Current opinion holds that vitamin D levels should be higher than previously thought and by this standard the levels in the German population are generally too low, especially in winter”, according to a problem analysis by Dr Birte Hintzpeter who represented the Robert Koch Institute in Berlin. Older women and children or young people with an ethnic minority background, whose levels are often lower than they should be even in summer, are worst affected.
The insufficiency is caused by the poor availability of the micronutrient: fatty fish is one of the few food sources which provide appreciable amounts of vitamin D. Other than this, the body produces most of its vitamin D in the skin under the influence of sunlight.
As a northern country, Germany enjoys relatively little sunlight and is especially vulnerable to vitamin D insufficiency. The problem is exacerbated in groups of people with limited mobility or generally poor diets, as was only recently confirmed by the National Study of Food Consumption, said Prof. Biesalski from the University of Hohenheim.
From reduced immunity to increased mortality: a deficiency with manifold consequences
The effects are many and diverse: “There is ever more evidence that an insufficient supply of vitamin D in people of middle age and older is linked to increased mortality," said PD Dr. Armin Zittermann from the Cardiac and Diabetes Center of North Rhine-Westphalia, citing the latest research. In addition, the data evidence that an inadequate intake of vitamin D in youth can increase the incidence of chronic diseases such as multiple sclerosis and type I diabetes.
Cancer patients are another important group of people with special vitamin D requirements, explained Prof. Jörg Spitz from the Gesellschaft für Medizinische Information und Prävention (Society for Medical Information and Prevention) in Wiesbaden. “In oncology, vitamin D causes tumor growth to be suppressed – including metastases. Thus the risk for carcinoma of the female mammary gland or the large intestine, for example, is reduced.”
Equally, the immune system requires a sufficient level of vitamin D in the blood. Even in the womb a lack of vitamin D can affect development and lead to excessive immune responses and increased allergies in later years. Moreover, vitamin D stimulates the production of physiological antibiotics in the cells. And finally vitamin D protects the nerve cells against disease.
Expert group discerns a need to act
In view of the effects discussed the group of experts saw a need to act on the part of policy-makers and professional associations. Prevention strategies to increase vitamin D consumption are needed, as well as a revision of the current recommended intakes.
That there are no simple answers to such a complex set of problems was emphasized by host Prof. Biesalski in his contribution “Prevention as Risk.” It is no use whatsoever – he pointed out – to recommend extensive sunbathing if this in turn leads to elevated rates of skin cancer.”
Press Release University of Hohenheim. March 30, 2009