(CNN)If you've been more concerned about your health lately, you might be wondering if taking a nutrition supplement containing vitamins, minerals or a combination is worthwhile.
It's estimated that more than half of Americans take one or more dietary supplements daily or on occasion.
The pills are popular in Europe, too: According to one estimate, the dietary supplement market was worth over $14 billion in 2018, although research has suggested that usage varies widely according to each country.
But are you wasting your money on vitamins and minerals you don't need or possibly harming yourself by taking high doses? Here's the lowdown.
A healthy diet comes first
Adding supplements only makes sense for some of us, experts say, such as the elderly, pregnant women, breastfeeding babies and people who have certain diseases or conditions that affect absorption of nutrients, potentially resulting in nutritional deficiencies.
In fact, mitigating nutritional deficiencies is where supplements "are best utilized" according to Craig Hopp, deputy director of the division of extramural research at the National Center for Complementary and Integrative Health, part of the US National Institutes of Health.
"Anytime somebody is missing major food groups, the first question is, can we target the missing nutrients with food? If not, then we would look into a supplement," said registered dietitian nutritionist Melissa Majumdar, who is a spokesperson for the Academy of Nutrition and Dietetics.
But there's a big difference between taking a pill as "nutritional insurance" if your diet is low in one or more nutrients versus taking it in the hopes of warding off disease. And even if you're popping a pill to simply up your vitamin C or calcium intake, health professionals agree it's not a substitute for a healthy diet.
"Eating a healthy diet is going to do far more for you than any supplement you can take, and yet we have a whole industry that is based on selling us all types of supplements," said Martha H. Stipanuk, James Jamison professor of nutrition emeritus in the division of nutritional sciences at Cornell University.
"When we look at health outcomes, no one supplement will have the effect of an overall healthy diet, in terms of immunity or chronic disease."
"Fruits and vegetables have phytochemicals and fiber; when you pop a pill, you never get the same outcomes," said Lisa Young, a registered dietitian nutritionist and adjunct professor of nutrition at New York University.
Experts worry that high doses of nutrients can give a false sense of promise.
"Often you feel you won't necessarily have to concentrate on getting these nutrients from your diet," said Young, who added that she often sees this with clients in her private practice. "You might feel like, 'This is insurance and I don't have to eat well,' and it might have a negative effect."
Supplements: The state of the science
"At the moment, evidence to support the use of individual vitamins and minerals for treatment or prevention of chronic disease outcomes is weak," Hopp said.
"A diet high in fruits in vegetables includes [lots of] vitamins and minerals ... and is epidemiologically associated with reduced instance of a whole host of chronic diseases," Hopp said. "But we have not seen that you can dietary supplement your way to good health. They are dietary supplements, not substitutes."