Food & Fitness After 50: Beware of Online Advice to Take Vitamin D or Zinc to Prevent COVID-19

Dietary supplements can help fill nutrient gaps or be used to treat deficiencies but lately I’ve seen lots of headlines implying supplements of vitamin D and zinc can make you immune to COVID-19. In a word? NO.

To top it off, many well-meaning people are touting these nutrients on their social media feeds with messages like, “wash your hands and take loads of vitamin D and zinc,” or “stock up on vitamins and minerals, they are natural so you can’t take too much.” Ouch. Hemlock is a natural poison, so clearly you can take too much of a “natural” substance.

vitaminddiscVitamin D

What do these headlines have in common?

  • Vitamin D deficiency may be linked to more severe cases of COVID-19.
  • New study claims vitamin D deficiency may impact coronavirus mortality rates.
  • Could vitamin D deficiency and coronavirus be connected?
  • New study suggests vitamin D is linked to COVID-19 mortality.
  • Coronavirus: How vitamin D could keep you healthy during the pandemic.

I’ve underlined the key words to give you a clue. These headlines are from the same study. The study found a relationship, not a cause and effect, with vitamin D and the virus. When you see the words or phrases like “appears to play a role,” “may be linked,” “may impact,” “suggests,” “related to,” or “associated with,” it tells you about a relationship between two things. It doesn’t tell you that one thing caused another. Did you know there is a strong relationship between the increase in bottled water consumption and rising rates of obesity in the U.S.? Clearly, it doesn’t mean that bottled water is “causing” obesity.

In addition to the well-recognized role in bone health, Vitamin D is important in immunity. It helps modulate the immune system, making immune cells less inflammatory. Various groups, from the Institute of Medicine (IOM is a nonprofit organization and part of The National Academies that works outside the framework of government to provide evidence-based research and recommendations for public health and science policy) recommends that all adults age 51 to 70 years get 600 IU (equal to 15 micrograms or mcg) a day and those over the age of 70 get 800 IU a day (20 mcg). The Endocrine Society suggests adults need 1000 to 1500 IU to ensure adequate blood levels of the vitamin.

It is hard to get enough vitamin D from food and older adults are at risk for insufficiency because skin doesn’t make vitamin D from sunlight as efficiently with aging. Many adults turn to vitamin D supplements to get the needed vitamin D.

And, we started this post with suggestions that the vitamin plays a role in COVID-19. At this point, it is only speculation, but there are at least nine clinical trials listed on ClinicalTrials.gov, exploring various aspects on the vitamin on the virus. A rapid review paper from University of Oxford in the UK (click here for the paper), published May 1, found that currently is there is no clinical evidence to support prevention or treatment of COVID-19 with vitamin D

The Bottom Line?

  • If you have had your blood levels of vitamin D measured by your doctor and she or he has recommended a supplement, continue to take the dose as recommended.
  • If you have not had a vitamin D blood test, don’t self-diagnose and start taking vitamin D.
  • If you take a multivitamin/mineral supplement you may be getting the recommended amount or slightly higher for vitamin D; multis formulated for “seniors” often contain 1000 IU of vitamin D. Don’t take any more than the Upper Limit of 4000 IU/day unless prescribed by an MD.
  • Best food sources of vitamin D are fatty fish; think salmon, tuna, sardines. We know eating fish is good for our health in many ways, so include a fish meal at least twice a week.

Zinc 

Picture1We have no storage site in the body for zinc, so it is needed in the diet every day. Zinc is better known for its role in inhibiting the common cold virus from sticking and replicating in the nose and throat. It can also stop inflammation that contributes to the symptoms of a cold…runny nose and stuffy head.

There is no research on using zinc for COVID-19.

While there are many zinc preparations in the cold and flu cold aisle of your local drug or grocery store, should you use them? The research results are mixed, of course, they often are, but the latest review from the Cochrane Collaboration (a group that reviews medical topics by reviewing many studies on a particular topic) found that when zinc is taken at the first sign of a cold the length of the illness is reduced by about one day.

When using it for warding off a cold, keep in mind the following:

  • Timing and dose are important, try one zinc lozenge at the first sign of a cold and take it every 4 hours (most have 10 to 15 milligrams of zinc per dose).
  • More isn’t better, in fact, in can make things worse; nausea and vomiting can occur if you take too much and it can leave a metal taste in the mouth.
  • Avoid zinc nasal sprays…the Food and Drug Administration warned consumers that zinc sprays can lead to changes in the sense of smell and sometimes permanent changes.
  • Zinc can interfere with some prescription medications, like antibiotics and blood thinners, so always consider potential drug interactions.

The Bottom Line?

  • Zinc is important for a healthy immune system but there is no evidence at this time that it will protect against COVID-19.
  • Too much zinc, which is easy to get in supplement form, can cause nausea and vomiting.
  • The Upper Limit for zinc is 40 milligrams so keep that in mind if you use zinc lozenges.
  • Aim for zinc-rich foods every day. Good choices are seafood (oysters, lobster, crab), beef, pork, poultry, baked beans, and fortified breakfast cereals.

I asked Connie Diekman, registered dietitian, food and nutrition consultant, and former President of the Academy of Nutrition and Dietetics to help sum it up:

“With this new virus, much is unknown which makes it more important that we depend on the science related to supplements, rather than opinions posted by a variety of people. The body of evidence related to vitamins and minerals is extensive, while the knowledge behind Covid-19 is evolving. Therefore, as an RD, the best advice I’d give is to focus on a well-balanced eating plan and talk to your MD or RD to determine if you would benefit from supplements – don’t go it alone!”

Dr. Christine Rosenbloom is a registered dietitian nutritionist and a nutrition professor emerita at Georgia State University in Atlanta. Along with Dr. Bob Murray, she is the author of Food & Fitness After 50.

Copyright © 2019 [Christine Rosenbloom]. All Rights Reserved