Kidneys

Kidneys do better on plant-based diets and worse with red meat

By WhyStopHarmingAnimals.com

Kidneys filter whatever the diet sends them, and red meat is the food most consistently tied to losing that function. People on the healthiest plant-based diets develop less chronic kidney disease[2], and people who eat the most red meat reach kidney failure more often[1].

Red meat and kidney failure

A study of 63,257 adults in Singapore followed them for 15.5 years, during which 951 reached end-stage kidney failure, the point where a person needs dialysis or a transplant (Journal of the American Society of Nephrology, 2017)[1]. The top quarter of red-meat eaters had 40% more kidney failure[1], and risk rose steadily with the dose[1]. Replacing one daily serving of red meat with another protein source came with up to 62% lower risk[1].

Poultry, fish, eggs and dairy showed no such association[1]. That points at red meat specifically rather than at protein in general[1], which is the usual worry about kidneys and diet.

Plant-based diets and new kidney disease

A study of 14,686 middle-aged adults followed for a median of 24 years recorded 4,343 new cases of chronic kidney disease (Clinical Journal of the American Society of Nephrology, 2019)[2]. The healthiest plant-based diets came with 14% less chronic kidney disease[2] and a slower decline in filtering rate[2], the measure of how well the kidneys clean the blood. Diets built on less healthy plant foods came with 11% more[2]. Refined grains and sugar are plant foods too, and the kidneys did worse on them.

High uric acid is a known route to kidney damage[3]. Among 3,618 patients with hyperuricemia, vegans had 31% lower odds of chronic kidney disease than omnivores after adjustment, with lacto-ovo vegetarians in between (Nutrients, 2023)[3]. That study is cross-sectional: it captures a single moment and can't say whether diet or kidney health came first[3].

How much weight to put on it

All three studies are observational, and the kidney evidence is thinner than the evidence on heart disease or diabetes. The results still line up. The most damaging food in these studies was red meat, in a clear dose-response[1]. The most protective pattern was plant-based and built on whole foods[2], with vegans at the low end of the risk range in the one study that separated them out[3].