Diet and Renal Disease

 

Diet and Renal
Disease

§     Objectives

§     Describe, in general terms, the work of the kidneys.

§     Explain why protein is restricted for renal clients.

§     Explain why sodium and water are sometimes restricted for renal clients.

§     Explain why potassium and phosphorus are sometimes restricted for renal clients.

 

§     Kidneys

Kidneys excrete wastes,

maintain volume and

composition of body

fluids, and secrete

certain hormones.

They filter the blood, cleanse it of waste products, and recycle other, usable, substances so that the necessary constituents of body fluids are constantly available.

§     Kidneys

One million working parts

 called nephrons.

Glomerulus is

 the filtering unit.

The kidneys maintain

 both the composition and the volume of body fluids.

They maintain fluid balance, acid-base balance and electrolyte balance.

§     Kidneys

Waste materials sent via 2 tubes called ureters from the kidneys to the urinary bladder.

1.5 liters of urine excreted per day.

Waste materials include end products of protein metabolism (urea, uric acid, creatinine, ammonia, and sulfates), excess water and nutrients, dead renal cells, and toxic substances.

§     Kidneys

Oliguria:  urinary output less than 500 ml/day.

Kidneys unable to adequately eliminate waste products–can result in renal failure.

Kidneys indirectly stimulate the bone marrow to produce red blood cells.

§     Types of Renal Disorders

Initially caused by infection, degenerative changes, diabetes mellitus, cardiovascular disorders, cysts, renal stones, trauma.

When severe, renal failure may result.

§     Acute Renal Failure

Acute renal failure occurs suddenly and may last a few days to a few weeks.

Caused by another medical problem such as a serious burn, a crushing injury, or cardiac arrest.

§     Chronic Renal Failure

Develops slowly, number of functioning nephrons constantly diminishing.

Uremia is a condition in which protein wastes that should normally have been excreted are instead circulating in the blood.

Symptoms include nausea, headache, coma, convulsions.  Severe renal failure will result in death unless dialysis used.

§     Nephritis

Inflammatory diseases of the kidneys.

Caused by infection, degenerative processes, or vascular disease.

Glomerulonephritis is a nephritis affecting the capillaries in the glomeruli.

§     Nephrosclerosis

Hardening of renal arteries.

Caused by arteriosclerosis and hypertension.

Usually occurs in older people, sometimes develops in young diabetic clients.

 

§     Polycystic Kidney Disease

Relatively rare, hereditary disease.

Cysts form and press on the kidneys.

Kidneys enlarge and lose function.

Although people with this condition have normal kidney function for many years, renal failure may develop near the age of 50.

§     Nephrolithiasis

Stones develop in the kidneys.

Stones classified according to their composition–calcium oxalate, uric acid, cystine, calcium phosphate, and magnesium ammonium phosphate (known as struvite).

Associated with metabolic disturbances and immobilization of the client.

Dietary Treatment of Renal Disease

Extremely complicated.

Intended to reduce the amount of excretory work demanded of the kidneys while helping them maintain fluid, acid-base, and electrolyte balance.

Clients with chronic renal failure may have protein, sodium, potassium and phosphorus restricted.

Dietary Treatment of Renal Disease

Sufficient calories necessary:  25 to 50 kcal per kilogram of body weight.

Energy requirements should be fulfilled by carbohydrates and fat.

Protein increases the amount of nitrogen waste the kidneys must handle.

Diet may limit protein to 40 grams based on glomerular filtration rate and weight.

Dietary Treatment of Renal Disease

Sodium may be limited if the client tends to retain it.

Fluids are typically restricted for renal clients.

Calcium supplements may be prescribed.

Vitamin D may be added and phosphorus limited, to prevent osteomalacia.

Dietary Treatment of Renal Disease

Potassium may be restricted in some clients because hyperkalemia tends to occur in end stage renal disease (ESRD).

Excess potassium can cause cardiac arrest.

Renal clients often have an increased need for vitamins B, C, and D, and supplements are often given.

Iron is commonly prescribed.

§     Dialysis

Done be either hemodialysis or peritoneal dialysis.

Hemodialysis requires permanent access to the bloodstream through a fistula.

Hemodialysis is done 3 times a week for 3-5 hours at a time.

Dialysis

Peritoneal dialysis makes use of the peritoneal cavity.

Less efficient than hemodialysis.

Treatments usually last about 10 to 12 hours a day, 3 times a week.

Complications include peritonitis, hypotension, weight gain.

§     Diet During Dialysis

Dialysis clients may need additional protein.

Amount must be carefully controlled.

A client on hemodialysis requires 1.0 to 1.2g of protein per kilogram of body weight to make up for losses during dialysis.

A client on peritoneal dialysis requires 1.2 to 1.5g protein per kilogram body weight.

§     Diet During Dialysis

75% of this protein should be high biological value (HBV) protein, found in eggs, meat, fish, poultry, milk, and cheese.

Potassium is usually restricted.

A typical renal diet could be written as   “80-3-3” which means 80g protein, 3g sodium, and 3g potassium daily.

§     Diet During Dialysis

Healthy people ingest from 2,000 to 6,000 mg of potassium per day.

Daily intake allowed clients in renal failure is 3,000 to 4,000 mg.

End stage renal disease clients intake allowed is 1,500 to 2,500 mg per day.

  

§     Diet After Kidney Transplant

Need for extra protein or for the restriction of protein.

Carbohydrates and sodium may be restricted.

Additional calcium and phosphorus may be necessary if there was substantial bone loss before the transplant.

A client with renal disease is on a potassium restriction of 3,000 mg.

What recommendations would you give the client?

Regulate intake by making careful choices.

Milk is normally restricted to ½ cup a day because it is high in potassium.

Suggest use of potassium content charts to select low potassium foods.

Low potassium (< 150 mg/serving) fruits include:

•                      Applesauce 

•                      Berries

•                      Figs

•                      Fruit cocktail

•                      Grapes

 

•                      Lemon, lime

•                      Nectors

•                      Mandarin oranges

•                      Peaches

•                      Pears

•                      Plums

•                      Rhubarb

§     Considerations for the Health Care Professional

Client with renal disease has a lifelong challenge.

Develop a trusting relationship with the client.

Help motivate clients to learn how to manage their nutritional requirements and help the dietitian assist them.

§     Conclusion

Kidneys rid the body of wastes, maintain fluid, electrolyte, and acid-base balance, and secrete hormones.

Entire body is affected by kidney disease.

Diet therapy extremely complex.

Untreated severe kidney disease can result in death unless client receives dialysis or kidney transplant.