Children and adults should take vitamin D supplements throughout the winter, up to St Patrick’s Day, the Department of Health has advised.
Its recommendation, provided in a response to The Irish Times, goes further than current guidelines, which cover only children aged up to five and adults aged 65 and over.
Vitamin D, which is formed by the body after exposure to sunlight and is found naturally in oily fish, eggs, meats and specially fortified foods, plays an important role in the musculoskeletal and immune systems; deficiency causes a loss of bone density, possibly leading to osteoporosis and fractures.
An official report published a year ago recommended supplementation with vitamin D in winter from age five up. The report by the Food Safety Authority of Ireland (FSAI) recommended 10μg of vitamin D supplement for children aged five and over in winter, and 15μg for adults. For darker-skinned people and pregnant women, it recommended year-round supplementation.
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The FSAI says that although causation has not been proven, several studies suggest associations with conditions such as heart disease, diabetes, inflammatory disorders, cancers and infectious diseases such as Covid-19.
Under existing guidelines, a smaller dose (5 μg) is recommended in winter for 1-4 year-olds, and for breastfed babies aged under one.
The Covit-D Consortium, a group of Irish scientists and doctors, have lobbied for stronger recommendations. According to one of its members, Dr Daniel McCartney of Technological University Dublin, vitamin D deficiency affects about half of Irish adults in wintertime, with severe deficiency present in 15-20 per cent of adults. Among nursing home patients, deficiency levels rise to two-thirds.
“Over the past three years, data from six separate Irish studies have clearly shown that low vitamin D levels are associated with worse Covid-19 outcomes including ICU admission and death,” he says. “This is in keeping with the international literature, where overwhelming evidence now shows that low vitamin D levels increase these risks and that vitamin D supplementation ameliorates them.”
Unvaccinated Covid-19 inpatients with low vitamin D levels were seven times more likely to be admitted to ICU and 25 times more likely to have died than patients with higher levels of the nutrient, according to one study cited by Dr McCartney.
The findings of Irish and international studies show the need for enhanced public health messaging for Irish adults to supplement with higher daily doses of vitamin D than those currently advised, he says.
HSE guidelines, rather than recommending supplementation, specify dosage levels for 5-64 year-olds “if you choose to take a vitamin D supplement”.
The Department said the FSAI report marked the first time vitamin D nutrition had been examined “in terms of how people aged 5 to 65 years can achieve optimal intakes for long-term bone and muscle health”.
“In addition to food sources, vitamin D supplements are recommended for everyone for at least part of the year, in particular pregnant women and people of dark-skinned ethnicity who are at highest risk of vitamin D deficiency.”
Taking too many vitamin D supplements over time can cause a build-up of calcium and weaken bones and organs.
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