Traditionally Living Populations in East Africa Have a Mean Serum 25-hydroxyvitamin D Concentration of 115 nmol/l

Br J Nutr. 2012 Nov 14;108(9):1557-61. doi: 10.1017/S0007114511007161. Epub 2012 Jan 23.

Abstract

Cutaneous synthesis of vitamin D by exposure to UVB is the principal source of vitamin D in the human body. Our current clothing habits and reduced time spent outdoors put us at risk of many insufficiency-related diseases that are associated with calcaemic and non-calcaemic functions of vitamin D. Populations with traditional lifestyles having lifelong, year-round exposure to tropical sunlight might provide us with information on optimal vitamin D status from an evolutionary perspective. We measured the sum of serum 25-hydroxyvitamin D₂ and D₃ (25(OH)D) concentrations of thirty-five pastoral Maasai (34 (SD 10) years, 43 % male) and twenty-five Hadzabe hunter-gatherers (35 (SD 12) years, 84 % male) living in Tanzania. They have skin type VI, have a moderate degree of clothing, spend the major part of the day outdoors, but avoid direct exposure to sunlight when possible. Their 25(OH)D concentrations were measured by liquid chromatography-MS/MS. The mean serum 25(OH)D concentrations of Maasai and Hadzabe were 119 (range 58-167) and 109 (range 71-171) nmol/l, respectively. These concentrations were not related to age, sex or BMI. People with traditional lifestyles, living in the cradle of mankind, have a mean circulating 25(OH)D concentration of 115 nmol/l. Whether this concentration is optimal under the conditions of the current Western lifestyle is uncertain, and should as a possible target be investigated with concomitant appreciation of other important factors in Ca homeostasis that we have changed since the agricultural revolution.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 25-Hydroxyvitamin D 2 / blood
  • Adolescent
  • Adult
  • African Continental Ancestry Group
  • Aged
  • Calcifediol / blood*
  • Clothing
  • Developing Countries
  • Female
  • Humans
  • Life Style / ethnology*
  • Male
  • Middle Aged
  • Nutritional Requirements
  • Rural Health* / ethnology
  • Skin Pigmentation
  • Sunlight*
  • Tanzania / epidemiology
  • Vitamin D Deficiency / blood
  • Vitamin D Deficiency / epidemiology
  • Vitamin D Deficiency / ethnology
  • Vitamin D Deficiency / prevention & control*
  • Young Adult

Substances

  • 25-Hydroxyvitamin D 2
  • Calcifediol