Frequent readers of ERV, or SciBlogs in general, are used to vitamin/mineral woo. “Megadoses of Vitamin C cures EVERYTHING!” “Vitamin D is better at preventing the flu than the VACCINE!” “Zinc cures the COMMON COLD!”
What we are used to dealing with, is snake-oil salesmen looking to sell their particular bottled garbage to people with medical anxieties/paranoia (but are otherwise healthy individuals) with disposable income.
But the world is not full of rich Westerners paranoid about The Big C.
There are lots of people on this planet who struggle to get themselves and their children adequate nutrition. When you are literally starving, vitamin and mineral deficiencies can and do have an impact on overall health, and your ability to respond appropriately to pathogens. This might be one of those stories:
Zinc adjunct therapy reduces case fatality in severe childhood pneumonia: a randomized double blind placebo-controlled trial
This paper is a good example of how scientists might go into a study with a set of expectations, but the data leads them in an unexpected direction. In this case, they collected a group of 352 children with severe pneumonia. Half got zinc supplementation with their pneumonia treatment, half got placebo.
They were expecting to see either a) differences in the two groups time to normal temperature, breath rate, and oxygen levels or b) no differences because zinc didnt do anything.
Well, they found b.
When you looked at the kids stats as they were getting better, there was no difference between the zinc and the placebo group. So zinc supplementation was a bust?
Not quite– When they looked at the expected parameters, there was no difference. But when they looked at the number of kids who *died* in the groups of kids, things got interesting.
- 7 of 176 kids in the zinc group died.
- 21 of 176 kids in the placebo group died.
This difference becomes even more stark when you focus on the HIV+ kids in the group–
- 0 of 28 HIV+ kids in the zinc group died.
- 7 of 27 HIV+ kids in the placebo group died.
How is this phenomenon occurring? Well, we dunno. But the authors have some guesses:
… zinc supplementation might increase phagocytosis  and zinc deficiency predisposes to apoptosis of T lymphocytes in HIV-infected patients . In fact, it has now been established that zinc deficiency compromises immunity through a number of mechanisms, such as T cell dysfunction and dysregulation of intracellular killing .
Does this mean that everyone should go out and chug megadoses of zinc and we will never ever EVER get a bacterial infection again because our immune systems are, like, SUPER BOOSTED?
Of course not.
Zinc supplementation could ‘work’ in these kids because they were all zinc deficient. The authors even stated that the kids zinc levels were lower than the ‘low’ that they expected to see– about 4.4-4.8 umol/L.
Normal is ~20 umol/L.
Kids with chronic malabsorption syndrome are at about 8.6 umol/L.
Kids who physiologically cant absorb nutrients well have twice as much zinc in their serum as the malnurished kids in this study.
These scientists crunched the numbers– it will take $4 to supplement 13 kids with severe pneumonia, to save 1 life.