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Eamon Laird
PhD; Researcher in Health and Ageing at Trinity College Dublin
Eamon Laird

What is vitamin D?

Vitamin D or the ‘sunshine vitamin’ is an important nutrient for bone health. It is actually a hormone that our bodies make when exposed to sunshine. Unfortunately, in Ireland, vitamin D production is almost negligible from late September to March each year due to the angle of the sun and decreased availability of UVB light. However, even during the Irish summer it can be difficult to make vitamin D due to cloud cover and rainy conditions. Typically, 10-15 minutes of sunshine exposure (before adding sun-cream protection) during the summer is enough to make sufficient vitamin D for each day. Vitamin D can also be obtained through the diet with oily fish (such as salmon or mackerel), eggs, liver or fortified food products (such as mushrooms or fortified milk/yogurt) being good dietary sources.

Why is this important for health?

We know that having a deficient blood status of vitamin D is a major risk factor for the development of osteoporosis – a condition where the bones get more porous and fragile with an increased chance of fractures. It is often a silent disease as it can go unnoticed, without symptoms, until a fracture occurs. New research has also shown that having a low vitamin D status could have other negative effects on health. Studies have associated low vitamin D with an increased risk of chronic disease, cancers, diabetes and inflammatory conditions such as COPD, arthritis and Crohn’s disease.

Is there a vitamin D problem in Ireland?

Many research studies have shown that the Irish population have a particular issue in achieving a sufficient blood status of vitamin D. Around 1 in 8 older Irish adults (>50 yrs) have a deficient vitamin D status, while this gets worse in the Winter time when up to 25% can be deficient. This is also not just a problem for older adults with research showing around 1 in 8 of the general population (including children, teenagers, and pregnant women) are also deficient. Individuals who smoke, are obese, physically inactive or from a lower socio-economic background are at the highest risk of deficiency. In addition, individuals who have no sun-exposure as result of being housebound or keeping their skin completely covered for religious reasons are at increased risk.

What advice would you give to someone that thinks they might have low vitamin D?

The most important approach is to report any worries to their GP who can measure vitamin D with a simple blood test. Other approaches can include consuming vitamin D rich foods and having some safe sun-exposure during the summer months. Individuals can also purchase vitamin D supplements from their local pharmacy or health food shops. These can be in the form of tablets or a mouth spray which are equally as effective. The international recommended daily requirement for vitamin D from all sources is 400IU/day for children, 600 IU/day for 18-70-year-olds and 800IU/day for 71+ years. Intakes from all sources should not exceed 4,000IU/day. The United Kingdom has recommended that everyone has an intake of 400 IU/day for the population. There are currently no Irish recommendations.