‘Alarmingly high’ levels of vitamin D deficiency in UK, says study

There is an “alarmingly high” rate of vitamin D deficiency in the UK, with people from Asian and Black backgrounds and lower socio-economic groups more at risk, a study has found.

More than 50 per cent of Asians living in the UK are severely deficient in vitamin D, which makes them more vulnerable to respiratory infections such as coronavirus and musculoskeletal disorders, according to the study led by the Australian Centre for Precision Health at the University of South Australia.

The study also points towards an earlier report published in the Clinical Nutrition journal, which found that more than a third of people with Black African ancestry living in the UK had high levels of vitamin D deficiency.

Severe vitamin D deficiency is particularly prevalent in lower socioeconomic groups and affects vulnerable groups throughout all the seasons, said the report.

Data from 440,581 UK Biobank participants revealed a “clear seasonal contrast” in vitamin D levels among white Europeans, as well as strong associations with high levels of TV and computer use leading to a greater change of vitamin D deficiency in white Europeans.

However, this association was “much weaker” for other ethnicities, researchers found.

The body produces vitamin D naturally through sun exposure, as well as the regular consumption of oily fish. Vitamin D is a hormone that helps the body build strong bones, regulates immune and muscle function and contributes to overall health.

But long winter months with fewer hours of daylight and less time spent outdoors have contributed to “alarmingly high vitamin D deficiency pockets of the UK”, said the study, adding that overall levels fall below the most conservative global recommendations.

Joshua Sutherland, first author on the report, said the findings reveal certain ethnic and socio-economic groups, as well as people living in the north of the UK, are far more likely to be lacking in the hormone.

He said people with darker skin have a higher risk of developing a vitamin D deficiency because of higher levels of melanin in the skin, which “can lessen the skin’s ability to make vitamin D”.

“But this, combined with spending more time indoors and consuming lower vitamin D-containing foods, can foster severe deficiency,” he added.

“Of almost half a million people surveyed, we found that 57 per cent of Asians were severely deficient in vitamin D in winter/spring and 50.8 per cent in summer and autumn.

“Black Africans were the next most vulnerable, followed by mixed race people and Chinese participants. White Europeans had the lowest prevalence of vitamin D deficiency but many are still affected.”

The study found that Black Africans were 38.5 per cent deficient in the winter and 30.8 per cent deficient in the summer. By contrast, white Europeans were 17.5 per cent deficient in the winter, compared to 5.9 per cent in summer.

Nearly a third of study participants lived in Edinburgh and Glasgow, and recorded low vitamin D levels in the winter, while those who lived in the south of the UK, in comparatively higher socioeconomic regions, had less winter deficiency, were more likely to take supplements and eat more oily fish.

Mr Sutherland said the findings highlighted “the continuing need for effective health interventions” to reduce vitamin D deficiency in the country.

“Fortification of a single food item, such as the proposed wheat fortification programme, is tricky because some South Asian groups are more likely to eat millet and rice than wheat,” he said. “It’s clear the UK requires targeted public health measures to mitigate deficiency risk in all affected populations.

The study was led by Professor Elina Hypponen, one of the world’s leading experts on vitamin D.

She said the results of the study were “really very alarming” as the rate of severe vitamin D deficiency was “much higher in most population groups” than expected.

“The severity of vitamin D deficiency is concerning, especially with the high rates of Covid-19 infections in Europe and elsewhere in the northern hemisphere this winter. Clinical trials have shows that vitamin D supplements are beneficial in the prevention of respiratory infections and even mortality,” she said.

“Vitamin D is not expensive and the doses which have shown the greatest benefits are those that we can all acquire over the counter from the local pharmacy. Given the Covid-19 pandemic, now is really the time for all who may be affected to take action.”