Corona Daily 213: The Sunshine Vitamin

In December 2020, sales for Vitamin D supplements increased 42% year on year in the USA. Since the beginning of the pandemic, interest in Vitamin D has been growing on both sides of the Atlantic. Vitamin D is said to protect bone health, improve functions of cells like T cells. Low levels of the vitamin may increase susceptibilities to infection.

This perception is not new. In 1940, when Winston Churchill’s government feared the British population was at risk of the musculo-skeletal condition rickets, margarine makers were ordered to strengthen their products with vitamin D “to safeguard the nutritional status of the nation”. Until 2013, margarine strengthening was required by UK law.

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In April 2020, dozens of doctors wrote to the British Medical Journal advocating correction of vitamin D deficiencies as a no-brainer, safe, simple remedy to mitigate Covid-19. In hospitals in Newcastle, D-deficient patients were given excessive oral doses, sometimes 750 times the recommended dose.

David Davis, a Tory MP earlier in charge of Brexit, has been a relentless campaigner. (Maybe he is attracted to this vitamin because of his name). He is 71, and takes D-supplements every day. He believes that Covid-19 exists seriously above 40 degrees latitude because of the lightless winters. His campaign points out that Finland (where dairy products are fortified with D-vitamin) and New Zealand (which prescribes vitamin D to all care home residents) have fewer cases and deaths. Blacks and Asians have higher levels of melanin in the skin, which reduces the creation of vitamin D from sunlight. They have been disproportionately affected in the UK.

At the end of November, the UK Government announced four months of free vitamin D supplements to all care homes and prisons, a total of 2.7 million people.  

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In the last nine months, dozens of studies have been conducted to find the relationship between Vitamin D and Covid-19.

A Chicago study found D-deficient people were 77% more likely to test positive. Italian researchers learnt that 81% of those hospitalized with acute respiratory failure were vitamin D deficient. The mortality risk was also higher for the D-deficient. A French study said the D vitamin supplements were associated with less severe cases, and the survival rates were higher. Korean scientists found that deficiencies decreased immune defences, and could cause a severe covid. Singapore offered a combination of vitamin D, magnesium and B 12, and believes it reduced the worst outcomes. In a large, pivotal study in Spain, vitamin D reduced the disease severity for the hospitalized patients.

On the other hand, a professional double-blind study with a placebo in Brazil found that vitamin D had no impact.

The key message of the Australian research was that if you are not vitamin D deficient, boosting it is not likely to stop you from getting a head cold or the flu. More is not better.

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Despite the universal noise, scientists are reluctant to promote vitamin D supplements. The key problem is that all the evidence so far shows correlation but not causation. They suggest caution, excessive intake can lead to toxicity, higher level of calcium in the blood, may cause kidney stones and other problems.

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After going through all the available material, I will summarise my thoughts on this subject.

(a) if you choose to take vitamin D supplements, adults should have 10 micrograms (and never more than 100 micrograms) a day, children half of it. Anyone with kidney malfunction should not take it.

(b)  Diet such as fatty fish or fortified dairy products can be a good source of vitamin D.

(c) Aim to be physically active for at least 150 minutes a week, go outdoors for 15-20 minutes a day.

Dr Anthony Fauci does not mind recommending it, he takes vitamin D supplements himself. That may boost your confidence.

Ravi