Study panned regarding effects of vitamin C and zinc on COVID-19
Fraught with problems, a nutrition study still found a reduction of symptoms by more than a day for supplement takers over the regular standard of care.
February 18, 2021
When it comes to nutrition science, there are a couple aphorisms that demand reheeding today: One study does not a conclusion make, and any time you see researchers declaring their study to be the definitive conclusion, that no further studies ever need undertaking again, that the compound in question absolutely 100% does not work—take those results with a grain of salt.
Researchers with integrity, when pressed to make larger statements about the utility of a studied bioactive, will always keep their conclusions close to the vest—“All we demonstrated,” they will tell you, “Is this ingredient with that study population with the dose used resulted in these effects this much of the time.”
Researchers with integrity are loath to go out on a limb.
Researchers with an axe to grind, with a clear and present bias, go too far the other way.
So it is with a new study published in the vaunted Journal of the American Medical Association JAMA Open Network.
The study had good intentions—supplying a COVID-19 population with vitamin C and zinc to see if their outcomes improved significantly. After all, many studies have shown such results with vitamin D in COVID-19 patients.
Zinc is known to play a role in immune function via antibody and white blood cell production. Vitamin C has some studies showing it could be protective against the novel coronavirus.
Researchers used 50 mg zinc and 8,000 mg vitamin C. They determined if patients achieved a 50% reduction in symptoms, the study would be a success. They enrolled 529 adult outpatients with confirmed infections.
Problems with the study's execution abounded
For one, complementary physicians assert at least 75 mg/day zinc is required to aid in COVID-19 symptoms, in the form of zinc gluconate lozenges, taken in many doses throughout the day.
For two, doses roughly above 4,000 mg vitamin C/day tend to lead to diarrhea—and that was cited as a primary adverse event in the vitamin D group.
For three, only 214 patients ended up participating, making any benefit difficult to tease out.
This is why the researchers ended the study prematurely after 10 days, for “futility,” before the 28-day trial was planned on concluding.
Even so, patients who took no supplements achieved a 50% reduction in symptoms in 6.7 days. Those taking zinc got to 50% reduction in 5.9 days. Vitamin C, and the combination of vitamin C and zinc, both got patients to 50% in 5.5 days.
That means supplements helped the patients get reasonably better about a day and a quarter faster. That’s nothing to sneeze at, though because of the small population size in the study the researchers concluded that the supplements did not work.
“Based on the current study,” concluded the researchers, “these supplements cannot be recommended to reduce symptom morbidity in such patients.”
There is much to kvetch about.
The study was conducted at The Cleveland Clinic. The accompanying editorial slamming supplements was written by physicians at John Hopkins University.
“These 2 supplements,” wrote the Johns Hopkins doctors, “failed to live up to their hype.”
The editorial opened with a quote from Neil deGrasse Tyson, “The good thing about science is that it’s true whether or not you believe in it.”
This was meant to pave the way for looking askance at the entire concept of dietary supplements.
They even found time to disparage vitamin D—but not for COVID-19, but for cardiovascular disease.
Ironically, the editorial contained a half-dozen reference citations, one of which concluded that vitamins A and D show potential benefit in COVID-19 cases, especially in deficient populations. It also concluded that selenium and zinc have shown favorable immune-modulating effects in viral respiratory infections. Probiotics were also found to “have some role in enhancing immune functions.”
Grasping at straws
But that didn’t stop the editorial writers from maligning the supplements, even under the less-than-stellar study design.