When they’re used to fill gaps in your diet or offset a known deficiency, supplements may help to improve your health by increasing your levels of important vitamins, minerals, amino acids, and enzymes. Yet along with the benefits of supplements can also come certain risks. In particular, doctors warn that some supplements can damage your digestive system, especially if you don’t follow dosage instructions or heed your doctor’s recommendations. Wondering which supplements are most likely to cause unpleasant gastrointestinal symptoms? Read on to learn which 10 supplements can harm your digestive tract.
RELATED: 9 Supplements That Can Damage Your Stomach, Doctors Say.
1. Iron
New Africa / ShutterstockIron is an essential mineral that’s crucial for growth and development. It also aids in the production of hemoglobin, a protein found in red blood cells that helps transport oxygen throughout the body. Many people take iron supplements to prevent or treat iron deficiency anemia.
However, RajDasgupta, MD, an ABIM Quadruple board-certified physician specializing in internal medicine, pulmonology, critical care, and sleep medicine, and a medical reviewer for the National Council on Aging (NCOA), says that iron can cause constipation, nausea, and stomach pain—especially when taken at doses over 45 mg per day. He adds that ferrous sulfate, a type of iron supplement commonly used to treat anemia, is the most likely to cause digestive issues.2. Calcium
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Calcium is crucial in helping your body to build and maintain strong bones, as well as healthy muscles and nerves. If you are deficient in calcium, your doctor may recommend taking both a calcium supplement to increase your levels and a vitamin D supplement to help with calcium absorption.
Unfortunately for your digestive tract, Dasgupta says that sometimes calcium supplements can also lead to constipation and bloating, particularly at doses above 1,200 mg per day.
“Calcium carbonate is more likely to cause discomfort than calcium citrate,” he tells Best Life.
3. Magnesium
iStockMagnesium is a nutrient that the body needs to regulate muscle and nerve function, maintain blood sugar levels and blood pressure, and build protein, bones, and DNA. Many people also use magnesium supplements as a sleep aid.
However, “doses over 350 mg per day often cause diarrhea,” says Dasgupta. “Magnesium oxide and citrate forms are more likely to cause digestive upset,” he adds.
4. Fish oil or omega-3
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Aiding in a range of functions from muscle activity to cell growth and enhancing brain health, fish oil or omega-3 supplements are some of the most popular on the market.
That said, Dasgupta warns, “at doses above three grams per day, they can cause stomach discomfort, acid reflux, and diarrhea."
To reduce potential side effects, he suggests taking them with food.
RELATED: 5 Supplements That Can Damage Your Kidneys, Doctors Say.
5. Vitamin C
iStockVitamin C may help boost your immune system and improve your body’s healing system. It can also help protect your cells against free radicals—an atom, molecule, or ion that can damage cells and increase your risk of heart disease, cancer, and other diseases.
Though vitamin C may be beneficial in general, Dasgupta warns against taking too much.
“High doses (over 2,000 mg/day) can lead to diarrhea, stomach cramps, and bloating due to its acidity and water-attracting effect on the intestines,” he says.
6. Probiotics
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In general, probiotics can be beneficial for gut health, helping to promote a diverse and balanced microbiota.
However, these supplements can also cause “gas, bloating, and stomach pain, especially in those with sensitive digestion or when taking high doses (over 10 billion CFUs),” says Dasgupta.
7. Protein powders
ShutterstockProtein powders can help you build muscle, repair tissue, and produce important hormones. However, Dasgupta says you may experience one especially unpleasant downside by taking them—especially if you choose those made of whey and casein.
“Protein powders can lead to bloating, gas, and diarrhea, particularly for those who are lactose intolerant or consume more than 40 grams per serving,” he says.
8. Fiber
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Fiber supplements, including those made from Psyllium husk or inulin, can aid digestion by bulking up your stool, making it easier to pass. Fiber can also help you feel fuller for longer, curb cravings, and maintain a healthy weight.
However, Dasgupta says they can also cause gas, bloating, and cramps if taken in high doses of over five grams per day if you take it without enough water.
RELATED: 6 Popular Supplements Can Damage Your Liver, New Research Shows.
9. Zinc
iStockZinc supplements can help improve your immune system, speed up the healing process when you’re wounded, and enhance your metabolism. However, taking over 40 mg of zinc per day has been linked to nausea, diarrhea, and painful stomach cramps.
10. Fat-soluble vitamins A, D, E, and K
ShutterstockFinally, fat-soluble vitamins like vitamins A, D, E, and K are important for your immune system, vision, blood clotting, and bone health. However, they can be difficult to digest and absorb—especially when you take them on an empty stomach. To avoid unpleasant digestive symptoms, try eating fat-rich food before you take them.
