Dubai, United Arab Emirates (CNN) — Vitamin D supplements cannot reduce the incidence of “Covid-19” infection, or respiratory infections such as the common cold or flu, even if your current vitamin levels are low, according to two clinical trials. two big Two new.
One of the two studies, conducted in the United Kingdom during the height of the pandemic, gave 3,100 people with low levels of vitamin D, a low or high dose of the vitamin, to see if the supplement would prevent infection with the Corona virus or respiratory infection.
Study author Dr. Adrian Martineau, professor of respiratory infection and immunity at the Institute of Population Health Sciences at Queen Mary University of London, told CNN that taking vitamin D supplements in both groups (low dose and high dose) did not reduce the risk of infection in the system. severe acute respiratory syndrome, or specifically reduce the risk or severity of illness caused by COVID-19.
A second, double-blind, randomized clinical trial, also conducted during the pandemic, gave more than 34,000 Norwegians cod liver oil or a placebo to test the effect of vitamin D on COVID-19 and the prevention of respiratory diseases.
Cod liver oil naturally contains low doses of vitamin D, as well as vitamin A, and omega-3 fatty acids.
The British Medical Journal released the two studies on Wednesday.
“The main benefit is that for people in general, vitamin D supplementation did not prevent COVID-19 or severe symptoms, or associated acute respiratory infections,” study author Dr. Arne Surias, a researcher in the Department of Microbiology at Oslo University Hospital in Norway, told CNN. with symptoms.”
Sorace added that the UK study design “compliments our study design in several ways, in which participants are given a higher dose of vitamin D only after their level has been measured. However, their findings support our findings and this is also the main objective, i.e. they did not find any Of the two studies, there was no protective effect after taking vitamin D supplements.”
The results of the two studies contrast with a 2020 study in Mexico City where health professionals were given 4,000 IU of vitamin D per day, or 100 micrograms, or a placebo.
Researchers found protective effects of the vitamin in just one month.
Martineau noted that two other clinical trials, taking place in the United States and Canada, will add more data.
The authors note that the two studies were conducted before vaccines were widely available.
“We can be absolutely certain that vaccination is a more effective method than vitamin D, which may not prevent COVID-19 at all,” Sorias said.
Vitamin D popularity
The primary function of vitamin D is to help the body absorb calcium and phosphate, thus maintaining healthy muscles, teeth, and strong bones.
However, vitamin D is also known to help the immune system fight off invading bacteria and viruses.
Research has shown that vitamin D deficiency weakens the immune system, and some studies have found that vitamin D supplementation may reduce the risk of respiratory virus infections and calm an overreaction of the immune system.
During the early days of the pandemic, doctors on the front lines began noticing that people with low levels of vitamin D appeared to be more likely to die from Covid-19.
Suddenly, the internet was flooded with speculation that supplementing with vitamin D, even if not needed, would prevent the spread of the coronavirus.
“Unlike vitamin C, vitamin D is fat-soluble and can build up in the system and cause toxicity if consumed in very high doses over long periods,” Martineau explained.
Research has suggested that long-term use of higher levels of vitamin D is associated with increased deaths from all causes, an increased risk of cancer, cardiovascular symptoms, and more falls and fractures among the elderly.
In the United States, the recommended daily dose of vitamin D for people ages 1 to 70 is 600 international units (UI) per day, and increases to 800 international units per day for people over 70.
In the UK, the recommended daily amount is 400 IU per day.
Levels in other parts of the world are country-specific, to reflect environmental and dietary differences, but usually also range from 400 to 800 IU per day.