NUTRITIONAL PREVENTION OF GALLSTONS
Introduction:
Bile serves two purposes:
Making dietary lipids more digestible
excreting cholesterol and other unwanted
materials from the body.
Bile is formed in the
liver from bile acids, bilirubin, cholesterol, minerals, water,
and phospholipids such as
phosphatidylcholine or lecithin .Once formed, bile is transported to the gallbladder, where it is concentrated and
stored until needed
A fatty meal
stimulates gallbladder contraction and
bile flow into the small intestine where it combines with food to emulsify the
fatty elements. It also enables digestive enzymes to break fats down into their
components.
Under normal circumstances, bile components remain in
solution as a liquid. But when bile becomes cholesterol-heavy, the cholesterol
may crystallize and start to form a stone. Gallstones are round or oval, smooth
or faceted lumps of solid matter found in the gallbladder .Most gallstones are
composed mainly ( about 85% ) of crystallized cholesterol with small proportion
of calcium carbonate, palmitate and phosphate. Cholesterol, which is excreted into
the bile would be completely insoluble in an aqueous fluid like bile if were
not kept in micelle microemulsion by the combined detergent action of the bile
salts phospholipids (chiefly lecithin) in bile.
Gallstones are more likely to
form if:
there is an
imbalance among the bile components
What is the cause of gallstone?
The pathophysiology of cholesterol gallstone formation
is complex because it is multifactorial
disease where both environmental and genetic factors play an important role.
several studies have evaluated the role of diet as a potential risk factor
for gallstone formation, including energy intake, cholesterol, fatty acids,
fiber, carbohydrates, vitamins and minerals, and alcohol intake . Formation
of pure cholesterol stones is initiated by an excessive intake of highly
purified carbohydrates, a large intake of animal fats and a restricted intake
of vegetable fibers. When the protein content of diet was reduced, mixed or
combined stones were formed
Who is at risk?
1-Sex:
The frequency of gallstones is two to four times greater in
women than in men. Why?
a-Women are predisposed to gallstones because of either
increased cholesterol synthesis or suppression of bile acids by estrogens,
estrogen stimulates the liver to remove more cholesterol from blood and
divert it into the bile..
b-Pregnancy increases the risk for
gallstones, because of elevated estrogen level .And higher serum progesterone
levels impair gallbladder motility .
c-Oral contraceptive , also elevate estrogen level.
d-Hormone Replacement Therapy. Several large
studies have shown that use of hormone replacement therapy (HRT) doubles or
triples the risk for gallstones or gallbladder surgery.
2-Age : The risk
increases with age, people over 60 face the highest risk, as people age, the
body tends to secrete more cholesterol into bile.
Risks in Children :Gallstone disease is rare in
children. When gallstones occur in this age group they are more likely to be
pigment stones. Girls do not seem to be more at risk than boys are. The
following condition may put children at higher risk:
Spinal injury.
History of abdominal surgery.
Sickle-cell anemia.
Impaired immune system.
Intravenous nutrition.
3- Ethnicity
the incidence of gallstones varies widely among nations and
regions. For example, Hispanics and Northern Europeans have a higher risk for
gallstones than people of Asian and African descent do. Such cases are most
likely due to a combination of genetic and dietary factors.
4-Personal history: people who
have previously developed gallstones are more likely to develop them again .
5-Genetics
Having a family member or close relative with gallstones may
increase the risk of gallstones. Up to a third of cases of painful gallstones
may be related to genetic factors, although the genetics of gallbladder disease
remains poorly understood. Many genes may be involved, including those that
lead to obesity or other risk factors that predispose to gallstones.
6-Diabetes
People with diabetes are at higher risk for gallstones
because those patients have high levels of fatty acids (triglycerides) .
7-Obesity and Weight Changes
Obesity. is a significant risk factor for gallstones. In such
cases, the liver over-produces cholesterol, which is delivered into the bile
and causes it to become supersaturated.
Weight Cycling. Rapid weight loss or cycling
(dieting and then putting back weight) increases cholesterol production in the
liver, with resulting super saturation and risk for gallstones. A 2000 study
suggested the following rates for gallstones related to extreme and rapid
weight loss:
The risk for gallstones is as
high as 12% after eight to 16 weeks of restricted calorie diets.
The risk is more than 30% within
a year to 18 months after gastric by-pass surgery.
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About one-third of gallstone
cases in these situations are symptomatic. The risk for gallstones is highest
in the following dieters:
Those who lose more than 24% of
their initial body weight.
Those who lose more than 1.5 kg
(3.3. lb.) a week.
Those on very low-fat,
low-calorie diets. Weight cycling also puts people at
risk for gallstones. For example, a 16-year study found that the risk for
gallstone surgery was 68% higher for women who lost and then regained more than
20 pounds at least once than in women whose weight remained stable. Also there
are common prescription weight-loss drug may increase gallstone risk
8-Low HDL Cholesterol and High Triglycerides and Their
Treatment
. Gallstone formation, is associated with low HDL cholesterol
levels and high triglyceride levels. Some evidence suggests that high
triglyceride levels may impair emptying actions of the gallbladder.
Unfortunately some fibrates, drugs used to correct these
conditions, increase the risk for gallstones by increasing the
amount of cholesterol secreted into the bile. They include gemfibrozil (Lopid),
fenofibrate (Tricor), and bezafibrate (Bezalip). (Other cholesterol-lowering
agents do not have this effect at all.) .
9-Other Risk Factors
Prolonged Intravenous Feeding. reduces the
flow of bile and increases the risk for gallstones.
Crohns Disease. inflammatory bowel disorder,
leads to poor reabsorption of bile salts from the digestive tract and increases
the risk of gallbladder disease. Patients over 60 and those who have had
numerous bowel surgeries are at especially high risk.
Cirrhosis. Make a major risk for
gallstones, particularly pigment gallstones.
Organ Transplantation. Bone marrow or solid organ
transplantation increases the risk.
Medications. Octreotide (Sandostatin) poses
a risk for gallstones.
Blood Disorders. Chronic
hemolytic anemia, including sickle cell anemia, increases the risk for pigment
gallstone by causing excess bilirubin in bile .
Signs and symptoms of gallstones:
Gallstones that do not cause
symptoms are called silent gallstones .Most people are asymptomatic , some
people experience symptoms that occur suddenly, which is known as gallstone
attack. The most common symptoms of an attack is biliary colic. This pain in
the upper abdomen lasts from 30 minutes to several hours. Pain can be felt in
the back between the shoulder blades or under the right shoulder. Biliary colic
is caused by the gallbladder contracting in response to a fatty meal, which
causes the gallstones to press against and block the cystic duct opening.
Attacks occur at night. Other symptoms of an attack may include: nausea or
vomiting , abdominal bloating or gas , belching , indigestion. Gallstones that
move into and block one of the ducts require immediate medical attention .
these blockage can cause inflammation of the gallbladder( acute cholecystitis)
or the pancreas (pancreatitis).
How can you prevent gallstone formation ?
Do not over-eat .
Diet high in fiber - lots of
vegetables
Avoid refined carbohydrates
(including sugar and white flour)
Omega 3 oils and other
polyunsaturated fats
Avoid saturated and trans fats
Eat moderate amounts of lean
meats
Drink at least 6-8 glasses of
water per day
Exercise
Lose excess weight but slowly
Supplemental bile salts and bile
thinning agents as found in the gallbladder products.
Lifestyle
changes that may be helpful
Maintaining an ideal body weight
is vital for preventing gallstones.
Some evidence suggests that, in
addition to controlling weight, exercise helps reduce cholesterol levels in the
biliary tract, which could help prevent gallstones.
What You Should Eat & Why.
fiber, insoluble :
A high-fiber
diet helps spare the gallbladder. Reducing the risk of gallstones by eating a
diet high in fiber, particularly the "insoluble" type found in
whole-wheat products and corn bran, figs, brown rice, fresh peas, prunes, nuts
and edible skin of fruits and vegetables including tomatoes, cucumbers, apples,
berries and pears.
How do foods rich in insoluble fiber
help prevent gallstones?
Researchers think
insoluble fiber speeds intestinal transit time .Because individuals with chronic
constipation are at an increased risk for gallstone formation, insoluble fiber
may help to prevent gallstones by promoting regularity. Wheat bran, commonly
used to relieve constipation when combined with fluid, has been reported to
reduce the relative amount of cholesterol in bile of a small group of people
whose bile contained excessive cholesterol (a risk factor for gallstone
formation). The same effect has been reported in people who already have
gallstones. Also, insoluble fiber increases insulin sensitivity and lowers
triglycerides
Soluble fiber:
Soluble fiber, particularly pectin, may be helpful in
preventing and dissolving gallstones. Psyllium, an excellent source of soluble
fiber, binds to the cholesterol in bile and can help prevent gallstone
formation. In addition, psyllium will help prevent constipation. Dietary fiber
appears to deter the synthesis and absorption of secondary bile acids (SBAs),
which are unhealthy bile metabolites that form in the intestinal tract. Certain
SBAs have been linked with increased cholesterol saturation of bile and thus
gallstone formation. Fiber not only allows less time for SBAs to form in the
gut by improving intestinal motility, it may also bind SBAs and escort them out
of the body. Population research has confirmed that low-fiber diets predispose
toward gallstone formation.
Leading Food Sources of fiber, soluble: Carrots, Peas, , Beans,
Oats, Barley, Apples
. Beans provide insoluble as well as soluble fiber .
folic acid
Considered a lipotropic factor, folic acid is believed to accelerate the
removal of fat from the liver by influencing the metabolism of fat.
Leading Food Sources of folic acid: Asparagus, Broccoli, Avocados,
Soybeans, Lentils, Oranges, Peas, Cabbage, Spinach,
Beans.
omega-3 fatty acids
Animal studies have shown that a diet rich in omega-3 fatty acids can have a
protective effect against the development of gallstones.
Leading Food Sources of omega-3 fatty acids: Salmon, Tun.
Vitamin B12
Similar to folic acid, vitamin B12 is a lipotropic factor that reduces the risk
of gallstones by affecting lipid metabolism and accelerating fat removal from
the liver.
Leading Food Sources of vitamin B12: Beef, Tuna, Lamb,
Yogurt .
Antioxidant intake may, in fact,
be more important than other dietary considerations. A recent study suggests
micronutrients such as vitamins and minerals may play a more important role in
the development of gallstones than macronutrients such as carbohydrates and
fats. Researchers found that subjects with a lower antioxidant intake
especially of vitamin E, manganese had a greater incidence of gallbladder
disease. The researchers theorize that oxidant stress within the liver leads to
unfavorable changes in bile composition that promote precipitation of both
cholesterol and bilirubin (thus favoring the formation of both cholesterol and
pigment stones).
vitamin C
Vitamin C appears to lower the amount of cholesterol in bile, making secretions
from the liver less likely to clump together and form stones. It is needed to
convert cholesterol to bile acids. In theory, such a conversion should reduce
gallstone risks. One 2000 study, which confirmed some previous ones, reported
that women who have higher blood levels of vitamin C have a reduced risk of
gallstones. Vitamin C is involved in cholesterol metabolism and deficiency may
increase the risk of gallstones. Leading Food Sources of vitamin C: Cabbage,
Oranges, Peppers, Kiwi fruit, Strawberries .
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vitamin E
Like vitamin C, inadequate circulating levels of vitamin E have been linked to
the development of gallstones. This important vitamin reduces the likelihood of
stone formation by lowering levels of cholesterol in bile.
Leading Food Sources of vitamin E: Broccoli, Sunflower seeds,
Peanuts, Almonds, Mangoes, Avocados .
Coffee
increases bile flow
and therefore might reduce the risk of gallstones. In a large study of men,
those drinking two to three cups of regular coffee per day had a 40% lower risk
of gallstones compared with men who did not drink coffee. In the same report,
men drinking at least four cups per day had a 45% reduced risk. Caffeine
appears to be the protective ingredient, as decaffeinated coffee consumption
was not linked with any protection. A more recent study in 2000 did not find
any general protective effect, although women with gallstones who drank coffee
reported fewer symptoms than those who didn't.
Lecithin.
Lecithin is a key component of bile. It contains choline and
inositol-two compounds that are important for the breakdown of fat and
cholesterol. Low levels of lecithin may precipitate the formation of
cholesterol gallstones. Animal studies have suggested that lecithin-rich soy
and buckwheat protein may protect against gallstones. Dietary lecithin found in
eggs, soybeans, liver, wheat germ, and peanuts.
Energy Intake.
It has been directly associated to cholelithiasis risk,
mainly by contributing to development of obesity. Obesity is a well known risk
factor of gallstones primarily acting by increasing cholesterol synthesis,
biliary cholesterol secretion and cholesterol super saturation
Carbohydrates.
The effect of carbohydrates on gallstone disease has been evaluated in
several studies. In general terms, most of the studies revealed that
consumption of refined sugars is directly associated with gallbladder disease .
This finding was attributed to a higher synthesis of cholesterol in the liver secondary
to an increase in insulin secretion. carbohydrates may induce changes in
lipoprotein metabolism that induce modifications in the bile composition,
eating sugar is also related to elevated serum triglycerides level, which in
turn associated with cholesterol saturation of bile .
Dietary fats
monounsaturated fats (i.e., olive oil), which appear to play
a protective role. some animal experiments indicate that the omega-3 class of
polyunsaturated (i.e., flaxseed oil) may prevent gallstones.
Increasing consumption of unsaturated fats can make cell
walls more sensitive to insulin which, in turn, reduces gallstone formation.
Other studies have also shown that unsaturated fats tend to prevent gallstone
formation. A Greek study found that high consumption of olive oil reduced the
incidence of gallstones, and a study of Arabs in Gaza and Jews in Tel Aviv
found that the Arabs consumed more unsaturated fats and had a lower incidence
of gallstones. A high intake of polyunsaturated and monounsaturated fats in the
context of an energy-balanced diet is associated with a reduced risk for
gallstone disease.
Paradoxically, some studies have shown fats in the form of
cholesterol actually protect against stone formation in humans. In a more
recent population-based study, risk of gallstone formation decreased when
cholesterol consumption increased. The explanation for this paradox may be that
the liver synthesizes less cholesterol as dietary cholesterol increases.
Food allergies may have a connection to gallbladder symptoms. More recent research by
J.C. Breneman, M.D., a pioneer in food allergy research, found that allergy-elimination
diets dramatically improved gallbladder symptoms in 100 percent of his test
subjects. The foods most likely to cause symptoms were eggs, followed by pork,
onions, poultry, milk, oranges, corn, beans and nuts. Breneman postulated that
allergenic substances induce inflammation of the biliary ducts, causing pain
and possibly impairing bile flow.
Points to
Remember:
•
Gallstones form when bile
hardens in the gallbladder.
•
Gallstones are more common among
older adults; women; American Indians; Mexican Americans; people with diabetes;
those with a family history of gallstones; people who are overweight, obese, or
undergo rapid weight loss; and those taking cholesterol-lowering drugs.
•
Gallbladder attacks often occur
after eating a meal, especially one high in fat.
•
Gallstones can cause serious
problems if they become trapped in the bile ducts.
•
Laparoscopic surgery to remove
the gallbladder is the most common treatment.
•
Gallstones can be prevented by
changing lifestyle , and changing bad eating habit .
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