- Supplements are not reviewed by the FDA for safety or efficacy before hitting the shelves.
- Most vitamins either get “peed out” or build up to harmful levels in the body’s tissues.
- There are a few exceptions where supplements are necessary, but always check with your health care provider first.
In the world of wellness, dietary supplements are a big—and somewhat controversial—business. The use of vitamins and supplements (such as fish oil, Vitamin C, or calcium) is at an all-time high: 70 percent of people ages 18–34 take them, according to a 2018 survey conducted by the Council for Responsible Nutrition. Supplements aren’t just limited to dietary vitamins and minerals. They also include the weight loss and sports nutrition supplements you see marketed on Instagram (respectively taken by 17 and 28 percent of people). In both cases, many experts say taking dietary supplements isn’t helpful—and some can actually be harmful. Here’s what you need to know about potential risks to help you make the healthiest decisions.
Supplements aren’t regulated
“The reason we’re concerned about supplements is that most of them aren’t actually regulated,” says Dr. Niket Sonpal, the associate program director for the Internal Medicine Residency Program at Brookdale University Medical Center in New York. Dietary supplements—including vitamins—aren’t reviewed for safety or efficacy by the Food and Drug Administration (FDA) or any other regulatory body before going to market, which means we can’t know for sure what’s in them or if the dosage is correct.
A large study published in JAMA in 2018 examined FDA warnings about contaminated supplements between 2007 and 2016 and found 776 reports of “potentially harmful” unapproved pharmaceutical ingredients—most commonly in supplements marketed for weight loss or muscle building. “Just because something is natural does not make it safe,” says Jenna Volpe, a registered and licensed dietician in Austin, Texas, and Woburn, Massachusetts. “Many weight loss supplements are associated with documented outcomes related to liver failure or irreversible cardiac issues that could result in death. People are better off mastering a healthy, balanced lifestyle with a nutrition and fitness foundation. Cutting corners is just not worth the risk.”
Are all vitamins and supplements that dangerous? For the most part, no. They’re just unnecessary—but there are some that can do serious damage.
Too much of a good thing
You’re probably thinking, “Wait a minute. Aren’t vitamins good for you?” They definitely are, but the truth is, we get almost all the vitamins we need from food. Most vitamin supplements aren’t necessary if you eat a well-balanced diet—with plenty of fruits, veggies, and protein—and have no underlying health conditions (more on that in a minute).
Ingesting too much of a certain vitamin can actually be harmful. Vitamins fall into two categories: water-soluble and fat-soluble. Water-soluble vitamins, which include Vitamins B and C, dissolve in water and pass through the body if it doesn’t need them. (In other words, you’ll “pee them out.”) On the other hand, fat-soluble vitamins, like Vitamin D, are stored in the body’s tissue and can cause harmful buildup. A study published in 2019 in the Annals of Internal Medicine found that in some cases, a buildup of excess calcium from taking dietary supplements (greater than 1,000 mg of calcium per day) was linked to an “increased risk for cancer death.”
That said, “we shouldn’t be worried that taking a multivitamin is going to result in an earlier death,” says Dr. Sonpal. The important thing is to always check with your doctor before taking any new supplement to make sure it’s safe for you.
When vitamin supplements are necessary
There are some cases where you might not be getting all the nutrients you need from your food alone.
Vitamin D is essential for bone health. We get most of it from exposure to the sun—the National Institutes of Health (NIH) recommends between 5 and 30 minutes daily—and from foods like salmon and tuna. If you don’t spend much time outside (or have very dark skin, the NIH notes) or don’t eat fish regularly, you might be Vitamin D deficient. If you have questions about your diet, check in with a nutritionist just to be sure.
People with conditions like Crohn’s disease or irritable bowel syndrome (IBS)—which can prevent the intestines from properly absorbing nutrients like Vitamin D—may also benefit from taking a supplement. These cases aren’t one-size-fits-all, however, so talk to your doctor and have your blood levels tested to check for deficiency before supplementing.
The body needs Vitamin B12 to make blood cells, nerves, and even DNA—in other words, it’s pretty important. B12 is naturally found in fish, meat, eggs, and milk, so if you eat a vegetarian or vegan diet, taking a B12 supplement is often necessary.
“If you’re not sure if you’re getting everything you need from your diet, nutritionists are available everywhere,” says Dr. Sonpal. Check in with your campus health services to see if they have a nutritionist on staff, or you can search online for one in your community.
What to avoid at all costs
One type of supplement that’s never necessary? Those that promise weight loss. “Two of the most common weight loss supplements on the market are ephedra and garcinia. Both have been reported to cause liver failure, heart failure, and even death,” says Volpe.
Reminder: Most of these supplements are totally unregulated, so there’s no way to tell what harmful ingredients might be in them. “Even Alli [a weight loss pill], which is FDA-approved and regulated, has a mechanism that destroys our body’s natural ability to digest and absorb fat,” Volpe explains. “We need fat for many functions, including but not limited to mental health, thyroid/hormone balance, vitamin absorption, heart health, blood sugar control, and even satiety and appetite regulation.”
There’s no such thing as a magic diet pill. “If someone does not have a healthy diet and fitness regimen in place, no herb or supplement is going to have a significant impact on any kind of health goals,” says Volpe.
The bottom line on supplements
If you’re interested in a buzzy new supplement, always approach with caution. Do your research and look for reputable supplement companies that are transparent in how they source their ingredients. “I like a couple of websites: labdoor.com and consumerlab.com. These websites publish lists of high-quality supplements that are vetted,” says Dr. Sonpal.
Also, always check with your doctor before you start taking anything new. “You’ve got startup companies that are promising you this proprietary blend where you input a bunch of things on an app and then it spits back, you should take this, this, this, this, this, this and this. But those companies aren’t taking into account the person’s individual medical history, and they’re not physicians,” says Dr. Sonpal. You risk getting something that’s been contaminated, could adversely interact with a medication you’re taking, or might simply just be too much for your diet.
“If you’re going to start a supplement, have a chat with your doctor, because so many of them aren’t even needed,” says Dr. Sonpal. And “if they are needed, we’ll tell you how much to take and how to do it safely.”GET HELP OR FIND OUT MORE
Niket Sonpal, MD, associate program director for the Internal Medicine Residency Program at Brookdale University medical center, Brooklyn, New York.
Jenna Volpe, RD, registered and licensed dietitian, Austin, Texas and Woburn, Massachusetts.
Bailey, R. L., Gahche, J. J., Miller, P. E., Thomas, P. R., et al. (2013). Why US adults use dietary supplements. JAMA Internal Medicine, 173(5), 355–361.
Chen, F., Du, M., Blumberg, J. B., Kwan Ho Chui, K., et al. (2019, May 7). Association among dietary supplement use, nutrient intake, and mortality among US adults: A cohort study. Annals of Internal Medicine, 170(9), 604–613. doi: 10.7326/M18-2478
Council for Responsible Nutrition. (2019, September 30). Dietary supplement use reaches all-time high. Retrieved from https://www.crnusa.org/newsroom/dietary-supplement-use-reaches-all-time-high-available-purchase-consumer-survey-reaffirms
Gavura, S. (2013, February 14). Who takes dietary supplements, and why? Science-Based Medicine. Retrieved July 25, 2014, from http://www.sciencebasedmedicine.org/who-takes-dietary-supplements-and-why/
National Institutes of Health, Office of Dietary Supplements. (2019, August 7). Vitamin D. Retrieved from https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/#h6
Tucker, J., Fischer, T., Upjohn, L., Mazzera, D., et al. (2018, October 12). Unapproved pharmaceutical ingredients included in dietary supplements associated with US Food and Drug Administration warnings. JAMA Network Open, 1(6). doi:10.1001/jamanetworkopen.2018.3337