'Alarmingly high' proportion of British people from ethnic minorities are severely deficient in vitamin D putting them at increased risk of infections such as Covid-19, study finds

• Researchers studied genomes of almost half a million British people 
• Found that 57% of Asians  are severely deficient in vitamin D in winter and spring
• Black Africans were the next most vulnerable with 38.5% deficient in winter 

Many people from ethnic minorities in the UK are severely deficient in vitamin D, a study reveals. 

More than half of Asians are severely deficient in winter and more than a third of black Africans suffer an 'alarmingly high' lack of the vitamin. 

Vitamin D has divided scientific opinion during the pandemic, with a plethora of studies finding it can fight coronavirus and others claiming it is of no benefit.But Australian researchers reviewed half a million British genomes from the UK BioBank and say because it is cheap, easy to access and has no negative side-effects, people should consider supplementing their diet with the sunshine vitamin regardless.

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Both vitamin D and Omega 3 supplements are essential for good overall health and are found in oily fish. A study of more than 2,000 pensioners revealed the pills reduce the risk of catching infections but have no impact on bone health, memory and muscle function

A UK Government review recently found there is 'not enough evidence' that taking vitamin D can prevent or treat Covid-19.  

Health Secretary Matt Hancock ordered a rapid review into the vitamin's effect on Covid in October, after coming under fire for writing it off without any evidence to back his claims. 

A panel of experts across multiple Government agencies, including Public Health England, analysed 'the best' scientific studies from around the world, though they did not say which or how many papers they looked at.

But the team, led by NHS watchdog NICE, said 'it was not possible' to determine a direct relationship between vitamin D and Covid, citing a lack of high-quality trials.

A mountain of studies have found that an overwhelming amount of people who get Covid-19 do not have enough vitamin D in their bodies and the sickest of patients are often deficient.

But scientists have so far been unable to pin down whether the deficiency makes people more vulnerable to Covid, or whether becoming unwell causes vitamin D levels to crash.

NICE is still urging Britons to supplement 10 micrograms (400 IU) of vitamin D every day between October and early March because of its other proven health benefits on bones, muscles and the immune system.

But a study published last month found taking regular vitamin D or Omega-3 supplements bolsters pensioners' immune systems, helping them to fend off infections including Covid-19. 

Researchers from Queen Mary University of London are currently carrying out a randomised trial probing the potential benefits of the nutrient on Covid-19.

The scientists gave 5,000 volunteers the vitamin in October and will assess them over six months if they do not already take high doses.

Experts will then assess whether participants are at less risk of catching the virus and developing a severe bout of the disease over the winter months.

Vitamin D is naturally produced in the body when skin is exposed to sunlight, but given the long winter months, people are not spending enough time outdoors.

As well as sunshine, vitamin D is also naturally found in oily fish such as salmon, egg yolks, mushrooms and red meat. The NHS says adults should have around 10 micrograms of vitamin D every day. Food is not fortified with the vitamin as standard in the UK, as it is in other countries of similar latitudes.  

People with dark skin are particularly vulnerable as they have more melanin, which reduces vitamin D production.   

Not getting enough Vitamin D makes people more vulnerable to certain health conditions and infections, with some studies claiming this includes Covid-19.  

The latest study, from the University of South Australia, looked at how vitamin D levels can vary by demographic.    

'Of almost half a million people surveyed, we found that 57 per cent of Asians were severely deficient in vitamin D in winter and spring, and 50.8 per cent in summer and autumn,' said PhD student Joshua Sutherland, lead author of the study.

'Black Africans were the next most vulnerable, 38.5 per cent deficient in winter and 30.8 per cent in summer, followed by mixed race people and Chinese participants.

'White Europeans had the lowest prevalence of vitamin D deficiency but many are still affected.'

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One study found that 72 per cent of NHS workers in Birmingham who were lacking in the 'sunshine vitamin' (left column) tested positive for coronavirus antibodies in the blood — a sign of previous infection. This compared to just 51 per cent for those who had a healthy amount of the vitamin (right column)

Among white Europeans, there were clear seasonal differences, with 17.5 per cent showing a deficiency in winter, compared to 5.9 per cent in summer.

People living in northern parts of the UK, which do not get enough sunlight during the winter, like Glasgow and Edinburgh, also recorded lower levels of the hormone.

While southern residents, living in wealthy parts of the country, were less likely to suffer from vitamin D deficiency and were more likely to pop supplements. 

Professor Elina Hypponen at the University of South Australia said: '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 shown that vitamin D supplements are beneficial in the prevention of respiratory infections and even mortality.'

Professor Hypponen added: '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.'   

The findings were published in the journal Clinical Nutrition.

What have studies into vitamin D and Covid-19 shown?

When? September.

By who? Cordoba University in Spain.

What did scientists study? 50 Covid-19 hospital patients with Covid-19 were given vitamin D. Their health outcomes were compared with 26 volunteers in a control group who were not given the tablets.

What did they find? Only one of the 50 patients needed intensive care and none died. Half of 26 virus sufferers who did not take vitamin D were later admitted to intensive care and two died.

What were the study's limitations? Small pool of volunteers. Patients' vitamin D levels were not checked before admission. Comorbidities were not taken into consideration.

 

When? September.

By Who? University of Chicago.

What did scientists study? 500 Americans' vitamin D levels were tested. Researchers then compared volunteers' levels with how many caught coronavirus.

What did they find? 60 per cent higher rates of Covid-19 among people with low levels of the 'sunshine vitamin'.

What were the study's limitations?  

Researchers did not check for other compounding factors. Unclear whether or not volunteers were vitamin D deficient at the time of their coronavirus tests. People's age, job and where they lived - factors which greatly increase the chance of contracting the virus - were not considered.

 

When? September.

By Who? Tehran University, in Iran, and Boston University.

What did scientists study? Analysed data from 235 hospitalized patients with Covid-19.

What did they find? Patients who had sufficient vitamin D - of at least 30 ng/mL— were 51.5 per cent less likely to die from the disease. They also had a significantly lower risk of falling seriously ill or needing ventilation. Patients who had plenty of the nutrient also had less inflammation - often a deadly side effect of Covid-19. 

What were the study's limitations? Confounding factors, such as smoking, and social economic status were not recorded for all patients and could have an impact on illness severity.  

 

When? July.

By Who? Tel Aviv University, Israel.

What did scientists study? 782 people who tested positive for coronavirus had their vitamin d levels prior to infection assessed retrospectively and compared to healthy people.

What did they find? People with vitamin D levels below 30 ng/ml - optimal - were 45 per cent more likely to test positive and 95 per cent more likely to be hospitalised.

What were the study's limitations?  Did not look at underlying health conditions and did not check vitamin D levels at the time of infection.

 

When? June.

By Who? Brussels Free University.

What did scientists study? Compared vitamin D levels in almost 200 Covid-19 hospital patients with a control group of more than 2,000 healthy people.

What did they find? Men who were hospitalised with the infection were significantly more likely to have a vitamin D deficiency than healthy men of the same age. Deficiency rates were 67 per cent in the COVID-19 patient group, and 49 per cent in the control group. The same was not found for women.

What were the study's limitations?  Independent scientists say blood vitamin D levels go down when people develop serious illness, which the study did not take into consideration. This suggests that it is the illness that is leading to lower blood vitamin D levels in this study, and not the other way around.

 

When? June.

By who? Inha University in Incheon, South Korea.

What did scientists study? 50 hospital patients with Covid-19 were checked for levels of all vital vitamins and compared to a control group.

What did they find? 76 per cent of them were deficient in vitamin D, and a severe vitamin D deficiency (<10 ng/dl) was found in 24 per cent of Covid-19 patients and just 7 per cent in the control group.

What were the study's limitations?  

Small sample size and researchers never accounted for vitamin levels dropping when they fall ill.

 

When? June.

By Who?. Independent scientists in Indonesia.

What did scientists study? Checked vitamin D levels in 780 Covid-19 hospital patients.

What did they find? Almost 99% of patients who died had vitamin D deficiency. Of patients with vitamin D levels higher than 30 ng/ml  - considered optimal - only  per cent died.

What were the study's limitations?  It was not peer-reviewed by fellow scientists, a process that often uncovers flaws in studies.

 

When? May.

By Who? University of Glasgow.

What did scientists study? Vitamin D levels in 449 people from the UK Biobank who had confirmed Covid-19 infection. 

What did they find? Vitamin D deficiency was associated with an increased risk in infection - but not after adjustment for con-founders such as ethnicity. It led to the team to conclude their 'findings do not support a potential link between vitamin D concentrations and risk of Covid-19 infection.'

What were the study's limitations?  Vitamin D levels were taken 10 to 14 years beforehand. 

 

When? May.

By Who? University of East Anglia.

What did scientists study? Average levels of vitamin D in populations of 20 European countries were compared with Covid-19 infection and death rates at the time.

What did they find? The mean level of vitamin D in each country was 'strongly associated' with higher levels of Covid-19 cases and deaths. The authors said at the time: 'The most vulnerable group of population for Covid-19 is also the one that has the most deficit in vitamin D.'

What were the study's limitations?  The number of cases in each country was affected by the number of tests performed, as well as the different measures taken by each country to prevent the spread of infection. And it only looked at correlation, not causation.

 

When? May.

By Who? Northwestern University.

What did scientists study? Crunched data from dozens of studies around the world that included vitamin D levels among Covid-19 patients. 

What did they find? Patients with a severe deficiency are twice as likely to experience major complications and die.

What were the study's limitations?  Cases and deaths in each country was affected by the number of tests performed.