Is Vitamin C Overdose Dangerous?

How Much Is the Daily Recommended Dose Of Vitamin C?

For adults (men), the recommended daily amount for vitamin C is 65 to 90 milligrams (mg) a day, and the upper limit is 2,000 mg a day [3].

For women, the recommended daily amount for vitamin C is 65 to 75 milligrams (mg) a day, and the upper limit is 2,000 mg a day.

A pregnant woman would need about 85 mg of vitamin C daily. For nursing mothers, the requirement of vitamin C daily is 120 mg. For infants, the recommended daily amount is 50 mg and for children, it is 45 mg.

If you smoke, add 35 mg to the above values to calculate your total daily recommended amount.

1. Gastrointestinal Issues

Too much vitamin C can cause cramps in the stomach, nausea, and diarrhoea. This happens when the vitamin does not get absorbed properly by the gastrointestinal system due to an overdose. The issues resolve when the dosage is reduced or temporarily stopped [4].

2. Kidney Stones

Compounds called oxalate are produced when vitamin C is metabolised, which are excreted in the urine. However, oxalate in high amount can combine with calcium in the bloodstream causing kidney stones [5].

It is advised that people who have a history of renal problems such as kidney stones should stay away from high doses of vitamin C supplementation or even fruits that are rich in vitamin C [6].

3. Iron Overdose

Absorption of iron is facilitated by vitamin C, which helps prevent anaemia, caused due to a deficiency of iron in the blood. Vitamin C promotes the absorption of non-heme iron which is obtained from plant-based foods and is also found in meat [7].

People who already have high iron stores could face iron toxicity when a high intake of vitamin C enhances iron absorption. Also, individuals who suffer from a hereditary illness known as hemochromatosis could face tissue damage when vitamin C consumption in large doses extends over a long duration [8].

4. Cardiovascular Diseases

Vitamin C possesses antioxidant properties which help prevent and protect the body from several illnesses. Studies have shown that high amounts of vitamin C supplements could trigger and increase the risk of heart disease, including high blood pressure. The chances of this are higher in people who already have certain underlying health conditions [9].

5. Chances Of Genetic Damage

Few studies have shown the pro-oxidant (induces oxidative stress) tendency of vitamin C, especially when the dosage is high. In a study that involved healthy subjects, vitamin C was administered daily for about 6 weeks [10].

At a dosage of 500 mg per day, oxidative damage was identified. Based on this, researchers have concluded that vitamin C can damage and alter DNA that can eventually lead to life-threatening diseases such as cancer [11].

6. Interference With Blood Thinning Drugs

Vitamin C has been found to adversely react with certain drugs. It has been observed that vitamin C in high doses can cause the blockage of blood thinner functionality or that of the anticoagulants, which would eventually need an increased dosage of the drug to show effect [12].

7. Blood In Urine

One of the most common side effects of vitamin C overdose is bloody urine. This can be accompanied by some sort of pain in the stomach. In most cases, pain is absent [13].

Some of the other common side effects of vitamin C overdose are as follows [14] [15]:

• Dizziness
• Back pain
• Stomach cramps
• Headache
• Heartburn
• Dental decay
• Skin rashes
• Fatigue
• Pain in the urinary tract

On A Final Note…

Stick to the recommended intake of vitamin C. Consuming too much of any food or supplement would never speed up the process of nutrient absorption, but can only result in negative outcomes for your body.