With our relatively low level of sunlight, Ireland’s population is at increased risk of a winter deficiency of vitamin D. There is now enough evidence to support a national vitamin D guideline for dietary supplementation in Ireland to prevent osteoporosis and infant rickets. However, developing national guidelines for food supplementation is tricky.

While expectant mothers are advised in maternity hospitals to take vitamin D supplements to prevent infant rickets and to give drops to their newborn babies, a recommendation for female lifelong supplementation with vitamin D to prevent adult-onset osteoporosis in adult women is lacking. 

Women’s osteoporosis risk increases year-on-year. And with factors including women working indoors for long hours, avoiding sun and using sun-block, not using HRT after the menopause, as well as a growing trend of avoiding dairy products, there may be a future pandemic of osteoporosis and fracture risk in women.

Supplementing the general population of adults in Ireland with adequate doses of vitamin D to replace lack of sunlight in the climate is a simple and at the same time complex solution. Which foods could be supplemented, at what dose and what cost? Should adult women be advised to take supplements for life? Should everyone regardless of gender who lives in our northerly climate take supplements? Or should GPs alone take responsibility and simply continue prescribing pharmaceutical treatments to patients who have already developed osteopaenia in older age? 

Studies on population vitamin D supplementation land heavily in favour of dietary supplements. It has been estimated that for the more than 30 million people with osteoporosis in the EU, who experience about 3.9 million fractures at a cost of over €50 billion to hospitals annually, there would be an estimated 544,687 fewer fractures per year, saving €6.9 billion.¹

New research from the study on ageing, TILDA, at TCD has associated lower levels of vitamins, including vitamin D with frailty in older age. According to the authors, the lack of a food fortification policy means that we are missing the opportunity of a cost-effective public health strategy. ²

Many patients feel they will be adequately protected by consuming commercially supplemented products such as milk. However, daily intake of fortified milks contains a fraction of the supplementation required to prevent deficiency. Reference index amounts of food intake are not a valid pharmaceutical recommendation. The RDI is a reference to the minimum food ingredient required to sustain life, not to promote health or treat disease. 

In the face of growing evidence, some GPs are now recommending vitamin D supplementation to adults as well as children, not just to prevent future osteoporosis but also to boost mood, immune function and protect against colds and flu. However, national guidelines on vitamin D supplementation advice for GPs are inadequate. The Food Safety Authority has published recommendations for small babies³ but points out that the recommended supplementation doses are different for different populations. For GPs, this makes things difficult because patients will inevitably seek guidance online if we cannot provide succinct advice. 

A number of UK sources recommend a daily dose of roughly 1,600-2,000 IU per day for the UK population,⁴ which could be a useful reference for an Irish climate too. 

References on request