J Am Diet Assoc. 2000 Apr; 100(4): 434-41.

Dietary intake of vitamin D in premenopausal, healthy vegans was insufficient to maintain concentrations of serum 25-hydroxyvitamin D and intact parathyroid hormone within normal ranges during the winter in Finland.

Outila TA, Kärkkäinen MU, Seppänen RH, Lamberg-Allardt CJ.

Department of Applied Chemistry and Microbiology, University of Helsinki, Finland.

OBJECTIVE: To study vitamin D status and bone metabolism of premenopausal vegetarians and omnivores during a 1-year period. DESIGN: Longitudinal, observational study. Bone mineral density was measured, blood samples from fasting subjects were obtained, and 24-hour urinary samples were collected in February 1994, August 1994, and January 1995. Serum 25-hydroxyvitamin D [S-25(OH)D] and intact parathyroid hormone (S-iPTH) concentrations were measured and intestinal calcium absorption was estimated. Dietary intakes of vitamin D and calcium were calculated. SUBJECTS/SETTING: Six vegans, 6 lactovegetarians, and 16 omnivores living in Helsinki, Finland. STATISTICAL ANALYSES PERFORMED: Student-Newman-Keuls test; unbalanced, repeated-measures multiple analysis of variance; analysis of covariance; Pearson correlation test; and linear regression analysis. RESULTS: Dietary intake of vitamin D was significantly lower in vegans (P < .05, yearly mean +/- standard deviation = 0.09 +/- 0.06 microgram/day) and in lactovegetarians (P < .05, 0.7 +/- 0.4 microgram/day) compared with omnivores (4.0 +/- 2.1 micrograms/day). Throughout the year S-25(OH)D (P = .01) concentrations were lower and S-iPTH (P = .01) concentrations were higher in vegans than in omnivores and lactovegetarians. Bone mineral density in the lumbar region of the spine was lower in vegans (yearly mean +/- standard deviation = 1.034 +/- 0.174 g/cm2) than in omnivores (P = .05, 1.177 +/- 0.099 g/cm2) and tended to be lower than that in lactovegetarians (P = .17, 1.138 +/- 0.06 g/cm2). Bone mineral density in the neck of the femur tended to be lower in vegans (0.843 +/- 0.116 g/cm2) than in omnivores (P = .07, 0.999 +/- 0.138 g/cm2) and lactovegetarians (P = .15, 0.961 +/- 0.059 g/cm2). No seasonal variation was found in bone mineral density in the study groups. CONCLUSIONS: At northern latitudes, dietary intake of vitamin D in vegans was insufficient to maintain S-25(OH)D and S-iPTH concentrations within normal ranges in the winter, which seems to have negative effects on bone mineral density in the long run. APPLICATIONS: An increase in vitamin D intake should generally be recommended for vegans at least during winter, or selections of foodstuffs fortified with vitamin D should be broadened in northern latitudes.