Heart Disease Linked to Cholesterol: A Controversy Study
History of Heart
Disease
Over the past
century, the world has witnessed an explosion of knowledge in science and
technology that has drastically affected the way we live. In particular, knowledge in science has
provided insight into our natural world and knowledge in technology has
provided numerous conveniences to enhance our daily lives. For example, at the turn of the century, coronary
artery disease was a relatively unknown illness, with victims few and far
between; however, over the past century, the prevalence of this disease has
exponentially increased, making coronary artery disease the #1 killer of people
today. The increased incidence of this
disease can be attributed to the changes in lifestyle and diet that accompanied
the onset of automation at the turn of the century. In the 1900’s, most people made their living through some sort of
manual labor, and in addition, beating carpets, hand-scrubbing and washing laundry,
and climbing stairs had not yet been replaced by vacuum cleaners, washing
machines, and elevators (2). The Industrial Revolution replaced manual
labor with machine power and rapidly accelerated the transformation of society
to our modern sedentary lifestyle. With
modern conveniences came modern foods; french fries, hamburgers, and potato
chips have become staples in many diets.
Thus, it is not difficult to imagine the changes in our bodies that
accompany these changes in diet and lifestyle.
Without proper exercise and a balanced diet with moderate fat content,
cholesterol levels increase in our bloodstream and eventually accumulate in
blood vessels.
Cholesterol and Coronary Artery Disease
Cholesterol is a soft, waxy lipid that is an
important component in cell membranes and steroid hormones, such as estrogen
and testosterone. It is produced and
regulated by the liver and is contained in foods that you eat. The liver produces approximately 1,000 mg of
cholesterol daily, in addition to 400-500 mg of ingested cholesterol (3). A
high level of cholesterol in the blood, a condition called
hypercholesterolemia, is a major risk factor for coronary artery disease. There are various types of cholesterol, but
those relevant to heart disease are low-density lipoprotein (LDL) and
high-density lipoprotein (HDL). LDL is
a major cholesterol carrier in the blood that directs cholesterol to the heart
and brain. High levels of LDL eventually
accumulate in the arteries in the form of plaque, a condition known as
atherosclerosis, commonly referred to as a “hardening of the arteries”, which
is the major risk factor for coronary artery disease (4). A clot,
or thrombus, that forms in a plaque-filled region of the coronary arteries, or
the arteries that supply oxygen and nutrients to the heart muscle, can lead to
heart attacks. A high level of LDL thus
increases the risk of coronary artery disease.
HDL cholesterol, on the other hand, which carries approximately ¼ of the
cholesterol in the blood, is thought to direct cholesterol to the liver where
it is removed from the body. A high
level of HDL is proven to protect against plaque formation, and thus reduces
the risk of heart disease.
Other Risk Factors for Coronary Artery Disease
In addition to
cholesterol, several other risk factors leading to coronary artery disease have
been identified. These include smoking,
diabetes, obesity, diet, family history, stress, male gender, a sedentary
lifestyle, and high blood pressure.
Smoking
Smoking is the most important preventable risk factor
for coronary artery disease. More
than 200 of the 4000 components of tobacco smoke have been linked to
cancer. Those relevant to coronary
artery disease include nicotine and carbon monoxide. Nicotine increases blood pressure and
heart rate, causing the heart to work harder and thus the heart requires
more oxygen. In addition, nicotine
causes platelets to become “sticky” which enables them to stick to plaque
formations more easily. These two
effects together can greatly increase the risk for coronary artery disease. Carbon monoxide decreases the flow of
oxygen to the body, including the heart muscle. Hemoglobin has a greater affinity for carbon monoxide than
oxygen and thus tissues are deprived of oxygen. Furthermore, carbon monoxide-saturated hemoglobin causes the
walls of the arteries to become more permeable to fats and thus enhances
plaque formation. Thus it is
evident that the components in cigarette smoke can lead to coronary artery
disease (5).
Stress
Both physical
and emotional stress can be detrimental to the heart, particularly if the
individual has other risk factors for coronary artery disease. Plaque formation in the arteries restricts
the flow of oxygen and nutrients to the heart.
Thus, under physical stress, the heart is forced to work harder and
therefore requires more oxygen and nutrients that are unable to reach their
destination fast enough because of clogged arteries. In regards to emotional stress, surges in adrenaline cause blood
vessels to constrict, resulting in decreased blood flow through the coronary
arteries. In addition, prolonged
periods of stress increase the serum level of homocysteine, an amino acid that
has been proven to increase the risk of coronary artery disease. In addition to these changes in body
chemistry, emotional stress also leads to behaviors that cause coronary artery
disease such as smoking, over-eating, and lack of exercise (6).
For more information on coronary artery disease risks, visit the American Heart Association: http://www.americanheart.org/
Treatments for Coronary Artery Disease
Various treatments
have been identified that are proven effective in combating heart disease, however,
not without a plethora of side effects.
Up to 50-60% reductions in cholesterol levels have been observed with
various drug treatments, however, because of harmful side effects, drugs should
only be used if levels cannot be reduced by changes in diet. Some effective treatments include gemfibrozil
(Lopid), lovastatin (Mevacor), simvastatin (Zocor), and pravastatin (Pravachol)
(1).
gemfibrozil (Lopid)
In the 1988 Helsinki Heart study, 4000 Finnish men with high cholesterol levels were treated with Lopid over a period of 5 years. Treatment with Lopid led to an 11% decrease in LDL and an 11% increase in HDL cholesterol levels. This was associated with a 34% reduction in fatal and non-fatal heart attacks. Side effects include nausea, abdominal pain, gallstone formation, reduced sex drive, heart rhythm irregularities and drowsiness.
simvastatin (Zocor)
In addition to drug
treatments, various alternative therapies have been elucidated, the most
important being treatment with medical foods.
Some medical foods proven to reduce cholesterol levels include garlic,
walnuts, soy products, and oat bran.
Some foods proven detrimental to health include coffee and alcohol (1).
For more information
on various drug treatments and trials, visit: http://ww2.mcgill.ca/chemistry/world_of_chem/cholesterol.html
The Oat Bran Controversy
Though there have been
many controversies that have arisen involving coronary artery disease,
including the safety of drug treatments and ideal blood cholesterol levels, a
well-known recent controversy involves the consumption of oat bran and it’s
effects on cholesterol levels in the body.
The course of this controversy can be analyzed using several of the
approaches outlined in “Scientific Knowledge, Controversy, and Public Decision
Making,” by Brian Martin and Evelleen Richards. Though all controversies are similar in that they consist of a
confliction of opposing views, the nature of the conflict, groups involved, and
scientific relevance all differ extensively from case to case. The oat bran controversy, therefore, cannot
be applied to every approach outlined by Martin and Richards; however, an
integration of several perspectives can provide new insight on steps for
resolution.
The
Controversy Approach
In analyzing the oat
bran controversy, a Group Politics approach is most effectively used. This perspective focuses on the
activities of social groups including corporations, expert panels, and
citizens’ organizations. In view of a
conflict, scientific knowledge is used as a powerful tool, and the two
contending sides usually consist of corporations, physicians/researchers,
versus community groups. Considering
that the superior side of a controversy has better access to financial
resources, political power, supporters, and scientific authority, they thus
usually triumph over the debate.
Furthermore, in regards to the scientific issues involved in the oat
bran controversy, a positivist approach, which assumes a boundary between
science and social science, can additionally be applied. It is based on the assumption that scientists
possess an infallible knowledge inherent in nature that lacks intervening
social factors, and thus are considered the authority on matters pertaining to
science. In the Positivist approach, a
scientific controversy is ultimately resolved by investigation of facts through
the scientific method, and the group that demonstrates a superior knowledge of
the issues prevails.
History of Clinical Studies
In 1963, a scientist
named de Groot first demonstrated the cholesterol-lowering power of oats in an
experiment involving laboratory rats.
In subsequent years, he performed similar experiments on humans,
substituting 140 g of oats in place of the normal bread in their diets. Since then, various studies have given the
impression that oat bran can be used to lower cholesterol levels. The Framingham study, which began in
1948, released valuable data in 1977 that demonstrated the beneficial role of
high-density lipoprotein (HDL) cholesterol and the negative consequences of
low-density lipoprotein (LDL) cholesterol.
This pertinent data launched a plethora of clinical studies testing the
effects of oat bran on cholesterol levels:
For Oat Bran
•1981- Dr. Kirby: eight hypercholesterolemic
men received crossover diet of 100 g of oat bran per day in muffins and hot
cereal
-LDL levels decreased
14% with no change in HDL (7)
•1984- Dr. Storch: crossover study of
normocholesterolemic college students using 50g of wheat bran in 1st
6 weeks vs. 50g oat bran in next 6 weeks
-No significant changes
in cholesterol in wheat phase
-12 % decrease in total
serum cholesterol in oat bran phase (7)
•1988- Drs. Gold & Davidson: double-blind study
of medical students with mean base serum cholesterol levels of 179 mg/dL using
oat bran vs. wheat bran
vs. oat bran/wheat bran muffins for 4 weeks
-No significant
differences in serum cholesterol from baseline values were observed for wheat
bran or oat bran/wheat bran muffins
-Decrease of 9.4 mg/dL
in oat bran muffin group (7)
Against Oat Bran
•New England Journal of Medicine: crossover
study of 20 normocholesterolemic men and women ages 23-49 using 93 g/day
low-fiber wheat bran muffins
and 87 g/day of high-fiber
oat bran muffins for six weeks: half of the experimental subjects consumed what
bran muffins and the other, oat bran.
Diet
regimens were switched after
six weeks. (8)
-Both diets
reduced total cholesterol and LDL levels 7-8 percent
•Australia, 1992: double blind study of 30
subjects with mild hyperlipidemia over 24 weeks. After 8 weeks of following a conventional lipid-lowering diet,
subjects received 60 g of
either oat bran or wheat bran muffins for alternating two-week intervals. (9)
-Wheat bran levels 4.95 mmol/L vs 4.97 mmol/L
for oat bran: not an impressive distinction
•Additional research has shown that eating 100
g of oat bran a day can reduce cholesterol levels up to 20 %; 40 g/day reduces
cholesterol levels by about
3 %. Both also lead to a decrease in beneficial
HDL levels. (1)
Group
Interests
The publication of
the Framingham data in 1977, concerning the negative effects of LDL and the positive
effects of HDL, initiated a burst of scientific research in the search for
possible treatments. In regards to
scientists’ interests and goals, excellent research opportunity yielded
revolutionary findings, publications, enhancement of professional reputation,
and subsequent job offers. Any
groundbreaking findings would be published, regardless of its effects on
colleagues, patients, the general population, or particularly, oat bran
corporations.
The interests of pharmaceutical and insurance companies are strictly anti-medical foods. It is estimated that billions of dollars are spent annually to treat 5 million coronary artery disease patients (13). Pharmaceutical and insurance companies thus are in favor of doctors prescribing expensive drug treatments as opposed to oat bran cereal and garlic home remedies.
Doctor’s interests parallel those of pharmaceutical and insurance companies. Treatment of 5 billion coronary artery patients is estimated to cost 30 million to 100 million for annual visits to doctors' offices (13). Magazine articles and television can inform the lay public about oat bran and walnuts, however, in order to receive drug treatment, a medical doctor must write the prescription.
Patients are outside of the boundary of the medical community, and thus aren’t experts on the type of treatment that is best for their condition. Patients are mostly concerned with their health and life, and secondarily concerned with the costs of treatment. Though oat bran “had long been thought of as one of those unpalatable good-for-you foods with the texture of cedar chips and the mouth-watering flavor of a packing crate,” its low price and availability are economical and practical for middle-class citizens (12). However, if their life is in danger, patients are often forced to pay bundles of money for life-saving treatment. Patients thus are at the mercy of everything and everyone including their financial status, doctors, scientists, pharmaceutical companies, oat bran industries, and most importantly, their disease.
Analysis
and Resolution
Since this
controversy is both inside and outside of the scientific arena, both the Group
Politics and the Positivist approach can be applied. In regards to the Group Politics approach, the oat bran controversy
is obviously a confliction of many different interests. Doctors and pharmaceutical companies vs. oat
bran corporations, and they all want to make a buck off of lay patients. Patients suffering from hyperlipidemia and
coronary artery disease are concerned with their individual lives and surviving
their threatening conditions. Similar
to the ALD parents in Lorenzo’s Oil, coronary artery disease victims
have complete faith in medical doctors and scientific researchers; after all,
they’re the ones with the medical degrees.
However, there is obviously a difference in each groups’ goals. Patients want to be well, and pharmaceutical
companies and oat bran corporations are concerned with their reputations and
their money. Thus, it is effortless to take
advantage of the trusting patients.
Expert scientists are recruited to research particular treatments in
favor of one group or another, at the expense of both pharmaceutical companies
and oat bran corporations. Both groups
attempt to gain credibility for their cause to enroll patient supporters. Patients will believe the scientific experts
because according to Thomas Gieryn’s article, there is a definite boundary
surrounding the medical/scientific community that is impenetrable to the lay
public. The group with the most
supporters, authoritative knowledge, and scientific evidence, or in other
words, the group with the greatest financial resources to pay researchers to
positively portray their hypothesis, triumphs over the debate. Both insurance companies and medical doctors
support pharmaceutical companies, whereas nutritionists and health nuts assist
oat bran corporations. Though oat bran
is still recommended as a substitute for high fat/high cholesterol foods, drug
treatments have been proven more effective, though their risks are still
somewhat controversial as well.
An additional conflict exists among scientific researchers. Being inside the scientific arena, this conflict can be explored using the Positivist approach. This perspective is a quest for scientific truth and can be explained by falsification and experimenter’s regress. Karl Popper’s theory of falsification is the process of generating hypotheses and then proving them wrong with new information. With each false hypothesis, new hypotheses are created until no information can be found to disprove them, in which case they must be true. In regards to the oat bran controversy, hypotheses are made about the effect of oat bran on blood cholesterol levels. For an extensive period of time, researchers continued to produce the same results, proving that oat bran did have positive effects on lowering blood cholesterol. The hypothesis was believed to be true, the public was informed, and as a result oat bran sales skyrocketed. The publication in the New England Journal of Medicine was sufficient to disprove previous hypotheses, and new ideas about the effect of oat bran on cholesterol were composed. Clearly, researchers are unsure of the effects of oat bran and each subsequent research finding generates new hypotheses, however, how will these questions ultimately be answered? Thus, science will inevitably be associated with experimenter’s regress. In endeavoring to discover knowledge about the natural world, our environment, and our bodies, we never know the range of outcomes and thus can never judge the value of experimentation. After both sides were analyzed using the scientific method, oat bran’s remarkable effects on lowering cholesterol in the bloodstream weren’t as convincing as those that demonstrated little to no change in blood cholesterol levels. At this point, oat bran has not yet redeemed its credibility. Though oat bran is currently not associated with major reductions in blood cholesterol, substituting oat bran for high cholesterol foods in your diet is a step in the right direction.
Conclusion
-To lower cholesterol, you have to eat a lot of oats...every day
-The labels on many foods won't say that you'd have to eat three servings a day to lower your cholesterol
-Oats lower cholesterol very little unless you start out with high cholesterol
-Oats could squeeze other good foods out of the diet (10)
Last Updated 7-May-2001
Annie Notarangelo