​​​​Are you overdosing on Vitamin C? | The Guardian Nigeria News

Vitamin C promises glowing skin and boosted immunity, but excessive use could silently harm your kidneys and digestive system. Find out how to strike the right balance.

“I was taking 3,000 mg every day, thinking it would improve my skin and boost my immune system,” says Tolu, a 28-year-old fitness enthusiast. “But over time, I started experiencing severe stomach cramps, followed by persistent back pain. One day, I was rushed to the emergency room with unbearable pain, only to find out my kidneys were failing.”

Tolu’s doctors confirmed that the kidney failure was due to excessive vitamin C intake. “I had no idea my ‘healthy’ habit was the cause,” she explains.

Vitamin C is widely praised for boosting immunity, improving skin texture, and fighting colds. Available as syrups, chewable tablets and effervescent powders, it’s become a popular daily supplement. But this ‘golden vitamin’ could be harmful if taken excessively, experts say.

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While vitamin C offers numerous benefits, consistently consuming too much or too little can lead to serious health issues.

The risks of excessive intake

The human body does not store vitamin C; excess amounts must be excreted. However, consuming it in excessively high amounts over time can overwhelm the body, potentially causing health complications.

Dr Ayoola Odeyemi, a leading nephrologist at Lagos State Teaching Hospital, explains that too much vitamin C increases oxalate levels, a compound linked to kidney stone formation. “Patients who consume more than 2,000 mg daily are at risk of developing kidney stones due to oxalate build-up in the kidneys. The damage can be gradual, and by the time symptoms appear, the stones may have already formed,” he notes.

Beyond kidney stones, high doses of vitamin C can also disrupt digestive health. Dr Olusina Ajidahun, an internal medicine specialist, explains that excessive vitamin C can trigger gastrointestinal distress. “Patients who take megadoses often report symptoms such as nausea, diarrhoea, and acid reflux,” he says. “The acidity of vitamin C can irritate the stomach lining, leading to gastritis over time.”.

Additionally, while vitamin C plays a crucial role in iron absorption, this can sometimes be harmful. “For individuals with haemochromatosis, a condition where the body absorbs too much iron, high doses of vitamin C can lead to iron overload, which may cause liver damage, heart problems, and pancreatic dysfunction,” Dr Olusina warns.

Pharmacist Adegunlola Gbemileke also highlights another overlooked risk: inaccurate medical test results. “Excess vitamin C can interfere with certain lab tests, including blood sugar readings in diabetic patients, leading to inaccurate diagnoses. This can result in inappropriate medication adjustments that may put the patient at risk,” she explains.

Consequences of vitamin C deficiency

While excessive intake poses risks, a deficiency can be just as harmful. Vitamin C is essential for collagen production, immune function, and wound healing. Without adequate amounts, serious health complications can arise.

Scurvy, a disease caused by severe vitamin C deficiency, remains a concern, particularly among the elderly and individuals with restrictive diets. “The early signs include fatigue, gum bleeding, and joint pain,” Dr Olusina explains. “Without intervention, scurvy can lead to anaemia, skin haemorrhages, and even death.”

A weakened immune system is another consequence of low vitamin C levels. “Individuals with insufficient vitamin C tend to fall ill more often and recover more slowly,” says Pharmacist Gbemileke. “It plays a critical role in immune defence, and even a moderate deficiency can make the body more susceptible to infections.”

Additionally, vitamin C is integral to skin health and wound healing. A deficiency can lead to dry skin, easy bruising, and slow recovery from cuts and injuries. Collagen formation relies on vitamin C, and when levels are too low, the skin loses elasticity, and healing processes slow down significantly.

The point of balance

So, how much vitamin C is too much or too little? The recommended daily intake of vitamin C varies based on age, gender, and life stage.

Adult men: 90 mg per day
Adult women: 75 mg per day
Babies under 1 year: 40–50 mg per day
Children over 1 year: 15–45 mg per day (depending on age)
Pregnant women: 85 mg per day
Lactating mothers: 120 mg per day
Elderly individuals: 75–90 mg per day

Although the upper limit for vitamin C is 2,000 mg per day, consistently exceeding this amount can lead to adverse effects, including kidney stones and digestive issues.
Experts recommend obtaining vitamin C primarily from natural food sources such as citrus fruits, bell peppers, and other vegetables, before considering supplements. Dr Olusina advised against taking vitamin C supplements when in good health, as dietary sources often provide sufficient amounts. “People should only take vitamin C supplements if advised by a doctor, otherwise, they risk exceeding safe levels without realising it,” he said.

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In all, the key to good health is balance. Vitamin C is essential, but excess intake does not provide extra benefits. Stick to recommended doses, and consult a healthcare provider if you have concerns about your intake. Also consider incorporating natural food sources, like citrus fruits and bell peppers, which deliver healthy doses of vitamin C into your diet.

So, before reaching for another high-dose tablet, remember that the body thrives on balance, not extremes. Most importantly, your skin will glow when you consume a well-balanced diet daily.