Fruits, Vegetables, and Legumes: Harnessing the Gut-Kidney Axis in Hypertensive Chronic Kidney Disease

Hypertension is the most common comorbidity in chronic kidney disease (CKD), affecting roughly 80–85% of patients overall and an even higher proportion in nondialysis CKD G3–G5. This narrative review examines whether, and under what clinical conditions, fruits, vegetables, and legumes can be used safely in adults with hypertensive CKD, especially nondialysis CKD G3–G5, as well as moderate to severe loss of kidney function, paying close attention to the gut microbiota, short-chain fatty acids, gut-derived uremic toxins, potassium bioavailability, and modifiable clinical risk factors. The clinical effect of plant foods on serum potassium cannot be predicted from total potassium content alone. The Kidney Disease: Improving Global Outcomes (KDIGO) 2024 guidelines explicitly advise individualized potassium management and emphasize limiting foods rich in bioavailable potassium, especially processed foods, rather than reflexively restricting fruits and vegetables. Across CKD studies, the association between dietary potassium and serum potassium is weak or inconsistent, and the risk of hyperkalemia is modified by kidney function, bowel function, metabolic acidosis, diabetes and hyperglycemia, medications, food processing, and the food matrix itself. Potassium bioavailability varies substantially according to the food matrix, preparation method, portion size, and processing method; some minimally processed plant foods may provide less readily absorbable potassium than potassium-rich processed foods, juices, or potassium additives. Fruits, vegetables, and legumes also provide fiber, resistant starch, and polyphenols that can support saccharolytic fermentation, short-chain fatty acid production, bowel transit, and lower concentrations of some gut-derived uremic toxins. However, blood-pressure and kidney-outcome benefits in CKD are supported more strongly by observational and selected alkali-diet trials than by large microbiome-focused randomized studies. In hypertensive CKD, fruits, vegetables, and legumes should not be universally restricted simply because they contain potassium. A safer and more evidence-aligned strategy is individualized, food-source-aware prescribing that prioritizes minimally processed plant foods, accounts for preparation method and portion size, corrects constipation and acidosis, reviews potassium-raising medications and additives, and monitors serum potassium according to baseline risk.