Vitamin C And Kidney Stones
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 isnt likely to be high enough to lead to kidney stones.
However, vitamin C supplements 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
Our bodies cant 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
- 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.
A persons levels of vitamin C can also change quickly if they take a supplement or the vitamin is given intravenously.
- red and green bell peppers
Can Too Much Vitamin C Lead To Kidney Stones
Being in the midst of cold season, many of us try to take as many preventive actions as possible to avoid the sniffles, whether it’s washing our hands more frequently, taking more vitamins, sucking on zinc lozenges or popping extra vitamin C supplements.
But if you are a male, be aware of how much vitamin C you are taking. A recent study in the “JAMA Internal Medicine” journal found that men who ingested vitamin C supplements of 1,000 mg/day or more were at increased risk for kidney stones. Vitamin C intake through diet did not carry the same risk.
The recommended dietary allowance for vitamin C in the United States is 75 mg/day for women and 90 mg/day for men.
“Most people get enough vitamin C from a balanced diet and our bodies absorb it most effectively from the foods we eat,” says Sarah Malik, MD, Nebraska Medicine gastroenterologist.
“People who might be susceptible to vitamin C deficiency, such as smokers, people with severe intestinal malabsorption or cachexia and cancer patients might be at increased risk of vitamin C inadequacy, may benefit from the use of vitamin C supplements under a doctor’s supervision,” says Dr. Malik.
Major sources of vitamin C include citrus fruits, tomatoes, cantaloupes and strawberries. Approximately 70% to 90% of vitamin C is absorbed in moderate intakes of 30 to180 mg/day. However, at doses above 1g/day, absorption falls to less than 50%. Absorbed, unmetabolized vitamin C is excreted in the urine.
How Can Your Diet Increase The Risk For Calcium Stones
Approximately four out of five kidney stones are calcium stones. These stones are often a combination of calcium and oxalate, but can also be a combination of calcium and phosphate or a combination of all three. A great deal of research has uncovered dietary factors that can lead to the development of these stones.
The beef about animal protein: Protein is an essential nutrient needed for numerous functions in our body. The average American consumes about twice the RDA for protein each day with the majority of it coming from animal sources. Some research has shown a link between kidney stones and diets high in animal protein, while others have found no difference in stone formation in animal versus plant protein consumption. If the majority of your meals contain a source of meat , then the recommendation would be to cut back on the quantity and/or frequency that these are consumed. Here are some ways to get protein from plant sources:
The salt that you add while cooking or eating can easily put you over your limit for the day. Each teaspoon of salt contains about 2,300 mg of sodium. Some techniques for keeping your sodium intake down are:
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Vitamin C In High Doses Related To Kidney Stone Formation In Men
Three-dimensional reconstructed CT scan image of a ureteral stent in a 26-year-old male. There is a kidney stone in the pyelum of the lower pole and one in the ureter beside the stent .
If you are a person who believes in moderation, and that less is sometimes better”, you may want to take note of some recent research published in JAMA Internal Medicine regarding the role of high dose vitamin C and kidney stone formation in men.
In this article, researchers in Sweden established a link between the use of vitamin C and development of kidney stones in more than 23,000 men over an 11 year period. During this prospective observational cohort study, about 2 % of the men developed kidney stones. It turns out that those who reported taking vitamin C supplements were about two times more likely to have suffered from kidney stones. Taking standard multivitamins did not appear to elevate the risk.
The normal requirement for vitamin C intake for a man is 90 mg a day, while the average woman needs only 75 mg a day. Vitamin C is integral for skin, bone and connective tissue health, and also helps the body to absorb iron. Foods rich in vitamin C include citrus fruits, as well as red peppers and papaya. Vitamin C supplements can potentially supply us with up to 10 times the recommended daily requirement.
Why People Think Vitamin C Increases The Risk Of Kidney Stones
The idea that vitamin C increases the risk of developing kidney stones came years ago as part of the medical attack on Linus Pauling.
Let me explain.
Linus Pauling is the only person awarded two unshared Nobel Prizes and one of the greatest scientists of the 20th century.
Dr. Pauling was not a medical doctor, but he had a great interest in nutrition science. He dedicated many years to research ascorbic acid and other nutrients.
Efforts to discredit him took place when he suggested that vitamin C may help fight chronic diseases like cancer and heart disease. Many scientists and doctors before him had suggested the same.
The story of kidney stones and vitamin C is part of this effort to discredit Dr. Pauling.
The idea is based on anecdotal evidence and not science, and the reasoning is as follows:
The fact is that many factors influence why and how stones form.
There is no scientific evidence that shows that an increase in oxalates results in more or larger kidney stones.
Dr. Stevey Hickey is one of the vitamin C experts. Heâs the author of the book Ascorbate, The Science of Vitamin C.
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Can Too Much Vitamin C Cause Kidney Stones
Before you knew much about vitamins, you can probably remember seeing Popeye eat a can of spinach and grow bulging biceps in an instant. As it turns out, veggies and fruits like spinach, oranges, broccoli, strawberries, and kiwi contain a powerful nutrient vitamin C. Although our bodies make some of the vitamins that we need for good health, it can’t make vitamin C so we must get it through our diets or supplements, according to Healthline.
Vitamin C, also known as ascorbic acid, is essential for many processes in the body. Vitamin C helps the body absorb iron, heal wounds, and it keeps our immune systems strong, helping to protect us from a number of diseases. Since vitamin C is not a fat-soluble vitamin, most people don’t worry about consuming amounts that can cause harm, notes Healthline. However, there are cases in which taking too much vitamin C, particularly through supplements, has been linked to the formation of kidney stones.
What Is A Kidney Stone
A kidney stone is a hard deposit of salts and minerals that form inside your kidneys. Your kidneys remove waste and fluid from your blood, which makes urine. If you don’t have enough fluid in your blood, the wastes can accumulate and form into stones. These stones can be as small a grain of salt or grow to be as big as a golf ball.
Vitamin C intake, also called ascorbic acid, has been proposed as a risk factor for kidney stones formation because vitamin C may increase urinary oxalate excretion, a type of calcium salt responsible for some stones.
“Ingested vitamin C is partly converted to oxalate and excreted in the urine, thus potentially increasing the risk of calcium oxalate stone formation,” says Dr. Malik. “In a metabolic study of 24 individuals, 2 grams daily of vitamin C increased urinary oxalate excretion by about 22%.”
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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 (
Consuming too much vitamin C may increase the amount of oxalate in your kidneys, which has the potential to lead to kidney stones.
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What Really Causes Kidney Stones
A recent widely-publicized study claimed that vitamin C supplements increased the risk of developing kidney stones by nearly a factor of two. The study stated that the stones were most likely formed from calcium oxalate, which can be formed in the presence of vitamin C , but it did not analyze the kidney stones of participants. Instead, it relied on a different study of kidney stones where ascorbate was not tested. This type of poorly organized study does not help the medical profession or the public, but instead causes confusion.
The study followed 23,355 Swedish men for a decade. They were divided into two groups, one that did not take any supplements , and another that took supplements of vitamin C . The average diet for each group was tabulated, but not in much detail. Then the participants who got kidney stones in each group were tabulated, and the group that took vitamin C appeared to have a greater risk of kidney stones. The extra risk of kidney stones from ascorbate presented in the study is very low, 147 per 100,000 person-years, or only 0.15% per year.
Key points the media missed:
So we have a poorly designed study that did not determine what kind of stone was formed, or what caused the stones that were formed. These are serious flaws. Drawing conclusions from such a study can hardly be a good example of “evidence based medicine.”
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The Recommended Dietary Allowance
The recommended dietary allowance for vitamin C is based on the amount of vitamin C intake necessary to maintain neutrophil vitamin C concentration with minimal urinary excretion of vitamin C and is proposed to provide sufficient antioxidant protection . The recommended intake for smokers is 35 mg/day higher than for nonsmokers, because smokers are under increased oxidative stress from the toxins in cigarette smoke and generally have lower blood concentrations of vitamin C .
Vitamin C Kills Bacteria
Stones appear to form around an infected area. Enough vitamin C kills bacteria and might prevent stones.
Why? Because vitamin C removes the bacteria around which the stones form.
Dr. Frederick Klenner used large amounts of vitamin C in his medical practice for over 40 years. He explains that when proper amounts are used, ascorbic acid destroys all virus organisms.
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Before Taking This Medicine
You should not use ascorbic acid if you have ever had an allergic reaction to a vitamin C supplement.
Ask a doctor or pharmacist about using ascorbic acid if you have:
kidney disease or a history of kidney stones
hereditary iron overload disorder or
if you smoke .
Your dose needs may be different during pregnancy or while you are breast-feeding a baby. Do not use ascorbic acid without your doctor’s advice in either case.
Kidney Stone Risk In Men Linked To Vitamin C Intake
Total and supplemental vitamin C intake is associated with a significantly elevated risk of kidney stones in men, according to a new study published online ahead of print in the American Journal of Kidney Diseases.
In a prospective cohort analysis, Pietro Manuel Ferraro, MD, of Columbus-Gemelli University Hospital, Catholic University of the Sacred Heart in Rome, Italy, and colleagues found that total vitamin C intake of 90249, 250499, 500999, and 1,000 mg/day or higher was associated with a 19%, 15%, 29%, and 43% increased risk of kidney stones among men compared with an intake below 90 mg/day . The researchers found no association between total vitamin C intake and stones among women.
Additionally, Dr. Ferraros group found that high supplemental vitamin C intake was associated with an increased risk of kidney stones in men, but not women. Supplemental vitamin C intake of 1,000 mg/day or more by men was associated with a significant 19% increased risk of kidney stones compared with no intake. Dietary vitamin C intake was not associated with kidney stone risk in either men or women.
We advise that male calcium oxalate stone formers abstain from supplemental but not dietary vitamin C intake, the researchers concluded.
The study included 156,735 women in the Nurses Health Study I and II and 40,536 men in the Health Professionals Follow-up Study.
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Family History Of Kidney Stones Watch Those Megadoses Of Vitamin C
New York, NY – Kidney stones are a common problem, affecting about half a million people each year. Men are more prone to kidney stones than women — nearly four out of five sufferers are men. Dietary habits may sometimes increase the risk of developing kidney stones. If you or anyone in your family has had a kidney stone, consider the following:
Taking high doses of vitamin C supplements, such as 500 mg or more a day on a regular basis, has been shown to increase the risk of developing kidney stones in some people. This is particularly true in people who have had calcium oxalate stones in the past or who have a family history of these stones. The reason for this may be that, at high doses, a significant amount of vitamin C is converted to oxalate in the body. A large amount of oxalate would then be present in the urine where it could combine with calcium to form calcium oxalate stones. “People who are at risk for this problem should not take more than the recommended daily allowance of vitamin C as a supplement,” says Garabed Eknoyan, MD, president of the National Kidney Foundation.
Eating foods that are high in oxalate may also trigger kidney stone formation in people who are prone to develop calcium oxalate stones. The following foods have been shown to increase oxalate in the urine, and they should be avoided by these individuals: spinach, rhubarb, beets, nuts , chocolate, tea, wheat bran and strawberries.
More About Ascorbic Acid
1. Levine M, Dhariwal KR, Welch RW, Wang Y, Park JB “Determination of optimal vitamin C requirements in humans.” Am J Clin Nutr 62 : s1347-56
2. Hathcock JN “Vitamins and minerals: Efficacy and safety.” Am J Clin Nutr 66 : 427-37
3. “How much vitamin C do you need?” JAMA 281 : 1460
4. “Product Information. Cemill .” Abbott Pharmaceutical, Abbott Park, IL.
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Symptoms Of Kidney Stones
Common symptoms of kidney stones include:
- Sharp pain in your side or lower part of your abdomen
- Pain while urinating
- Urinary urgency
- Pink, red or brown urine
Kidney stones can become stuck in the kidney if they are too large to pass on their own, which may lead to symptoms such as severe kidney pain, nausea and vomiting, explains Dr. Malik. If there is kidney obstruction, permanent kidney damage can occur if left untreated.
If urine is infected next to the obstructing stone, this is a urologic emergency that requires rapid decompression, Dr. Malik says. If this occurs, you may experience fever, chills, frequent and strong urge to urinate, blood in your urine, cloudy and foul-smelling urine.
“If you have any symptoms of a blocked stone or infection, see your doctor or go to an emergency department as quickly as possible for assessment and treatment,” says Dr. Malik. “This is a situation in which a patient could become septic very quickly if left untreated.”