Experts review vitamin D advice that greater access to cheap vitamin D supplements would improve the health of at-risk groups. The exports at the Royal College of Paediatrics and Child Health (RCPCH) said up to 25% of UK children are vitamin D deficient, leading to a rise in rickets cases. In the BBC's Scrubbing Up column, the college's Prof Mitch Blair called for concerted action to tackle the problem. The government said those with the greatest need already received free supplements. The RCPCH said other options to increase vitamin D levels, such as fortifying a wider range of foods, should be considered. Half of the UK's white population, and up to 90% of the black and Asian people in the country are thought to be affected by vitamin D deficiency. The first signs of deficiency include muscle and bone pain as well as swelling around the wrists and ribs. A lack of the nutrient is linked to a higher incidence of diabetes, tuberculosis, multiple sclerosis as well as rickets - a disease that causes bones to become soft and deformed. Dr Barbara Murray said children spend too much time indoors and need "more sunlight". The number of cases of rickets has been rising, from 183 in 1996 to 762 in 2011. In January this year, the chief medical officer for England, Dame Sally Davies, recommended all pregnant and breastfeeding women, children aged six months to five-years-old and the over-65s should take vitamin D supplements.