At her practice in Pasadena, California, Belardo often takes a hard line, regularly “de-prescribing” supplements. Last year, she persuaded one patient to stop taking 132 of them, including some to “detox” the kidneys and liver. Marily Oppezzo, an instructor of medicine at Stanford Prevention Research Centre and a registered dietitian, said she channels decluttering powerhouse Marie Kondo by asking patients which ones spark “real, evidence-backed joy”.
A wide variety of gummies, pills and powders are categorised as supplements, including vitamins and minerals, compounds like creatine and herbal products such as ashwagandha and kava. Almost all doctors say a few of them have their place; women benefit from taking folic acid, for example, when trying to have a baby. Some people have vitamin or mineral deficiencies that supplements can help address.
But supplements can also come with side effects, which patients are sometimes “shocked” to learn about, said Dr Mitra Rezvani, a hospitalist at Westchester Medical Center in New York. Many are merely uncomfortable – stomach issues, for example. But some are more serious. One paper in The New England Journal of Medicine estimated that supplements are responsible for 23,000 emergency room visits a year.
The ways doctors broach the issue can vary. Rezvani has had patients list everything they’re taking and explain why, which helps start a discussion about what they should reconsider.
And Dr Jen Gunter, an OB-GYN in San Francisco, tries to not push too hard. “The worst thing you can do is make a patient feel like they can’t talk to you,” she said.
Still, when she sees yet another patient taking probiotic supplements, “I’m always like, ‘Well, if those worked, you wouldn’t be coming to see me.’”
Nausea and rashes
The Food and Drug Administration only lightly regulates supplements, monitoring them less rigorously than drugs and not approving them for safety or effectiveness before they reach the public. Supplements have been found to be mislabelled, in terms of both the ingredients and their concentration. And some mix poorly with certain medications or with one another.
Because of what some have called “the wild west” nature of the market, it can be difficult to predict adverse side effects. Dr Pieter Cohen, an associate professor of medicine at Harvard Medical School who studies supplements, had one 45-year-old patient who developed rashes on her legs and back after starting on an anti-migraine supplement. Cohen suggested she stop taking the supplement, and the rashes went away.
Gunter worries about Ayurvedic supplements, some of which have been found to include lead, arsenic and mercury. Other doctors watch out for signs of supplement-related liver damage. Last year, researchers at the University of Michigan estimated that 15 million American adults take a supplement that could potentially cause liver toxicity, such as turmeric or red yeast rice.
Rezvani once treated a 70-year-old woman who had been experiencing nausea, jaundice and dark urine after starting a turmeric supplement, as well as semaglutide, the compound in the medication Ozempic. She and her team determined the supplement had likely damaged the liver and possibly interacted with the medication.
The patient stopped taking the supplement. Soon after, her liver function improved.
Overlooking underlying issues
Belardo said she understands why her patients turn to supplements. Prominent doctors sell and promote them online. The pharmaceutical and health care industries have left many Americans disillusioned. And some patients feel dismissed at the doctor, leading them to seek out alternative treatments for their pain.
In some cases, people may take a supplement to manage an unwanted symptom, instead of undergoing medical testing that would reveal the root cause of the issue.
In 2021, a 44-year-old woman came to Belardo for an evaluation. During the visit, the patient noted that, on a naturopath’s recommendation, she had been taking an iron supplement to treat anaemia and fatigue, but she still felt tired.
The iron supplement itself didn’t concern Belardo. What did was that the naturopath had not probed the underlying problem. In hopes of figuring it out, Belardo sent the patient to a gastroenterologist, who performed a colonoscopy. The diagnosis: stage IV colon cancer.
It was an extreme version of a type of situation that frustrates her most.
“Months, if not years, of opportunity for earlier detection and treatment had been lost,” Belardo said, “because her care was reduced to supplement prescriptions.”
This article originally appeared in The New York Times.
Written by: Ashwin Rodrigues
Photographs by: Ard Su
©2025 THE NEW YORK TIMES
