The Grapevine

Vitamin C Shocking Side Effects: Kidney Stone Formation, Heartburn And More

Doctors say that while overdosing on dietary Vitamin C (ascorbic acid) is unlikely to be harmful, megadoses of vitamin C supplements might cause headache, diarrhea, nausea, vomiting, heartburn, abdominal cramps and insomnia.

These are the more common side effects of taking too much Vitamin C. You can avoid ODing on Vitamin C if you remember that for adults, the recommended daily amount for vitamin C is only 65 to 90 milligrams a day. The upper limit is 2,000 mg a day.

But then there is the rarer but more consequential side effect called kidney stone formation that comes with the intake of far too much Vitamin C.

 A study published in the peer-reviewed journal JAMA Internal Medicine in 2015 revealed that men who consume high levels of vitamin C are at twice the risk of kidney stones than men who do not.

Kidney stones are tiny masses of crystals that can painfully obstruct the urinary tract. Serious cases of kidney stones will need surgery.

Researchers suspected that greater amounts of vitamin C might elevate the risk of kidney stones because the body breaks down Vitamin C into material known as oxalate, which is part of the stones.

"It is important that the public is aware that there may be risks associated with taking high doses of vitamin C,” study co-author Agneta Akesson, an associate professor with the Karolinska Institute in Stockholm, Sweden, said.

“Those with a history of kidney stones should consult their doctor before taking high-dose vitamin C supplements."

During the study, researchers followed over 23,000 Swedish men between 45 and 79 years old from 1997 to 2009. None of them had kidney stones at baseline.

Close to 900 of the men took 1,000 mg doses of vitamin C, and 3 percent of them (31 men) later had kidney stones. Less than 2 percent of those in the rest of the group developed kidney stones.

Vitamin C The recommended daily intake of vitamin C for adults is in the range of 65 to 90 milligrams per day. sydney Rae/Unsplash

After adjusting for factors that might undermine the reliability of the findings, researchers found out the men who received the high-dose supplements had an elevated kidney stone risk ranging between 1.7 and 2.2 times.

The study authors emphasized that there are no significantly proven reasons for any person to take such large amounts of vitamin C. The results of the study, however, apply to vitamin C that comes from food.

The study also showed that multivitamin supplements without large doses of vitamin C didn’t increase the risk of kidney stones.

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