REBECCA L. OSHIRO
Vitamin D Council, 1241 Johnson Ave. #134, San Luis Obispo, CA 93401, USA

Abstract

The role of vitamin D in ensuring skeletal health is undisputed; its role in extra-skeletal health conditions is currently debated. Critics contend there is insufficient evidence from randomized, controlled trials to define the role of vitamin D outside of skeletal health. However, an evolutionary perspective along with observed 25(OH)D levels in modern humans under various circumstances provide useful guidance for determining a natural blood level of vitamin D for optimum health and disease prevention. The evidence supporting a vitamin D blood level of 40-60 ng/mL as the new normal is reviewed. Emerging evidence indicates the benefits of therapeutic sun exposure outweigh the risks of developing skin cancers while providing unique health benefits in addition to vitamin D production. Oral supplementation is a useful alternative to sun exposure for raising 25(OH)D status.

INTRODUCTION

An extraordinary increase in the quantity of vitamin D research published in the last ten years supports a link between vitamin D and a variety of ails including, but not limited to, various cancers, heart disease, autoimmune diseases, and infectious diseases (1). The promise of vitamin D to alleviate the burden of the most serious diseases of our time has drawn the attention of both the medical community and the lay public alike, spurring a meteoric rise in the sales of vitamin D supplements from $40 million in 2001 to $425 million in 2009 (2). The sunshine vitamin has not received a warm reception by all in the medical and research communities, igniting a controversial debate regarding the precise role of vitamin D in human health and how much is needed to ensure nutritional adequacy. To clarify this controversy, it is necessary to examine various biological endpoints as well as contemplate our evolutionary relationship to the sun. When these factors are taken into account, a “new normal” emerges for determining optimal vitamin D status in humans.
Entering the vitamin D debate, The Institute of Medicine (IOM) released a report ...