Vitamin D Reduces Respiratory Infections
More Evidence To Take A Supplement
Background
Vitamin D is responsible for increasing intestinal absorption of calcium, magnesium, and phosphate. It also boosts the body’s immune system and reduces inflammation. The major natural source of Vitamin D is the skin that is dependent on exposure to ultraviolet rays from the sun. Only a few foods, such as fatty fish (salmon and tuna), contain significant amounts of vitamin D. In the U.S. and other countries, cow’s milk and milk substitutes are fortified with vitamin D as are many breakfast cereals.
Sources of Vitamin D – a pill, salmon, and sunshine
In an earlier post, I reported results of an analysis of 25 studies that showed that taking Vitamin D reduced respiratory tract infections. A new report provides further support for taking a Vitamin D supplement.
Study
A recent study by Dr. David A. Jolliffe and investigators updated the information by adding 17 new studies. They analyzed a total of 42 studies involving 46,331 subjects that examined the role of Vitamin D supplementation and acute respiratory infections. The compared outcomes between vitamin D supplementation and placebo. The study was published on-line in the journal medRxiv on November 25, 2020.
Results
Compared with placebo, vitamin D supplementation reduced the risk of acute respiratory infections by 9%. Protective effects were seen for trials in which vitamin D was given daily and at daily dose equivalents of 400 to 1,000 international units (IU). There were no serious side effects associated with Vitamin D supplementation.
Conclusions
Taking Vitamin D was safe and reduced the risk of acute respiratory infections. Protection was associated with administration of daily doses of 400 to 1,000 IU vitamin D for up to 12 months.
My Comments
There is some evidence that Vitamin D may play a role in COVID-19. In a study of 489 patients who had a vitamin D level measured in the year before COVID-19 testing, the relative risk of testing positive for COVID-19 was 1.77 times greater for patients with likely deficient vitamin D status compared with patients with likely sufficient vitamin D status. This difference was statistically significant. Dr. David Meltzer, a professor of medicine at The University of Chicago Medicine, and first author of the study, summarized the findings, “Patients who have lower vitamin D levels were more likely to test positive for COVID-19.”
An article on November 27, 2020, in the newspaper The Telegraph announced that the United Kingdom government is sending free Vitamin D supplements to almost three million “clinically vulnerable” people and home care residents in order to help protect them during the pandemic. The article stated that under current health advice in the UK, everyone in the country is told to consider taking Vitamin D, amid concerns that lock downs have deprived many of sunshine, which is key to its production.
While deliveries to vulnerable people will start in January, those able to purchase supplements in the meantime should do so, officials said.
Dr Alison Tedstone, chief nutritionist at Public Health England, said: “We advise that everyone, particularly the elderly, those who don’t get outside and those with dark skin, takes a Vitamin D supplement containing 10 micrograms (400 IU) every day. This year, the advice is more important than ever with more people spending more time inside, which is why the Government will be helping the clinically extremely vulnerable to get Vitamin D.”
I encourage you to discuss taking Vitamin D with your health care professional. Years ago my internist recommended that I take 1,000 IU daily for its anti-inflammatory effect. The risk of taking too much Vitamin D is a high calcium level – called hypercalcemia. This can lead to nausea, vomiting, muscle weakness, loss of appetite, dehydration, excessive thirst, and kidney stones. Like every medication or activity, you need to weigh expected benefits with possible side effects.