More than a billion may suffer from vitamin D deficiency

More than a billion may suffer from vitamin D deficiency. Consequences may be more severe than thought. Prominent clinician calls for action.

Clinicians estimate that about half of the European population is suffering from mild vitamin D deficiency. Now a prominent European clinician has called for international action to address the problems which may lead to increased osteoporosis, cancer, and other diseases.

Vitamin D was discovered about a century ago. Its widespread use in infants has virtually eradicated severe vitamin D deficiency and rickets. The elderly and immigrant populations with darker skin are even the populations most seriously and most frequently deficient. Moreover insufficient vitamin D may have broader health consequences than previously thought.

Speaking at the European Congress of Endocrinology in Glasgow, Professor Roger Bouillon of the University of Leuven called for concerted research projects to back up the animal work linking vitamin D insufficiency with global health risks such as osteoporotic fractures, cancer and auto-immune diseases.

Vitamin D status can be readily estimated by measurements of serum 25-hydroxyvitamin D, and optimal health requires at least 20 ng 25(OH)D/ml. By this definition, half of the over 60s in Europe are already deficient. In some populations this figure is even higher, for example 2/3 of the UK Pakistani population is deficient.

Vitamin D can either be obtained from food but natural food sources except fatty fish has a low vitamin D content. Exposure to sunlight can also produce vitamin D but the very same ultraviolet light is also responsible for accelerated ageing and cancer of the skin. Therefore, vitamin D intake should be increased by food supplementation.

Professor Bouillon said:

We already know that insufficient vitamin D increases the risk for osteoporosis, falls and fractures. This is preventable by additional calcium and vitamin D intake (400-800 IU/d) for the elderly people. There are now however new and growing evidence that mild vitamin D deficiency is also associated with more tuberculosis, and some epidemiological studies suggest an increased risk for colon, breast and prostate cancer, and also auto-immune diseases such as type 1 diabetes. Animal data clearly support an essential role of vitamin D metabolites in the regulation of cell proliferation (cancer) and the immune system (auto-immune diseases and infection such as tuberculosis).

As this insufficiency of vitamin D is a worldwide problem we need large scale prospective studies to proof that improved vitamin D intake translates into less cancer, auto-immune diseases and better global health status. If such studies show the expected beneficial effects suggested by animal studies then more than a billion people of all ages worldwide would need to increase their vitamin D intake.

The message is thus simple: there is already sufficient evidence of efficacy so that the elderly population should increase their calcium and vitamin D intake (about 1g of extra calcium and about 400-800 IU vitamin D/day) to prevent osteoporotic fractures.

Additional larger scale prospective studies are needed to evaluate the potential general health effects of better vitamin D nutritional status.