Doctors Warn Against Taking ‘Mega Doses’ of Vitamin D To Prevent COVID-19


Taking vitamin D amid coronavirus: Doctors warn against ‘megadoses’ of the dietary supplement

Doctors Warn Against Taking ‘Mega Doses’ of Vitamin D To Prevent COVID-19

Amidst the ongoing coronavirus pandemic people are looking for ways to keep their immune systems in tip-top shape, and there’s evidence that vitamin D can help with exactly that. But taking too much of this dietary supplement can be dangerous, doctors warn against taking ‘mega doses’ of vitamin D in a paper published earlier this month in the British Medical Journal.

Scientists from the UK, Ireland and the USA, have published a vitamin D consensus paper in which doctors warn against taking ‘mega doses’ of vitamin D supplementation to support one’s immune system during the coronavirus outbreak.

And this update comes after a recently published medical study which showed a strong correlation between this key supplement and mortality rates that have come with the coronavirus: Vitamin D.

Although, vitamin D is “essential for good health” (especially for bones and muscles) and may bolster the immune system, it can also be dangerous in high doses.

According to the author “Many people have low blood levels of vitamin D, especially in winter or if confined indoors, because summer sunshine is the main source of vitamin D for most people,” and “Taking a daily supplement … and eating foods that provide vitamin D is particularly important for those self-isolating with limited exposure to sunlight.”

And we know that foods high in vitamin D include fatty fish (such as salmon and tuna), portobello mushrooms, fortified milk and yogurt and eggs. 

But high doses of the vitamin — which the authors refer to as “mega doses” can be extremely dangerous, hence doctors warn against taking mega doses of vitamin D.

Also, he said that inundating the body with vitamin D can cause toxicity, and emphasize that there is no proof that doing so prevents the coronavirus. “There is no strong scientific evidence to show that very high intakes (i.e., mega supplements) of vitamin D will be beneficial in preventing or treating COVID-19,”

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Furthermore, the report reads that “There are evidenced health risks with excessive vitamin D intakes especially for those with other health issues such as a reduced kidney function.”

Also, an infectious disease expert and senior scholar at the Johns Hopkins University Center for Health Security, Amesh D. Adalja, says that vitamin D deficiency is actually prevalent in the U.S.A, especially among black people, but agrees that taking large doses of it blindly can be dangerous. “Vitamin D is a medication, it’s a drug, so it can have side effects,” Adalja tells Yahoo Life. “When you have acute intoxication you can get a lot of different problems including confusion, vomiting — all kinds of things can happen.”

Vitamin D toxicity — officially referred to by the Mayo Clinic as hypervitaminosis D — is rare, but can cause “a buildup of calcium in your blood (hypercalcemia), which can cause nausea and vomiting, weakness and frequent urination.” The condition can prove most dangerous for those with liver or kidney problems, which Adalja says may lead to a “lower threshold for overdose.”

What Is Vitamin D

Vitamin D is a hormone, produced in the skin during exposure to sunlight, and helps regulate the amount of calcium and phosphate in the body, which are needed to keep bones, teeth and muscles healthy.

Vitamin D And The Coronavirus Pandemic: Should You Take It?

In an earlier interview on the topic with Yahoo Life, medical contributor Dr. Kavita Patel said it’s important to be aware of the potential dangers, but adds that overdosing on vitamin D is extremely uncommon. “It’s pretty low-risk, especially if you have normal kidney function,” says Patel. “Vitamin D is not the best for everyone, but if you have normal kidney function then your body should be able to process and clear it through the urine.”

Also, professor Sue Lanham-New, Head of the Department of Nutritional Sciences at the University of Surrey and lead author of the study, said: “An adequate level of vitamin D in the body is crucial to our overall health, too little can lead to rickets or the development of osteoporosis but too much can lead to an increase in calcium levels in the blood which could be particularly harmful.”

The Mayo Clinic notes that “taking 60,000 international units (IU) of vitamin D a day for several months” has been shown to cause toxicity. But in the U.S., current recommendations are just a fraction of that. The National Institutes of Health’s Office of Dietary Supplements recommends 600 IUs a day of vitamin D for most people, 400 IUs for those under 2 and 800 IUs for those over 70.

And the BMJ authors write that high doses — up to 10,000 IUs/day — of the nutrient are being recommended online, but the authors “strongly caution against doses higher than the upper limit 4,000 IUs/day.”

Although a major a link between COVID-19 and vitamin D has not been drawn, there is still research that suggests taking the supplement may help with immune function.

But one large meta-analysis published by Harvard University in 2017, for example, found that taking vitamin D may help prevent serious respiratory infections, such as influenza, especially in those who are deficient in the vitamin.

Dr. Karl Z. Nadolsky Jr., an endocrinologist and clinical assistant professor of medicine at Michigan State University, says that he recommends it for some patients. “I often tell people who seem to be at risk (northern hemispheres, not much sunlight, risk of potential bone disease, etc.) to take 1,000 international units,” Nadolsky tells Yahoo Life. “This BMJ article cites many appropriate guidances for that and emphasizes to avoid overdosing via keeping under 4,000 international units daily. Doses higher than 1,000 international units should not be necessary for most people with normal absorption.”


But Adalja says that those who feel unsure how to proceed should talk to their doctor about getting their vitamin D levels tested. “You want to avoid vitamin D deficiency but you don’t want to overdose on vitamin D,” says Adalja. He adds, like the BMJ authors, that on top of supplements and vitamin D-rich foods, sunlight can be extremely beneficial. “Sunlight is important because it helps synthesize the active form of vitamin D in your body,” says Adalja. “So sun exposure does help with keeping your vitamin D levels higher.”

Professors Carolyn Greig and Martin Hewison from Birmingham University, are co-authors on the paper. Professor Greig says: “Most of our vitamin D comes from exposure to sunlight, however for many people, particularly those who are self-isolating with limited access to sunlight during the current pandemic, getting enough vitamin D may be a real challenge. Supplementing with vitamin D is recommended but should be done under the current UK guidance.

And he said “Although there is some evidence that low vitamin D is associated with acute respiratory tract infections, there is currently insufficient evidence for vitamin D as a treatment for COVID-19 and over-supplementing must be avoided as it could be harmful.”

Also a co-author of the paper and Director General British Nutrition Foundation, Professor Judy Buttriss said: “In line with the latest Public Health England guidance on vitamin D, we recommend that people consider taking a vitamin D supplement of 10 micrograms [400 iu] a day during the winter months (from October to March), and all year round if their time outside is limited.

“Levels of the vitamin in the body can also be supplemented through a nutritionally balanced diet including foods that provide the vitamin, such as oily fish, red meat, egg yolk and fortified foods such as breakfast cereals, and safe sunlight exposure to boost vitamin D status.”


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