Learning Outcomes
By the end of this section, you should be able to:
- 16.1.1 Describe the impact of nutrition on the renal and urologic systems during pregnancy.
- 16.1.2 Describe the impact of nutrition on the renal and urologic systems during infancy.
- 16.1.3 Describe the impact of nutrition on the renal and urologic systems during childhood.
- 16.1.4 Describe the impact of nutrition on the renal and urologic systems during adolescence.
- 16.1.5 Describe the impact of nutrition on the renal and urologic systems during adulthood.
- 16.1.6 Describe the impact of nutrition on the renal and urologic systems during later adulthood.
Pregnancy
Nutrition plays a role in the development and function of every system in the body, including the renal system. This role starts with the in utero development of a person and continues throughout their life. Nutrition combined with lifestyle decisions can interact with normal and pathologic processes in the renal system, sometimes resulting in system failure.
Poor nutrition during pregnancy can lead to fetal abnormalities that can cause kidney disease in the future (National Kidney Foundation, 2022). Additionally, individuals with renal disease experience more problems during pregnancy and must manage their nutritional intake differently. This section will cover these nutritional considerations and their impact on the renal system during pregnancy.
The Healthy Pregnant Client
Pregnancy is accompanied by expected urinary and renal changes. Increased blood volume and cardiac output result in increased glomerular filtration rate (GFR) and renal blood flow, which in turn causes increased excretion and reduced blood levels of bicarbonate, urea, creatinine, and urate (Willacy, 2022). In increased GFR, the renal tubules are unable to meet the increased fluid demands, resulting in mild glycosuria and proteinuria; fluid retention increases, reducing plasma osmolality. The smooth muscle of the renal pelvis, ureters, and bladder relaxes and dilates, causing the kidneys to increase in length; the ureters to lengthen, curve, and increase in residual urine volume; and the bladder to increase its capacity. The uterus may also put pressure on the bladder and ureters as it increases in size.
Good nutrition during pregnancy can prevent problems and support overall renal health for the pregnant client and fetus. To achieve these aims, the client should:
- Increase caloric intake by 340 calories per day starting with the second trimester and 452 calories per day starting with the third trimester (for a singleton pregnancy).
- Take a prenatal vitamin that includes iron or take a separate iron supplement in addition to a prenatal vitamin to prevent iron-deficiency anemia.
- Avoid caffeine or limit it to less than 200 mg/day (Gleason, et al, 2022).
- Increase fluid intake, especially water.
(source: American College of Obstetricians and Gynecologists, 2023; Holcombe, 2022)
Because of the normal physiologic changes expected, specific renal issues that most commonly arise during pregnancy include urinary tract infections (UTIs), pyelonephritis, and nephrolithiasis (kidney stones). Changes make urine less acidic, and it contains more hormones and sugars, increasing risk for bacterial growth (Sissons, 2019). Signs and symptoms of UTI include dysuria, frequency of urination, hematuria (American College of Obstetricians and Gynecologists, 2023b), abdominal cramps, and dyspareunia (pain during sexual intercourse).
If a UTI spreads from the lower urinary tract into the kidneys and develops into a more serious infection, pyelonephritis, signs and symptoms may then also include fever of 38.0°C (100.4°F) or higher; flank pain; costovertebral angle tenderness (American College of Obstetricians and Gynecologists, 2023b); chills; nausea; vomiting; and back, side, or groin pain. Significant fetal and maternal morbidity and mortality have been associated directly with pyelonephritis (Wing & Johnston, 2017). For instance, it has been linked to preterm delivery, in which case all of the newborn’s systems will be underdeveloped; disseminated intravascular coagulation (DIC), which can lead to hemorrhage and death of both mother and fetus; and maternal sepsis and respiratory distress, which can lead to renal failure and maternal and fetal death (Wing & Johnston, 2017).
Prevention of UTIs, and subsequently pyelonephritis, is based on urinary hygiene and nutritional recommendations. The nurse should instruct the client to drink 64–96 oz of water daily (American College of Obstetricians and Gynecologists, 2020). Drinking 8–10 oz of unsweetened cranberry juice or taking cranberry supplements daily may also help decrease the risk of UTI. Pregnant clients should also keep caffeine intake to 200 mg or less daily (Holcombe, 2022) and eat an overall healthy diet that includes proper nutritional and caloric intake (Sissons, 2019).
Nephrolithiasis usually occurs in the second or third trimester, when there is greater pressure on the renal organs from the growing uterus, and within the first year of giving birth (Furst, 2021; Urology Care Foundation, 2023). The pressure and narrowing of the passages for urine flow can concentrate urine and thus increase the risk for stone formation. Another factor that increases the risk for kidney stones is an elevated vitamin D level, which increases calcium levels in the urine (Orlando Health, 2023). Signs and symptoms the pregnant client may experience include nausea; vomiting; urgency and frequency of urination; hematuria (blood in the urine); and pain in the back, flank, or upper abdomen. The nurse should provide the following nutritional recommendations for nephrolithiasis during pregnancy:
- Get adequate daily amounts of vitamin B6 and magnesium (Weinberg, 2023).
- Avoid excessive vitamin C (Peerapen & Thongboonkerd, 2023).
- Limit sodium intake to less than 2.3 g/day (UT Southwestern Medical Center, 2023).
- Drink ten 10 oz glasses of water or other fluids daily (Urology Care Foundation, 2023).
- For calcium oxalate stones, maintain calcium intake at 1000–2000 mg/day and limit intake of oxalate-rich foods (Peerapen & Thongboonkerd, 2023; UT Southwestern Medical Center, 2023).
- For uric acid stones, limit animal proteins and eat more plant proteins (Peerapen & Thongboonkerd, 2023).
A recent study has shown that healthy individuals who developed hypertension during pregnancy had twice the risk of developing kidney disease within the first several years after the birth of their baby. Risks were even higher in those who had hypertension before pregnancy and had worsening of their condition during the pregnancy (Malek et al., 2022; Williamson, 2022). Nutritional recommendations for hypertension include limiting sodium intake to less than 2 g/day, getting 4700 mg of potassium daily, limiting meats and saturated fats, eating 4–5 servings each of fruits and vegetables, and following all other recommendations included in the Dietary Approaches to Stop Hypertension (DASH) diet.
Special Considerations
Disparity Implications—Pregnancy and Hypertension
Research evidence reveals a racial disparity exists showing that Black women were much more highly affected than White women: Black women who had hypertension before and during pregnancy were three times more likely to develop kidney disease (Malek et al., 2022).
The Pregnant Client with Preexisting Renal Disease
Pregnant clients with preexisting renal conditions will be more severely impacted by mild anemia, due to dilution of the blood from fluid retention; an increased GFR, putting more work on the glomeruli; decreased serum sodium, potassium, urea, creatinine, calcium, and albumin; mild glycosuria and proteinuria; reduced plasma osmolality; increased urine retention in the system, which increases infection risks; decreased urine acidity; and increased pressure in the system due to the growing uterus. Preexisting maternal renal conditions that can be affected by pregnancy include polycystic kidney disease (PKD); post–renal transplant status; and chronic kidney disease (CKD), a progressive disease of the kidneys that eventually ends in kidney failure.
Individuals with CKD are at much greater risk for experiencing adverse pregnancy outcomes, which can include preeclampsia; acceleration in the loss of kidney function, thereby speeding the process of CKD to end-stage renal disease (ESRD) or complete renal failure; fetal intrauterine growth restriction (IUGR); preterm delivery; the infant being of low birthweight or/and small for gestational age (SGA); the need for the infant to receive care in the neonatal intensive care unit (NICU); and maternal or fetal demise (Siligato et al., 2020; Wiles et al., 2019, 2020).
Kidney function declines as much in the 9 months of pregnancy as it does for a client living 1.7–4.9 years with kidney disease. Therefore, pregnancy could lead the client with CKD to complete kidney failure and need for a transplant or dialysis, purification of blood through means other than the kidneys, which can be extremely dangerous for the mother and fetus (Wiles et al., 2020).
Clients with CKD who have problems with chronic anemia, hypertension, proteinuria, or fluid and electrolyte imbalance before pregnancy will have continuation, and likely worsening, of these problems during pregnancy. Nutritional modifications for these clients involve a delicate balance between the needs of the growing fetus and the requirements of CKD. It has been found, however, that plant-based diets that are moderately restricted in protein decrease risks for preterm delivery and SGA status resulting from IUGR (Attini et al., 2022).
The Fetus
Certain nutritional components have been found to be critical for renal development in utero, and the pregnant person’s nutrition before and during pregnancy, as well as during early lactation, has been shown to have a substantial impact on this system. Clients with severe iron deficiency anemia during pregnancy have been shown to have elevated risks for preterm birth, placental abruption, and fetal malformation, which can include malformations of the fetal renal system (Shi et al., 2022). Pregnant clients with various disease processes may need specific dietary restrictions, but low-protein, low-carbohydrate, low-calorie, and low-sodium diets, as well as diets deficient in the micronutrients folic acid, iron, zinc, and vitamin A, have all been shown to have potential long-term adverse effects on the development of the renal system in the fetus (Nusken et al., 2020). High-fat, high-sodium, and high-fructose diets have also been shown to be detrimental to renal system development. Depending on the exact timing of the deficiency or the amount of exposure during development, adverse effects could include an altered number of nephrons, blood pressure dysregulation, mitochondrial dysfunction, altered sodium handling, endothelial dysfunction, inflammation, and oxidative stress of the kidney.
Studies have shown that increases in fetal growth and infant birth weight may be achieved by enhancing maternal nutrition during pregnancy (Columbia University Irving Medical Center, n.d.). Inadequate maternal nutrition during pregnancy is also a significant modifiable determinant for the development of chronic diseases in the child (Lee et al., 2021). Nutritional intake that is not sufficiently supplied with key nutrients such as iodine, iron, folate, calcium, and zinc can cause severe health problems in the mother (UNICEF, n.d.) that will directly affect fetal development and the individual’s lifelong health. The nurse should instruct a pregnant client to take in 30 mg of iron, 220 mg of iodine, 600 mcg of folate, 1000 mg of calcium, and 0.6 mg of zinc daily.
Infancy
Infants must receive proper nutrition for growth and development because all organs are impacted by malnutrition. Well-balanced nutrition should provide enough calories for energy expenditure. Healthy, full-term infants require around 100 kcal/kg/day (Patel & Rouster, 2022), whereas preterm infants require around 130 kcal/kg/day (Medical Home Portal, n.d).
Other nutritional recommendations to consider in an infant’s diet concern micronutrients, including iron, zinc, copper, chromium, manganese, and selenium (Patel & Rouster, 2022). Infants 7–12 months old should get 11 mg of iron (Gavin, 2021), 3 mg of zinc (Stanford Medicine Children’s Health, n.d.), 220 mcg of copper (National Institutes of Health, 2022a), 5.5 mcg of chromium (Duda, 2022), 0.6 mg of manganese (National Institutes of Health, 2021), and 20 mcg of selenium daily (Lubeck, 2023). Infants can quickly become dehydrated, so proper fluid intake is extremely important.
The preceding recommendations are for infants born without renal system defects. Those born with renal issues may need nutritional alterations and fluid restrictions based on their level of kidney function. These restricted diets may be in the form of a specially balanced formula that includes 2–4 mEq of sodium per 100 mL of formula and a restriction of 1–3 mmol/kg/day of potassium (Nelms, 2018). Depending on the specific needs, restrictions may also be in place for calcium, phosphorus, protein, calories, and fluids.
Oligohydramnios, a very low to almost absent amount of amniotic fluid, is a severe condition that must be managed before birth and can be related to impaired or absent kidney function in the fetus (Keilman & Shanks, 2022). Starting at 16 weeks’ gestation, around 90% of the amniotic fluid is made up of urine produced by the fetal kidneys. Immediate treatment for oligohydramnios is imperative because the fetus’s lungs need this fluid to develop properly.
Unfolding Case Study
Part A
Read the following clinical scenario and then answer the questions that follow. This case study will evolve throughout the chapter.
Jennifer Davis had a difficult pregnancy. Prior to conceiving, she lived with type 2 diabetes, hypertension, chronic moderate anemia, and stage 2 CKD. During the pregnancy, despite being very adherent, her kidney disease advanced. She closely followed her nutritional restrictions for low sodium, low sugar, low carbohydrate, low fat, and low protein, and as she progressed closer to kidney failure, she had to restrict fluids as well. Even though she followed these dietary modifications, after delivery she was diagnosed with ESRD and was scheduled to have a catheter placed to start hemodialysis (mechanical waste filtration).
Because of her health issues, she experienced preeclampsia that developed into eclampsia (seizures), requiring an emergency cesarean birth of her infant at 32 weeks’ gestation. Her infant demonstrated effects from Jennifer’s health issues as well. Due to Jennifer’s chronic anemia, nutritional restrictions, and preterm delivery, the infant was of very low birth weight and small for gestational age (SGA) due to intrauterine growth restrictions. She required 8 weeks of care in the NICU after birth.
Kayla Davis is now 1 week old. She weighs 1 kg (2.2 lb) and is 33 cm (13 in.) long.
Childhood
The U.S. Department of Agriculture (USDA) updated nutritional requirements in 2020, including recommendations for infants and toddlers for the first time. It is recommended that children have no added sugar in their diet until age 2 years (USDA, 2020). They should eat a large selection of fruits, vegetables, and grains, preferably with at least half of the grains being whole grains, and their proteins should come from lean meat sources or plant-based proteins (McCarthy, 2021), with low-fat dairy products added after age 2 years. They should not receive the same portion sizes as adults.
In children with altered kidney function, it may be difficult to ensure that they get enough calories and protein to grow within the confines of their restrictive nutritional needs. To protect renal health in children who do not have altered kidney function, sodium should be limited to less than 2 g/day because amounts greater than this can lead to fluid retention and hypertension. Sugar intake should be limited to less than 25 g/day (American Heart Association, n.d.) because it can lead to obesity, hypertension, and kidney hyperfiltration. Children should be encouraged to eat fruits and vegetables because, in addition to their other benefits, the fiber will help prevent constipation (Deshpande, n.d.) and keep cholesterol in check. Fruits also contain citrate, which helps prevent stone formation (Deshpande, n.d.). Adequate water intake of 34–61 oz/day (1–1.8 L) can prevent urinary infections, constipation, dehydration, and kidney stones and assist in weight control (Deshpande, n.d.).
Common conditions that can develop even if children are not born with renal problems are UTIs, enuresis (bladder incontinence after the age of 3 years), and nephrolithiasis. Nutritional recommendations can help maintain optimal renal health.
Nephrolithiasis has become more common than it once was in children and adolescents (American Academy of Pediatrics, 2021) due to diets higher in processed foods, low vegetable intake, and lower physical activity levels. Risk factors for developing kidney stones in children and adolescents include family history of nephrolithiasis; a diet high in salt, meat, and processed foods; a diet low in fruits and vegetables; dehydration with low urine output; inherited conditions such as cystinuria (a rare condition in which kidney stones form from an amino acid called cysteine) and hyperoxaluria (excessive oxalate in the urine); some medications, including furosemide and topiramate; blocked urine flow; bowel diseases; kidney infection; prolonged sedentary periods, especially bed rest; weight loss surgery (American Academy of Pediatrics, 2021); and urinary tract infections (UTIs).
Enuresis may be diurnal (occurring in the daytime), nocturnal (occurring in the nighttime), primary (occurring in someone who has never had total bladder control), or secondary (occurring in someone who previously could control their bladder) (Johns Hopkins Medicine, n.d.). Enuresis has many psychological and physical causes. Renal causes include bladder pressure from constipation, overactive bladder (OAB), small bladder, structural problems in the urinary tract, inability to feel when the bladder is full (such as during sleep), UTI, and failure to urinate enough. Many of these causes would need to be addressed with the child’s primary care provider. However, teaching the child different hygiene habits can be helpful, and OAB can be helped by following special nutritional considerations, discussed later in this chapter.
Children urinate more often than adults because they tend to drink more fluids in relation to their size, have smaller bladders, and have less control over their urinary muscles, which results in feeling the need to “go” more often. UTIs can be very common in this age group; therefore, young children need to be educated on proper urinary hygiene (American Academy of Pediatrics, 2015). Females are more susceptible to UTIs than males because they have shorter urethras, so bacteria can more readily enter the urinary tract (American Academy of Pediatrics, 2015). General signs and symptoms of a UTI include vomiting, high temperature, lethargy, irritability, poor feeding, poor weight gain, and jaundice (NHS Inform, 2023). More specific signs and symptoms include pain or burning with urination; frequency or urgency of urination; deliberate holding of urine; change in toileting habits (such as enuresis); pain in the side, back, or abdomen; bloody or cloudy urine; and foul-smelling urine.
Some nutritional measures can help prevent UTIs. Children should drink plenty of water to avoid constipation and to maintain the kidneys’ function in eliminating waste products. Cranberry or blueberry juice can help create a more acidic urinary environment that will discourage bacterial growth (American Academy of Pediatrics, 2015). Colas and caffeinated beverages should be discouraged because these irritate the bladder and cause diuresis.
Certain foods are beneficial in preventing UTIs as well. Yogurts with live and active cultures and other fermented products are recommended because they contain bacteria that help balance the body’s systems and can thereby decrease the risk for UTIs (Norton Children’s, 2020; Urology Specialists, 2015). Foods high in vitamin C, including oranges, lemons, strawberries, grapefruits, tomatoes, broccoli, and spinach, are beneficial to maintain a balanced urine acidity level (Figure 16.2). Foods containing proanthocyanidins, including cranberries, raspberries, and blueberries, are a good addition because these substances help prevent Escherichia coli infection, the number one bacterial cause of common UTIs (Norton Children’s, 2020; Urology Specialists, 2015). High-fiber foods such as whole grains, apples, bananas, and legumes are important to prevent constipation, which can block urine excretion from the body and in turn cause urine stasis, which encourages bacterial growth (Norton Children’s, 2020). Sugar intake should be limited because it provides a fuel source and breeding ground for bacteria to thrive (Urology Specialists, 2015).
Unfolding Case Study
Part B
Read the following clinical scenario and then answer the questions that follow. This case study is a follow-up to Case Study Part A.
Kayla was diagnosed with hydronephrosis (swollen kidney due to urine accumulation) related to uteropelvic junction obstruction (blockage). This resolved on its own after 2 weeks of life. She was transferred from the NICU to the regular pediatric floor for care at 8 weeks of age and was discharged home the following week. Her prematurity and intrauterine growth restriction have resulted in ongoing effects on her development. She was diagnosed with type 1 diabetes because her pancreas is nonfunctioning, and one of her kidneys is nonfunctioning. The kidney is small and undeveloped. The other kidney is functioning despite the hydronephrosis.
Unfortunately, by age 6, Kayla has developed CKD and is in stage 3 when diagnosed.
Adolescence
During adolescence, puberty, hormonal changes, and growth spurts occur. The body goes through many changes that require healthy and supportive nutrition to ensure proper growth and maturity. Food should include high levels of calcium, vitamin D, and iron for bone and muscle development (Castle, 2022). Iron for males and females aged 9–13 should be around 8 mg/day. Males aged 14–18 should receive 11 mg/day, whereas females in this age group should receive 15 mg/day. The calcium recommendation for adolescents is 1300 mg/day, and the vitamin D recommendation is 600 International Units daily. Caloric intake should range from 1800–3200 calories daily for males and from 1600–2400 calories daily for females, depending on activity level (USDA, 2020).
Adolescents should follow the same nutritional guidelines as other age groups for urinary health. UTIs and nephrolithiasis are the more common kidney-related issues in this age group. The same nutritional restrictions and recommendations discussed elsewhere in this chapter for these conditions apply for adolescents as well.
UTIs have different causes in this group, necessitating additional educational points to discuss with the adolescent. All of the earlier hygiene recommendations are still important, but an additional cause of UTIs in adolescents (as well as in adults) is sexually transmitted infections (STIs). Chlamydia, gonorrhea, and trichomoniasis all can infect the urethra and advance into the urinary system. Females also have increased risk for developing cross infections from bacterial vaginosis (BV) and yeast infections.
Nutritional recommendations to help avoid BV and yeast infections include staying hydrated with plenty of water and avoiding sugary, caffeinated, and carbonated beverages to help maintain a healthy pH balance. Probiotic and prebiotic foods also help maintain the pH balance in the vagina and prevent yeast or bacterial overgrowth. Foods that contain probiotics include yogurt with live cultures, sauerkraut, kimchi, pickles, miso, tempeh, and kombucha (Sass, 2022). Prebiotics can be found in chicory root, leeks, garlic, asparagus, and onions.
Foods with a low glycemic index may also help prevent BV by helping maintain the pH balance; such foods include whole grains, including oatmeal and barley; quinoa; yogurt; milk; nuts; legumes; beans; grapefruit; oranges; and carrots (Sass, 2022). High-fiber foods support healthy bacterial growth and help prevent BV. Vitamin D has been found to be important in overall vaginal health and pH balance). Foods that contain vitamin D include trout, cooked salmon, sardines, eggs, cheddar cheese, and fortified milk (Sass, 2022). Another important addition to the diet is apples, at least one daily, as these have been shown to improve vaginal lubrication (Sass, 2022; Tommaso et al., 2014). Foods to restrict include white bread, high-sugar foods, white rice, honey, processed grains, and highly processed foods (Sass, 2022).
Unfolding Case Study
Part C
Read the following clinical scenario and then answer the questions that follow. This case study is a follow-up from Case Study Parts A and B.
Kayla and her mother have been managing her condition well, and her stage 3 CKD has remained stable. She is now 13 years old and has come into the clinic for a regular check-up. The nurse is planning to provide Kayla with education on continued management of her CKD.
Adulthood
Adults will not require as much from their nutritional intake for growth, although certain hormonal changes still occur in adulthood. Individuals in this age group face more health risks that can impact the kidneys and their functioning, including hypertension, diabetes types 1 and 2, CKD, PKD, benign prostatic hyperplasia (BPH), nephrolithiasis, cardiovascular disease, and hyperlipidemia. Foods should be nutrient dense; low in sugars, sodium, and saturated fats; high in fiber and calcium; and include vitamin D (USDA, 2020, p. 101). Nutritional recommendations specific for renal health mentioned previously in the chapter apply to this age group as well. Nephrolithiasis, UTIs, BPH, and CKD are more common in this age group due to the comorbidities that often develop.
Unfolding Case Study
Part D
Read the following clinical scenario and then answer the questions that follow. This case study is a follow-up from Case Study Parts A, B, and C.
At age 18, Kayla becomes pregnant. Her GFR is 49 mL/min/1.73 m2, and she has hypertension, type 1 diabetes, and chronic anemia. Despite the known risks to her and the fetus, she wants to go through with the pregnancy. She is currently not restricting fluids, but she is restricting protein, potassium, phosphorus, sodium, sugar, and carbohydrates. She is following all heart-healthy recommendations.
Kayla decides to continue with the pregnancy despite the risks. During her second trimester, the fetus is markedly small due to intrauterine growth restriction, and Kayla has advanced to stage 4 CKD and is approaching the need for dialysis. Because of Kayla’s rapid decline and the struggle to keep her potassium levels normal, her health care provider orders a catheter to be placed for the impending need for dialysis and plans to deliver the baby as early as safely possible. Unfortunately, 2 days before she is scheduled to have the catheter placed, Kayla goes into cardiac arrest due to a dysrhythmia from hyperkalemia. She is unable to be revived, and her fetus is too premature to survive.
Later Adulthood
For adults aged 60 years and older, the risk for chronic disease is highest. Such conditions include cardiovascular disease, type 2 diabetes, obesity, hypertension, hyperlipidemia, CKD, congestive heart failure, cancers, and BPH. Renal function also naturally declines in this age group, with defined GFR being less than 60 mL/min/1.73 m2 (National Kidney Foundation, 2023). Therefore, preserving kidney function is very important, and medication dosages may need to be adjusted to ensure safety.
Nutritional intake should include nutrient-dense foods and be rich in whole grains, fruits, vegetables, and dairy, as well as protein to prevent muscle loss. Older individuals should also increase their intake of vitamin B12 because the ability to absorb this vitamin declines as people age (USDA, 2020, p. 128). Foods high in B12 include beef liver, clams, cooked salmon, tuna, eggs, fortified breakfast cereal, spinach, and kidney beans (National Institutes of Health, 2022b). Adults in this age group must also be sure to drink enough fluids, especially water, because the sensation of thirst declines with age, increasing the risk for dehydration and UTIs (U.S. Department of Agriculture, 2020, p. 129).