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Millions of British people are at risk of developing serious health conditions because of low vitamin D levels declares a new scientific review commissioned by the Health Supplements Information Service (HSIS).
Despite the proven health benefits of vitamin D, about three quarters of British adults fail to reach even their basic requirements thanks to poor dietary intakes and a lack of sun in this country. Now nutrition experts are calling for the shortfall in our diets to be made up by improved dietary intakes and vitamin D supplementation. As studies show, supplementation has a guaranteed effect on vitamin D status.
In this latest study review, called Health Impacts of Vitamin D: Are We Getting Enough?, independent researchers analysed the current evidence surrounding vitamin D. The aims were to identify the main health benefits associated with the vitamin and to explore issues surrounding optimal daily intakes.
Leading dietitian, Dr Carrie Ruxton, and senior lecturer in Human Nutrition at Manchester Metropolitan University, Dr Emma Derbyshire, reviewed more than 100 published research papers relating to the potential power of vitamin D, mechanisms to explain its benefits, vitamin D intakes and recommendations. Their paper will be published in the June issue of Nutrition Bulletin, the journal of the British Nutrition Foundation.
Scientific research suggests that vitamin D plays an important role in helping combat a host of serious health conditions, including cancer, heart disease, multiple sclerosis and immune disorders, as well as boosting bone health. Recent research work has linked vitamin D deficiency with a significantly increased risk of poor mental and physical health.
Normally vitamin D is produced by the body following skin exposure to sunlight. However, the northern latitude of the UK means that adequate access to sunlight is only possible over 7 months of the year. During the winter months, there is simply not enough sunlight to stimulate our bodies to make vitamin D. An increased awareness of the risks of skin cancer has also limited typical skin sun exposure levels, as have cultural reasons for covering the skin.
A regular intake of vitamin D-rich foods or a multivitamin rich in vitamin D can help enhance our skin production. Good food sources include oily fish, meat, fats and spreads, breakfast cereals, dairy products and eggs. However, consumption of many of these foods has declined in recent years. For example, in 1974, the average person bought 147g a week of butter compared with just 41g a week in 2007.
Currently in the UK, there are no recommended intake levels of vitamin D for most adults. The European Union recommends a daily intake of 5µg (micrograms) for food labelling purposes, while the European Food Safety Authority suggests a maximum of 25µg a day for children and 50µg a day for 12 to 70 year olds. Dr Ruxton and Dr Derbyshire found that in the UK, 71 per cent of men and 78 per cent of women failed to reach even 5µg of vitamin D intake a day, with an average of just 3.7µg for men and 2.8µg for women.
The recommended safe upper level in America, Australia and New Zealand is 80µg a day, but studies now suggest that levels of 500 to 1,000µg a day may well be safe. One study reported that to lower the risk of osteoporotic bone fractures, adults needed to take at least 55µg of vitamin D through diet, in addition to usual sun exposure.
Commenting on the latest review commissioned by HSIS, Dr Ruxton says: There is a growing body of literature to show that vitamin D is important for maintaining health and lowering the risk of some chronic diseases. A better vitamin D status appears to be linked with a lower risk of cardiovascular disease, diabetes and inflammatory conditions, and less cognitive impairment in older people.
Taking the evidence as a whole, a rather worrying picture emerges implying that British adults and children are at increased risk of chronic disease due to vitamin D insufficiency. We need to re-examine UK dietary recommendations for vitamin D, which were originally informed by research from the 1960s and 1970s. In particular, vitamin D recommendations for those unlikely to achieve sufficient sun exposure, or those with particular health needs, need to be addressed.
We also need to address declining intakes of foods rich in vitamin D. Most people are still failing to eat enough oily fish or low fat dairy foods which are useful sources of the vitamin. Vitamin supplementation such as taking a daily multivitamin rich in vitamin D could play a useful role in addressing low vitamin D intakes as studies show they help boost vitamin D levels in the blood. Not everyone gets all the nutrients they need from their diet so a multivitamin containing vitamin D can be a good insurance policy while long-term dietary changes are being made.
For more information on vitamins and minerals visit www.HSIS.org.uk.