In a piece posted on Mercola.com back in 2017, Dr. Joseph Mercola explained the advantages of Vitamin D use for flu prevention. Pay special attention to what Mercola says about the NNT. He wrote:
Conventional health authorities claim getting a flu shot each year is the best way to ward off influenza. But where’s the actual science backing up that claim?
If you’ve repeatedly fallen for this annual propaganda campaign, you may be surprised to find the medical literature suggests vitamin D may actually be a FAR more effective strategy, and the evidence for this goes back at least a decade.
Dr. John Cannell, founder of the Vitamin D Council, was one of the first to introduce the idea that vitamin D deficiency may actually be an underlying CAUSE of influenza. His hypothesis1 was initially published in the journal Epidemiology and Infection in 2006.2 It was subsequently followed up with another study published in the Virology Journal in 2008.3
The following year, the largest nationally representative study4 of its kind to date discovered that people with the lowest vitamin D levels indeed reported having significantly more colds or cases of the flu. In conclusion, lead author Dr. Adit Ginde stated:
“The findings of our study support an important role for vitamin D in prevention of common respiratory infections, such as colds and the flu. Individuals with common lung diseases, such as asthma or emphysema, may be particularly susceptible to respiratory infections from vitamin D deficiency.”
Vitamin D Works Better Than Flu Vaccine if Your Levels Are Low
Since then, a number of studies have come to similar conclusions. More recently, a scientific review5,6 of 25 randomized controlled trials confirmed that vitamin D supplementation boosts immunity and cuts rates of cold and flu.
Overall, the studies included nearly 11,000 individuals from more than a dozen countries. As reported by Time Magazine:7
“… [P]eople who took daily or weekly vitamin D supplements were less likely to report acute respiratory infections, like influenza or the common cold, than those who did not … For people with the most significant vitamin D deficiencies (blood levels below 10 [ng/mL]), taking a supplement cut their risk of respiratory infection in half.
People with higher vitamin D levels also saw a small reduction in risk: about 10 percent, which is about equal to the protective effect of the injectable flu vaccine, the researchers say.”
Like Cannell before them, the researchers believe vitamin D offers protection by increasing antimicrobial peptides in your lungs, and that “[t]his may be one reason why colds and flus are most common in the winter, when sunlight exposure (and therefore the body’s natural vitamin D production) is at its lowest …”8
According to this international research team, vitamin D supplementation could prevent more than 3.25 million cases of cold and flu each year in the U.K. alone.9 Another statistic showing vitamin D is a more effective strategy than flu vaccine is the “number needed to treat” (NNT).
Overall, one person would be spared from influenza for every 33 people taking a vitamin D supplement (NNT = 33), whereas 40 people have to receive the flu vaccine in order to prevent one case of the flu (NNT = 40).
Among those with severe vitamin D deficiency at baseline, the NNT was 4. In other words, if you’re vitamin D deficient to begin with, vitamin D supplementation is 10 times more effective than the flu vaccine.
Read more here.
Originally posted December 11, 2023.
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