First things first: Do you need to be taking a supplement or multivitamin?
"It really depends on the person," Funk says. "Just like on any medication, you take (supplements) for a specific reason."
While there isn't a blanket supplement for everyone, Wood says a multivitamin is a good option. "There's a lot of research coming out about vitamin D and how important it is," Wood says. "Almost everyone is deficient. A calcium-vitamin D combo is important to prevent osteoporosis." He says there's also a lot of research coming out on health benefits from omega-3 fatty acids.
Before you begin taking any supplement, however, Funk says it's a good idea to talk to your doctor or pharmacist to make sure it's safe for you as an individual. "Even a multivitamin has things that interact (with other drugs)," Funk says. "If you're on a blood thinner, you may not be able to take a multivitamin. Most have vitamin K, which goes against coumadin."
The effect they may have on other medications is one of the primary concerns with supplements and vitamins, which is why it's important to talk to someone familiar with your medical history. "A pharmacist is free," Wood says. "(Your pharmacist) is the best resource to find out what interacts with what. It's very confusing and complicated."
In the worst-case scenario, a supplement works against medication that's been prescribed by a doctor. "It can affect the mechanism or action of a drug," Funk says. "The supplement works in an opposing way. It can affect absorption of a drug, too much or too little. It can affect how the liver breaks down the drug. Not all supplements do that; it depends on the supplement and the drug."
However, sometimes the reverse is true. "A big thing not many people realize is that a lot of medications deplete the body of vitamins," Wood says. In those cases, supplements are a good idea.
Funk warns about being lured in by "all-natural" and herbal supplements. "People think all-natural equals all-safe, and that's not the case," he says. "Cocaine and opium are all natural. You have to be very careful. A number of popular herbs interact with a number of medications. Make sure to tell the pharmacist to check any possible interactions."
Another concern with so-called "all-natural" products is the lack of FDA regulation. "The guidelines and regulations by the FDA on supplements and herbal supplements are very loose," Funk says. Manufacturers "put whatever (they) want, claim whatever (they) want and then put an asterisk saying 'not approved by the FDA.'"
To avoid this, both Wood and Funk suggest getting supplements from a reputable source and avoiding Internet retailers.
"Really, just stay with a big-name company," Wood says. "It's a littler pricier, but some supplements are pharmaceutical grade. They have gone through some sort of manufacturer testing. ... It's a higher quality, safer product."
Ultimately, the most important thing to remember when taking a supplement or vitamin is to discuss it with a health care professional.
"Treat all drugs with due respect," Funk says. "Just because it's over-the-counter or natural, doesn't mean you can take it lightly."