Randomized control trials show that daily vitamin D supplementation appears to reduce the risk of acute

respiratory infections in children and adolescents, but does not seem to make a difference in adults,

nor does D appear effective for boosting antibody responses to influenza vaccination.

What about vitamin E?

Most places, you read that there are eight different tocopherols and tocotrinols

that are collectively known as vitamin E,

but only alpha-tocoferol has been shown to protect against human vitamin E deficiency.

So alpha-tokovarol is the only bona fide vitamin E and is the one found in vitamin E supplements.

There are observational data suggesting those self-reporting supplementation with vitamin E have, for example,

better pneumonia outcomes, but only interventional trials can prove if this

is the case.

Compared to placebo supplements, vitamin E was able to significantly boost immunity to hepatitis

B and tetanus vaccinations, though not to diphtheria or pneumonia.

One randomized controlled trial found that vitamin E supplementation of the elderly

did not cut down on lower respiratory tract infections like pneumonia,

but did reduce the incidence of upper respiratory tract infections like the common cold

by about 20% over one year.

But another study using the same dose found no preventive benefit,

and vitamin E supplementation actually made the infections they did get even worse,

with a greater number and severity of symptoms, including a greater likelihood of fever

and activity restriction. By far the largest study on vitamin E and respiratory infections was the ATBC study that

randomized nearly 15,000 smokers to vitamin E or placebo for about five years.

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