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Diet closely tied to Diabetes, High Blood Pressure, Chronic Kidney Disease |
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by Brian Brooks, R.D.
Diet closely tied to Diabetes,
High Blood Pressure,
Chronic Kidney Disease
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 lose 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.
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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