Want to Protect Your Kidneys? Scientists Say This Diet May Be Key

The study, published in the Canadian Medical Association Journal, looked at health information of nearly 180,000 people without chronic kidney disease and evaluated their self-reported diets—specifically, their adherence to (or lack thereof) the plant-forward EAT-Lancet planetary health diet, an eating pattern that focuses on whole foods like whole grains, fiber-rich vegetables and fruits, nuts, and legumes with limited consumption of animal proteins like fish, dairy, and meat.

Using patient bloodwork, researchers identified specific proteins and metabolites that indicated the state of their kidneys. After 12 years, researchers followed up with participants, and 4,819 had developed CKD. In conclusion, higher EAT–Lancet diet adherence was associated with a lower risk of CKD.

While there are existing studies that highlight the importance of diet in kidney disease prevention, says Dr. Joshi, this one “is novel in its size, duration of follow-up, detail of dietary measures, and usage of metabolic and proteomic profiling,” he explains.

How might this diet boost kidney health?

Your kidneys filter waste products from your blood, explains Ryan Woolley, M.S.P.H., R.D.N., senior director of public education at the American Kidney Fund. So the study focuses on the theory that following a diet that supports while avoiding straining the kidneys may help protect them in the long run. The EAT-Lancet planetary health diet is “designed to promote human health and also support a sustainable food system,” explains Woolley. The food choices (listed above) “can contribute to kidney health and overall health by helping you maintain a healthy weight, supporting lower blood pressure and cholesterol, and lowering your risk for [type 2] diabetes,” all of which may increase CKD risk, she says.

The EAT-Lancet diet is similar to other health-focused eating plans like the DASH and Mediterranean diets, Woolley says. “These eating patterns also have benefits for lowering blood pressure and preventing and slowing progression of chronic diseases like heart disease, kidney disease, and diabetes,” she concludes.

How does what we eat affect kidney health?

Diet impacts kidneys both directly and indirectly by playing a role in the development of certain kinds of diabetes and high blood pressure, which are the leading causes of kidney dysfunction, says Dr. Joshi. “Plant foods are some of the healthiest foods on the planet, so it’s not surprising they would also be helpful for the kidney,” he adds.

For example, eating foods high in fiber and low in added sugars helps curb insulin resistance, which may lead to type 2 diabetes, “which is the leading cause of kidney disease,” Woolley says. “And, limiting your consumption of sodium, often high in processed foods, helps to prevent high blood pressure and avoid strain on your kidneys.”

Additionally, the EAT-Lancet diet limits animal proteins because when your body digests protein, it creates waste for the kidneys to remove from your blood, Woolley explains. And when you have kidney disease, the organs can’t perform that job as well, which may then cause a build-up and subsequent issues. “Therefore, limiting your intake of protein [may] help reduce the work your kidneys need to do,” she says. “Additionally, animal sources of protein have high amounts of phosphorus, which is also filtered by the kidneys. Your body isn’t able to absorb as much phosphorus from plant sources, so plant-based proteins can help reduce the phosphorus your kidneys need to filter.”

The bottom line

What we eat impacts our bodies in so many ways, and doing your best to adhere to lifestyle factors to boost overall health (including kidney health), like getting enough exercise, stop smoking or using tobacco, and limiting alcohol intake, are key, says Woolley. “In addition, it’s important to know how well your kidneys are working so that you can take additional steps to manage your kidney health. We recommend asking your doctor about getting an eGFR test and a uACR urine test.”

As always, Woolley concludes: “If you are thinking about changing your eating pattern or you’re not sure if a certain one is right for you, talk to your doctor or dietitian before starting.”