Vitamin C is a very important nutrient that is abundant in many fruits and vegetables. Getting enough of this vitamin is important for maintaining a healthy immune system. It also plays an important role in wound healing, keeping your bones strong, and enhancing brain function.
Interestingly, some claim that vitamin C supplements provide benefits beyond those that can be obtained from the vitamin C found in food.
One of the most common reasons people take vitamin C supplements is the idea that they help prevent the common cold.
However, many supplements contain extremely high amounts of the vitamin, which can cause undesirable side effects in some cases.
This article explores the overall safety of vitamin C, whether it’s possible to consume too much, and the potential adverse effects of taking large doses.
Vitamin C is water-soluble and not stored in your body.
Vitamin C is a water-soluble vitamin, which means it dissolves in water. In contrast to fat-soluble vitamins , water-soluble vitamins do not get stored within the body. Instead, the vitamin C that you consume gets transported to your tissues via body fluids, and any extra gets excreted in urine.
Since your body does not store vitamin C or produce it on its own, it’s important to consume foods that are rich in vitamin C daily.
However, supplementing with high amounts of vitamin C can lead to adverse effects, such as digestive distress and kidney stones.
That’s because if you overload your body with larger-than-normal doses of this vitamin, it will start to accumulate, potentially leading to overdose symptoms.
It’s important to note that it’s unnecessary for most people to take vitamin C supplements, as you can easily get enough by eating fresh foods, especially fruits and vegetables.
Too much vitamin C may cause digestive symptoms.
The most common side effect of high vitamin C intake is digestive distress.
In general, these side effects do not occur from eating foods that contain vitamin C, but rather from taking the vitamin in supplement form.
You’re most likely to experience digestive symptoms if you consume more than 2,000 mg at once. Thus, a tolerable upper limit (TUL) of 2,000 mg per day has been established.
The most common digestive symptoms of excessive vitamin C intake are diarrhea and nausea.
Excessive intake has also been reported to lead to acid reflux, although this is not supported by evidence.
If you’re experiencing digestive problems as a result of taking too much vitamin C, simply cut back your supplement dose or avoid vitamin C supplements altogether.
Taking supplements in high doses may lead to kidney stones.
Excess vitamin C is excreted from the body as oxalate, a bodily waste product.
Oxalate typically exits the body via urine. However, under some circumstances, oxalate may bind to minerals and form crystals that can lead to the formation of kidney stones.
Consuming too much vitamin C has the potential to increase the amount of oxalate in your urine, thus increasing the risk of developing kidney stones.
In one study that had adults take a 1,000-mg vitamin C supplement twice daily for 6 days, the amount of oxalate they excreted increased by 20%.
High vitamin C intake is not only associated with greater amounts of urinary oxalate but also linked to the development of kidney stones , especially if you consume amounts greater than 2,000 mg.
How much vitamin C is too much?
It’s nearly impossible to consume too much vitamin C from food. However, if you’re supplementing with this vitamin, you can minimize your risk of getting too much by taking no more than 90 mg per day if you’re a man, or 75 mg per day if you’re a woman.
The Bottom Line.
Vitamin C is generally safe for most people. This is especially true if you get it from foods, rather than supplements. Individuals who take vitamin C in supplement form are at greater risk of consuming too much of it and experiencing side effects, the most common of which are digestive symptoms.
However, more serious consequences, such as iron overload and kidney stones, may also result from taking extreme amounts of vitamin C.