It is estimated that about 15% of US adults have chronic kidney disease (CKD) (1). It is a fact that 37 million Americans have renal function below normal, which means they may be headed toward renal failure. Renal function does decline over time as the result of normal aging. Renal failure can result from an acute illness like an infection, but the more common chronic kidney disease seen in millions of Americans mostly is the result of dietary and metabolic insults that cause kidney function to deteriorate more rapidly. Elevated blood sugar and high blood pressure are two common factors leading renal function to decline more rapidly over time. So diet and lifestyle can certainly help prevent a lot of those 37 million Americans with CKD from progressing to renal failure where dialysis or, for the lucky ones, a kidney transplant, becomes the only option. Without them, renal failure is fatal as toxins like ammonia build up and/or electrolyte imbalance become incompatible with life. More than 100,000 Americans will end up with failed kidneys each year. A significant fraction of those with CKD will progress to end stage renal disease (ESRD) with about 650,000 people per year in the United States ending up with ESRD and requiring dialysis or perhaps waiting for a kidney transplant if a suitable donor can be found. CKD disproportionately affects the nation’s minority and lower income patients in part perhaps because of access to an unhealthy lifestyle. Compared to white Americans, African Americans are about 3.5 times more likely to develop ESRD. Who develops CKD and how quickly it progresses to ESRD varies depending on several diet and lifestyle risk factors. There is increasing evidence suggesting that the risk of chronic conditions like obesity, type 2 diabetes, dyslipidemia, and high blood pressure (BP) all promote faster loss of kidney function over time. We know that the typical modern American diet is high in animal products with excess added salt and low in whole plant foods. This pattern impacts all of these CKD risk factors.
The consumption of plant-based diets is becoming more common for ethical, environmental, and health reasons. The quality of plant sources of food can differ, however, with nutrient-rich whole plants generally more health promoting than a diet in high in refined grains and sugars. Since many of the risk factors associated with the development of chronic kidney disease (CKD) can lead eventually to failing kidneys and the need for dialysis, there is reason to believe that a more whole food plant-based diet should cut the risk of CKD and reduce the development of ESRD and the need for dialysis or a renal transplant to survive..
To evaluate the associations between more plant-based diets and the development of CKD in a general population, a team led by Hyunju Kim and Casey M. Rebholz, PhD at Johns Hopkins Bloomberg School of Public Health analyzed information on 14,686 middle-aged (age 45-64) adults enrolled in the Atherosclerosis Risk in Communities (ARIC) study. Subjects who had evidence of CKD were excluded. To see if a healthier plant-based diet would be associated with a reduced risk of CKD, these middle-aged Black and White adults were followed for 24 years. The results of this study were published in the May 2019 issue of the Clinical Journal of the American Society for Nephrology. During a median follow-up of 24 years, these researchers observed 4,343 new cases of CKD.
More Whole Plants in the Diet Led to Less CKD
Participants with the greatest consumption of whole plant foods had a 14% lower risk of developing CKD than participants with least consumption of whole plant foods. Subjects who consumed more refined grains and sugars had an 11% greater risk of developing CKD than subjects who consumed the least refined carbohydrates. This association between whole foods, plant-based diets and reduced CKD risk was especially pronounced for participants who initially had a normal body weight. Higher consumption of healthy plant foods (fruits, vegetables, whole grains, nuts, legumes, coffee, tea) was significantly associated with a lower risk and slower decline in the estimated glomuler filtration rate (eGFR). Overall, the Dr. Rebholz study found that closer adherence to a whole plant-based diet was associated with a slower decline of kidney function over those 24 years of follow up and was similarly associated with a significantly reduced risk of developing CKD.
According to Dr. Rebholz, “For kidney disease risk, it appears to be important to choose healthy options for plant sources of food, including fruits, vegetables, whole grains, nuts, and legumes.” Dr. Rebholz added, “Also, our finding of a significant interaction by weight status at baseline [and CKD risk] suggests that following a healthy eating pattern may be particularly beneficial before becoming overweight or obese.”
Bottom Line: The findings of this study reinforced the growing scientific evidence linking a diet with less animal protein foods and more whole plant-based foods with better kidney health and a significantly lower risk of ending up with CKD. It is more than likely that those with early CKD can slow their progression to end stage renal disease (ESRD) and failed kidneys by consuming a diet with more whole plant foods and less animal protein and added salt. Quitting smoking, getting regular exercise, and losing some excess weight are also likely to help slow the loss of kidney function over time.
By James J. Kenney, PhD, FACN
Note: Dietitians can and should be paid for their work to save kidneys since all that dialysis and all those kidney transplants cost about $50 billion each year. This cost is only increasing because of the aging population (about 10,000 Americans hit 65 years old each day) and with more obesity and worse diets, more Americans are developing elevated BP and elevated blood sugar levels. We know that with a healthy diet at least 2/3 to 90% of those two ills could be prevented. We know that most kidney stones can be prevented with a healthier diet too. Since elevated BP & blood sugar and kidney stones all promote faster loss of kidney function, it is likely that the number of people ending up with failed kidneys could be cut by at least 75% with a better eating pattern. This new study showed that cutting back on animal protein foods also likely helps slow the loss of kidney function by at least another 10% or more. Obesity, even without type 2 diabetes mellitus (DM) also speeds the loss of renal function. But health insurance and Medicare won't pay for the dietary treatment of hypertension (HTN) and won't pay for dietary counseling for those with elevated BP not high enough for a diagnosis of HTN. They also won't pay for weight loss counseling to prevent type 2 DM or for the treatment of people with chronic kidney disease until they are on dialysis. Billions are spent on medial treatments that never cure HTN or type 2 DM. There is no coverage for dietary counseling for people with recurrent kidney stones as far as I know and certainly no coverage for people with early to mid-stage renal disease even though most people could significantly slow and most would likely be able to prevent the development of failed kidneys if they adopted a largely whole foods, plant-based diet low in added salt.
Stephanie Ronco has been editing for Food and Health Communications since 2011. She graduated from Colorado College magna cum laude with distinction in Comparative Literature. She was elected a member of Phi Beta Kappa in 2008.