• The kidneys filter excess vitamin C from the body.
  • Getting high doses of vitamin C from supplements could increase your risk of kidney stones.
  • Some research shows that higher vitamin C intake may lower your risk for kidney cancer, but further study is needed.

Vitamin C is an important nutrient for the body. It helps you absorb iron from foods and heal from cuts and bruises. It also plays a role in repairing bones and tissues in your body.

Getting the right amount of vitamin C is especially important if you have kidney disease. Extra vitamin C is filtered by the kidneys. If those organs aren’t working well, too much vitamin C could cause harm.

Here’s what to know about the connection between vitamin C and kidney health.

The recommended dietary allowance for vitamin C is 90 milligrams (mg) for adult men and 75 mg for adult women.

When you consume excess vitamin C, your kidneys process the nutrient and help your body excrete it through urine.

Too much vitamin C can cause a buildup of oxalate in your body if you have chronic kidney disease. Therefore, your vitamin C needs may be different if your kidneys aren’t working well or you’re on dialysis.

Dialysis can also deplete your blood of vitamin C. Research from 2012 found that people on dialysis can help increase their iron absorption by taking a low-dose vitamin C supplement of 60 to 100 mg.

Vitamin C intake may play a role in the risk of renal cell carcinoma, the most common type of kidney cancer among adults.

A 2015 meta-analysis showed that people with a higher vitamin C intake had a lower risk of kidney cancer, but more research is needed.

Researchers have been exploring the potential of using high doses of vitamin C to treat cancer for decades. However, high levels of vitamin C are not recommended for people with kidney cancer, as it could do more damage.

High doses of vitamin C can increase your risk of the most common type of kidney stone, calcium oxalate.

Kidney stones happen when waste accumulates and clumps together in your kidneys, causing pain and difficulty urinating. More than half a million people seek emergency care for kidney stones every year, according to the National Kidney Foundation.

Since the kidneys partly convert the vitamin C you ingest into oxalate, an excess could increase the risk of calcium oxalate kidney stones, according to research from 2015.

Generally speaking, the vitamin C people get from food isn’t likely to be high enough to lead to kidney stones.

However, vitamin C supplements (such as ascorbic acid tablets) could increase the risk. A 2013 study on 23,355 men found that those who took vitamin C supplements experienced double the rate of kidney stones.

To help minimize the risk of kidney stones, the National Institutes of Health recommends that adults consume no more than 2,000 mg of vitamin C per day.

Our bodies can’t make vitamin C. Instead, we get it from food or supplements.

Vitamin C offers a number of important benefits for the body, including:

  • helping wounds heal
  • protecting cells from damage
  • keeping blood vessels, skin, bones, and cartilage healthy
  • improving absorption of other nutrients

A severe vitamin C deficiency can lead to scurvy, a condition that can cause serious complications throughout the body.

It can be hard to assess our vitamin C levels because the nutrient is found all over the body. Researchers often use the blood concentration of vitamin C to figure out how much of the vitamin is in a person’s body.

A person’s levels of vitamin C can also change quickly if they take a supplement or the vitamin is given intravenously.

Most people can meet their vitamin C needs through foods. Many fruits and vegetables are rich in vitamin C, including:

  • red and green bell peppers
  • strawberries
  • kiwis
  • oranges
  • grapefruit
  • potatoes
  • tomatoes
  • broccoli

Most adults need between 75 and 90 mg of vitamin C daily. If you smoke, you may need an extra 35 mg of vitamin C per day.

Talk with your doctor before taking a vitamin C supplement. For some people, such as those with kidney disease, a vitamin C supplement may increase your risk of kidney stones.

Vitamin C is an important nutrient found in many fruits and vegetables. It helps the body heal wounds and protects cells from damage.

Vitamin C can also affect kidney health. On the one hand, higher levels of vitamin C intake have been associated with lower rates of kidney cancer. But high doses of vitamin C supplements can increase your risk of kidney stones.

If you’re considering adding a vitamin C supplement to your diet, talk with a healthcare professional to see if the benefits outweigh the risks for your health.