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Dangerous Effects of Too Many Supplements, Say Experts

Experts explain harmful side effects of taking too many supplements. 
FACT CHECKED BY Emilia Paluszek

Taking supplements might sound like a great way to stay healthy, especially if your diet isn't the best, but there can be serious risks involved that you may not be aware of. "Taking too many vitamins can be unhealthy – more is not always better! Stick to the recommended doses on the packaging," Dr. Suzanna Wong, a licensed Doctor of Chiropractic and health expert with Twin Waves Wellness tells us. She adds, "The FDA  doesn't approve supplements or regulate their safety because they are dietary aids rather than medications. It is the responsibility of the supplement company to ensure that they are safe and labeled appropriately. The FDA simply monitors products and reports of adverse effects, and they will step in if necessary." Before taking any supplements read below and speak with your physician—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID.


Vitamin A

Vitamin A is an essential nutrient needed for good vision, a healthy immune system and it helps your heart, lungs and other lungs function properly.  However, Dr. Wong says, 'Vitamin A causes liver damage and birth defects when taken in excess, as well as reducing your bone mineral density. It can also cause nervous system disorders."




Paula Doebrich, Registered Dietitian Nutritionist, Master of Public Health and Owner of Happea Nutrition says, "Biotin is a common ingredient in hair and nail supplements. It's a water-soluble B-vitamin that cannot be stored in the body, meaning any excess will be excreted through urine. But excessive biotin supplementation may result in falsely high levels of thyroid hormones on a blood test. This could lead to a wrong diagnosis of hyperthyroidism or a wrong dosage of hormones – both of which could have serious consequences. If you take a supplement with biotin in it, make sure to inform your healthcare practitioner about this before any testing."


Vitamin D

woman taking vitamin D3

We need vitamin D to help absorb calcium and phosphate, which helps keep bones strong. A deficiency can cause mood changes and extreme fatigue, but according to Dr. Wong, "Taking too much vitamin D causes damage to your kidneys and causes bone pain and calcium stones. If you overdose on vitamin D you end up with a build up of calcium in your blood (hypercalcemia) which causes symptoms of nausea, vomiting, frequent urination and weakness."



young woman taking pill
Shutterstock / New Africa

Iron is vital for maintaining healthy blood and Dr. Wong tells us, "If you take too much iron you can cause liver problems, an accumulation of fluid in your lungs, low blood sugar levels, coma, and testicular problems in men. Because iron levels build up over time, you need to make sure that if you are taking it as a supplement, that you get your levels tested regularly."



Vitamin pills spilling from an open bottle

Doebrich shares, "Zinc is found in many supplements and has gained a lot of popularity as it was marketed for improving immune function. Taking too much zinc for long periods of time may result in a copper deficiency, which actually causes lowered immunity."

Heather Newgen
Heather Newgen has two decades of experience reporting and writing about health, fitness, entertainment and travel. Heather currently freelances for several publications. Read more about Heather