The traditional view of Vitamin D is that it is essential for maintaining bone health. Vitamin D deficiency is linked to rickets – in children; and osteomalacia – in adults. These two conditions can lead to bone deformities with an increased risk of fractures.
Beyond the focus on bone health the evidence for other health effects of Vitamin D has been inconsistent and controversial. Claims have been made about the possible benefits of Vitamin D supplementation in reducing the risk of cancer, heart disease and strokes. Enhancements to the immune system have also been postulated with potential impacts on infections and conditions such as multiple sclerosis.
Research from the University of California published in the current edition of the American Journal of Public Health shows that individuals with lower levels of vitamin D in their blood are twice as likely to die prematurely compared with those with higher levels of vitamin D.
A low level of vitamin D was defined as less than 30ng/ml of 25-hydroxyvitamin D (25-OH vitamin D); 25-OH Vitamin D is the main form of vitamin D found in human blood. The research involved collecting and re-analysing the data from 32 separate studies involving 566,583 participants.
In a separate study published in the current edition of the British Medical Journal, not only was the risk from low blood levels of vitamin D confirmed – for cancer as well as for heart disease – but supplementation with vitamin D was actually demonstrated to reduce such death rates.
A recent nationwide survey showed that more than 50% of the UK adult population has insufficient levels of vitamin D and that 16% have severe deficiency during winter and spring. Most of vitamin D comes from sunlight with about a further 10% being derived from diet – especially oily fish, eggs and cereals. There are also a variety of vitamin D supplements available from pharmacists or on prescription.