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

J Am Diet Assoc. 2000 Apr;100(4):434-41. doi: 10.1016/S0002-8223(00)00134-6.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorptiometry, Photon
  • Adult
  • Body Mass Index
  • Bone Density / drug effects*
  • Bone Density / physiology
  • Calcium / analysis
  • Calcium / urine
  • Diet, Vegetarian / adverse effects*
  • Exercise
  • Female
  • Femur / physiology
  • Finland
  • Humans
  • Longitudinal Studies
  • Lumbar Vertebrae / physiology
  • Parathyroid Hormone / blood*
  • Phosphates / urine
  • Premenopause
  • Seasons
  • Statistics, Nonparametric
  • Sunlight
  • Surveys and Questionnaires
  • Vitamin D / administration & dosage*
  • Vitamin D / analogs & derivatives*
  • Vitamin D / blood
  • Vitamin D / metabolism
  • Vitamin D / pharmacology
  • Vitamin D Deficiency / etiology
  • Vitamin D Deficiency / physiopathology

Substances

  • Parathyroid Hormone
  • Phosphates
  • Vitamin D
  • 25-hydroxyvitamin D
  • Calcium