Doctor Issues Warning: 5 Popular Supplements Linked to Heart Attacks and Liver Damage

“Just because it’s labeled ‘natural’ doesn’t mean it’s safe,” warns Dr. Evan Levine, a cardiologist at Mount Sinai in New York. His cautionary statement has sent shockwaves across the growing global wellness industry — one where millions of people consume vitamins, herbal capsules, and “natural” powders daily, believing they’re doing their bodies a favor.

But according to Dr. Levine, some of these popular supplements could actually be silently damaging your heart and liver — and, in extreme cases, even lead to heart attacks, liver failure, or stroke.

The statistics paint a grim picture. According to the Centers for Disease Control and Prevention (CDC), over 800,000 Americans experience a heart attack or stroke each year. One American dies of some form of heart disease every 33 seconds. Meanwhile, around 5 million Americans live with liver disease, and nearly 60,000 die from liver failure annually.

As Dr. Levine points out, “What makes this more worrying is that an increasing number of young adults are now suffering from heart attacks — often linked not to lifestyle, but to what they believe are health supplements.”

Below are the five supplements Dr. Levine warns could be the most dangerous for heart and liver health.

Niacin, or Vitamin B3, is essential for energy production, healthy nerves, and digestive regulation. Naturally, it’s found in red meat, fish, nuts, seeds, and bananas. It’s also prescribed to lower cholesterol or ease arthritis pain.

However, when consumed in high doses, niacin can do more harm than good.

A 2024 study in Nature Medicine found that excess niacin can double the risk of cardiovascular disease by increasing inflammation and plaque buildup in arteries — a direct path to heart attack and stroke.

The safe daily limit for adults is 14–18 mg, but many supplements contain 2,000–6,000 mg, levels that can be extremely dangerous.

Symptoms of excess niacin include dry skin, hair loss, bone problems, and in severe cases, liver damage or birth defects in pregnant women.

Green tea is often hailed as a superfood — rich in antioxidants that can boost metabolism, improve skin, and protect against cancer. But in its concentrated extract form, it can be toxic.

Dr. Levine explains, “While green tea as a beverage is safe, green tea extract in high doses can injure the liver. The damage can range from mild enzyme elevation to severe cases requiring liver transplantation.”

This is due to a compound called EGCG (epigallocatechin gallate), which, in excessive amounts, overwhelms the liver’s ability to process toxins.

The European Food Safety Authority (EFSA) warns that doses above 800 mg per day can be dangerous — particularly for people already on blood thinners or with pre-existing liver or heart conditions.

Simply put, a capsule isn’t the same as a cup of tea.

Erythritol and xylitol have become the go-to sugar substitutes in “keto-friendly” snacks, sugar-free gums, and even oral hygiene products. They are FDA-approved and praised for helping diabetics manage blood sugar.

However, new research paints a worrying picture.

“Erythritol and xylitol can increase platelet aggregation — the clumping of blood cells that leads to clots and, eventually, heart attacks or strokes,” Dr. Levine notes.

A 2024 Cleveland Clinic study found that people who regularly consumed xylitol were significantly more likely to develop blood clots and heart attacks within three years. A 2023 study revealed similar results for erythritol — users were twice as likely to suffer a major cardiovascular event.

In short, these “sugar-free” sweeteners might not be as heart-friendly as they seem.

Many supplements come in soft gel capsules, which are easy to swallow and widely used in pain relievers, multivitamins, and cold medicines. But what few know is that these capsules often contain phthalates — chemical compounds used to make plastics flexible.

Inside the body, phthalates irritate artery walls, causing inflammation and narrowing — both key risk factors for heart disease.

A 2021 study in Environmental Pollution found that exposure to phthalates correlates with a higher risk of death from cardiovascular disease.

Dr. Levine cautions that long-term exposure can also lead to oxidative stress, damaging heart cells, raising triglyceride and LDL levels, and increasing vulnerability to strokes and aneurysms.

Even though phthalates are everywhere — from food packaging to cosmetics — getting extra doses through pills can accelerate cardiovascular decline.

While Dr. Levine focused on specific substances, he also highlighted a broader issue: the unchecked overuse of multivitamins.

Many people take multiple supplements without realizing that vitamins can interact, causing imbalances or strain on organs. For example, too much Vitamin A or iron can overload the liver, while excessive Vitamin E can thin the blood and raise the risk of hemorrhagic stroke.

As Dr. Levine explains, “The human body isn’t designed to handle mega doses of every vitamin at once. More is not better — it’s often toxic.”

• Consult a doctor before starting or combining any supplement.
• Stick to food sources whenever possible — whole foods contain nutrients in safer, balanced forms.
• Read labels carefully; watch for additives like phthalates, artificial sweeteners, and excessive doses.
• Monitor your liver and heart health regularly, especially if you’re taking long-term supplements.

The wellness industry may sell “health in a bottle,” but science says otherwise. Even the most harmless-looking vitamin can backfire when taken incorrectly or excessively.

Dr. Levine’s final advice is clear:

“Supplements are meant to supplement, not replace, a healthy lifestyle. Respect that line — your heart and liver depend on it.”