High Cholesterol is also known as: Dyslipidemia,
Dyslipidemic Diet, Hypercholesterolemia, Hypercholesterolemic Diet,
Hyperlipoproteinemia.
Cholesterol is a lipid that is an important constituent of body cells and widely
distributed throughout the body. It is especially abundant in the brain, nervous
tissue, adrenal glands and skin. It is also found in egg yolk and gallstones. It
plays an important role in the body, being essential for the production of the
sex hormones, plus the repair of membranes. It is also the source from which
bile acids are manufactured. The total amount in the body of a man weighing 70
kilograms (10 stones) is around 140 grams, and the amount present in the blood
is 3-6 to 7.8 m.mol per litre or 150 to 250 milligrams per 100 millilitres.
A high blood-cholesterol level (over 6 m.mol per litre or 238 mg per 100 ml) is
undesirable as there may be a correlation between a high blood cholesterol and
atheroma, the form of arterial degenerative disease associated with coronary
thrombosis and high blood-pressure. This is well exemplified in diabetes
mellitus and hypothyroidism, two diseases in which there is high blood
cholesterol, sometimes going as high as 20 m.mol per litre; patients with these
diseases are particularly prone to arterial disease. There is also a familial
disease known as hypercholesterolemia, in which members of affected families
have a blood cholesterol of around 18 m.mol per litre, or more, and are
particularly liable to premature degenerative disease of the arteries.
Cholesterol exists in two forms in the blood: high-density lipoproteins (HDLS)
which are believed to protect against arterial disease, and a low-density
version (LDLS) and very low density type (VLDLs), these latter two being risk
factors.
The rising incidence of arterial disease in western countries in recent years
has drawn attention to this relationship between high levels of cholesterol in
the blood and arterial disease. The available evidence indicates that there is a
relationship between blood-cholesterol levels and the amount of fat consumed.
However, the blood-cholesterol level bears little relationship with the amount
of cholesterol consumed, most of the cholesterol in the body being produced by
the body itself.
On the other hand, diets high in saturated fatty acids, chiefly animal fats such
as red meat, butter and dripping, tend to raise the blood-cholesterol level;
while foods high in unsaturated fatty acids, chiefly vegetable products such as
olive and sunflower oils, and oily fish such as mackerel and herring, tend to
lower it. There is a tendency in Western society to eat too much animal fat, and
current health recommendations are for everyone to decrease saturated-fat
intake, increase unsaturated-fat intake, increase daily exercise, and avoid
obesity. This advice is particularly important for people with high
blood-cholesterol level, with diabetes mellitus, or a history of coronary
thrombosis.
Although it is by no means the only major risk factor, elevated serum
cholesterol is clearly associated with a high risk of heart disease. Most
doctors suggest cholesterol levels should stay under 200 mg/dl. Cholesterol
levels lower than 200 mg/dl are not without risk, however, as many people with
levels below 200 have heart attacks. As levels fall below 200, the risk of heart
disease continues to decline. Many doctors consider cholesterol levels of no
more than 180 to be optimal.
Medical laboratories now subdivide total cholesterol measurement into several
components, including LDL ("bad") cholesterol, which is directly linked to heart
disease, and HDL ("good") cholesterol, which is protective. The relative amount
of HDL to LDL is more important than total cholesterol. For example, it is
possible for someone with very high HDL to be at relatively low risk for heart
disease even with total cholesterol above 200. Evaluation of changes in
cholesterol requires consultation with a healthcare professional and should
include measurement of total serum cholesterol, as well as HDL and LDL
cholesterol.
The following discussion is limited to information about lowering serum
cholesterol levels using natural approaches. Because high cholesterol is linked
to atherosclerosis and heart disease, people concerned about heart disease
should also read the article on atherosclerosis.
What are the symptoms of high cholesterol? This condition does not produce
symptoms. Therefore, it is prudent to visit a health professional on a regular
basis to have cholesterol levels measured.
Conventional treatment options: People with high cholesterol are commonly
advised to reduce their consumption of dietary cholesterol and saturated fats.
In addition, cholesterol-lowering medications, such as bile acid sequestrants
(e.g., cholestyramine [Questranr] and colestipol [Colestidr]) and HMG-CoA
reductase inhibitors (e.g., atorvastatin [Lipitorr], cerivastatin [Baycolr],
fluvastatin [Lescolr], lovastatin [Mevacorr], pravastatin [Pravacholr], and
simvastatin [Zocorr]) are often prescribed. For women who have gone through
menopause, conventional treatment may also include hormone replacement therapy.
Dietary changes that may be helpful: Eating animal foods containing saturated
fat is linked to high cholesterol levels1 and heart disease.2 Significant
amounts of animal-based saturated fat are found in beef, pork, veal, poultry
(particularly in poultry skins and dark meat), cheese, butter, ice cream, and
all other forms of dairy products not labeled "fat free." Avoiding consumption
of these foods reduces cholesterol and has been reported to reverse even
existing heart disease.3
Unlike other dairy foods, skimmed milk, nonfat yogurt, and nonfat cheese are
essentially fat-free. Dairy products labeled "low fat" are not particularly low
in fat. A full 25% of calories in 2% milk come from fat. (The "2%" refers to the
fraction of volume filled by fat, not the more important percentage of calories
coming from fat.)
In addition to large amounts of saturated fat from animal-based foods, Americans
eat small amounts of saturated fat from coconut and palm oils. Palm oil has been
reported to elevate cholesterol.4 5 Research regarding coconut oil is mixed,
with some trials finding no link to heart disease,6 while other research reports
that coconut oil elevates cholesterol levels.7 8
Despite the links between saturated fat intake and serum cholesterol levels, not
every person responds to appropriate dietary changes with a drop in cholesterol.
A subgroup of people with elevated cholesterol who have what researchers call
"large LDL particles" has been reported to have no response even to dramatic
reductions in dietary fat.9 (LDL is the "bad" cholesterol most associated with
an increased risk of heart disease.) This phenomenon is not understood. People
who significantly reduce intake of animal fats for several months but do not see
significant a reduction in cholesterol levels should discuss other approaches to
lowering cholesterol with a doctor.
Yogurt, acidophilus milk, and kefir are fermented milk products that have been
reported to lower cholesterol in most,10 11 12 13 14 15 16 but not all,
double-blind and other controlled research.17 18 19 Until more is known, it
makes sense for people with elevated cholesterol who consume these foods, to
select nonfat varieties.
Eating fish has been reported to increase HDL cholesterol20 and is linked to a
reduced risk of heart disease in most,21 but not all, studies.22 Fish contains
very little saturated fat, and fish oil contains EPA and DHA, omega-3 fatty
acids that appear to protect against heart disease.23
Vegetarians have lower cholesterol24 and less heart disease25 than meat eaters,
in part because they avoid animal fat. Vegans (people who eat no meat, dairy, or
eggs) have the lowest cholesterol levels,26 and switching from a standard diet
to a vegan diet, along with other lifestyle changes, has been reported to
reverse heart disease in controlled research.27 28
Dietary cholesterol
Most dietary cholesterol comes from egg yolks. Eating eggs has increased serum
cholesterol in most studies.29 However, eating eggs does not increase serum
cholesterol as much as eating foods high in saturated fat, and eating eggs may
not increase serum cholesterol at all if the overall diet is low in fat.30
Egg consumption does not appear to be totally safe, however, even for people
consuming a low-fat diet. When cholesterol from eggs is cooked or exposed to
air, it oxidizes. Oxidized cholesterol is linked to increased risk of heart
disease.31 Eating eggs also makes LDL cholesterol more susceptible to damage, a
change linked to heart disease.32
Whether or not egg eaters are more likely to die from heart disease is a matter
of controversy. In one preliminary study, egg eaters had a higher death rate
from heart disease, even when serum cholesterol levels were not elevated.33
However, another preliminary study found no evidence of an overall significant
association between egg consumption, and risk of heart disease or stroke, except
in people with diabetes.34 Until more is known, limiting egg consumption may be
a good idea, particularly for people with existing heart disease or diabetes.
Fiber
Soluble fiber from beans,35 oats,36 psyllium seed,37 glucomannan, and fruit
pectin38 has lowered cholesterol levels in most trials.39 40 Doctors often
recommend that people with elevated cholesterol eat more of these high-soluble
fiber foods. However, even grain fiber (which contains insoluble fiber and does
not lower cholesterol) has been linked to protection against heart disease,
though the reason for the protection remains unclear.41 It makes sense for
people wishing to lower their cholesterol levels and reduce the risk of heart
disease to consume more fiber of all types. Some trials have used 20 grams of
additional fiber per day for several months to successfully lower cholesterol.42
Oat bran is rich in a soluble fiber called beta-glucan. In 1997, the U.S. Food
and Drug Administration passed a unique ruling that allowed oat bran to be
registered as the first cholesterol-reducing food at an amount providing 3 grams
of beta-glucan per day, although some evidence suggests this level may not be
high enough to make a significant difference.43 Several double-blind and other
controlled trials have shown that oat bran44 45 46 and oat milk47
supplementation may significantly lower cholesterol levels in people with
elevated cholesterol, but only weakly lowers them in people with healthy
cholesterol levels.48
Flaxseed, another good source of soluble fiber, has been reported to lower total
and LDL cholesterol in preliminary studies.49 50 A double-blind trial found that
while both flaxseed and sunflower seed lowered total cholesterol, only flaxseed
significantly lowered LDL.51 Amounts of flaxseed used in these trials typically
range from 30-50 grams per day. A controlled trial found that partially defatted
flaxseed, containing 20 grams of fiber per day, significantly lowered LDL
cholesterol, suggesting that at least one of the cholesterol-lowering components
in flaxseed is likely to be the fiber in this product, as opposed to the oil
removed from it.52 Controlled trials of flaxseed oil alone have shown
inconsistent effects on blood cholesterol.53 54 55
Alpha-linolenic acid
Doctors and researchers are interested in alpha-linolenic acid (ALA)-the special
omega-3 fatty acid found in large amounts in flaxseeds and flaxseed oil. ALA is
a precursor to EPA, a fatty acid from fish oil that is believed to protect
against heart disease. To a limited extent, ALA converts to EPA within the
body.56 However, unlike EPA, ALA does not lower triglyceride levels (a risk
factor for heart disease).57
Preliminary research on the effects of ALA from flaxseed has produced
conflicting results. For example, ALA has improved parameters of arterial health
that should protect people from heart disease, yet ALA may cause damage to LDL
cholesterol.58 Such damage is believed to be a precursor to heart disease.
In 1994, researchers conducted a study in people with a history of heart
disease, using what they called the "Mediterranean" diet.59 The diet was
significantly different from what people from Mediterranean countries actually
eat, in that it contained little olive oil. Instead, the diet included a special
margarine high in ALA. Those people assigned to the "Mediterranean" diet had a
remarkable 70% reduced risk of dying from heart disease compared with the
control group during the first 27 months. Similar results were also confirmed
after almost four years.60 Although cholesterol levels fell only modestly in the
"Mediterranean" diet group, the positive results suggest that people with
elevated cholesterol attempting to reduce the risk of heart disease should
consider such a diet. The diet was high in beans and peas, fish, fruit,
vegetables, bread, and cereals; and low in meat, dairy fat, and eggs. Although
the authors believe that the high ALA content of the diet was partially
responsible for the surprising outcome, other aspects of the diet may have been
partly or even totally responsible for decreased death rates. Therefore, the
success of the "Mediterranean" diet does not prove that ALA protects against
heart disease.61
Soy
Tofu, tempeh, miso, and some protein powders in health food stores, are derived
from soybeans. In 1995, an analysis of many trials proved that soy reduces both
total and LDL cholesterol.62 Since then, other double-blind and other controlled
trials have confirmed these findings.63 64 65 66 Trials showing statistically
significant reductions in cholesterol have generally used more than 30 grams per
day of soy protein. However, if soy replaces animal protein in the diet, as
little as 20 grams per day has been shown to significantly reduce both total and
LDL cholesterol.67 Isoflavones found in soy beans appear to be key
cholesterol-lowering ingredients of the bean,68 69 but animal research suggests
other components of soy are also important.70 71
Sugar
Eating sugar has been reported to reduce protective HDL cholesterol72 and
increases other risk factors linked to heart disease.73 However, higher sugar
intake has been associated with only slightly higher risks of heart disease in
most reports.74 Although the exact relationship between sugar and heart disease
remains somewhat unclear, many doctors recommend that people with high
cholesterol reduce their sugar intake.
Coffee
Drinking boiled or French press coffee increases cholesterol levels.75 Modern
paper coffee filters trap the offending chemicals and keep them from entering
the cup. Therefore, drinking paper-filtered coffee does not increase cholesterol
levels.76 77 Espresso coffee has amounts of the offending chemicals midway
between those of other unfiltered coffees and paper-filtered coffee,78 but there
is little research investigating the effect of espresso on cholesterol levels,
and studies to date have produced conflicting results.79 80 The effects of
decaffeinated coffee on cholesterol levels remain in debate.81
Alcohol
Moderate drinking (one to two drinks per day) increases protective HDL
cholesterol.82 This effect happens equally with different kinds of
alcohol-containing beverages.83 84 Alcohol also acts as a blood thinner,85 an
effect that should lower heart disease. However, alcohol consumption may cause
liver disease (e.g., cirrhosis), cancer, high blood pressure, alcoholism, and,
at high intake, an increased risk of heart disease. As a result, some doctors
never recommend alcohol, even for people with high cholesterol. Nevertheless,
those who have one to two drinks per day appear to live longer86 and are clearly
less likely to have heart disease.87 Therefore, some people at very high risk of
heart disease-those who are not alcoholics, who have healthy livers and normal
blood pressure, and who are not at high risk for cancer, particularly breast
cancer-are likely to receive more benefit than harm, from light drinking.
Olive oil
Olive oil lowers LDL cholesterol,88 89 especially when the olive oil replaces
saturated fat in the diet.90 People from countries that use significant amounts
of olive oil appear to be at low risk for heart disease.91 A double-blind trial
showed that a diet high in monounsaturated fatty acids from olive oil, lowers
cardiovascular disease risk by 25%, as compared with a 12% decrease from a
low-fat (25% fat) diet.92 The trial also found that low-fat diets decrease HDL
cholesterol by 4%, which is undesirable, since HDL cholesterol is protective
against heart disease. Diets high in monounsaturated fatty acids from olive oil
do not adversely affect HDL levels. Although olive oil is clearly safe for
people with elevated cholesterol, it is, like any fat or oil, high in calories,
so people who are overweight should limit its use.
Trans fatty acids and margarine
Trans fatty acids (TFAs) are found in many processed foods containing partially
hydrogenated oils. The highest levels occur in margarine. Margarine consumption
is linked to increased risk of unfavorable changes in cholesterol levels93 and
heart disease.94 Margarine and other processed foods containing partially
hydrogenated oils should be avoided.
However, special therapeutic margarines are now available that contain
substances, called phytostanols, that block the absorption of cholesterol.95 The
FDA has approved some of these margarines as legitimate therapeutic agents for
lowering blood cholesterol levels. The best-known of these products is BenecolT.
The cholesterol-lowering effect of these margarines has been demonstrated in
numerous double-blind and other controlled trials.96 97 98 99 100 101 102
Garlic
Garlic is available as a food, as a spice in powder form, and as a supplement.
Eating garlic has helped to lower cholesterol in some research,103 though
several double-blind trials have not found garlic supplements to be thusly
effective.104 105 106 Although some of the negative reports have been
criticized,107 the relationship between garlic and cholesterol lowering remains
unproven.108 However, garlic is known to act as a blood thinner109 and may
reduce other risk factors for heart disease.110 For these reasons, some doctors
recommend eating garlic as food, taking 900 mg of garlic powder from capsules,
or using a tincture of 2 to 4 ml, taken three times daily.
Nuts
Preliminary research consistently shows that people who eat nuts frequently have
a dramatically reduced risk of heart disease.111 112 This apparent beneficial
effect is at least partially explained by preliminary and controlled research
demonstrating that nut consumption lowers cholesterol levels.113 114 Of nuts
commonly consumed, almonds115 116 and walnuts117 118 119 may be most effective
at lowering cholesterol. Macadamia nuts have been less beneficial in most
studies,120 121 122 although one controlled trial found a cholesterol-lowering
effect from macadamia nuts.123 Hazelnuts124 and pistachio nuts125 have also been
reported to help lower cholesterol.
Nuts contain many factors that could be responsible for protection against heart
disease, including fiber, vitamin E, alpha-linolenic acid (found primarily in
walnuts), oleic acid, magnesium, potassium, and arginine. Therefore, exactly how
nuts lower cholesterol or lower the risk of heart disease remains somewhat
unclear. Some doctors even believe that nuts may not be directly protective;
rather, people busy eating nuts will not simultaneously be eating eggs, dairy,
or trans fatty acids from margarine and processed food, the avoidance of which
would reduce cholesterol levels and the risk of heart disease.126 127
Nonetheless, the remarkable consistency of research outcomes strongly suggests
that nuts do help protect against heart disease. Although nuts are loaded with
calories, a preliminary trial surprisingly reported that adding hundreds of
calories per day from nuts for six months did not increase body weight in
humans128 -an outcome supported by other reports.129 Even when increasing nut
consumption has led to weight gain, the amount of added weight has been
remarkably less than would be expected, given the number of calories added to
the diet.130 Given the number of calories per ounce of nuts, scientists do not
understand why moderate nut consumption apparently has so little effect on body
weight.
Number and size of meals
When people eat a number of small meals, serum cholesterol levels fall compared
with the effect of eating the same food in three big meals.131 132 People with
elevated cholesterol levels should probably avoid very large meals and eat more
frequent, smaller meals.
Lifestyle changes that may be helpful: Exercise increases protective HDL
cholesterol,133 an effect that occurs even from walking.134 Total and LDL
cholesterol are typically lowered by exercise, especially when weight-loss also
occurs.135 Exercisers have a relatively low risk of heart disease.136 However,
people over 40 years of age, or who have heart disease, should talk with their
doctor before starting an exercise program; overdoing it may actually trigger
heart attacks.137
Obesity increases the risk of heart disease,138 in part because weight gain
lowers HDL cholesterol.139 Weight loss reduces the body's ability to make
cholesterol, increases HDL levels, and reduces triglycerides (another risk
factor for heart disease).140 141 Weight loss also leads to a decrease in blood
pressure, which reduces the risk of heart disease in people with high blood
pressure.
Smoking is linked to a lowered level of HDL cholesterol142 and is also known to
cause heart disease.143 Quitting smoking reduces the risk of having a heart
attack.144
The combination of feelings of hostility, stress, and time urgency is called
type A behavior. Men,145 146 but not women,147 with these traits are at high
risk for heart disease in most, but not all, studies.148 Stress149 or type A
behavior150 may elevate cholesterol in men. Reducing stress and feelings of
hostility has reduced the risk of heart disease.151
Nutritional supplements that may be helpful: Glucomannan is a water-soluble
dietary fiber that is derived from konjac root. Controlled152 153 and
double-blind154 155 trials have shown that supplementation with glucomannan
significantly reduced total blood cholesterol, LDL cholesterol, and
triglycerides, and in some cases raised HDL cholesterol. Effective amounts of
glucomannan for lowering blood cholesterol have been 4 to 13 grams per day.
The combined results of nine double-blind trials indicate that supplementation
with beta-hydroxy-beta-methylbutyrate (HMB) effectively lowers total and LDL
cholesterol.156 All trials used 3 grams per day, taken for three to eight weeks.
Vitamin C appears to protect LDL cholesterol from damage.157 In some clinical
trials, cholesterol levels have fallen when people with elevated cholesterol
supplement with vitamin C.158 Some studies report that decreases in total
cholesterol occur specifically in LDL cholesterol.159 Doctors sometimes
recommend 1 gram per day of vitamin C. A review of the disparate research
concerning vitamin C and heart disease, however, has suggested that most
protection against heart disease from vitamin C, is likely to occur with as
little as 100 mg per day.160
Pantethine, a byproduct of vitamin B5 (pantothenic acid), may help reduce the
amount of cholesterol made by the body. Several preliminary161 162 163 164 165
and two controlled166 167 trials have found that pantethine (300 mg taken two to
four times per day) significantly lowers serum cholesterol levels and may also
increase HDL. However, one double-blind trial in people whose high blood
cholesterol did not change with diet and drug therapy, found that pantethine was
also not effective.168 Common pantothenic acid has not been reported to have any
effect on high blood cholesterol.
Chromium supplementation has reduced total cholesterol,169 170 LDL
cholesterol171 172 and increased HDL cholesterol173 174 in double-blind and
other controlled trials, although other trials have not found these effects.175
176 One double-blind trial found that high amounts of chromium (500 mcg per day)
in combination with daily exercise was highly effective, producing nearly a 20%
decrease in total cholesterol levels in just 13 weeks.177
Brewer's yeast, which contains readily absorbable and biologically active
chromium, has also lowered serum cholesterol.178 People with higher blood levels
of chromium appear to be at lower risk for heart disease.179 A reasonable and
safe intake of supplemental chromium is 200 mcg per day. People wishing to use
brewer's yeast as a source of chromium should look for products specifically
labeled "from the brewing process" or "brewer's yeast," since most yeast found
in health food stores is not brewer's yeast, and does not contain chromium.
Optimally, true brewer's yeast contains up to 60 mcg of chromium per tablespoon,
and a reasonable intake is 2 tablespoons per day.
High amounts (several grams per day) of niacin, a form of vitamin B3, lower
cholesterol, an effect recognized in the approval of niacin as a prescription
medication for high cholesterol.180 The other common form of vitamin
B3-niacinamide-does not affect cholesterol levels. Some niacin preparations have
raised HDL cholesterol better than certain prescription drugs.181 Some
cardiologists prescribe 3 grams of niacin per day or even higher amounts for
people with high cholesterol levels. At such intakes, acute symptoms (flushing,
headache, stomachache) and chronic symptoms (liver damage, diabetes, gastritis,
eye damage, possibly gout) of toxicity may be severe. Many people are not able
to continue taking these levels of niacin due to discomfort or danger to their
health. Therefore, high intakes of niacin must only be taken under the
supervision of a doctor.
Symptoms caused by niacin supplements, such as flushing, have been reduced with
sustained-release (also called "time-release") niacin products. However,
sustained-release forms of niacin have caused significant liver toxicity and,
though rarely, liver failure.182 183 184 185 186 One partial time-release
(intermediate-release) niacin product has lowered LDL cholesterol and raised HDL
cholesterol without flushing, and it also has acted without the liver function
abnormalities typically associated with sustained-release niacin
formulations.187 However, this form of niacin is available by prescription only.
In an attempt to avoid the side effects of niacin, alternative health
practitioners increasingly use inositol hexaniacinate, recommending 500 to 1,000
mg, taken three times per day, instead of niacin.188 189 This special form of
niacin has been reported to lower serum cholesterol but so far has not been
found to cause significant toxicity.190 Unfortunately, compared with niacin, far
fewer investigations have studied the possible positive or negative effects of
inositol hexaniacinate. As a result, people using inositol hexaniacinate should
not take it without the supervision of a doctor, who will evaluate whether it is
helpful (by measuring cholesterol levels) and will make sure that toxicity is
not occurring (by measuring liver enzymes, uric acid and glucose levels, and by
taking medical history and doing physical examinations).
Soy supplementation has been shown to lower cholesterol in humans.191 Soy is
available in foods such as tofu, miso, and tempeh and as a supplemental protein
powder. Soy contains isoflavones, naturally occurring plant components that are
believed to be soy's main cholesterol-lowering ingredients. A controlled trial
showed that soy preparations containing high amounts of isoflavones effectively
lowered total cholesterol and LDL ("bad") cholesterol, whereas low-isoflavone
preparations (less than 27 mg per day) did not.192 However, supplementation with
either soy193 or non-soy isoflavones (from red clover)194 in pill form failed to
reduce cholesterol levels in a group of healthy volunteers, suggesting that
isoflavone may not be responsible for the cholesterol-lowering effects of soy.
Further trials of isoflavone supplements in people with elevated cholesterol,
are needed to resolve these conflicting results.
Soy contains phytosterols. One such molecule, beta-sitosterol, is available as a
supplement. Beta-sitosterol alone, and in combination with similar plant
sterols, has been shown to reduce blood levels of cholesterol in preliminary195
and controlled196 trials. This effect may occur because beta-sitosterol blocks
absorption of cholesterol.197 In studying the effects of 0.8, 1.6, and 3.2 grams
of plant sterols per day, one double-blind trial found that higher intake of
sterols tended to result in greater reduction in cholesterol, though the
differences between the effects of these three amounts were not statistically
significant.198
A synthetic molecule related to beta-sitosterol, sitostanol, is now available in
a special margarine and has also been shown to lower cholesterol levels. In one
controlled trial, supplementation with 1.7 grams per day of a plant-sterol
product containing mostly sitostanol, combined with dietary changes, led to a
dramatic 24% drop in LDL ("bad") cholesterol compared with only a 9% decrease in
the diet-only part of the trial.199 Other controlled and double-blind trials
have confirmed these results.200 201 202 203 204 A review of double-blind trials
on sitostanol found that a reduction in the risk of heart disease of about 25%
may be expected from use of sitostanol-containing spreads, a larger clinical
effect than that produced by people reducing their saturated fat intake.205
Tocotrienols, a group of food-derived compounds that resemble vitamin E, may
lower blood levels of cholesterol, but evidence is conflicting. Although
tocotrienols inhibited cholesterol synthesis in test-tube studies,206 207 human
trials have produced contradictory results. Two double-blind trials found that
200 mg per day of either gamma-tocotrienol208 or total tocotrienols209 were more
effective than placebo, reducing cholesterol levels by 13-15%. However, in
another double-blind trial, 200 mg of tocotrienols per day failed to lower
cholesterol levels,210 and a fourth double-blind trial found 140 mg of
tocotrienols and 80 mg of vitamin E (d-alpha-tocopherol) daily resulted in no
changes in total cholesterol, LDL cholesterol, or HDL cholesterol levels.211
Deficiency of the trace mineral, copper, has been linked to high blood
cholesterol.212 213 In a controlled trial, daily supplementation with 3 to 4 mg
of copper for eight weeks decreased blood levels of total cholesterol and LDL
cholesterol, in a group of people over 50 years of age.214
Beta-glucan is a type of soluble fiber molecule derived from the cell wall of
baker's yeast, oats and barley, and many medicinal mushrooms, such as maitake.
Beta-glucan is the key factor for the cholesterol-lowering effect of oat
bran.215 216 217 218 As with other soluble-fiber components, the binding of
cholesterol (and bile acids) by beta-glucan and the resulting elimination of
these substances in the feces is very helpful for reducing blood cholesterol.219
220 221 Results from a number of double-blind trials with either oat- or
yeast-derived beta-glucan indicate typical reductions, after at least four weeks
of use, of approximately 10% for total cholesterol and 8% for LDL ("bad")
cholesterol, with elevations in HDL ("good") cholesterol ranging from zero to
16%.222 223 224 225 226 For lowering cholesterol levels, the amount of
beta-glucan used has ranged from 2,900 to 15,000 mg per day.
Some preliminary227 and double-blind228 229 trials have shown that supplemental
calcium reduces cholesterol levels. Possibly the calcium is binding with and
preventing the absorption of dietary fat.230 However, other research has found
no substantial or statistically significant effects of calcium supplementation
on total cholesterol or HDL ("good") cholesterol.231 Reasonable supplemental
levels are 800 to 1,000 mg per day.
In one double-blind trial,232 vitamin E increased protective HDL cholesterol,
but several other trials,233 234 235 found no effect of vitamin E. However,
vitamin E is known to protect LDL cholesterol from damage.236 Most cardiologists
believe that only damaged LDL increases the risk of heart disease. Studies of
the ability of vitamin E supplements to prevent heart disease have produced
conflicting results,237 but many doctors continue to recommend that everyone
supplement 400 IU of vitamin E per day to lessen the risk of having a heart
attack.
L-carnitine is needed by heart muscle to utilize fat for energy. Some,238 239
but not all, preliminary trials report that carnitine reduces serum
cholesterol.240 HDL cholesterol has also increased in response to carnitine
supplementation.241 242 People have been reported in controlled research to
stand a greater chance of surviving a heart attack if they are given L-carnitine
supplements.243 Most trials have used 1 to 4 grams of carnitine per day.
Magnesium is needed by the heart to function properly. Although the mechanism is
unclear, magnesium supplements (430 mg per day) lowered cholesterol in a
preliminary trial.244 Another preliminary study reported that magnesium
deficiency is associated with a low HDL cholesterol level.245 Intravenous
magnesium has reduced death following heart attacks in some, but not all,
clinical trials.246 Though these outcomes would suggest that people with high
cholesterol levels should take magnesium supplements, an isolated double-blind
trial reported that people with a history of heart disease assigned to magnesium
supplementation experienced an increased number of heart attacks.247 More
information is necessary before the scientific community can clearly evaluate
the role magnesium should play for people with elevated cholesterol.
Chondroitin sulfate has lowered serum cholesterol levels in preliminary
trials.248 249 Years ago, this supplement dramatically reduced the risk of heart
attacks in a controlled, six-year follow-up of people with heart disease.250 The
few doctors aware of these older clinical trials sometimes tell people with a
history of heart disease or elevated cholesterol levels, to take approximately
500 mg of chondroitin sulfate three times per day.
Although lecithin has been reported to increase HDL cholesterol and lower LDL
cholesterol,251 a review of the research found that the positive effect of
lecithin was likely due to the polyunsaturated fat content of the lecithin.252
If this is so, it would make more sense to use inexpensive vegetable oil, rather
than take lecithin supplements. However, an animal study found a
cholesterol-lowering effect of lecithin independent of its polyunsaturate
content.253 A double-blind trial found that 20 grams of soy lecithin per day for
four weeks had no significant effect on total cholesterol, LDL cholesterol, HDL
cholesterol, or triglycerides.254 Whether taking lecithin supplements is a
useful way to lower cholesterol in people with elevated cholesterol levels
remains unclear.
The fiber-like supplement chitosan may lower blood cholesterol.255 A preliminary
trial reported that 3 to 6 grams per day of chitosan taken for two weeks
resulted in a 6% drop in cholesterol and a 10% increase in protective HDL
cholesterol.256 However, a double-blind trial found a smaller 2.4 gram daily
dose did not produce significant beneficial changes in total, LDL, or HDL
cholesterol.257
Royal jelly has prevented the cholesterol-elevating effect of nicotine258 and
has lowered serum cholesterol in animal studies.259 Preliminary human trials
have also found that royal jelly may lower cholesterol levels.260 261 An
analysis of cholesterol-lowering trials shows that 50 to 100 mg per day is the
typical amount used in such research.262
A double-blind trial found that 20 grams per day of creatine taken for five
days, followed by ten grams per day for 51 days, significantly lowered serum
total cholesterol and triglycerides, but did not change either LDL or HDL
cholesterol, in both men and women.263 However, another double-blind trial found
no change in any of these blood levels in trained athletes using creatine during
a 12-week strength training program.264 Creatine supplementation in this
negative trial was lower-only 5 grams per day were taken for the last 11 weeks
of the study.
Octacosanol, a substance found in wheat germ oil, is sometimes available as a
supplement. Small amounts (5 to 20 mg per day) of policosanol, an experimental
supplement from Cuba consisting primarily of octacosanol, has led to large
reductions in LDL cholesterol and/or increases in HDL.265 266 267 268
Octacosanol may lower cholesterol by inhibiting the liver's production of
cholesterol.269
Homocysteine, a substance linked to heart disease risk, may increase the rate at
which LDL cholesterol is damaged.270 While vitamin B6, vitamin B12, and folic
acid lower homocysteine,271 a recent trial found no effect of supplements of
these vitamins on protecting LDL cholesterol, even though homocysteine was
lowered.272
Are there any side effects or interactions? Refer to the individual supplement
for information about any side effects or interactions.
Herbs that may be helpful: Researchers have determined that one of the
ingredients in red yeast rice, called monacolin K, inhibits the production of
cholesterol by stopping the action of the key enzyme in the liver (i.e., HMG-CoA
reductase) that is responsible for manufacturing cholesterol.273 The drug
lovastatin (Mevacorr) acts in a fashion similar to this red-yeast-rice
ingredient. However, the amount per volume of monacolin K in red yeast rice is
small (0.2% per 5 mg) when compared to the 20 to 40 mg of lovastatin available
as a prescription drug.274 This has prompted researchers to suggest that red
yeast rice may have other ingredients, such as sterols, that may also contribute
to lowering cholesterol.
Along with its evaluation in animal studies,275 red yeast rice has been
clinically investigated as a treatment for reducing cholesterol in two human
double-blind trials. In a Chinese trial, both men and women taking 1.2 grams
(containing approximately 13.5 mg total monacolins) of a concentrated red yeast
rice extract per day for two months had significant improvements in total, LDL,
and HDL cholesterol levels and in triglyceride levels.276 In a U.S. double-blind
trial, a similar red yeast rice product in the amount of 2.4 grams per day
(approximately 10 mg total monacolins) significantly decreased total, LDL, and
triglyceride cholesterol levels but did not affect HDL values.277 Red yeast rice
is commercially available in capsules and is typically used at 2.4 grams
(approximately 10 mg monacolins) per day for a trial period of up to 12 weeks.
If successful after this period of time, it may be used for long-term management
of high cholesterol.
Use of psyllium has been extensively studied as a way to reduce cholesterol
levels. An analysis of all double-blind trials in 1997 concluded that a daily
amount of 10 grams psyllium lowered cholesterol levels by 5% and LDL cholesterol
by 9%.278 Since then, a large controlled trial found that use of 5.1 grams of
psyllium two times per day significantly reduced serum cholesterol as well as
LDL-cholesterol.279 Generally, 5 to 10 grams of psyllium are added to the diet
per day to lower cholesterol levels. The combination of psyllium and oat bran
may also be effective at lowering LDL cholesterol.280
Guggul, a mixture of substances taken from a plant, is an approved treatment for
elevated cholesterol in India and has been a mainstay of the Ayurvedic approach
to preventing atherosclerosis. One double-blind trial studying the effects of
guggul reported that serum cholesterol dropped by 17.5%.281 In another
double-blind trial comparing guggul to the drug clofibrate, the average fall in
serum cholesterol was slightly greater in the guggul group; moreover, HDL
cholesterol rose in 60% of people responding to guggul, while clofibrate did not
elevate HDL.282 A third double-blind trial found significant changes in total
and LDL cholesterol levels, but not in HDL.283 Daily intakes of guggul are based
on the amount of guggulsterones in the extract. The recommended amount of
guggulsterones is 25 mg taken three times per day. Most extracts contain 5 to
10% guggulsterones, and doctors familiar with their use usually recommend taking
guggul for at least 12 weeks before evaluating its effect.
In a double-blind trial, people with moderately high cholesterol took a tincture
of Achillea wilhelmsii, an herb used in traditional Persian medicine.284
Participants in the trial used 15 to 20 drops of the tincture twice daily for
six months. At the end of the trial, participants experienced significant
reductions in total cholesterol, LDL cholesterol and triglycerides, as well as
an increase in HDL cholesterol compared to those who took placebo. No adverse
effects were reported.
Reports on many double-blind garlic trials performed through 1998 suggested that
cholesterol was lowered by an average of 9 to 12% and triglycerides by 8 to 27%
over a one-to-four month period.285 286 287 Most of these trials used 600 to 900
mg per day of garlic supplements. More recently, however, several double-blind
trials have found garlic to have minimal success in lowering cholesterol and
triglycerides.288 289 290 291 One negative trial has been criticized for using a
steam-distilled garlic "oil" that has no track record for this purpose,292 while
the others used the same standardized garlic products as the previous positive
trials. Based on these findings, the use of garlic should not be considered a
primary approach to lowering high cholesterol and triglycerides.293
Part of the confusion may result from differing effects from dissimilar garlic
products. In most but not all trials, aged garlic extracts and garlic oil (both
containing no allicin) have not lowered cholesterol levels in humans.294 295
Therefore, neither of these supplements can be recommended at this time for
cholesterol lowering. Odor-controlled, enteric-coated tablets standardized for
allicin content are available and, in some trials, appear more promising.296
Doctors typically recommend 900 mg per day (providing 5,000 to 6,000 mcg of
allicin), divided into two or three admininstrations.
Green tea has been shown to lower total cholesterol levels and improve people's
cholesterol profile, decreasing LDL cholesterol and increasing HDL cholesterol
according to preliminary studies.297 298 299 300 However, not all trials have
found that green tea intake lowers lipid levels.301 Much of the research
documenting the health benefits of green tea is based on the amount of green tea
typically drunk in Asian countries-about three cups per day, providing 240 to
320 mg of polyphenols.
Artichoke has moderately lowered cholesterol and triglycerides in some,302 but
not all,303 human trials. One double-blind trial found that 900 mg of artichoke
extract per day significantly lowered serum cholesterol and LDL cholesterol but
did not decrease triglycerides or raise HDL cholesterol.304 Cholesterol-lowering
effects occurred when using 320 mg of standardized leaf extract taken two to
three times per day for at least six weeks.
Fenugreek seeds contain compounds known as steroidal saponins that inhibit both
cholesterol absorption in the intestines and cholesterol production by the
liver.305 Dietary fiber may also contribute to fenugreek's activity. Multiple
human trials (some double-blind) have found that fenugreek may help lower total
cholesterol in people with moderate atherosclerosis or those having
insulin-dependent or non-insulin-dependent diabetes.306 307 308 One human
double-blind trial has also shown that defatted fenugreek seeds may raise levels
of beneficial HDL cholesterol.309 One small preliminary trial found that either
25 or 50 grams per day of defatted fenugreek seed powder significantly lowered
serum cholesterol after 20 days.310 Germination of the fenugreek seeds may
improve the soluble fiber content of the seeds, thus improving their effect on
cholesterol.311 Fenugreek powder is generally taken in amounts of 10 to 30 grams
three times per day with meals.
Preliminary Chinese research has found that high doses (12 grams per day) of the
herb fo-ti may lower cholesterol levels. Double-blind or other controlled trials
are needed to determine fo-ti's use in lowering cholesterol. A tea may be made
from processed roots by boiling 3 to 5 grams in a cup of water for 10 to 15
minutes. Three or more cups should be drunk each day. Fo-ti tablets containing
500 mg each are also available. Doctors may suggest taking five of these tablets
three times per day.
Wild yam has been reported to raise HDL cholesterol in preliminary research.
Doctors sometimes recommend 2 to 3 ml of tincture taken three to four times per
day, or 1 to 2 capsules or tablets of dried root taken three times per day. 312
Animal studies suggest that the mushroom maitake may lower fat levels in the
blood.313 This research is still preliminary and requires confirmation with
controlled human trials.
Animal studies indicate that saponins in alfalfa seeds may block absorption of
cholesterol and prevent the formation of atherosclerotic plaques.314 However,
consuming the large amounts of alfalfa seeds (80 to 120 grams per day) needed to
supply high doses of these saponins may potentially cause damage to red blood
cells in the body.315