From Kidney Stones to Liver Damage: Side Effects of Excess Vitamin C Intake Are More Serious Than You Think

Vitamin C supports immunity and skin health, but excessive intake can cause kidney stones, iron overload, enamel erosion, false glucose readings, a...

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Vitamin

C is among the most important nutrients your body needs for overall health and well-being. Apart from boosting your immune system, promoting collagen production for skin and wound healing, it is also a powerful antioxidant that protects against cell damage. However, despite so many positives, overdosing on vitamin C can be detrimental to your health. According to experts, vitamin C, which is usually safe for most people, can lead to several adverse effects if overdosed. Rare, serious side effects of vitamin C occur – especially when taken in large quantities over an extended period. A few of these include:

Kidney stones

Taking high doses of vitamin C increases the levels of oxalate in your urine. Oxalates bind with calcium to form kidney stones due to extreme metabolisation. According to doctors, the process is especially concerning for those who are predisposed to kidney stones or those with existing kidney conditions. Individuals with a history of kidney stones, chronic kidney disease, or high oxalate levels may be at an increased risk.

Overload of iron

Vitamin C is known to enhance the absorption of non-heme iron, which is usually found in plant foods. While it is beneficial for your body, too much iron can be harmful for those with hemochromatosis - a genetic disorder that makes your body store excess iron – thereby increasing the risk of liver damage, heart disease, and even diabetes. Those who have iron metabolism disorders should avoid high-dose vitamin C supplements unless recommended by their doctor.

False blood glucose readings

Too much vitamin C can also interfere with certain laboratory tests, giving false readings in blood glucose monitors. Doctors say urine tests for creatinine, and tests that use chemical reagents sensitive to oxidation alter the results of urinalysis.

Erodes dental enamel

Vitamin C supplements –mostly the gummies and chewable tablets are super acidic in nature and wear down dental enamel over time. This erosion leads to increased tooth sensitivity, discolouration, and a higher risk of cavities. According to experts, you must rinse your mouth with water after consuming vitamin C supplements and avoid brushing immediately after.

Cause cellular damage

Even though vitamin C promotes antioxidant properties, it can also become pro-oxidant under certain conditions, especially at high doses and in the presence of free metal ions like iron or copper. It can then increase oxidative stress rather than reduce it. Studies suggest that very high levels of vitamin C may generate free radicals, thereby causing cellular damage.

How much vitamin C is too much?

Also known as ascorbic acid, vitamin C is extremely essential for the growth, development, and repair of all body tissues. Since vitamin C is usually not stored in your body, it is important to get adequate amounts from foods like citrus fruits, strawberries, bell peppers, and even supplements. The recommended dietary allowance (RDA) for vitamin C varies by age, sex, and life stage. Adequate intake levels in adults include:10

Men: 90 mg/day
Women: 75 mg/day
Pregnant women: 85 mg/day
Breastfeeding women: 120 mg/day.

The tolerable upper intake level (UL) for adults is 2,000 milligrams per day.10 Going beyond this amount, especially for prolonged periods, increases the risk of side effects. Supplements and fortified foods make it easy to exceed this limit unintentionally.