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Dangerous Effects of Too Many Vitamins, Says MD

MD explains the dangers of overdosing on vitamins and what to know before taking them.

We've all been told that taking vitamins is a good thing, but is it really? That depends on who you talk to. While many people can get the nutrients they need from eating a balanced diet, vitamin deficiency is a real issue for others and supplements can be a solution. That said, there's harmful side effects to be aware of that Dr. Bayo Curry-Winchell, Urgent Care Medical Director and Physician, Carbon Health and Saint Mary's Hospital explains to us and before taking any vitamin, please consult with your physician first. Read on—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID.


What Should People Know About Vitamins Before Taking Them?

Doctor showing test results to a patient, portrait.

Dr. Curry-Winchell emphasizes "First and foremost, make sure you discuss the vitamins you are taking with your healthcare provider. There is a myth that vitamins cannot cause harm. However, they can if taken in high quantities or with specific medications or health conditions including pregnancy. So be careful!"


Why is Taking Too Many Vitamins Unhealthy?

vitamins and supplements

Dr. Curry-Winchell says, "Your body receives several vitamins such as A, C, D, E, and K from the food you eat every day. Plus, your body naturally makes vitamin D and K. Therefore, taking in too much can cause health issues and complications that otherwise would not have been present."


What Should People Know About the FDA Regulation of Supplements?

vitamins in store

Dr. Curry-Winchell shares, "Vitamins are not regulated by the FDA for their safety, effectiveness, or marketing practices before they land on your local grocery store shelves."


Overdosing Can Happen

Sick woman coughing, experiencing hiccup.

Dr. Curry-Winchell explains, "Believe it or not, there is such a thing as too many vitamins! Taken in large amounts, vitamins can be harmful. Because your body gets most of its vitamins through your diet, and naturally makes D, and K — an extra dose can lead to complications and serious health issues." 

The Mayo Clinic states, "Vitamin D toxicity, also called hypervitaminosis D, is a rare but potentially serious condition that occurs when you have excessive amounts of vitamin D in your body. Vitamin D toxicity is usually caused by large doses of vitamin D supplements — not by diet or sun exposure. That's because your body regulates the amount of vitamin D produced by sun exposure, and even fortified foods don't contain large amounts of vitamin D. The main consequence of vitamin D toxicity is a buildup of calcium in your blood (hypercalcemia), which can cause nausea and vomiting, weakness, and frequent urination. Vitamin D toxicity might progress to bone pain and kidney problems, such as the formation of calcium stones."


Giving the Label Credibility


"Don't be fooled, a manufacturer can misrepresent the contents and effectiveness of the vitamin they are selling," Dr. Curry-Winchell warns.


Vitamin A


Dr. Curry-Winchell states, "Too much vitamin A is associated with several ailments such as nausea, changes in vision, headache, and difficulty with coordination. High intakes of vitamin A while pregnant have been associated with birth defects and can interact with certain medications." 


Vitamin C

Man at home having a headache in front of laptop

Dr. Curry-Winchell reminds us, "It's important to remember vitamin C is naturally available through a healthy diet.  If you ingest a large dose of vitamin C it can lead to several adverse effects such as headache, vomiting and stomach cramps." 


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
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