Skip to content

The #1 Supplement Dr. Fauci Takes

Support your immune system with this science-backed nutrient.

As the COVID Delta variant surges in all 50 states, many of us are wondering what we can do to help our bodies fight off coronavirus infection or reinfection (besides getting vaccinated and following public health guidelines on social distancing and masking). Dr. Anthony Fauci, the nation's top infectious disease expert, says he takes one particular supplement to support the immune system. It has not been proven to stop COVID—get vaccinated!—nor cure COVID—there is no cure—but does do a body good. "If you're deficient in vitamin D, that does have an impact on your susceptibility to infection," he said in an interview last fall. "I would not mind recommending—and I do it myself—taking vitamin D supplements." Read on to find out why, and to ensure your health and the health of others, don't miss these Sure Signs You Have "Long" COVID and May Not Even Know It.


What Science Says About Vitamin D

medical or scientific researcher or doctor using looking at a clear solution in a laboratory

"There is good evidence that if you have a low vitamin D level, that you have more of a propensity to get infected when there are infections around," said Fauci. "Those data are pretty good data."

To wit: One review of studies published in BMJ looked at more than 11,000 people and found that those who took weekly or daily vitamin D supplements were less likely to develop respiratory tract infections than those who didn't. 

"There is clear evidence that vitamin D does help fight off respiratory infections," Amesh A. Adalja, senior scholar at the Johns Hopkins Center for Health Security, told Health magazine. 

Additionally, "Laboratory studies show that vitamin D can reduce cancer cell growth, help control infections and reduce inflammation," says the Harvard T.H. Chan School of Public Health. The National Institutes of Health notes that vitamin D helps regulate immune function. 

RELATED: The #1 Best Supplement to Take For Immunity


What Is Vitamin D?

vitamin d3 supplements

One of vitamin D's primary jobs is to help our bodies absorb calcium, which supports bone health. But there are vitamin D receptors in cells throughout the body, pointing up its wide-ranging role in our health: D also reduces inflammation, helps modulate cell growth, aids neuromuscular function, and helps the body regulate blood sugar.

D is known as "the sunshine vitamin" because it's produced naturally by our bodies when sunlight hits the skin. It's also present in a few foods like fortified milk, fatty fish (like salmon) and egg yolks. But many Americans have insufficient blood levels of the vitamin or outright vitamin D deficiency. 

"For most people, the best way to get enough vitamin D is taking a supplement, because it is hard to eat enough through food," says Harvard.

RELATED: Everyday Habits That Make You Older, Say Experts


How Much Vitamin D Should You Take?

woman taking fish oil
Shutterstock / blackzheep

According to the Office of Dietary Supplements at the National Institutes of Health, adults up to age 70 should get 600 IU of vitamin D daily from all sources (food and supplements). Adults 71 and older should get 800 IU (that's because they're at increased risk of bone fractures and vitamin D helps preserve bones). The daily upper limit of the supplement is 4,000 IU.

Always consult your doctor before adding a new supplement to your routine. You might want to ask them if your blood vitamin D level is of concern—this can be determined by a simple blood test.

RELATED: 5 Ways to Prevent Dementia, Says Dr. Sanjay Gupta


More Immunity-Boosting Tips From Fauci

woman smiling while sleeping

Besides Vitamin D, Dr. Fauci has three other tips on how to boost your immune system, which he shared in an interview with Business Insider:

  • "Get a reasonable amount of sleep." Fauci and other experts, including the National Sleep Foundation, recommend seven to nine hours of quality sleep each night. Doing so can lower your risk of a range of serious illnesses, from heart disease and cancer to dementia.
  • "Get a good diet." Focus on whole foods like fruits and vegetables, lean protein, olive oil, and nuts, while limiting processed food, fast food, saturated fat, and added sugar.
  • "Try to avoid or alleviate severe stress, which we know can sometimes impact the immune system," said Fauci.

And to get through this pandemic at your healthiest, don't miss these 35 Places You're Most Likely to Catch COVID.

Michael Martin
Michael Martin is a New York City-based writer and editor whose health and lifestyle content has also been published on Beachbody and Openfit. A contributing writer for Eat This, Not That!, he has also been published in New York, Architectural Digest, Interview, and many others. Read more about Michael