Vitamin C and Kidney Disease
Ann Haibeck, RD, LDN
Vitamin C and Your Kidneys
Loading up on vitamin C is a common strategy to boost the immune system and ward off illnesses such as the common cold. Vitamin C is a powerful antioxidant that can be beneficial in safe quantities, but may be harmful in large doses. For kidney patients, it’s especially important to remember that foods that are high in vitamin C can also be high in potassium.
What is Vitamin C?
Vitamin C, also known as ascorbic acid, is a water-soluble vitamin that is critical to tissue growth and repair in our bodies. Vitamin C helps to heal wounds, form scar tissue, maintain structure of bones and teeth, and absorb iron. Signs of vitamin C deficiency, commonly known as scurvy, include leg weakness, easy skin bruising, and swollen gums. Vitamin C deficiency is relatively uncommon in the United States and Canada because many food items such as juices are fortified with vitamin C. Vitamin C is found naturally in foods such as oranges, guavas, sweet peppers, grapefruits, and kiwis.
How Much Vitamin C Do I Need?
According to the National Institutes of Health, the recommended daily intake of vitamin C is 90mg per day for nonsmoking men, and 75mg per day for nonsmoking women. Smoking increases the production of cell-damaging free radicals, so smokers need to consume an additional 35mg of vitamin C daily. For reference, 60mg of vitamin C can be found in four ounces of orange juice, a half cup of sweet green peppers, or one kiwi fruit. As you can see, only a small amount of fresh fruit or vegetables can help you meet your daily vitamin C needs.
If you eat a varied diet that includes fresh fruits and vegetables, including juices, it is likely that you do not need a supplement to get enough vitamin C. It is notable that the National Kidney Foundation’s guidelines indicate that there is not sufficient evidence to recommend use of vitamin C in anemia management for individuals with chronic kidney disease.
Can I Get Too Much Vitamin C?
Too much vitamin C can cause gastrointestinal side effects such as diarrhea, nausea, and stomach cramps. In some cases, such as non-food supplementation of vitamin C greater than 1000mg per day, excessive oxalate production can occur. This can potentially lead to kidney stones.
Balancing Vitamin C, Phosphorus, Potassium, and Protein
Consider overall dietary balance when choosing how to get adequate vitamin C in your diet. Fruits and vegetables tend to contain the most vitamin C, and have little protein and phosphorus. In addition, some fruits and vegetables can be high in potassium.
Sources of vitamin C that have the least amount of potassium include:
- one cup of pineapple
- one guava
- one cup of sliced strawberries
- one kiwi
Each has at least 60mg of vitamin C and less than 250mg of potassium.
Higher potassium sources of vitamin C include:
- one cup of sweet green peppers
- one cup of mango pieces
- one cup of chopped broccoli
- one cup of orange juice
Each have at least 60mg of vitamin C and greater than 250mg of potassium.
Foods that are high in vitamin C are an important part of a well-balanced diet at any stage of kidney disease. For optimal health, try to get your vitamin C from food rather than supplements. This will maximize the benefits of vitamin C in your diet while lowering the risk of excessive vitamin C intake. Finally, be mindful of the potassium content of foods that are rich in vitamin C to ensure well-balanced food choices.
The content of this article is for informational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment. KidneyChef urges you to seek the advice of your physician or other qualified health provider with any questions you may have regarding any medical condition. KidneyChef advises you to never disregard professional medical advice or delay in seeking it because of something you have read on the Website.
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Michaels, A.J., & Frei, B. (2013) Myths, Artifacts, and Fatal Flaws: Identifying Limitations and Opportunities in Vitamin C Research. Nutrients. 5(12): 5161–5192. doi: 10.3390/nu5125161.
National Institutes of Health. (2011, June 24). Vitamin C. Retrieved from https://ods.od.nih.gov/factsheets/VitaminC-Consumer/
National Kidney Foundation. (2004). KDOQI Clinical Practice Guidelines and Clinical Practice Recommendations for Anemia in Chronic Kidney Disease. Retrieved from http://www2.kidney.org/professionals/kdoqi/guidelines_anemia/cpr33.htm.
United States Department of Agriculture Food Composition Databases. (2017). Retrieved from https://ndb.nal.usda.gov.