Preventing and Treating Kidney Failure With Diet

Preventing and Treating Kidney Failure With Diet

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

  • 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.

  • Carole Davis

    I still don’t understand if a diabetic with kidney problems can still eat plant-based protein or should plant-based proteins be eliminated as well? When one reads about a renal diet, which is low protein, are nutritional guidelines including plant-based proteins or not? Can’t figure this out! I

    • Thea

      Carole: I can’t comment on your specific condition of diabetes *and* kidney problems. (what a bummer). But I did want to respond to this part of your comment: “can still eat plant-based protein or should plant-based proteins be eliminated as well?”

      I don’t think the question fully makes sense since all plant foods have protein. You might be surprised at how much protein even veggies have. So, unless you were planning on never eating plants, you can’t eliminate plant based proteins. You could try to eat plants that only have less proteins, but then you would be missing out on some super-healthy foods – foods that in general are less in protein than animal foods I believe. So, I don’t see how you could go wrong eating them??? (I’m not a doctor and don’t know about advising you for your specific condition.)

      For a really great tutorial in understanding proteins and our need for it and how much plants of all types have, check out this awesome page:

      I hope this helped at least a little. Good luck.

  • thecompassionateRD

    I am a registered dietitian in Long Beach, California. I was
    vegetarian for over 40 years, and about 4 years ago, when realizing the cruelty
    of the dairy and egg industry, became vegan.
    The patient population I work with have end stage renal
    disease and are on dialysis, either hemodialysis or peritoneal dialysis.
    One of our biggest problems, besides high phosphorus levels, are low albumin
    levels (goal being 4.0 or higher). For thirty years I have been
    encouraging my patients to eat more animal protein in effort to raise albumin
    levels, as this has always been the recommended practice.
    As I am sure you are well aware, albumin is not a great
    indicator of nutritional status, but for renal failure patients it seems to be
    the best, if not least expensive, parameter we have. One of the markers of
    inflammation is a low albumin, and our patients have plenty of co morbid
    conditions which contribute to inflammation. My new hesitancy in recommending
    increased intake, especially of red meat, is that consumption of animal protein
    itself is a contributor to inflammation. I therefore, have begun
    encouraging more nut butters and limited amounts of beans and nuts to my
    patients. Because of the higher phosphorus it has long been recommended that
    dialysis patients avoid these foods. (we now know that the
    bioavailability of phosphorus in plant foods is lower than that of animal foods)
    However, I can no longer, in good faith, continue to advise my patients
    to increase animal products when the number one cause of death in dialysis
    patients is cardiovascular disease. But is this possible???
    My question to you is the following: Are you aware of any
    literature or studies regarding a vegan diet for dialysis patients which
    I could share with my doctors? There is much research about the benefits of a
    vegan diet in preventing renal disease, but I am now referring only to
    those patients with renal failure, CKD stage 5. I do have meal plans for
    vegan diets for renal failure, but I am specifically looking for something to
    present to my doctors which would help them come on board with more of a
    plant based diet (while still maintaining potassium and phosphorus levels
    within goal ranges) for their patients? Or is the current state of the
    art diet for dialysis patients, a diet lacking in fiber and phytonutrients and
    high in fat, still what the doctor ordered?