Supplements are not harmless

The U.S. Preventive Services Task Force is an independent panel of national experts. They don’t sell anything. In 2022 they looked at 84 studies with more than 700,000 people. Their conclusions:

• Beta-carotene: do not take it to prevent heart disease or cancer. In large studies, it raised the risk of lung cancer in smokers and people exposed to asbestos. It also raised the risk of dying from heart disease.
• Vitamin E: do not take it to prevent heart disease or cancer. It doesn’t work. In one large trial, men who took vitamin E got prostate cancer more often.
• Multivitamins and most other single vitamins: there isn’t enough evidence that they prevent heart disease, cancer, or early death.

Vitamin D is a good example. One of the largest trials ever done gave more than 25,000 healthy older adults vitamin D or a placebo (dummy pill) for about 5 years. Vitamin D did not prevent cancer, heart attacks, or strokes. It didn’t help even in people who started out with low vitamin D levels.

• Emergency room visits. Weight-loss and “energy” products cause racing heartbeats and chest pain, mostly in young adults. Older adults choke on large vitamin pills.
• Liver damage. Some cases lead to liver failure or a liver transplant. Common causes include green tea extract, turmeric, ashwagandha, garcinia, kratom, bodybuilding products, and “proprietary blends.”
• Hidden drugs. The FDA has found more than 1,000 supplements secretly spiked with real drugs — Viagra-type drugs in “sexual enhancement” products, banned weight-loss drugs in diet pills. Years after FDA warnings, some are still for sale and still contain the banned ingredient.
• Interactions with your real medicines. St. John’s wort can make blood thinners, birth control, statins, and transplant drugs stop working. Ginkgo, garlic, ginger, and turmeric can raise your bleeding risk if you take blood thinners.
• More is not better. In large heart studies, high-dose fish oil slightly raised the risk of atrial fibrillation, a common irregular heartbeat.

Under U.S. law, supplement makers don’t have to prove their product is safe or that it works before selling it. They don’t even have to prove the pill contains what the label says. In one study of sports supplements, 4 in 10 had none of the main listed ingredient. Some contained ingredients the FDA has banned.

Who is telling you to take this, and why should you believe them?

Before national experts recommend anything, they have to review all of the research — the studies that worked and the studies that didn’t. They publish their reasoning for anyone to read, and update it when new evidence comes in. Cardiologists set heart guidelines. Cancer specialists set cancer guidelines. Liver specialists warn about liver injury.

Compare that with the person on a podcast, social media, or a “wellness” clinic who tells you to take 12 supplements:

• Do they have training in the field they’re talking about? A title, a white coat, or a huge following is not the same as expertise in heart disease, cancer, or hormones.
• Are they showing you all the evidence, or just one study, one lab result, or one story?
• Do they sell the products they recommend? If the person giving you health advice also sells the cure, that is a conflict of interest. Treat it like one.
• Do they say your doctor and “the guidelines” are hiding something? That’s a sales pitch, not science.

One confident person is not a better source than thousands of experts who have reviewed all of the data. When an influencer and the guidelines disagree, the guidelines win.

Some people do need a supplement for a specific medical reason: folic acid before and during pregnancy, or vitamin B12, iron, or vitamin D when a blood test shows a true deficiency and your clinician recommends treatment. That’s medicine with a clear purpose. It is not “insurance” for healthy people.

These are less exciting, but they’re proven:

• Know your numbers — blood pressure, cholesterol, blood sugar, and weight — and treat them if they’re high.
• Don’t smoke.
• Move your body most days.
• Eat mostly whole foods: vegetables, fruits, beans, whole grains, fish, nuts.
• Limit alcohol.
• Get the cancer screenings recommended for your age and sex.

1. 1Ask your doctor or pharmacist whether it’s safe with your medicines.
2. 2Ask what proof there is that it helps people like you — not just mice or a lab dish.
3. 3Bring every supplement you take to your next appointment.
4. 4Skip anything sold for weight loss, energy, muscle building, or sexual performance, and anything labeled a “proprietary blend.”

Your money is better spent on good food and a pair of walking shoes than on a pill that hasn’t been shown to help and may hurt you.