Vitamin D hype is entirely unhealthy
Although Donald Trump’s suggestion that we give bleach injections a shot received the lion’s share of attention at his infamous April 23 “news” conference, let’s not forget he also floated the idea of finding a way to get UV rays into our bodies, based on his notion that the sun kills SARS-CoV-2.
As original as his theories may seem, neither was entirely new. We’ve covered drinking bleach in this space before and articles touting the healing power of the sun (and vitamin D) in relation to COVID-19 have been circulating online for months.
And a recently released study from Northwestern University that found a correlation between populations with high vitamin D levels and better COVID-19 outcomes (a.k.a. lower mortality) is likely to prompt even more articles urging people to take daily supplements.
Before we go any further, though, there is absolutely no evidence to support the idea that vitamin D has therapeutic value for people infected with or exposed to the virus. Supplementing the sunshine vitamin may well be a good idea for a lot of Canadians, especially those over 65 and/or people who don’t get outside during daylight hours who have spoken to their physicians about supplementation. Vitamin D levels are important for optimal health, but there’s no data to support it can do anything for COVID-19.
The reason it’s too soon to jump on the D bandwagon is that, as the Northwestern study’s lead researcher, Dr. Vadim Backman, points out, correlation isn’t causation. A population with high vitamin Dlevels could be an indication of people who follow medical advice closely and, as such, also exercise regularly and eat well. Maybe it was the exercise that did it. Or the fresh veggies. The researchers don’t know if vitamin D is the reason. They weren’t even looking for it. They were just looking for broad patterns to explain discrepancies in outcomes in various regions.
“I’m not a vitamin D researcher. We didn’t even think about vitamin D, frankly, it was just one of the things that came out in the data,” says Backman, a professor of biomedical engineering. “And vitamin D as a medicine induces very — I wouldn’t say polarizing — but almost, embedded opinions in some people who study it one way or the other.”
So why are we starting to hear a lot about D in connection with COVID-19? Part of the reason is that some of those “embedded opinions” are held by a camp of grassroots health gurus and doctors who tend to view vitamin D as a cure for everything. It’s sort of understandable, given that sunshine is associated with happiness, brightness and better days — and, of course, is important to human health. Vitamin D, which we synthesize from exposure to the sun, does help us absorb calcium (and other minerals), which means it’s a key piece for bone health — a fact discovered in the 1920s as researchers tackled rickets, a childhood bone disease.
Since then, researchers have investigated its potential as a therapeutic agent for a range of things, including, most recently, as a potential anti-inflammatory. And, since COVID-19 appears to sometimes trigger an exaggerated inflammatory response that does damage to the body, vitamin D boosters are positioning it as a possible tool in the fight.
The problem is that the research is still in its infancy. That won’t stop people from trying to frame vitamin D as a way to beat COVID-19.
“The important thing to the story is people’s inclination to try to make inferences on, in this case, very low-quality evidence,” says Dr. Gordon Guyatt, distinguished professor in the department of clinical epidemiology and biostatistics at McMaster University. “You might as well say drinking three glasses of water a day might prevent COVID-19. Giving people suggestions they do things, without making it very clear that there isn’t any good evidence for them, is misleading.”
Guyatt, one of the founders of “evidence-based medicine,” says this illustrates a bigger problem we’re seeing with COVID-19: an epidemic of speculation regarding therapeutic solutions and preventatives based on preliminary results of studies that haven’t yielded conclusive evidence. And while vitamin D supplements may be relatively harmless, not all the suggestions (bleach, for example) are as benign.
“It’s been a catastrophe that way,” says Guyatt, referring to the widely disseminated misinformation, including advice that azithromycin and hydroxychloroquine might be an effective combination, despite there being no solid evidence to back that up. “If there are antibiotics being given out, they might increase antibiotic resistance. And if everybody gives out hydroxychloroquine and you persuade people that it’s good for them and they need it, you can’t do randomized trials to find out whether it’s any good or not.” (Guyatt recently wrote about his concerns at greater length in the Hamilton Spectator.)
So, approach all the breathlessly touted new developments with caution. Evidencebased medicine takes time and, while it’s understandable we all want good news that gives us a little hope for an end to this, we need to put the brakes on.
The good news about vitamin Dis that a lot of the important research is well established and nearly 100 years old. We know we do need some for optimal health, but we also know that it’s possible to take too much and damage your kidneys, since it’s a “fat-soluble” vitamin. (We don’t pee out the excess, like we do with water-soluble vitamins.)
So, if you feel that you’re not getting enough sun because of the lockdown, it might be time to ask your doctor if you need to supplement. The recommended daily levels are all worked out for us and listed online by the Canadian government, which, to our knowledge is still a totally reliable source for this kind of thing.
“The important thing to the story is people’s inclination to try to make inferences on, in this case, very low-quality evidence.”
DR. GORDON GUYATT MCMASTER UNIVERSITY