Many patients in intensive care are deficient in vitamin D

Australian researchers have discovered that many critically ill patients in intensive care are deficient in vitamin D.

A small study by researchers at the Garvan Institute of Medical Research in Sydney, has found that as many as 45% of patients in an intensive care unit were vitamin D-deficient.

The lead author of the study Dr. Paul Lee, an endocrinologist and research fellow at the Institute says the sicker the patients were, the lower their vitamin D levels and he says it is unclear whether this is just an association, or whether vitamin D deficiency itself contributes to the severity of the disease.

Vitamin D is a fat-soluble vitamin that is naturally present in only a few foods - some fish, such as salmon and tuna, cheese, egg yolks and some mushrooms - vitamin D is also found in fortified milk and cereals.

The best natural source is when sunlight strikes the skin and triggers vitamin D production in the body.

Vitamin D is essential for the body's calcium absorption in the gut and bone growth and health - a shortage of vitamin D means bones can become thin, brittle, or misshapen.

Vitamin D prevents rickets in children and osteomalacia in adults and together with calcium, helps protect older adults from osteoporosis.

Vitamin D also plays a roles in the immune system and the reduction of inflammation and some experts believe vitamin D deficiency is increasingly being linked to adverse health outcomes.

For the study, the researchers measured vitamin D levels in 42 people being treated in an intensive care unit and found almost half were vitamin D-deficient.

The researchers say three patients died during the study and it was found that they had the lowest levels of vitamin D in the study group.

Dr. Lee says that vitamin D is involved in controlling blood sugar levels, calcium levels, heart function, gastrointestinal health and in defending against infection.

While the researchers are unable to explain the exact cause of the vitamin D deficiency, they suggest an absence of sun exposure could play a role, as could a lack of dietary intake of vitamin D. Dr. Lee says it may be that the tissue demand for vitamin D is increased during infection, metabolic disturbances and inflammation and vitamin D may therefore be used up during critical illness.

He says this hypothesis and the relationship between vitamin D and critical illness needs more research as vitamin D deficiency is likely to be common in seriously ill patients.

While some experts agree that more research is called for, some suggest that further studies need to be done to see if replacing the lost vitamin D would benefit these patients.

They say it is known that in stable situations, vitamin D deficiency has a potential link to mortality, and vitamin D replacement does improve outcomes, but they say it is too early to tell from this study, if there would be a mortality benefit from vitamin D replacement and for immobile patients, there is a risk of creating calcium levels that are too high.

In the current study, 10 patients were given vitamin D supplements, and no protective effect was found.

The study results were published in letter form in the April 30th issue of the New England Journal of Medicine.