Irish researchers call for increased vitamin D fortification, supplementation to battle high deficiency rates

14 Jun 2019 --- Over a quarter of adults aged over 50 are deficient in vitamin D, according to researchers from Trinity College Dublin. Over half (57 percent) had inadequate serum vitamin D levels, of which 26 percent were classed as vitamin D deficient. The research demonstrates that vitamin D deficiency is prevalent in older adult populations living at Northern latitudes and highlights the importance of public health strategies throughout midlife and older age to achieve optimal vitamin D status. The researchers emphasize low supplement use in these regions and call for food fortification and other strategies to be considered at policy level for older populations.

Vitamin D has a known role in bone health, with growing evidence for beneficial effects on muscle strength and other non-skeletal outcomes. A better understanding of factors that contribute to vitamin D deficiency is needed to identify people most at-risk, note the researchers. They identified determinants of deficiency to be female gender, advanced age (80 years and over), smoking, non-caucasian ethnicity, obesity and poor self-reported health.

On the other hand, being of a healthy weight, retired, engaging in regular vigorous physical activity, regular vitamin D supplement use, sun travel in the past 12 months and summer season were identified as positive determinants, and therefore potentially protective against vitamin D deficiency in older people.

“The high rates of deficiency are similar to rates seen in other high-latitude countries, such as Ireland. However, other more northern countries such as Finland have implemented a successful vitamin D fortification policy which has all but eliminated deficiency in the population. Such a policy could easily be implemented in the UK and Ireland,” says Co-Author and Trinity Research Fellow Dr. Eamon Laird.

Published in Nutrients, the findings were based on 6004 midlife and older adults, living at Northern latitudes (England, 50-55oN) derived from the English Longitudinal Study of Ageing (ELSA). Since UVB radiation (sunlight) is a known determinant of vitamin D status, this was investigated. Interestingly, residents in the South of England had a reduced risk of deficiency, compared with the North, even after adjustment for socioeconomic and other predictors of vitamin D status.

In recent vitamin D research, it was found that vitamin D supplementation may be less effective in people with obesity, according to a study published in the Journal of Bone and Mineral Research. The researchers conclude that it may be more effective to treat vitamin D deficiency in obese individuals with calcidiol, rather than with other forms of vitamin D.