16.2 Nutrition and Chronic Renal Illness

Overactive Bladder

Overactive bladder (OAB), affecting more than 33 million Americans, causes urinary incontinence and urinary urgency resulting from involuntary contraction of the detrusor muscle of the bladder (Mobley et al., 2020). Anticholinergic medications and beta-3 adrenoceptor agonists are prescribed to treat this condition (Mobley et al., 2020). Some individuals also take 2–4 g of sodium bicarbonate twice daily to alkalinize the urine and make it less irritating to the bladder (Mobley et al., 2020).

Nutritional considerations for urologic illness center around reducing symptoms and avoiding medication interactions. Anticholinergic drugs should not be taken with alcohol because this combination can increase the risk for respiratory depression, unconsciousness, and death (Cafasso, 2023). Alcohol also acts as a diuretic, so clients should avoid it to prevent increased urinary frequency (Stoppler, 2020). They should also avoid carbonated beverages because they contain substances that can irritate a sensitive bladder and increase symptoms. Another important nutritional modification is to eliminate caffeine. Coffee, tea, other caffeinated beverages such as energy drinks, and brown chocolate all contain an acid that acts as a bladder irritant and aggravates OAB symptoms (Mobley et al., 2020; Stoppler, 2020).

Citrus fruits, including oranges, grapefruits, lemons, limes, and clementines, are also acidic; they can alter the urine pH and contribute to urgency and incontinence, so clients should avoid or reduce consumption of them (Mobley et al., 2020; Stoppler, 2020). Pineapple, tomatoes, wasabi, chili, spicy salsa, and other spicy condiments are all acidic foods, as are cranberries; although cranberries are beneficial for avoiding UTIs, they contain irritants that exacerbate OAB (Mobley et al., 2020; Stoppler, 2020). Sugar, artificial sweeteners, honey, grapes, bananas, apples, peaches, plums, strawberries, raw onions, dairy products (especially sour cream and aged cheeses), prunes, ketchup, vinegar, soy sauce, and mayonnaise can all contribute to an increase in OAB symptoms (Mobley et al., 2020; Stoppler, 2020). Nocturia can be decreased if individuals restrict their fluids during the day, especially after 6 p.m. (Mobley et al., 2020).

Nurses can encourage clients to try food substitutions. Dill, rosemary, thyme, and garlic are great substitutes for the more irritating spices (Stoppler, 2020). White chocolate is recommended instead of regular chocolate because it contains no caffeine, but clients should be cautioned not to eat too much because it contains sugar. Peas and carrots, along with other high-fiber foods, are encouraged to keep bowel movements regular and prevent symptoms resulting from increased pressure on the pelvic floor from constipation (Stoppler, 2020). In addition to estrogen supplementation for women with OAB symptoms related to estrogen deficiency, these clients can benefit from consuming vegetables that contain phytoestrogens, such as yams and carrots (Mobley et al., 2020). These clients should also increase their intake of potassium, protein, and, especially, vitamin D, which works to reduce urinary urgency at the site of the detrusor muscle (Mobley et al., 2020).

Another significant change clients can make is a lifestyle change, not a nutritional one: Clients who use tobacco should stop, as its use is linked with OAB symptoms (Mobley et al., 2020).

Interstitial Cystitis

Interstitial cystitis, also known as chronic pelvic pain syndrome, causes pelvic pain and a persistent desire to urinate, as well as nocturia, urinary frequency, and voiding of only small amounts at a time (Mobley et al., 2020). These symptoms mimic those of UTI, but urine cultures will consistently show no infection. Pentosan polysulfate sodium, sodium bicarbonate with calcium glycerophosphate, and dimethyl sulfoxide have all been used to treat this condition, and dietary modifications to reduce bladder irritants can effectively supplement pharmacotherapy. Nurses should give the same nutritional recommendations to clients with interstitial cystitis as for those with OAB.

Benign Prostatic Hyperplasia

Benign prostatic hyperplasia (BPH) is an enlargement of the prostate gland, affecting men (19 million in the United States) as they age and as their testosterone levels decrease. Lower urinary tract symptoms (LUTS) include urinary frequency and urgency, a weak urine stream, the feeling of being unable to empty the bladder, postmicturition dribbling, and nocturia (Mobley et al., 2020). Nutrition has not been shown to directly affect testosterone levels, but evidence indicates that the Mediterranean diet can be helpful in decreasing LUTS (Mobley et al., 2020). The Mediterranean diet promotes daily consumption of plant-based foods to replace some meats and starches, and the replacement of unhealthy fats, such as butter and margarine, with healthier fats (Modglin, 2022). This diet is rich in olive oil, small amounts of fish and other seafood, and plant-based options.

Bladder Cancer

Bladder cancer is the seventh most common form of cancer diagnosed, with the highest incidence occurring in White men (Mobley et al., 2020). Tobacco use is the greatest risk factor for the disease. Eating a diet high in isothiocyanates, which are found in cruciferous vegetables such as cabbage and kale, and drinking tea have both been linked to a decreased risk for developing bladder cancer.

Nephrolithiasis

Nephrolithiasis, commonly referred to as kidney stones, can occur as a single incident or as a chronic condition. Kidney stones can cause a wide range of issues, from extreme pain to kidney failure due to hydronephrosis if they block urine flow and are not treated in a timely manner. Nurses should instruct clients to drink at least 88 oz (2.5 L) of fluids daily to help prevent stone formation (Mobley et al., 2022). Fruit juices are also recommended because they contain citrate, which inhibits calcium oxalate and calcium phosphate stone formation (Dai & Pearle, 2022).

The type of nutritional modification required depends on the type of stone and its composition (Table 16.1).

Chronic Kidney Disease

Chronic kidney disease (CKD) affects more than 31 million Americans, but many remain undiagnosed because the early stages are relatively asymptomatic (Mobley et al., 2020). Many things can cause CKD, but the most common causes are diabetes types 1 and 2 and hypertension, conditions that need to be managed correctly to slow disease progression. Nutrition plays a very important role in the health of clients with CKD, even if they advance to end-stage renal disease (ESRD) and require dialysis treatment or a renal transplant to sustain life.

The stage of CKD is determined by GFR levels, which indicate how well the kidneys are filtering wastes from the blood. (See Table 15.2 in Applying Clinical Judgment to Promote Nutrition for Renal Wellness.) Creatinine and blood urea nitrogen (BUN) levels are also monitored closely and change more as the kidneys progress toward failure.

Nutritional restrictions are vital for clients with CKD. Referral to a certified renal dietician can ensure that clients are properly educated and that their nutritional needs are individualized to improve their quality and length of life.

Foods high in calcium include cheese, yogurt, edamame, canned sardines, canned salmon, tofu, almonds, leafy green vegetables, and calcium-fortified foods. Foods high in magnesium include dark chocolate, avocados, nuts, legumes, tofu, seeds, whole grains, fatty fish, bananas, and leafy green vegetables.

Phosphorus should be restricted to less than 800–1000 mg/day, protein to 0.6–0.8 g/kg/day, and potassium to less than 2000 mg/day (Mobley et al., 2020). Protein should come from lean sources as much as possible, which are those that come from low-fat, high-protein foods such as eggs and skinless chicken.

For clients receiving dialysis treatments, strict fluid restriction is extremely important because gaining too much weight due to fluid retention in between treatments can cause serious side effects. The average fluid restriction for a client on dialysis is 32 oz daily (Fresenius Kidney Care, n.d.). Nurses should instruct clients that fluids are not just beverages and substances that are liquid at room temperature; this category also includes gelatin, ice cream, ice, ice chips, and soup.

Renal Cancer

Renal cancer, or kidney cancer, occurs sporadically, but associations with aging, obesity, hypertension, smoking, acquired cystic kidney disease, and exposure to asbestos, cadmium, or petroleum have been observed (Mas Que Ideas Foundation, 2022). Most of the time, renal cancer is asymptomatic and found incidentally on an abdominal scan performed for other medical purposes; however, on occasion, a client may experience hematuria, an abdominal lump, or a symptom related to paraneoplastic syndrome, such as anemia, hypertension, weight loss, anorexia, or muscle wasting. Renal cancer will not necessarily cause immediate or automatic kidney failure.

Proper nutrition and nutritional modifications can help lower the risk for renal cancer, prevent adverse effects of cancer treatments and medications, support the highest level of renal function possible, and maintain a client's life expectancy after cancer remission.

Preventing renal cancer is the first priority. Eating grilled and pan-fried foods as well as red meats increases the risk, so nurses should instruct clients to restrict or avoid these (Richards, 2022). Increased intake of vegetables, with special emphasis on cruciferous vegetables, and foods containing vitamin C, such as citrus fruits, strawberries, bell peppers, tomatoes, and white potatoes, shows promise for decreasing the risk for developing renal cancer (Liao et al., 2022). High-fiber foods; foods rich in antioxidants such as vitamin E and selenium; and foods containing phytochemicals, such as whole grains, may also reduce the risk (Thompson, 2023). See Figure 16.3.

Figure 16.3 A diet rich in cruciferous vegetables (purple cabbage), phytochemicals (quinoa), antioxidants (carrots), and vitamin C (bell peppers and peas) may lower the risk for developing renal cancer. (credit: “Asian Quinoa salad food” by Watts/Flicker, Public Domain)

Nutritional changes can address adverse effects of cancer treatment. Many side effects of chemotherapy—such as nausea and vomiting, anorexia, diarrhea, constipation, flatus, bloating, weight loss, sore throat, gastrointestinal problems, dysphagia, heartburn, dry mouth, mouth sores, and changes in taste and smell—make it difficult for the individual to take in enough calories. Therefore, a nutrient-dense diet with sufficient calories, vitamins, and minerals to ensure proper nutrition is important (Richards, 2022; Thompson, 2023). It should include whole foods, such as fruits, vegetables, and whole grains, and limit foods high in salt and phosphorus (Richards, 2022). Fluid volume status should be monitored because decreased kidney function may necessitate fluid restriction (Richards, 2022). Nurses can suggest that clients with painful mouth sores avoid acidic or spicy foods, alcohol, and foods that are too hot or too cold, and instead eat foods that are soft and easy to chew (Thompson, 2023).

Because of the eating issues that chemotherapy can cause, clients may better tolerate smaller, more frequent meals and maybe even different food consistencies, such as soft, lightly mashed, or pureed foods (Richards, 2022). Brief periods of fasting may even be beneficial during chemotherapy treatment because fasting can generate environments in the body that make survival of cancer cells less likely and help normal cells resist the negative effects of chemotherapy. These periods should be very short, and the client should eat calorie-rich, nutrient-dense foods after fasting.

Another significant effect of chemotherapy is the risk for developing infection. Some nutritional precautions to lower this risk include avoiding unpasteurized juice and dairy products as well as raw fish and raw meat (Richards, 2022). Food preparation and storage are also important in infection prevention, so the nurse should educate the client on appropriate methods.

In maintenance, a plant-based diet may improve survival after renal cancer (Richards, 2022). Because chronic inflammation has been shown to play a major role in cancer, and fruits and vegetables have strong anti-inflammatory properties, fruits and fiber-rich vegetables may have protective effects against renal cancer and its reoccurrence (Thompson, 2023). Since whole grains are high in fiber and contain antioxidants such as selenium and vitamin E as well as phytochemicals, they are also important nutritionally and may help prevent the occurrence and reoccurrence of renal cancer.