Diet closely tied to Diabetes, High Blood Pressure, Chronic Kidney Disease

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Earlier this year, Dr. Frank Vinicor, director of the diabetes division of the Centers for Disease Control and Prevention, called a press conference to announce that diabetes had reached "epidemic levels" in the United States.

He said the incidence of Type II diabetes, which accounts for 90-95 percent of all diabetes cases, had climbed 33 percent nationally in the past decade and that an estimated 17 million Americans now have diabetes. Type I diabetes also is a growing problem with about one million in the United States now suffering from this disease. Each year about 30,000 Americans are diagnosed with Type I diabetes--over 13,000 of whom are children, according to the Juvenile Diabetes Foundation.

As if that news isn't bad enough, the fact is that many individuals who suffer from diabetes eventually end up with an even worse condition--end stage renal disease, or ESRD. In fact, diabetes is the leading cause of chronic kidney failure and accounts for about a third of new cases of chronic kidney failure in the United States each year, according to the National Kidney Foundation (NKF).

The key to managing diabetes and avoiding ESRD and other serious conditions such as stroke and heart disease is maintaining good blood sugar control. This requires a balanced diet with regular meals. For some diabetics a good diet must be combined with medication. It is important to establish a meal plan and medication based on one's basal metabolic requirement for total calories and protein.

The second leading cause of chronic kidney failure, according to the NKF, is uncontrolled or poorly controlled high blood pressure, which leads to another 30 percent of all chronic kidney failure in the country. Experts now say that 10-15 percent of American school children suffer from high blood pressure, mostly due to obesity and high salt intake. A low sodium diet and taking medication to control blood pressure on a daily basis can help prevent high blood pressure leading to chronic kidney failure.

Both diabetes and high blood pressure are closely tied to diet but with ESRD, diet may be a matter of life and death. Once a patient has ESRD, s/he has little choice--regular dialysis or a kidney transplant.

So how can diabetes end up leading to ESRD? It might be helpful to first explain what kidneys do for our bodies.

Healthy kidneys have several important functions, including the production of urine. These functions are to:

? Kidneys maintain water balance by removing excess fluid from the body.

? Kidneys remove waste products. There are many chemical reactions that take place in the body to maintain life. This process is called metabolism. Metabolism results in waste products that become toxic (poisonous) if they are left to accumulate in the body. The healthy kidney filters the blood to remove waste products such as urea and creatinine.

? Kidneys maintain normal blood chemistry. A number of chemicals such as potassium, sodium, phosphorus, calcium, bicarbonate, magnesium and chloride are important to one's blood chemistry. Healthy kidneys help to keep the right amounts of these chemicals and get rid of those not needed.

Kidneys also make three important hormones--renin, erythropoietin and calcitriol:

? Renin helps regulate blood pressure.

? Erythropoietin (er-ree-throw-po-e-ten) helps maintain the right amount of blood in the body (blood volume) by simulating bone marrow to make more red blood cells.

? Calcitriol helps the body absorb calcium from the food one eats. Bones need calcium to stay strong and healthy.

Our bodies digest the protein we eat, leaving waste products that build up in the blood. In the kidneys there are millions of capillaries that act as filters. As blood flows through these capillaries, small molecules of waste squeeze through the holes and become part of the urine. Useful substances such as protein and red blood cells are too big to pass through the holes, so they stay where they belong in the blood.

When a person has diabetes, however, high levels of glucose make the kidneys filter too much blood. This extra work is hard on the "filters" in the kidney. After many years the filters start to leak and useful protein is lost in the urine. When large amounts of protein are lost in the urine, it is called "proteinuria or macroalbuminuria."

Eventually the stress of overwork causes some filters to collapse. As they collapse it makes more work for remaining filters and they, too, begin to collapse. Finally the kidneys fail.

What happens when the kidneys stop working? When kidneys stop working, the condition is called kidney failure or renal failure. End stage renal disease is another term for kidney failure.

If one develops ESRD, you cannot get rid of excess fluid and it stays inside the body. Urine output may go down. This can cause a rise in blood pressure, shortness of breath and swelling in many areas of the body.

The body can't get rid of waste products for protein breakdown either and these build up in the body too. The buildup of waste products in the body results in uremia, which means "the excessive amount of by-products from protein metabolism in the blood." Uremia affects all the systems in the body and can make one feel quite ill. If uremia is not treated one may develop symptoms such as headache, nausea, vomiting, poor appetite, extreme fatigue and mental cloudiness.

The body may not be able to make enough red blood cells and the blood chemistry may become abnormal. This means the body no longer has the right balance of chemicals such as potassium, calcium and phosphorous.

What is the treatment for kidney failure? Kidney failure can be very gradual. Patients who have had recent kidney failure may have felt fine until the last few weeks or months. As their kidney failure progressed they were probably given medications to control their blood pressure. They may have also been put on a low-protein, low-salt diet to lessen the work their diseased kidneys have to do.

When drugs and diet are no longer effective, patients need treatment to do the work of their failed kidneys. If someone loses close to 90 percent of kidney function, s/he needs to start dialysis or have a kidney transplant to stay alive.

Dialysis means "to clean the blood." Dialysis cannot cure a patient's kidney disease but it can remove the waste products and excess water from their bodies and stabilize their blood chemistries. There are two types of dialysis available to treat kidney failure: hemodialysis and peritoneal dialysis.

Currently most patients with kidney failure choose hemodialysis as their treatment option. Being on dialysis is a traumatic and overwhelming experience for patients and their families. The treatment schedule is three days a week ranging from 3-4 hours per dialysis treatment. The medical staff helps the patient cope in making this difficult lifestyle change. The dialysis patient, both young and old, has an inner strength and determination to live. Being a part of the medical staff, we help support the patient's medical, nutritional and psychological needs to make a smooth transition to live and maintain a good quality of life on dialysis.

Making good, healthy choices in the diet is very important when a person is on dialysis. Diet is a big part of the total treatment. When kidneys fail, waste products and extra fluids build up in the blood. By limiting certain foods, less of these waste products will stay in the body.

The renal dietitian meets with patients and their families to create a customized meal plan. The dietitian educates patients on the types and amounts of food to eat, eating habits and food preferences. The dietitian monitors monthly lab tests and may recommend changes in the food plan based on test results.

When kidney disease begins, some parts of the kidney can become damaged while other parts continue to function. It is difficult for a damaged kidney to complete the job of filtering waste products from the blood. The more waste products that need to be removed from the body, the harder the kidney must work. This increased workload can result in faster progression of kidney failure. The diet for the early stages of kidney failure, sometimes called Pre-ESRD, is designed to minimize the amount of waste products in the blood, which will decrease the work of the kidney.

As kidneys rose the ability to function, diet therapy may be helpful to conserve remaining kidney function and keep blood tests in an acceptable range. Controlling the amount of protein, phosphorus and sodium in the diet can help slow down the buildup of waste products.

Protein
Protein is an important part of the diet but for people with limited kidney function, the amount and type of protein must be carefully controlled. The waste by-product of protein is called urea. Urea can build up in the blood and cause symptoms such as nausea and loss of appetite. It is important to avoid a buildup of urea in the blood (Blood Urea Nitrogen or BUN). A renal dietitian can help plan the correct amount and type of protein to include in the daily diet. It is important to set protein intake at a level that keeps wastes from building up but still provides enough for the body to build and repair tissues.

Phosphorus
Damaged kidneys do not remove enough phosphorus from the blood. Phosphorus is an important mineral working hand in hand with calcium to maintain good bone health. Too much phosphorus can increase the workload of the kidney. Foods containing high phosphorus content such as dairy products, nuts, dried peas and beans may need to be limited or avoided. The patient's physician or dietitian can provide a list of these foods and suggest some acceptable substitutes. In some cases, limiting phosphorus in food is not enough. A physician may prescribe certain phosphorus-binding medications. Phosphorus binders are medications taken with meals, which bind onto the phosphorus and prevent it from being absorbed.

Sodium
It may be a good idea to control salt or sodium intake. Sodium-restricted diets can help to control blood pressure and prevent retaining fluid. Avoiding the salt shaker, cured and processed foods, convenience foods and condiments containing sodium can greatly reduce sodium intake. When following a restricted diet it can be difficult to take in all of the necessary nutrients, calories, vitamins and minerals. A patient's physician may choose to prescribe an appropriate renal multivitamin/mineral preparation to supplement the diet.

Ultimately, those who become diabetes and high blood pressure patients will also become possible candidates for end stage renal disease, heart disease, stroke and other problems, if they don't take care of themselves. Don't add yourself to the growing number of individuals who are suffering from these chronic diseases. The most important objective for diabetic/hypertensive patients is to comply with their specialized dietary regimens and take their medication regularly to prevent kidney failure. Kidney failure can be a slow, progressive deterioration of kidney function. Do not take your disease process for granted--prevent ESRD.

PHOTO (COLOR): Experts now say that 10-15 percent of American school children suffer from high blood pressure, mostly due to obesity and high salt intake.

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By Brian Brooks, R.D.

Brian Brooks is a registered dietitian at Gambro Healthcare's Saddleback Clinic in Laguna Hills, California, where nearly 150 patients with ESRD undergo dialysis treatment regularly. Gambro Healthcare is one of the largest dialysis providers in the United States, with 530 clinics that provide dialysis treatments to about 40,000 patients each year.

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