BOSTON, MASSACHUSETTS. It is well established that many older people are deficient in vitamin D. Research has also shown that winter sunlight at latitudes at or above 42o N (northern USA and Canada) is incapable of producing vitamin D in the skin. Researchers at the Boston University School of Medicine now report that young people living in the Boston area are even more likely to be vitamin D deficient, especially during the winter months, than are older people. The study involved 307 Bostonians (61 per cent women) who were divided into four age groups – 18-29 years, 30-39 years, 40-49 years, and 50 years and older. The participants had their level of parathyroid hormone and 25-hydroxyvitamin D measured either at the end of winter (March, April) or at the end of summer (September, October). Thirty per cent of all participants were found to be deficient in vitamin D (blood level of 25-hydroxyvitamin D below 20 ng/mL) at the end of winter and 11 per cent were deficient at the end of summer. In the 18-29 year age group 36 per cent were vitamin D deficient at the end of winter as compared to 16 per cent in the 50 years and older group.
The researchers found no difference in vitamin D levels between participants who drank milk and those who
did not. They did, however, find that supplementing with a multivitamin containing 400 IU of vitamin D was
quite effective in preventing vitamin D deficiency. At the end of winter only 11 per cent of supplement users
were found to be deficient as compared to 42 per cent among those not taking a daily vitamin.
Editor's comment: Vitamin D is an essential factor in bone formation. Being deficient at a young age when bone formation is supposed to peak could predispose to osteoporosis later in life. This study also clearly shows that milk (even fortified) is a poor source of vitamin D, but that a daily multivitamin containing 400 IU of vitamin D is an effective means of reducing the risk of a deficiency.