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Recurrence
of Kidney
Stones
The chance of having recurring stones are about
70-80 percent once a person suffers their first
stone attack. After the first kidney stone attack
occurs in a person they have a cumulative 10
percent chance per year of forming another stone
(if no other stones are present at the time of the
first stone attack). This translates into a 50%
chance over a 5 year period of time. Family genetic
tendencies can increase this risk.
The younger a
person is when they have their first kidney stone
attack the greater their personal risk of having
additional attacks. Those between the ages of 35
and 50 are in their peak stone formation
period.
Historically
about 60 percent of individuals who have
experienced one kidney stone will develop another
within 7 years. But whereas just a few years ago
recurrence of kidney stones was unavoidable, modern
medical science has made recurrent kidney stones a
preventable disease. With individualized medical
therapy recurrence can be prevented in more than 95
percent of suffers.
Chemical
Composition of Kidney
Stones
Knowing which one of the several types of chemical
composition has caused a suffer's kidney stone to
form will allow medical treatment to prevent that
particular type of stone and thereby prevent
recurrent kidney stone attacks. Therefore it is
very important to catch the stone - when and if it
is passed - so that it can be chemically
analyzed.
Most stones are
made up of calcium or a combination of calcium and
oxalate. These stones show up quite well on x-rays.
Calcium mineral combination stones cannot be
dissolved with any known medicine. However kidney
stones made up of uric acid are invisible to
x-rays, but can sometimes be dissolved with the
proper medications.
A series of nine
magnified PHOTOGRAPHS
of these various types of
stones
is available online from Herring Lab, the company
who analyzes more kidney stones than any other -
over 125,000 per year.
The southeastern
area of the United States is known as the Kidney
Stone Belt because of the relative high ratio of
people suffering from kidney stones in those
states. North Carolina (where this author, a fellow
kidney store sufferer happens to live) has more
kidney stone cases per capita than any other state.
Several factors probably come into play to create
this situation. One is the typical southern diet
which is high in green vegetables and brewed tea -
both of which are high in oxalates. The second is
the hot climate which causes increased amounts of
perspiration and loss of body fluid. And finally,
modern life styles often reduce physical
activity.
Together these
factors put people at high risk for kidney stones.
Oxalate from foods is usually present in urine. The
oxalate forms a salt with calcium that has a low
soluability factor (it does not dissolve
easily; it does precipitate into crystals
easily). Even mild chronic dehydration can increase
the likelihood of kidney stone formation.
Inactivity has been associated with increased
kidney stone formation: Russian astronauts in space
for long periods have developed kidney stones. Thus
a southerner with high levels of oxalate combined
with chronic dehydration and a sedentary life style
is more likely to suffer from their increased risk
of forming kidney stones.
Vitamin C and
Vitamin D increase the formation of oxalates during
the food digestion processes. (Not only do certain
foods contain oxalate, additional oxalates can be
formed as a byproduct of the natural metabolic
process.)
Preventing
Kidney Stone
Formation
The easiest step to take is to increase hydration.
This applies to sufferers of all types of kidney
stones. Drinking very large amounts of water -
two or more quarts per day - is probably the most
important step in reducing stone formation. It
is recommended that sufferers increase their urine
output to at least 2 quarts per 24 hour period.
Drinking 2 to 3 quarts per day may reduce
recurrence of stones by up to 90
percent.
Initially many kidney stone
sufferers may find it difficult to raise their
fluid intake to this level. However, with a
consistent conscious effort a person will develop a
taste for water. After about a month their body
will readjust its normal level of hydration. Once
this new norm has become established a person will
start to feel thirsty whenever their fluid intake
falls below this level. Some tips
on increasing fluid
intake may prove
helpful. One kidney stone sufferer says: I like
water now. You acquire a taste for
it.
High calcium in urine can be
caused by too much salt in a person's diet. Salt
causes excretion of larger amounts of calcium and
thus increases calcium in the urine. Increasing a
person's intake of water will reduce the relative
concentration of calcium in the urine and thus
reduce the risk of crystal formation and kidney
stone formation.
Additionally, persons prone to
the most common type of kidney stones (calcium
oxalate) may find it advisable to cut back on foods
with high oxalate levels such as those listed below
to help prevent future stone formation:
- apples
- asparagus
- beer
- beets
- berries, various
- black pepper
- broccoli
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- cheese
- chocolate
- cocoa
- coffee
- cola drinks
- collards
- figs
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- grapes
- ice cream
- milk
- oranges
- parsley
- peanut butter
- pineapples
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- spinach
- Swiss chard
- rhubarb
- tea
- turnips
- vitamin C
- yogurt
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Stone suffers should consult
with their doctor, of course, but in most cases,
these foods can be eaten in limited
amounts.
A diet with high
levels of sodium, sucrose, or animal protein
increase the likelihood of kidney stone formation.
Conversely, high levels of potassium, magnesium,
and fluids lower the likelihood of kidney stone
formation.
The Division of
Urology at the Toa Payon Hospital in Singapore
offers dietary
advice for kidney stone
patients
including both what to eat as well as what
not to eat. There are, also, medications
available to reduce the tendency towards formation
of certain types of stones.
One type of
medication to reduce risk of formation of calcium
oxalate stones introduces high levels of citrate
into the kidneys. This citrate in the urine reduces
the tendency for calcium oxalate stone formation. A
similar increase in urinary citrate is generated by
drinking lemonade (lemons are one of the
good foods) containing at least 4 ounces of
lemon juice per day.
It has been
discovered that avoiding calcium may do more
harm than good when it comes to kidney stone
sufferers who have, in the past, been warned to
avoid foods rich in calcium. According to a study
of over 45,000 men conducted by the Harvard School
of Public Health, men who get lots of calcium in
their diets have a one-third lower risk of having
kidney stones than do those who consume calcium
sparingly. It seems that high dietary calcium
actually blocks a chemical action which causes the
formation of kidney stones by binding with
oxalates (from foods) in the intestine which then
prevents both from being absorbed into the blood
stream and later transferred to the kidneys.
Urinary oxalate may be more important to formation
of calcium-oxalate kidney stone crystals than is
the urinary calcium.
However it must
be quickly noted here that calcium
supplements increase kidney stone
risks
according to the Annuals of Internal Medicine,
March 1997. High normal dietary calcium reduces
kidney stones by 35 percent, but high calcium from
non-foods - like calcium supplements - actually
increase the risk of kidney stones by 20
percent.
That same
Harvard study found that:
- Those with
the highest consumption of potassium, from
eating fruits and vegetables, had only half the
risk of stones;
- A high fluid
intake was associated with a 29 percent lower
risk; and
- Those who
ate the most animal protein had a 33 percent
higher risk of developing kidney
stones.
Winning the
battle with kidney stones is a two stage war. The
first hurdle - which is sometimes elected to be
skipped by doctors and patients - is to become
stone free to reduce later stone formation due to
the presence of those existing stone crystals. Then
the second hurdle is to eliminate (or at least
reduce) the risk factors that might lead to
formation of new kidney stones.
A review of the
information on kidney stones every 3 to 6 months
may be necessary to keep the benefits and
importance of constant and long term viligence at
the stone prevention process in the sufferer's
conscious mind. To assist your remembrance you can
be periodically alerted to updates to The Kidney
Stone WebSite by registering with the
NetMind
service
below.
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