Do Vitamin Supplements Prevent Colds?

Know the facts before you rush to the drug store.
Jupiterimages via Getty Images

The Question: Will supplements really prevent a cold or shorten one from lingering?

The Answer: Dietary supplements and other over-the-counter products aimed at cold prevention, like Zicam or Emergen-C, sound miraculous in theory. But do they actually help to eliminate that nasty bug? The answer from experts is a resounding “no.”

Zicam promises to be a “cold shortening” homeopathic remedy, and some variations of the product use zinc at the major active ingredient. (The brand does make other products that are pharmaceutical-based, so be sure to check the label.) Emergen-C is a popular dietary supplement made from vitamin C which claims to provide extra support to the immune system. Another variation of the dissolvable powder includes melatonin for sleep and relaxation.

“Nothing cures the cold,” Kathleen Deegan, a registered dietitian and adjunct professor at the School of Nursing at the University of San Francisco, told HuffPost. “They’re trying to promote the antioxidant capacity of vitamin C...and there is not much in the literature that supports vitamin C preventing a cold.”

Research suggests that a vitamin overload will do very little to prevent a cold or help you out once you’re in the throes of one. But not only that, taking too much can have consequential health effects.

How natural supplements could backfire

Just one serving of Emergen-C provides 1,000 milligrams of vitamin C, which is well above the recommended daily dose. Adult men should get 90 milligrams a day, and adult women should get 75 milligrams per day, according to the National Institutes of Health.

Most people meet these requirements through their diet because it is easy to do so ― for example, just a half cup of red peppers is enough to get your daily values. And statistically, most American men and women meet the recommended daily intake, according to data from the National Health and Nutrition Examination Survey.

The mineral is responsible for helping the body’s immune system, but the upper limit for vitamin C is 2,000 milligrams per day. While vitamin C is a low-toxicity mineral, it is important to note that consuming above the 2,000 milligram limit could possibly lead to diarrhea, nausea and abdominal cramps, according to the National Institute of Health.

Zinc, on the other hand, is actually dangerous if you overdo it. Your body requires only a minimal amount of the supplement to reap its healthy benefits, which includes helping the immune system fight of viruses and bacteria. Men need just 11 milligrams a day, women just 8 milligrams, according to the Institute of Medicine. Most people get enough zinc through their diet.

“I would definitely not recommend people taking individual supplementation of zinc,” Deegan said. “There’s just not enough research to support that [zinc supplements prevent illness]. There just isn’t ― and there’s a lot in the literature to support [the toxicity].”

The upper limit for zinc for adults is 40 milligrams per day. Beyond that, people can experience nausea, vomiting, decreased appetite, stomach cramps, diarrhea and headaches. And, ironically, too much zinc over a long course of time can actually decrease immunity, according to the National Institute of Health.

Furthermore, some zinc nasal sprays and gels have been linked to losing the ability to smell.

Skip the nonsense and eat your nutrients instead

“I am extremely in support ― especially in terms of diet and nutrients ― of doing things the most natural way possible,” Colin Robinson, a clinical instructor of medicine at the University of California, Los Angeles, told HuffPost. That means instead of taking supplements, you should aim to get zinc and vitamin C from a healthy, well-rounded diet of fruits and vegetables, he explained.

Oysters are high in zinc. Red meat, crab, lobsters and fortified breakfast cereals will also do the trick. Beans, nuts, whole grains and dairy products provide a bit of zinc, too, according to the National Institute of Health.

Research shows to eat more sweet red peppers, orange juice, grapefruit juice and kiwi for vitamin C. Broccoli, Brussels sprouts and strawberries are good sources as well.

Eating this way will help you hit the recommended levels of each nutrient, as well as contribute to your health overall.

Additionally, here’s surefire way you can effectively and safely lower your risk of getting a nasty bug ― and it’s free: Scrub those hands. Research shows it’s one of the most foolproof ways to halt germs from getting into your system.

“You know the best way to prevent a cold? Wash your hands three to four times a day. And get plenty of sleep,” Deegan stressed.

It’s age-old advice from someone with nothing to sell. Sounds right to us.

Correction: The original version of this article misspelled Kathleen Deegan’s last name. It is Deegan, not Duggan. Language has also been amended to better describe the range of Zicam products.

Support HuffPost

Before You Go


Do you have info to share with HuffPost reporters? Here’s how.

Go to Homepage

Popular in the Community


Gift Guides