Is Vitamin C Bad For Your Kidneys?

Did you know that the word ‘vitamin’ was derived from the Latin word ‘vita,’ meaning life, and the word ‘amine,’ as vitamins were originally thought to contain amino acids? While scientists soon discovered that vitamins don’t contain amino acids, they are indeed vital for a healthy life. But can some vitamins do damage to your body as well? Vitamin C in particular is often subject to a lot of scrutiny, but are those fears warranted? Let’s take a closer look.
​
Put simply, if you consume an appropriate amount of vitamin C each day, it shouldn’t pose any risk to your kidneys. However, too much vitamin C could potentially be a cause for concern. In this article, we’ll explain how vitamin C and your kidneys interact, how much vitamin C is too much, and what other vitamins you should pay attention to if you have chronic kidney disease.

---

How Does Vitamin C Interact With Your Kidneys?

Your kidneys help with two crucial tasks: filtering waste from the body, and distributing essential vitamins and minerals throughout your body. Vitamin C is one of those vitamins that depend on the kidneys to be distributed throughout the body. When you consume a healthy amount of vitamin C each day, your kidneys help ensure it is distributed throughout your body, allowing you to: 

• Produce collagen
• Absorb the iron (another essential mineral for your health) from leafy greens
• Produce infection-fighting white blood cells that keep your healthy

It’s also crucial to note that while vitamin C is a vital part of a healthy diet, it isn’t the cure-all it’s sometimes made out to be. Vitamin C hasn’t been proven to prevent or shorten the common cold, nor has it been proven to reduce risk for conditions like eye disease or cancer.

Kidney stones are the most direct risk of excess vitamin C consumption, but keep in mind that this risk isn’t unique to vitamin C. Oxalate, which is found in fruits and other foods rich with vitamin C, can combine with calcium to crystalize and ultimately form kidney stones. However, oxalate is also found in many common foods that aren’t high in vitamin C, like spinach and potatoes. 
​
The best way to avoid calcium oxalate kidney stones from vitamin C or any other food is to ensure that you’re consuming enough fluids on a daily basis. This will ensure that waste and excess vitamin C is flushed from your body.

How Much Vitamin C is Too Much?

Vitamin C is water-soluble, meaning it’s easily dissolved, absorbed, and excreted. Therefore, your body needs a relatively-constant supply of vitamin C. Most people should consume between 60-100 milligrams (mg) of vitamin C each day, or roughly 90 mg for men and 75mg for women.

Vitamin C has a tolerable upper intake level of 2,000mg. This means that for most people, consuming as much as 2,000 mg is unlikely to cause any negative side effects. However, that doesn’t mean you should get all the vitamin C you can.
After about 1,000mg of vitamin C, your body will probably be unable to absorb any more and the excess will simply be flushed out in urine. More importantly, consuming too much vitamin C can have negative outcomes like diarrhea and an increased likelihood of kidney-stone formation.

What Vitamins Should You Avoid if You Have Chronic Kidney Disease?

As we’ve established, vitamins are essential for your body. However, too much of certain vitamins can have negative consequences. Vitamin C doesn’t always need to be avoided if you have CKD, but you should monitor your intake to avoid excessive oxalate buildup.
​
Other vitamins that can cause problems if you have chronic kidney disease (CKD) include vitamins A, D, E, and K. While water-soluble vitamins will be excreted in urine, vitamins A, D, E, and K are fat-soluble, meaning the body can store them for a longer period.

If you have CKD, your physician or nephrologist may recommend you limit your intake of these vitamins, as they can build up to dangerous levels. Vitamin A in particular should be consumed with caution if you have CKD, as too much can cause blurry vision, impact your body’s ability to benefit from vitamin D, and cause bone pain.

Vitamin C is Safe at the Recommended Level

In short, vitamin C is unlikely to damage your kidneys if you take the recommended 60-90mg a day. A healthy body can usually handle much more vitamin C than that amount, but vitamin C megadoses exceeding the recommended daily allowance can potentially lead to the formation of kidney stones and other health risks.
​
If you have CKD or other kidney-health complications, consulting with your physician or nephrologist is essential for consuming a safe amount of vitamins while reducing your risk for deficiencies.

Concerned About Your Kidneys? Talk to Milwaukee Nephrologists

Milwaukee Nephrologists are Southeast Wisconsin’s go-to kidney specialists. With four locations in the Milwaukee metro area and 15 hospital affiliations, we’re always nearby. To connect with a kidney doctor about your health, contact us today to schedule an appointment.