The COVID-19 pandemic has unleashed a flood of clinical trials on dietary supplements, as researchers race to evaluate nutritional products that may help to fend off one of the deadliest viruses the world has seen in modern times.

The University of Michigan’s Mark Moyad, M.D., M.P.H., considered to be one of the leading global medical authorities on dietary supplements, says today’s high level of interest and research on supplements is unprecedented in his 30-year career as a public health educator and clinical/medical epidemiologist.

“We’ve gone from famine to feast because of the COVID-19 pandemic,” Moyad said. “By last count, there were several hundred ongoing clinical trials on supplements.”

Moyad holds an endowed position as the Jenkins/Pokempner Director of Complementary and Alternative Medicine Education in U-M’s Urology Department. His endowment was funded and created in 1998-99, shortly after he joined the Michigan Medical School staff. It was one of the first of its kind, established globally at a major medical center to advance research and objective education on dietary supplements, over-the-counter products, and other potential health options.

Fast track

Moyad says that the vitamin and dietary supplement manufacturing industry has grown exponentially over the past three decades. Today, nutrition is a $35-billion industry in the United States and a nearly $120-billion industry worldwide.

American consumers shell out upwards of $46 billion annually on vitamins, minerals, herbs, amino acids, enzymes, and other OTC products, including many made overseas. Some of the most popular supplements are multivitamins, digestive enzymes, melatonin, vitamins A, B, C, D, E, and K, calcium and zinc.

“When I was in my 20s, there were hundreds of supplement products sold over the counter,” Moyad said. “Now I’m in my late 50s, and there are more than 100,000 OTC products. It is one of the biggest and fastest-growing areas in medicine.”

For years, many practitioners in the traditional medical community have viewed the loosely regulated supplement industry with skepticism. That perception is gradually changing, according to Moyad, as the supplement industry begins to embrace a multiphase product-development process.

Headlines from the frontlines: The power of scientific discovery harnessed and delivered to your inbox every week. Subscribe to the Michigan Health Lab blog newsletter

“Some of the current COVID-inspired clinical trials on supplements are methodologically sound,” he said. “We can achieve a threshold of efficacy, or proof, that is similar to what you see in the pharmaceutical industry. We’re definitely moving in that direction.”

He cites the recent results of the Harvard-affiliated VITAL study, which demonstrated the potential of moderate daily dosages of vitamin D3 (2,000 IU) supplements or fish oil (1,000 mg) to reduce the risk of autoimmune diseases compared to a placebo in over 25,000 participants.

Supplements and COVID-19

Medical researchers are now conducting outpatient and inpatient studies to determine whether specific supplements will enable healthy individuals to ward off COVID-19 and help patients with severe illness shorten their stay in the hospital.

Preliminary results seem to suggest that supplements may be more effective in improving immunity and lessening the chances of contracting COVID than in speeding the recovery of very sick individuals.

“COVID-19 is a highly specific disease that has required highly specific FDA-approved vaccines and antiviral drugs to stop it,” Moyad said. “It’s like a lock and key. I don’t think you are going to get that kind of specificity from taking supplements once someone has been hospitalized with severe COVID.”

One inpatient study conducted in Brazil compared the recovery rates between COVID-19 patients who received a single dose of 200,000 IU of vitamin D and those who were given a placebo. Early results indicated the high dose of vitamin D did not reduce the length of hospitalization.

“I’m most excited about the outpatient trials that are looking at whether supplements can help reduce people’s risk of contracting COVID or when someone has a mild case, to help prevent progression of symptoms and avoid hospitalization,” Moyad said.

Going to trial

Two major U.S. studies on supplements may provide some answers.

For one study, Harvard Medical School is collaborating with major medical institutions and industry partners on the Vitamin D and COVID-19 Trial (VIVID). Clinical researchers are investigating whether taking a daily dietary supplement of vitamin D for four weeks reduces the disease severity in participants who are newly diagnosed with COVID-19 and lowers the risk of transmission to other members of their household. The national randomized clinical trial involves 2,700 men and women who are given either a high dose of vitamin D3 (9,600 IU per day on days one to two and 3,200 IU per day on days three-28) or a placebo.

A second high-profile COVID clinical trial, being conducted by Mayo Clinic, is comparing the effect of high-dose (69.6 mg per day) zinc supplementation versus multivitamin supplementation on immune health in 2,700 people who are at high risk for COVID -19, including health-care workers. Participants randomly receive PreserVision AREDS formulation gel tabs (which contain a high level of zinc) or Adult (under 50) Centrum formulation multivitamins.

A third promising inquiry, taking place in the United Kingdom, is the ELVIS COVID-19 study at the University of Edinburgh. There, researchers are exploring whether a saline solution for nasal washes and gargling ― which has been found to shorten the duration of the common cold ― can lessen the symptoms and length of the COVID-19 illness. Up to 30 percent of colds are caused by four different coronaviruses, and COVID is caused by a separate member of the same coronavirus family, so they share some similarities and differences.

Closer to home, Moyad, with the help of generous donors, has established an endowment with the eventual goal of increasing research funding for Michigan medical students and faculty who are interested in conducting studies on lifestyle and supplements. He also collaborates with other major universities on clinical trials.

Back to basics

Until more clinical data are available, medical researchers will not know conclusively which supplements, if any, are effective against COVID-19.

In the meantime, Moyad cautions people about becoming too enamored with pills.

Instead, he urges everyone to “get back to the basics” of a healthy lifestyle. This entails monitoring and improving the “5Bs”: blood cholesterol, blood sugar, blood pressure, and BMI/belly fat (aka healthy weight/waist loss). He also emphasizes the importance of immune boosting (the fifth B) by staying up to date on all vaccinations, including those for COVID-19.

Live your healthiest life: Get tips from top experts weekly. Subscribe to the Michigan Health blog newsletter

“What we’ve learned in the pandemic is that making lifestyle changes to reduce your risk of cardiovascular disease could, in some cases, mean the difference between a mild and severe case of COVID-19,” Moyad said. “Many things that are heart-healthy also improve your immune health.”

For example, a 2021 Kaiser Permanente study of nearly 50,000 people with COVID-19 suggested regular physical activity provided strong protection from hospitalization, intensive-care-unit admission and death. Sedentary individuals, on the other hand, had poor outcomes from COVID during the pandemic.

Likewise, a 2022 Cleveland Clinic study showed that patients with obesity who had undergone weight-loss surgery and shed excess pounds were able to reduce their risk for developing severe COVID-19 complications by 60%.

“There’s no magic supplement,” Moyad said. “But maintaining a healthy lifestyle can provide some protection and also pay off by keeping you out of the hospital for other reasons.”

This article was originally published by Michigan Today.

This article was additionally reviewed by Ridhima Kodali.

Like Podcasts? Add the Michigan Medicine News Break on Spotify, Apple Podcasts or anywhere you listen to podcasts.