Research Article

Relative contributions of diet and sunlight to vitamin D state in the elderly.

Br Med J 1979; 2 doi: (Published 04 August 1979) Cite this as: Br Med J 1979;2:303
  1. D E Lawson,
  2. A A Paul,
  3. A E Black,
  4. T J Cole,
  5. A R Mandal,
  6. M Davie


    In winter the vitamin D state of elderly people may reach levels associated with osteomalacia, although the disease may not be clinically apparent. A statistical correlation was observed in a group of elderly subjects during the winter between dietary vitamin D intake and vitamin D state, but the intake was generally too low to make a biologically important contribution to maintaining vitamin D concentrations. Ultraviolet light (UVL) is the primary determinant of vitamin D state in summer and winter, in winter owing to the pools of vitamin D built up during the previous summer. Plasma concentrations of 25-hydroxy vitamin D (25-OHD) in winter of 15.0-22.5 nmol/l (6-9 ng/ml) require that the concentration in the previous summer was over 40 nmol/l (16 ng/ml). To maintain plasma concentrations in the elderly above those associated with osteomalacia a mean dietary vitamin D intake of over 5 microgram/day is required. A more physiological approach, however, would be to increase exposure to UVL.