British Medical Journal Piece Says Evidence Does Not Back Vitamin D Supplements

There is not enough evidence to support taking vitamin D supplements, according to an article in a leading medical journal.

Earlier this year, Public Health England (PHE) said vitamin D was vital for bone and muscle health but warned that people were generally not getting enough from sunlight during the winter months

It said everyone should ensure they were getting 10 micrograms of vitamin D per day, and should consider a supplement during the autumn and winter.

But a new article published in The British Medical Journal (The BMJ) concludes that: "Current evidence does not support the use of vitamin D supplementation to prevent disease".

Three experts from the University of Aberdeen and the University of Auckland, New Zealand, argued that people at risk of vitamin D deficiency should be advised about sunlight exposure and diet and offered low dose supplements.

But those who are not at risk should eat a healthy and balanced diet with food containing vitamin D and get regular short bursts of sunshine.

Sunlight is the main source of vitamin D for most people and it can be found in a small number of food including oily fish, red meat, liver and egg yolks and in fortified food like breakfast cereals and fat spreads.

Not having enough vitamin D can lead to bone deformities such as rickets in children and a condition called osteomalacia in adults which results in bone pain and tenderness.

The authors of The BMJ piece said that analysis of randomised controlled trials show that vitamin D supplementation alone does not improve musculoskeletal outcomes - such as bone fractures.

However, in a supplementary article, Dr Louis Levy, head of nutrition science at Public Health England, wrote that advice to take a vitamin D supplement of 10 micrograms a day is backed by a Scientific Advisory Committee on Nutrition (SACN) review of the evidence on musculoskeletal health outcomes.

He wrote it is "not easy to get what you need from your diet alone", adding: "Public Health England advises that eating a healthy, balanced diet and getting some sun means you are likely to get enough vitamin D during spring and summer.

"But during autumn and winter the only source is diet and so everyone should consider a daily supplement of 10 micrograms during these months."

Commenting on the study, Martin Hewison, professor of molecular endocrinology at the University of Birmingham, said: "It is clear that people in the UK are at high risk of vitamin D deficiency, particularly in winter.

"The SACN recommends taking vitamin D supplements for the whole UK population to prevent vitamin D-deficiency.

"SACN indicated that their recommendations were particularly relevant for people at high risk of deficiency: those with darker skin from African, Afro-Caribbean and South Asian backgrounds; people who are confined indoors, and people who cover up their skin while outdoors.

"The level of vitamin D intake recommended by SACN is 10 micrograms per day, a relatively low but safe level of supplementation."

Professor Mark Baker, director of the centre for guidelines at the National Institute for Health and Care Excellence, said: "Nice guidance recommends that people who are at risk of low vitamin D should be given better access to supplements to protect their health.

"In the UK at this time of year, sunlight doesn't have the correct wavelength to create vitamin D in the skin. So as the sources of vitamin D available from food are limited, people who are at risk of low vitamin D status may need dietary supplements."