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 build up calcium deposits, and eventually result in skin necrosis, gangrene amputations; all sorts of bad stuff.

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 when omnivores have been compared to those eating vegan, “Vegans had significantly [less protein leaking out into their urine]”—a sign of intact kidney function.

So while they 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.” And 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 figure that out, 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 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, here’s the level of phosphorus stuck in the bloodstream of those on the meat diet, compared to those on the veg diet.

So, there’s just something about plant foods that enables our bodies to better handle their phosphorus content. The same amount of phosphorus, but plant phosphorus appears easier to cleanse away from our body.

Positive results have been seen even with 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 [this] study. Taken together, vegetarian-based diets may be beneficial for the control of phosphorus [balance] in patients with [chronic kidney disease].”

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Serena.

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