Low serum 25-hydroxyvitamin D concentrations and secondary hyperparathyroidism in middle-aged white strict vegetarians

Abstract

The vitamin D status of vegetarians was studied in the winter. The groups studied were strict vegetarians (G1), lactovegetarians (G2), lactoovovegetarians eating some fish (G3), and vegetarians who were taking vitamin D supplements or who had been exposed to abundant sunlight during the last 6 mo (G4). A group of healthy women served as control subjects (C). The serum 25-hydroxyvitamin D [25(OH)D] concentration was significantly lower, the serum intact parathyroid hormone (S-iPTH) concentration significantly higher, and the dietary vitamin D intake significantly lower in G1 than in C. S-iPTH correlated negatively with serum 25(OH)D and dietary calcium intake. In conclusion, white strict vegetarians are at risk of vitamin D deficiency, at least in the winter, primarily because of a low dietary vitamin D intake, despite a normal sunlight exposure in summer. Low serum 25(OH)D concentrations are accompanied by high S-iPTH concentrations, which also are affected by a low calcium intake. The effect of these changes on bone health remains to be evaluated.