Living with chronic kidney disease (CKD) presents many challenges, and diet is one of them. People with CKD may find it difficult to consume enough fiber-rich foods while following the other diet recommendations for CKD. As kidney function declines, individuals with CKD may be recommended to limit foods high in phosphorus and potassium. As some of the restricted foods may also be high in fiber, these restrictions may result in a diet lower in fiber.
National guidelines for fiber intake by individuals with CKD do not specifically address the amount of fiber that they should consume (Ikizler et al. 2020), but it is generally recommended that people with CKD consume a diet higher in fiber. The fiber recommendations for CKD may be similar to what is recommended for healthy individuals: 21 to 25 g of fiber per day for women and 30 to 38 g of fiber for men depending on age (Trumbo et al. 2002). On average, people with CKD consume only about 15 g of fiber per day (Evenepoel and Meijers 2012). However, it is possible to follow the dietary restrictions for the later stages of CKD and still consume the recommended amount of fiber. This guide will discuss the health benefits of fiber and provide some examples of fiber-rich foods that may be good choices for CKD.
Health Benefits of Fiber and CKD
Fiber is naturally found in all plant foods, including fruits, vegetables, grains, nuts, seeds, and legumes. Fiber, when isolated from plants, can also be added to foods to create higher fiber foods. Consuming adequate fiber maintains a healthy digestive tract and lowers the risk of developing heart disease, type 2 diabetes, and other chronic diseases (Dahl and Stewart 2015). Higher fiber intakes are also recommended for the management of many chronic diseases, as fiber helps lower cholesterol and control blood sugar. Fiber, particularly viscous fibers (e.g., psyllium and beta-glucans from oats and barley), may also be beneficial for the management of blood pressure (Khan et al. 2018).
Consuming the recommended amount of fiber may have several benefits for people with CKD. Higher fiber intakes are linked to improved survival (Veronese et al. 2018), as are healthy dietary patterns that provide fiber from fruit, vegetables, legumes, and whole grains (Kelly et al. 2016).
Adequate fiber, particularly insoluble fiber, may be helpful in promoting laxation (Salmean, Zello, and Dahl 2013), and thus preventing constipation in people with CKD. Diabetes is a leading cause of kidney failure. Consuming foods that contain fiber may help with blood glucose control (Post et al. 2012); higher intakes of fiber are associated with a lower risk of diabetes (Veronese et al. 2018). The higher risk of cardiovascular disease that comes with CKD may be lessened with fiber by lowering cholesterol and inflammation (Dahl et al. 2016).
Increasing Fiber with CKD
In the early stages of CKD, when there are usually no restrictions of potassium, it is recommended to consume a variety of foods providing fiber, such as whole grains, legumes, fruits, vegetables, nuts, and seeds.
Many whole-grain foods and legumes are good sources of fiber but have traditionally been limited in the CKD diet due to their phosphorus content. Although plant foods such as whole grains contain a significant amount of phosphorus, they are healthful food choices for those with CKD. This is because only a fraction of the phosphorus from whole grains is absorbed into the body (Williams, Ronco, and Kotanko 2013). Table 1 provides a list of whole-grain foods.
Foods with added fiber can help to achieve fiber recommendations and may have beneficial health effects (Chiavaroli et al. 2014). Table 2 gives some examples of grain-based foods with added fiber. For more information on foods with added fiber, see https://edis.ifas.ufl.edu/pdffiles/FS/FS23500.pdf.
Fruits and vegetables are also important sources of fiber. Legumes, such as beans, peas, and lentils, are especially high in fiber, providing as much as 8 g of fiber per ½ cup serving. However, some people with CKD may need to restrict legumes and some fruits and vegetables due to their potassium content. For those people with CKD who have been advised to restrict potassium, there are lower potassium fruits and vegetables to choose from. Examples are listed in Table 3.
It is recommended that people with CKD consult with a registered dietitian nutritionist (RDN), preferably one who specializes in kidney disease, before changing their diet. A dietitian can help with choosing optimum food sources of fiber for each stage of CKD.
For more information about the phosphorus contents of select foods, visit the United States Department of Agriculture’s website at https://www.nal.usda.gov/legacy/sites/default/files/phosphorus_0.pdf. This site provides an extensive index of all types of foods and their specific contents of phosphorous.
Khan, K., E. Jovanovski, H.V.T. Ho, A.C.R. Marques, A. Zurbau, S.B. Mejia, J.L. Sievenpiper, and V. Vuksan. 2018. “The Effect of Viscous Soluble Fiber on Blood Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.” Nutrition, Metabolism and Cardiovascular Diseases 28 (1): 3–13. https://doi.org/10.1016/j.numecd.2017.09.007
Chiavaroli, L., A. Mirrahimi, J.L. Sievenpiper, D.J. Jenkins, and P.B. Darling. 2014. "Dietary Fiber Effects in Chronic Kidney Disease: A Systematic Review and Meta-Analysis of Controlled Feeding Trials." European Journal of Clinical Nutrition. https://doi.org/10.1038/ejcn.2014.237
Dahl, W. J., and M.L. Stewart. 2015. "Position of the Academy of Nutrition and Dietetics: Health Implications of Dietary Fiber." Journal of the Academy of Nutrition and Dietetics 115(11):1861–70. https://doi.org/10.1016/j.jand.2015.09.003
Dahl, W.J., N.C. Agro, A.M. Eliasson, K.L. Mialki, J.D. Olivera, C.T. Rusch, and C.N. Young. 2016. "Health Benefits of Fiber Fermentation." Journal of the American College of Nutrition.
Evenepoel, P., and B.K. Meijers. 2012. "Dietary Fiber and Protein: Nutritional Therapy in Chronic Kidney Disease and Beyond." Kidney International 81(3):227–9. https://doi.org/10.1038/ki.2011.394
Ikizler, T. Alp, Jerrilynn D. Burrowes, Laura D. Byham-Gray, Katrina L. Campbell, Juan-Jesus Carrero, Winnie Chan, Denis Fouque, et al. 2020. “KDOQI Clinical Practice Guideline for Nutrition in CKD: 2020 Update.” KDOQI Clinical Practice Guideline for Nutrition in CKD: 2020 Update 76 (3, Supplement 1): S1–107. https://doi.org/10.1053/j.ajkd.2020.05.006
Kelly, J.T., S.C. Palmer, S.N. Wai, M. Ruospo, J.J. Carrero, K.L. Campbell, and G.F. Strippoli. 2016. "Healthy Dietary Patterns and Risk of Mortality and ESRD in CKD: A Meta-Analysis of Cohort Studies." Clinical Journal of the American Society of Nephrology. https://doi.org/10.2215/cjn.06190616
Post, R.E., A.G. Mainous, D.E. King, and K.N. Simpson. 2012. "Dietary Fiber for the Treatment of Type 2 Diabetes Mellitus: A Meta-Analysis." Journal of the American Board Family Medicine 25(1):16–23. https://doi.org/10.3122/jabfm.2012.01.110148
Salmean, Y.A., G.A. Zello, and W.J. Dahl. 2013. "Foods with Added Fiber Improve Stool Frequency in Individuals with Chronic Kidney Disease with No Impact on Appetite or Overall Quality of Life." BMC Research Notes 6:510. https://doi.org/10.1186/1756-0500-6-510
Trumbo, P., S. Schlicker, A.A. Yates, and M. Poos. 2002. "Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein and Amino Acids." Journal American Dietetic Association. 102(11):1621–30.
U.S. Department of Agriculture and U.S. Agricultural Research Service. n.d. “FoodData Central.” n.d. Accessed May 15, 1017. https://fdc.nal.usda.gov/index.html.
Table 1. Fiber and nutrient contents of some whole-grain foods. (USDA n.d.).
Table 2. Fiber and nutrient content of some grain-based foods with added fiber. (USDA n.d.).
Table 3. Fiber and nutrient contents of some lower potassium vegetables and fruits.* (USDA n.d.).