Kidney disease ranks as the ninth leading cause of death in the U.S. So, what foods should we eat to keep our kidneys healthy? Here’s our first story.
Chronic kidney disease is one of the top ten leading causes of premature death in the United States, and its incidence is increasing. Chronic kidney disease affects more than 10 percent of the adult population, and each year, more than 100,000 Americans develop end-stage kidney disease and have to go on dialysis. What’s crazy is that a staggering 96 percent of individuals with mild to moderate decreases in kidney function and about half of individuals with severely decreased kidney function go undiagnosed. Meaning the vast majority, like 24 out of 25 people with chronic kidney disease, don’t even know they have it.
What can we do to maintain our kidney function? Well, in a study that followed more than a thousand older women for a decade, those consuming a diet that was richer in plant-based protein had a slower decline in kidney function, extending support for the health benefits of plant-rich diets in the general population to maintain kidney health. Compared with protein from plant sources, animal protein has been associated with an increased risk of end-stage kidney disease in several such studies. We’re not exactly sure why. Kidney damage from animal protein could result from the dietary acid load, excess phosphorus, or gut microbiome bad bacteria and the resultant inflammation.
The dietary acid load in a Standard American Diet is derived mostly from animal sources such as meats, eggs, and cheeses. In contrast, by including a higher proportion of foods with natural alkali, such as fruits and vegetables, a strictly plant-based diet is nearly acid neutral. Even just eating plant-based 2 or 3 days a week can significantly bring down the acid load delivered to the kidneys, and eating plant-based full time, and you can actually flip over into alkaline territory. Even just cutting out meat can yield an alkaline load compared to the acid load in the nonvegetarians. All this is important, since dietary acid may promote kidney injury and a progressive decline in kidney function.
The intake of animal protein can also cause an imbalance in the composition of the gut microbiome by producing more ammonia and the rotten egg gas hydrogen sulfide, and have a proinflammatory effect that may result in reduced kidney function, but it also may be the animal fat. In the Harvard Nurses Study, higher intake of animal fat was directly associated with the loss of protein into the urine, which is a sign of kidney damage, and to protect against that, they suggest diets lower in animal protein, animal fat, and cholesterol.
That may help explain why vegetarians have better kidney function than nonvegetarians matched for sex, age, size, physical activity, alcohol, smoking, etc. So effectively, even a meat eater who is just as slim as a vegetarian, just as healthy cholesterol, blood pressure, and blood sugar control-wise still has inferior kidney function. They think it might be the higher dietary fiber intake on more plant-based diets contributing to the protective effect on kidney function, again through a microbiome mechanism. Whereas the consumption of animal protein may lead to a proliferation of meat-eating bugs, which can result in a leaky gut, uremic toxins, and resulting inflammation, oxidative stress, and chronic kidney disease progression. That can be blocked, with the decreased inflammation and acid load, thanks to eating more fiber rich foods.
No wonder an egg-free vegetarian dietary pattern was associated with a 37 percent decreased odds of developing chronic kidney disease. But, what about plant-based diets for not just the prevention but the management of chronic kidney disease? Can comprehensive lifestyle change alter the course of chronic kidney disease? This was the case report of someone diagnosed with minimal change disease. That’s when someone’s kidneys start leaking protein, even though there are minimal changes seen in biopsies under the microscope. You give people steroids and, in a few months, you can knock it down, but a significant fraction may fail to respond to the steroid therapy. He was diagnosed 18 years prior, but only by replacing animal protein with plant-based protein was he able to put his chronic kidney disease into remission.
At age 44, he suddenly developed swelling that crept up throughout his body, since he was losing so much protein. He was weak, unable to concentrate, and lethargic. Diagnosed with minimal change disease and treated with a water pill and four different blood pressure lowering agents. Because of unresponsiveness to high-dose steroids, a powerful immunosuppressant was added; yet, severe protein loss continued and his hypertension and kidney function worsened, until he started eating plant-based, started exercising, and lost 60 pounds. His kidney disease went away and stayed away.
Let’s hear it in his own words. “I appreciate the recommendations my doctor gave me about making dietary modifications: ‘replace your protein intake with plant-based protein.’ This one change has had a monumental impact on my life. I have gained back a quality of life that I thought was gone forever. My benchmark for normal has been my ability to keep up with my professional work demands and still be able to exercise. For the last seven months, I now swim over three miles every other day: a distance that surpasses my pre–kidney disease life. I perceived I lived a healthy lifestyle before kidney disease; today, I live a healthier, happier lifestyle, and I have my kidneys to thank for it.
In our next story, we look at the significant dietary risk factors for declining kidney function.
Kidney failure may be both prevented and treated with a plant-based diet—and no wonder; kidneys are highly vascular organs. Harvard researchers found three significant dietary risk factors for declining kidney function: animal protein, animal fat, and cholesterol. Animal fat can alter the actual structure of our kidneys, based on studies showing plugs of fat literally clogging up the works in autopsied human kidneys.
And, the animal protein can have a profound effect on normal kidney function—inducing what’s called hyperfiltration (increasing the workload of the kidneys) but, not plant protein. Eat a meal of tuna fish, and you can see the increased pressure on the kidneys go up within one, two, three hours after the meal, in both nondiabetics and diabetics. So, we’re not talking adverse effects decades down the road, but literally within hours of it going into our mouth.
Now, if instead of having a tuna salad sandwich, though, you had a tofu salad sandwich, with the exact same amount of protein, what happens? No effect. Dealing with plant protein is no problem.
Why does animal protein cause the overload reaction, but not plant protein? It appears to be due to the inflammation triggered by the consumption of animal products. How do we know that? Because, if you give a powerful, anti-inflammatory drug along with that tuna fish, you can abolish the hyperfiltration protein leakage response to meat ingestion.
Then, there’s the acid load. Animal foods—meat, eggs, and dairy—induce the formation of acid within the kidneys, which may lead to tubular toxicity (damage to the tiny, delicate, urine-making tubes in the kidney). Animal foods tend to be acid-forming—especially fish, which is the worst, then pork and poultry—whereas plant foods tend to be relatively neutral or actually alkaline (base-forming) to counteract the acid. So, the key to halting the progression of chronic kidney disease might be in the produce market, rather than the pharmacy.
Finally today – I share a touching story of the power of plant-based eating for chronic kidney failure.
Is it possible to ameliorate chronic kidney disease using a whole food, plant-based diet? In my last video on kidney disease, I talked about how randomizing people to cut just around 10 grams of protein from their daily diet could cut their risk of dialysis and death by a whopping 77 percent. That was cutting protein across the board. But while animal-based protein ingestion—meat, dairy, and egg white protein ingestion—promotes an acidic environment in the kidneys, inflammation, and stresses the kidneys into what’s called hyperfiltration mode, plant-based protein can be alkaline-producing and anti-inflammatory, and contain kidney-protective properties. So, what if you have kidney patients a plant-dominant low-protein diet, abbreviated adorably as PLADO, I guess for plant-dominant.
If you fashion up a plant-based diet index score, where you get points for healthy plant foods and get points deducted for eating animal foods, those with serious kidney disease with higher scores were found to have lower systemic inflammation. But does that actually translate into living a longer life?
Apparently so. Even a 10 percent increase in the proportion of plant-based protein was associated with a significant reduction in all-cause mortality. Even just eating more servings of fruits and vegetables, like two a day compared to two a week, is linked to living longer.
Without fully functioning kidneys, there are concerns about phosphorus and potassium overload, though, on a plant-based diet. But the phosphorus in plant-based foods is not as much of a problem as the phosphorus additives in processed and animal foods. And, the risk of potassium overload from plant-based diets appears overstated and is not supported by the evidence. But you don’t know about ameliorating chronic kidney disease using a whole food plant-based diet, until you put it to the test.
Here’s a case report of a 69-year-old man with type 2 diabetes, high blood pressure, and stage 3 chronic kidney disease, resulting in elevated phosphorus and potassium in the blood. He was interested in changing his diet to improve his medical condition. That’s my kind of patient! He was on 12 different medications, eating a diet that may actually be slightly better than the average American’s. Some whole grains and beans, but then his doctor advised him to try eating whole food, plant-based. So, oatmeal with fruit and flax, beans and greens, whole wheat spaghetti and veggies, fruit as snacks. He was counseled to eat as much as he wanted from whole healthy foods—no carb counting, no calorie counting, no portion size restriction—improving the quality of food rather than restricting the quantity of food.
He adopted the whole food, plant-based diet, packed with carbs, yet rapidly reduced his insulin requirements by more than 50 percent, and subsequently saw improvements in weight, blood pressure, and cholesterol. Because eating healthy can have such a rapid effect on improving your body’s insulin sensitivity, immediate adjustments in insulin dosing were made. Within four days, his insulin dose was able to be reduced from roughly 210 units of insulin a day down to 70 units daily, and an oral blood-sugar lowering medication had to be stopped due to rapidly improving blood sugar.
He also was able to stop his carvedilol, hydrochlorothiazide, amlodipine, and sitagliptin within the first two months, due to improving blood pressure and blood sugars. His insulin dose was steadily titrated downward. His pravastatin dose was cut in half, and he lost about 50 pounds. Okay, so what happened to his stage 3 kidney failure? He was no longer in stage 3 kidney failure!
He experienced an increase in estimated GFR of 73 percent, suggesting that the improvement in estimated kidney function was greater than what would be expected from weight loss alone. For example, lose about 60 pounds with bariatric surgery, and you only get about a 12 to 15 percent boost. Bottom line: for individuals with chronic kidney disease, especially those with obesity, hypertension, or diabetes, a strict, all-you-care-to-eat whole food, plant-based diet may confer significant benefit. I mean, apart from the kidney-specific outcomes, overall mortality is significantly lower among kidney patients who eat more plants. And, that’s critical, because most kidney patients don’t even make it to dialysis because they die first, most often from cardiovascular disease.
Let’s hear from the patient: “At the outset, it seemed like this was going to be a difficult and restrictive way to eat,” but “I began feeling different almost immediately and we had to decrease my insulin after ONE day. It seemed like almost overnight I had more energy than I’d had in years. Weight I had been trying to lose for a decade began dropping off. As the weight came off, I felt lighter, and more able to move my body again.”
“This lifestyle change has been the greatest gift I’ve ever received. I am off most of my medications, I’ve lost over 70 pounds, and I’ve regained control over my health. I feel empowered by this lifestyle change, and I finally feel like I’m in charge of my health, not just an unlucky victim shuffling from one specialist to the next. My only regret was that I didn’t know about this sooner.”