Vitamin D prevents Cold and Flu according to several scientific studies, as elaborated below. First of all, it is an established fact that Vitamin D plays an important role in keeping our immune system healthy.1 Unfortunately, most people are low in Vitamin D. The problem worsens during winter months, which may explain a high prevalence of Flu and Common Cold during winter months.
In addition, the dose of Vitamin D is important. You need a large dose of Vitamin D to prevent Cold and Flu. That’s why some studies that utilize the usual recommended dose of 600 IU per day may not show any benefits and that’s what creates confusion. More on the dose of Vitamin D later in this post…
Evidence that Vitamin D Prevents Cold and Flu
An excellent study from Japan compared the effects of Vitamin D in preventing Flu. In this randomized, double-blind, placebo-controlled trial, researchers gave Vitamin D3 supplements (1200 IU/d) to 167 schoolchildren. The results were astonishing! An almost 50% reduction in the risk of getting Flu.1 In addition, there was an impressive 83% reduction in the risk of having asthma attacks.
In another study, researchers from Queen Mary University of London, UK analyzed 25 trials that looked at the question, “Does Vitamin D help prevent Cold and Flu, also known as upper respiratory illnesses? “A total of 10,933 individuals were included. The findings were impressive! Researchers found that Vitamin D supplements cut down the risk of Cold and Flu in all participants.2
These studies provide conclusive scientific evidence that Vitamin D helps prevent Flu and Cold.
Does Vitamin D Help to Treat the Common Cold?
Several studies show beneficial effects of Vitamin D to treat the Common Cold. In a rigorous analysis of these studies, the authors from Italy concluded the usefulness of Vitamin D as well as Vitamin C, Zinc and Echinacea in treating the Common Cold.3
How Much Vitamin D to Prevent Flu and Colds?
The dose of Vitamin D is important to prevent Flu and Cold. How much Vitamin D you need depends on your weight because Vitamin D is fat-soluble. Therefore, use a daily dose of 5000 IU per 100 Lbs. to prevent Cold and Flu.
For example, if you weigh 200 Lbs. you should take 10,000 IU of Vitamin D3 every day.
How Much Vitamin D per day when Sick?
Increase your daily dose of vitamin D3 to 10,000 IU (international units) for every 100 Lbs. of body weight for a few days when you are sick with Cold, Flu or any other infection. There is no evidence of Vitamin D toxicity at these doses. Risk of Vitamin D toxicity occurs if you take vitamin D as 80,000 IU per day for several months.
Scientific studies support the use of Vitamin D to prevent as well as treat Common Cold and Flu.