Vitamin D in Ireland — who actually needs it?

As an Irish pharmacist, one of the most common questions I get asked at the counter, especially as the days get shorter, is whether a vitamin D supplement is really necessary. The short answer is yes. While we might occasionally be blessed with a sunny spell, the reality of living in Ireland means that our natural exposure to the sun is simply not enough to maintain healthy vitamin D levels year-round. This essential nutrient plays a crucial role in maintaining healthy bones, teeth, and muscles, and it also supports our immune system. Yet, despite its importance, low levels of vitamin D are widespread across the Irish population.

The Irish "vitamin D winter"

To understand why vitamin D deficiency is such a common issue here, we need to look at our geography. Ireland is situated at a latitude of between 51 and 55 degrees north. Because of this northern position, the sun sits quite low in the sky for a significant portion of the year. From October through to March, the ultraviolet B (UVB) rays from the sun are simply not strong enough for our skin to produce vitamin D. This period is often referred to as the "vitamin D winter." During these six months, we are entirely reliant on dietary sources and our body's stored reserves, which are rarely sufficient to see us through to the spring.

HSE and FSAI recommendations

The Health Service Executive (HSE) is very clear on this matter: everyone in Ireland needs to take a vitamin D supplement during the winter months. The Food Safety Authority of Ireland (FSAI) provides specific guidance on the recommended daily doses to ensure we are getting enough. For adults, the recommended dose is 15 micrograms (µg) per day. For young children aged between one and four years old, the recommendation is 10 micrograms per day. It is important to note that these are the standard recommendations for the general population to prevent deficiency, and some individuals may require higher doses if they are already deficient or have specific medical conditions.

Who is at risk all year round?

While the general population needs to be mindful of their vitamin D intake during the winter, certain groups are at a higher risk of deficiency throughout the entire year and should consider supplementing continuously. People over the age of 65 are particularly vulnerable because our skin becomes less efficient at producing vitamin D as we age. Individuals with darker skin tones also need to be careful, as the melanin in their skin reduces the body's ability to make vitamin D from sunlight. Those who are housebound, living in residential care, or who cover their skin for cultural or religious reasons are also at a higher risk due to a lack of sun exposure. Furthermore, pregnant women and babies have increased requirements and should follow specific supplementation advice from their healthcare provider.

Food sources and choosing a supplement

While it is difficult to get enough vitamin D from food alone, it is still important to include dietary sources in your meals. Oily fish such as salmon, mackerel, and sardines are excellent natural sources. You can also find vitamin D in red meat, liver, and egg yolks, as well as in fortified foods like certain breakfast cereals and dairy products. However, to meet the FSAI recommendations, a supplement is usually necessary. When choosing a supplement, look for Vitamin D3 (cholecalciferol), as this is the form most effectively absorbed and utilised by the body. Supplements come in various forms, including tablets, capsules, and oral sprays, so you can choose the one that best suits your preferences.

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When should levels be tested?

Routine testing for vitamin D levels is not generally recommended for the healthy population, as the advice is simply to take a daily supplement during the winter months. However, if you fall into one of the high-risk groups mentioned earlier, or if you are experiencing symptoms of severe deficiency such as bone pain or muscle weakness, you should speak to your GP. They can arrange a simple blood test to check your levels and prescribe a higher-dose treatment if necessary. If you have any concerns or questions about choosing the right supplement for you or your family, please do not hesitate to ask your pharmacist.

Stay well, and remember to look after your vitamin D levels this winter. Best wishes, Aidan