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Health

3 Potentially Dangerous Supplements Doctors Warn You Should Be Careful With Because They Can Damage Your Digestive System: Iron, More

August 15, 2025 by Mariam Qayum
shefinds | Health
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Supplements are often marketed as quick fixes for energy, weight loss, or overall health—but not all of them are as harmless as they seem. According to doctors, some popular supplements can actually wreak havoc on your digestive system, causing everything from bloating and cramping to more serious long-term gut issues. Here are three potentially dangerous supplements experts say you should approach with caution.

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1. Iron Supplements

Believe it or not, high doses of iron can irritate the digestive tract, leading to common side effects such as constipation, nausea, and stomach pain.

Although iron is important, Michael O. McKinney, MD from Healthy Outlook, says large amounts of it can "lead to an altered flora in the digestive system. Intake of large amounts of iron may promote the growth of pathogenic bacteria, thus resulting in upset stomach, constipation, bloating, and inflammation."

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2. Calcium Carbonate

Another supplement to take cautiously is calcium supplements. Best known for its bone health benefits, they can also cause constipation, bloating, and gas, as they can slow down the digestive process.

McKinney elaborates on this and notes that "calcium is an essential element for the development of bones; however, calcium carbonate supplements produce a constipating effect and may be uncomfortable in the digestive system. This type of calcium is less soluble and may bring disturbances in the intestines, so it becomes difficult for the digestive tract to become healthy."

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3. Magnesium Supplements

Magnesium supplements, especially in higher doses or specific forms like magnesium oxide, can mess up gut health by causing digestive issues such as diarrhea, cramping, and bloating. This could happen because magnesium acts as a laxative by drawing water into the intestines, leading to loose stools and dehydration if taken in excess.

"Too much consumption of magnesium can lead to a laxative effect, causing diarrhea. This can cause an imbalance in the natural gut flora and irritate the gastrointestinal tract, leading to discomfort and disrupting digestive health," says Dr. Kubanych Takyrbashev, MD, Health & Wellness Advisor at NAO.

Author:

Editorial Assistant

Mariam is an Editorial Assistant and writer at SheFinds, covering everything from style and beauty to health and wellness. Splitting her time between New York and Philadelphia, she brings a sharp eye for trends and a passion for storytelling to the digital space. With a strong editorial background, she’s always exploring the latest in fashion, skincare, and wellness. When she’s not writing or pitching, you’ll find her in the kitchen experimenting with new recipes or planning her next travel adventure. You can reach Mariam at mariam@shefinds.com.

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Woman holding her head in distress.
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Popular coffee and donut brands side by side.
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Pouring vitamin D into palm for supplementation.
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Older woman taking dietary supplements with water.
Brazilian dish featuring rice, beans, and chicken.
Handful of assorted dietary supplements in palm.
Checking the time while enjoying breakfast.
Pouring supplement powder into a glass of water.
Woman performing yoga on a mat in a studio
Healthy seeds displayed instead of pastries.
Grocery store aisle with sugar and sweeteners.
Person having a lunch meal.
Woman enjoying spearmint tea in a cozy setting.
Frustrated older woman touching her head in distress
Woman experiencing chest pain, seeking medical attention
Assortment of different bread types on display.
Woman holding her head in distress.
Woman experiencing joint pain and discomfort.
Popular coffee and donut brands side by side.
Woman adding sugar to her aromatic coffee.
Wooden board with bagels, blueberries, and butter.
Pouring vitamin D into palm for supplementation.
Comparing cooking spray and olive oil for cooking.
Older woman taking dietary supplements with water.
Brazilian dish featuring rice, beans, and chicken.
Handful of assorted dietary supplements in palm.
Checking the time while enjoying breakfast.
Pouring supplement powder into a glass of water.
Woman performing yoga on a mat in a studio