Vitamins are essential nutrients and must be consumed daily for our body to function optimally. Most essential nutrients are those that the body cannot synthesise or cannot do so in adequate amounts; hence, consumption of foods that provide these essential nutrients is a must. Vitamins are broadly classified as water soluble and fat-soluble Vitamins. There are 13 Vitamins in all and each one carries out critical functions that keep us alive and Vitamin C is one of them.
Vitamin C is a water-soluble vitamin and has several functions within our body. It has been associated with protection against some cancers like those of the mouth, oesophagus, stomach, and breast. It is also been seen to protect against cataracts. Vitamin C is needed to produce collagen - the protein that holds our body together, heals our wounds and maintains the integrity of our blood vessels. Vitamin C is involved in the production of neurotransmitters like serotonin and norepinephrine. The most important function of Vitamin C is that it acts as an antioxidant and bolsters the immune system. In these COVID times, this is the reason most of us are popping Vitamin C pills.
Being a water-soluble vitamin, excessive intake of Vitamin C usually leads to excretion of the extra amount through urine. Vitamin C consumed in the form of natural food sources seldom causes an overdose; however, while taking Vitamin C in the form of tablets, you may overdose. This is extremely rare but is seen occasionally.
Symptoms Of Having Too Much Vitamin C
While taking supplements, it has been observed that not the full amount is absorbed. It is believed that in lower doses about 70-90% absorption occurs while in mega doses of 1g and above only 50% is absorbed. The excessive amount left over in the GI tract may irritate the system leading to symptoms like:
- Abdominal cramps
Other Side Effects Of Taking Excessive Amounts Of Vitamin C Are:
Kidney stones: Excessive Vitamin C is excreted as oxalate from our body through urine. Sometimes this oxalate binds to other minerals forming crystals that may lead to stones in the kidneys. As Vitamin C is responsible for increasing the oxalate formation, excessive intake has been found to be linked to kidney stones. Some studies have shown high Vitamin C intakes to be linked to kidney failure, though in very rare cases only.
Absorption of Nutrients: Excessive Vitamin C may interfere with the absorption of Vitamin B12. In fact, it is advised that if you are taking both these vitamin supplements, you should keep about 2 hours of gap between them. Vitamin C has also found to decrease the uptake of Copper in the body.
Bone health: Vitamin C is a precursor for collagen formation, which is essential for healthy bones, and several studies have shown it beneficial effect on keeping bone and joint diseases at bay. However high levels of Vitamin C in our body may lead to activation of a protein that causes painful bone spurs (bony projections that develop along bone edges especially at the joints). High intakes of Vitamin C over long periods of time may lead to acceleration of painful osteoarthritis.
The Rusting Theory: A study carried out by the scholars of University of Florida, it was found that if you had an injury, sprain or inflammation, and were taking more than 100mg of Vitamin C/day, you may be rusting inside. The premise was that all these conditions lead to free iron within the body which reacts negatively with Vitamin C causing a reaction like rusting of an iron rod when exposed to water and oxygen. So even though Vitamin C helps lower inflammation and hasten healing, taking the right amount is recommended.
Recommended Daily Intake Of Vitamin C (ICMR/NIN)
To protect against these possible outcomes (side effects), upper limit of Vitamin C supplementation has been set. The UI or upper limit of Vitamin C according to the Office of Dietary Supplements - USA is:
- Adults: 2000mg/day
- Pregnant and Lactating mothers: 1800mg/day
- Infants: 400mg/day
- Children 4-8 Years: 650mg
- 9-13 Years: 1200mg
- 14-17 Years: 1800mg
Recommended Daily Intake Of Vitamin C (ICMR/NIN) For The Indian Population Is:
- Adult Man: 40mg/day
- Adult woman: 40mg /day
- Pregnant and lactating mothers: 60-80mg/day
- 0-1 year: 25mg
- 1-17 years: 40mg
Taking lots of citrus fruits, peppers, tomato, papaya, green chutney, amla and green leafy vegetables regularly will provide you with adequate Vitamin C. Supplementation should be done judiciously and only under a doctor's supervision.
Stay safe, stay healthy!
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About Rupali DattaRupali Datta is a Clinical Nutritionist and has worked in leading corporate hospitals. She has created and lead teams of professionals to deliver clinical solutions for patients across all medical specialties including critical care. She is a member of the Indian Dietetic Association and Indian Association of Parenteral and Enteral Nutrition.