Kidney Coach

Vitamin C: Good For Kidney Disease Or A Cause Of Kidney Stones?


As I am sitting here waiting for 2 new tyres to be placed on my car, I thought what better way to use the time than write a blog post on this sunny afternoon.

Today I would like to discuss and clarify a reader’s question I received just the other day. The reader was confused as I routinely state that vitamin C and kidney disease are a good marriage – he thought it was a cause of kidney stones and therefore bad for all kidney diseases. Initially my reader spoke to my lovely assistant Erika (a naturopath) to confirm that what he had read from me was true. Erika confirmed this. Even with confirmation the reader (let’s call him Steve) had to ask his doctor to triple-check this fact, and of course the doctor said “definitely not”. I don’t hold anything against Steve for asking his doctor, 9 times out of 10 if you encounter an article based on the topic of vitamin C and kidney disease you will read that it should be avoided. So if you have routinely read something – that most of the population agrees on – then you will want to be damn sure before you act on ‘different’ advice, especially when your health is at stake.

So why would I go against 9 others who seemingly know what they are talking about? Good question. The response I have to this is that a lot of the people writing articles on the internet do not have any formal training. They are simply health enthusiasts, or worse, a writer with no health background that has been asked to write a health article for a company’s website. This second person is far more dangerous, and this because even though they are excellent researchers (and writers), most research now is purely from the internet, and therefore they rehash what everybody else has written without any ‘real’ research – a vicious, vicious circle.

So the purpose of this blog post is twofold

1.    Whenever reading a health article, and then basing your actions off that article, please do your due diligence and make sure that the source/writer has been formally trained in the health sciences. But on top of that, if they are giving you natural medicine advice make sure they have been trained in natural medicine, not just any health training. For instance, many of the doctors and nurses out there are giving advice on how to use natural medicines, but have no training in that field. Which leads us to the question: “how can we seriously believe the information that they are giving us?” Well, we can’t. It might surprise you, but doctors and nurses receive no formal training in herbs, nutrition, and diet as part of their education. At the most, there could be an elective 6 week course within their education that they choose to do (not have to do). In comparison, naturopaths are trained in this for 4-5 years. Who would you say is the better source for this type of information? It would be like me prescribing you drugs. Yes as part of naturopathic training we study biochemistry and pharmaceutical drugs, but only for 6 months.

2.    And two, detail in brief the health benefits that vitamin C has on kidney disease, and debunk the myth that vitamin C is a cause of kidney stones.

The Benefits of Vitamin C and Kidney Disease

It is well known that an increase in oxidative stress plays a role in the development of kidney diseases. Furthermore vitamin antioxidant supplementation improves kidney blood flow and pressure (renal hemodynamics), decreases inflammation, and improves fibrosis in kidneys with poor blood flow.

In a study published by the Journal of American Society of Nephrology (2004), Vitamin C and E supplementation increased eNOS (endothelial nitric oxide synthase), decreased NF-kappaB, NAD (P) H-oxidase, inducible-NOS, and nitro tyrosine, signifying decreased oxidative stress and inflammation.

On top of that, vitamin C and E supplementation saw a decrease in the elements that cause fibrosis, leading to considerably reduced glomerulosclerosis and kidney fibrosis. The study concluded “chronic antioxidant intervention in early experimental renovascular disease improves renal functional responses, enhances tissue remodeling, and decreases structural injury.”

Clearly vitamin C is good, yes?

Cause Of Kidney Stones Put To The Test

You see back in the 60s Linus Pauling of the Linus Pauling Institute published a book on how vitamin C is an excellent remedy for colds and flu’s. During that time the critics claimed that this was a dangerous notion as vitamin C would be a cause of kidney stones (calcium oxalate kidney stones). Their criticism made sense, ascorbate (found in vitamin C) is metabolized by the body and turned into oxalic acid and then excreted via the kidneys. So they figured it would stand to reason that the oxalic acid might join with calcium to produce calcium oxalate kidney stones; and this is how the vitamin C myth began.

While the thinking was logical it never really proved accurate. Since then vitamin C is one of the most consumed vitamins in the world,  if not the vitamin, and we have not had an increase in kidney stones due to this.

There have been studies done on this, though they show conflicting results. In the 1980s Dr. Constance Tsao, formerly with the Linus Pauling Institute, conducted two studies to see if vitamin C was a cause of kidney stones. In the initial study 3-10 grams/day of vitamin C for 2-10 years did not show any irregular levels of oxalic acid in the blood. And in the second study Dr. Tsao showed that 10 grams/day of vitamin C caused mild elevation of oxalic acid in the urine (this is a very high dose), however the quantity ended up being inside the range received from the intake of typical diets.

In 1996 a different doctor by the name of Dr. Mark Levine conducted his own studies to see if vitamin C is a cause of kidney stones, and demonstrated that there was in fact an increase of oxalic acid in the urine after taking 200-1000mg of vitamin C a day. However, he noted that this did not prove the oxalic acid combined with calcium to turn into kidney stones and that earlier studies had not found any correlation with 1000mg a day of vitamin C being linked as a cause of kidney stones.

kidney stones in CKD, vitamin C and kidney stones

There are many a cause of kidney stones, but evidence shows thus far that vitamin C is not one of them. Here are a few know causes: Inactive lifestyle; Dehydration; High phosphorus diet; Soft drinks; High meat consumption; Excess intake of calcium, oxalate, or purines in food; Hyperparathyroidism; Bone loss; Inflammatory bowel diseases; and Genetics.

I will say this much however, those with a present, past, or family history of kidney stones may or may not wish to take vitamin C. Though the evidence to date shows there is no correlation between vitamin C and kidney stones, it may be prudent to err on the side of caution.

So to summarise…

•    Make sure you source your health information from reliable sources
•    Vitamin C = really good for kidney health
•    Err on the side of caution if you have a history of kidney stones.

I hope that this has been an interesting and enlightening topic today, and put to rest that vitamin c is ‘bad’ for kidney disease and that it is a cause of kidney stones.

Until next time!

More Research: Vitamin C, A Cause Of Kidney Stones?

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