Doctors in the US have raised recommended levels of vitamin D for infants because they say exposure to sunlight, which generates production of the vitamin in the skin, is no longer a safe way to prevent deficiency in children.
Writing in the journal Pediatrics, Dr Lawrence M. Gartner and Dr Frank R. Greer say that cases of rickets have been rising over recent years. The disease prevents healthy development of bones and can result in bowed legs, as well as leading to respiratory and heart problems.
The authors recommend that vitamin D supplements are given to children being breast-fed as breast milk does not contain the required 200 International Units daily of vitamin D. Children receiving fortified formula may also need supplements if their intake of formula is less than 500ml daily, they added.
The doctors also highlighted children and adolescents who do not get regular sunlight exposure and do not drink at least 500ml per day of vitamin D-fortified milk as a group at risk of vitamin deficiency. They too would need to take a food supplement to increase their vitamin D levels.
Supplementation should begin within the first two months of life, write the authors, describing the guidelines which are based on the recommendations of the National Academy of Sciences.
They add that additional research is suggested to more fully understand the factors underlying the development of vitamin D deficiency and rickets in some breastfed infants.
Vitamin D is increasingly being studied for its role in the prevention of bone disease, especially osteoporosis. A new study is underway in the UK to evaluate the potential of the vitamin in preventing osteoarthritis.