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Issue #66 (April 2020)

From the Editor

Just before I was about to launch the second installment of this issue, someone brought an interesting hot-off-the-presses review article to my attention on nutritional interventions’ effects on viral immunity, with a focus on COVID-19. Since this looked like it strongly jibes with the NERD’s purpose of reviewing the latest important and interesting nutritional science, I jumped at the chance of crafting a NERD Mini on the topic to publish in this issue.

It doesn’t take super-keen eyes to notice that this NERD Mini doesn’t appear in this issue. The reason for this isn’t that I missed my deadline, got bored, or went off to finish watching Better Call Saul Season 5 (although I really, really want to!). The reason is that, after putting a bit of work into the review, I didn’t think it was worth completing the article.

My doubts started when I looked at the impact factor of the journal in which it was published. While impact factor is a weak proxy for article quality, I still find it to be a useful place to start. I discovered it was lower than most articles I include in the NERD. So, while that was a strike against it, it was a weak one. I then continued to the first sentence of the introduction, which mentioned the need for good prevention strategies for the current pandemic of … COVID-12. This was the first of several typos I noticed. Like impact factor, I consider typos only a weak proxy for article quality since they’re pretty common in scientific articles. So I continued combing the article, since, typos and impact factor aside, it’s the quality of analysis that matters at the end of the day.

And, at first blush, the quality looked okay. For instance, the authors followed PRISMA in their review process. But a look at the PRISMA checklist revealed that a large proportion of the items weren’t actually reported. And their search strategy didn’t look that great, either. Things got even more confusing when I looked at the justification for some of the nutritional recommendations they gave. For instance, while their search strategy explicitly excluded HIV (reasonable, since HIV shares little in common with viruses that cause respiratory infections), one of the nutritional recommendations they gave was based on a study in HIV patients. Also, they cited a COVID-19-specific article when discussing their justification for vitamin D’s possible utility, which seemed useful and relevant at first. But, when I looked at the reference, it had little to do with vitamin D at all. After finding several more cases of their references only weakly supporting their recommendations, I decided that this article was simply not worth reviewing.

This review article, like a lot of the literature on COVID-19, was published quite rapidly. Rapid publication is a great thing for researchers, given the seriousness of this pandemic. Speed, combined with the fact that a lot of the literature is open access, is great for researchers because more freely-shared information allows scientists to act more quickly to find out what works and what doesn’t. But, if the average person finds a review article like this, scrolls down, and sees some nutritional recommendations, there’s a good chance they could take it at face value and think that the recommendations are well supported, when many are actually pretty dubious.

If you find yourself digging around the scientific literature concerning COVID-19, I recommend taking this as a cautionary tale: sometimes, just a little digging is worse than no digging at all.


Gregory Lopez, MA, PharmD
Editor-in-chief, Nutrition Examination Research Digest

See other articles in Issue #66 (April 2020) of Study Deep Dives.