Preventing and Treating Kidney Failure With Diet

Preventing and Treating Kidney Failure With Diet
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Our kidneys are highly vascular organs. That’s why when you see kidneys in the meat case they look so red. After all, our two little kidneys have to filter through our entire blood supply and as such receive about 20% of our cardiac output every time our heart beats. So if the standard American diet can be so toxic to the blood vessels in our heart, back, abdomen, and pelvis, contributing to heart attacks (Heart Attacks and Cholesterol: Purely a Question of Diet), spinal disc degeneration (Cholesterol and Lower Back Pain), aneurisms (Abdominal Aortic Aneurysms: Ticking Time Balloons), and sexual dysfunction (Cholesterol and Female Sexual Dysfunction), what might it be doing to our kidneys?

In my 2-min. video, Preventing Kidney Failure Through Diet, I profile a recent Harvard study putting that question to the test. Thousands of women, their diets, and their kidney function were followed for a decade. The researchers found three significant risk factors for declining kidney function in these women; none of which come as a surprise given that we’re talking about clogged and inflamed blood vessels: animal protein, animal fat, and cholesterol. All three of these risk factors are only found in animal-based foods. No such association was found for plant protein or plant fat.

Failing kidneys can be a canary in a coal mine, informing us about the health of our blood vessels. Quoting from the Harvard study, “modest decrements in kidney function are powerfully associated with subsequent overt kidney disease, cardiovascular risk, and all-cause mortality,” meaning a shortened lifespan. “In summary, diets lower in animal protein, animal fat, and cholesterol may be protective” against this kind of kidney damage.

What if the damage has already been done, and you’re already suffering from chronic renal failure? That’s the subject of my video Treating Kidney Failure Through Diet.

One of the important functions of our kidneys is to filter out excess phosphorus from our bloodstream, and so when our kidney function declines, phosphorus can build up in our bodies and cause something called metastatic calcification, where your heart valves and muscles and other parts of your body can buildup calcium deposits and eventually result in skin necrosis, gangrene, and amputations.

So, if a person has diminished kidney function their doctor will likely put them on a low phosphate diet, which is tough, because basically everything with protein has phosphorus. So both plant foods and animal foods have phosphorus. But vegans have been shown to have significantly better kidney function, on average, compared to omnivores. So while researchers concluded that “These results can confirm the usefulness of vegetarianism here and support the use of a vegan diet for the patients with kidney failure,” maybe it was just because the omnivores were getting a higher protein load. We know that lower protein diets appear to delay the progression of kidney failure, so did the plant based diet help because they were eating less protein or because the body somehow is able to handle plant protein better than animal protein?

To do that you’d have to split people into two groups, half on a vegetarian diet, half not, with the critical caveat to make sure both groups eat the exact same amount of protein and the exact same amount of phosphorus. And that’s exactly what researchers did. Published recently in the journal of the American Society of Nephrology, they took vegetarians and put them on a meat diet, and then took meat-eaters and put them on a vegetarian diet. Even though  phosphorus and protein intake were kept the same in both diet groups, in the video you can see an illustration of the level of phosphorus stuck in the bloodstream of those on the meat diet, compared to those on the veg diet. Something about plant foods appears to enable our bodies to better handle their phosphorus content. Plant phosphorus appears easier to cleanse away.

Positive results have been seen with even semi-vegetarian diets, but the reason the new study  “observed more dramatic differences after only 1 week, was perhaps because of the pure vegetarian diets used in our study. Taken together, vegetarian-based diets may be beneficial for the control of phosphorus balance in patients with chronic kidney disease.”

This is another reason why Plant Protein is Preferable. Food is, after all, a package deal. In addition to kidney failure, plant based diets can help prevent and treat diabetes, prevent and treat COPD, prevent and treat arthritis, prevent and treat cancer, prevent and treat heart disease, and prevent and treat obesity. Why, then, don’t more providers in the medical community embrace plant-based diets? Part of the reason may be The Tomato Effect.

-Michael Greger, M.D.

Image credit: Dr Michel Royon / Wikimedia Commons

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  • Darris B. Nelson

    If we need another reason to eat a plant-based diet this would be a good one to add to the exhaustive list.

    Thank you for great information presented in in easily digestible fashion. Love the videos too!

  • Nomeat6

    A good video, but my compputer had you speaking over yourself about a different topic.  I’m not sure if everyone has this problem, but I did, and it’s under no other e-mail I have ever read.

  • André Saine

    Hi Michael, I am a great fan of the extraordinary work you do.  I have 4 questions for you: 1- in the Spanish study, Crossover study of diets enriched with virgin olive oil, walnuts or almonds. Effects on lipids and other cardiovascular risk markers, how significant are the results of this study considering the fact that the groups went from a baseline intake of cholesterol of 231 mg/d to about 130 mg/d when they change from their regular diet to the experimental diet with olive oil or nuts?2- When you attended McDougall Adavance Weekend last February you were going to ask a question following Fuhrman’s and McDougall’s debate. I am curious to know what you were going to ask? I am assuming that you are not a great supporter of McDougall’s high CHO diet. 3- Contrary to McDougall Dr. Willett from Harvard substantiates well the need for PUFA and MUFA in the diet. What is your take on Willett position? 4- What is the risk for vegans who eat the way you suggest to become deficinet in DHA, as reported by Fuhrman? Thank you for taking the time to answer these questions, André Saine

  • S

    Dr. Greger, thank you for all that you do.

    Is there any risk in worsening chronic kidney disease with a vegan diet, due to the increased potassium in plant foods? If someone has diminished GFR, would the extra potassium from plants overwhelm there glomeruli or would it bring their kidney function back?

    Thank you.