion levels were recorded at the beginning of the experiment a 12 and again the end of weeks. The following data, based on the results of the study, provide the decrease (negative values indicate increase) in PTH levels for those drinking the ortified juice and for those drinking the unfortified juice.