Abstract online databases on the topic of choice



following research essay discusses and critically analyzes the topic of
moderate dark chocolate consumption and its effects on the risk factors of
cardiovascular disease, namely; hypertension, high cholesterol and insulin
resistance. Research of multiple online databases on the topic of choice was
conducted and results of these articles have displayed positive outcomes linked
to something that society would naturally label as unhealthy-chocolate. It
indicated that moderate dark chocolate consumption (50-100 mg per day) has cardioprotective effects on the body.
It can significantly lower blood pressure, assist in maintaining healthy
cholesterol levels and can help fight insulin resistance.

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re-iterate what was mentioned above, the chosen topic for investigative
exploration is the moderate consumption of dark chocolate and its effects on
cardiovascular disease risk factors. Ischemic heart disease and stroke, two
cardiovascular diseases, are the first and second leading causes of death in
the world (WHO, 2011). Cardiovascular disease has multiple risk factors such as
diabetes, obesity, high cholesterol, hypertension and following an unhealthy
diet to name a few (World Heart Federation, 2014).  Over the years, chocolate, specifically dark
chocolate has been associated to a cardioprotective effect in the body by means
of controlling the risk factors of cardiovascular disease to normative levels,
which could possibly aid in the prevention of cardiovascular disease; a
life-threatening, yet very avoidable disease. The research question; “What is
the effect of moderate dark chocolate consumption on the risk factors of
cardiovascular disease in middle-aged people?” was answered through assessment
and review of available evidence-based resources of good quality, reliability
and validity on the chosen topic. The paradigm of this topic is positivism.
This can be explained through the fact that positivism aims to discover general
relations between variables, particularly cause and effect. Furthermore, experiments
are designed to measure and explain associations and to test whether a
hypothesis can be approved or disapproved (Alderson, 1998). The biological
theory is most befitting to this topic, as it is directly related to the human
body and health outcomes of the body, whether it be in structure and/or
function.  An in-depth look at this
theory will be examined further in this research essay in terms of what
actually happens to the above mentioned risk factors when dark chocolate is
consumed and why, as well as the methodology that was utilized, an account of the
current state of knowledge will be given and interpretation/analysis, synthesis
and conclusions of the data will be provided.




The Research Process

articles used to understand this topic further as well as answer the key
research question involved conducting online, advanced database searches. The databases
used were; PubMed, Directory of Open Access Journals, Google Scholar, Monash
University Library as well as Ovid Medline. A total number of 33 articles were
reviewed out of a total of 2 026 hits. The keywords that were used in these
searches included: ‘cardiovascular disease’, ‘cardiovascular health’, ‘dark
chocolate’, ‘cardioprotective effects’, ‘risk factors’, insulin resistance’,
‘hypertension’ and ‘cholesterol’. It is useful to note that only English
articles, published from 2001 onwards were used. Persons with existing
cardiovascular disease of some sort were not included in these studies as the
aim was to focus on methods of preventing
cardiovascular disease to curb the significantly high figures around the globe
in at-risk populations. Data of middle-aged people (45 years old to 65 years
old) were observed, however, pregnant women or women on hormone-replacement
therapies were discarded from the scope as changes in hormone levels already
contribute to fluctuating cholesterol levels which may preserve or be
detrimental to cardiovascular function (Francis, 2013).


Study Design

examining all the primary data found, it can be said that the most suitable
study design for addressing the key research question was through a randomized
control trial, of which 45% (15 out of 33) of the articles made use of and
showed to be effective. It is one of the simplest but most powerful tools of
research, and is also known as the gold
standard of investigation, especially in establishing casual relationships
i.e. chocolate causing a reduction in blood pressure (Stolberg, Norman &
Trop, 2004). It would be ideal in the context of this topic as at-risk
participants (those who possess any of the three mentioned risk factors) would
be allocated randomly to one of two groups, either the control or the intervention;
this ensures rigor and fairness within the sampling (Sibbald & Roland,
1998). Baseline data will then be collected before any interventions/controls
are administered. Thereafter, a decided dose of dark chocolate is given to the
intervention group everyday and the control group receives some type of placebo
that resembles chocolate, for about 4-8 weeks and within that time, both
groups’ hypertension, cholesterol, and blood sugar/insulin resistance is
measured weekly to examine the changes. The study samples also consist of both
male and female participants. This is how a classic randomized control trial is
usually conducted.

State of Knowledge


             Although several studies have been conducted,
especially in the last 15 years or so, of this specific topic, it seems that
the results of these studies have not widely been received or acknowledged by
the common folk. In the field of health research however, there seems to be a
growing interest in the area of chocolate having health benefits. To date,
after reviewing many journal articles, there are a few key points that we
should understand and can be put down as what we know thus far regarding these
benefits, such as:

The beneficial ingredient in the chocolate is
called Flavonoids and is found within the cocoa of the chocolate. The specific
flavonoid is known as Flavan-3-ol (Steinberg, Bearden & Keen, 2003). Many
sources of food appear to possess these flavonoids such as tea, fruit,
vegetables and red wine (Afoakwa, 2008), but it can be said that cocoa, and
therefore dark chocolate exhibits the highest flavonoid capacity compared to
the other foods (Shrime, Bauer, McDonald & Coltart, 2011). Flavonoids are a
natural occurring polyphenolic dietary antioxidant that can effectively remove
potentially damaging oxidizing agents in the body as well as have natural
anti-inflammatory characteristics (Mathur, Deveraj & Grundy, 2002). The
reason why this essay talks about dark chocolate rather than milk chocolate is
because the darker the chocolate, the higher the cocoa volume (Cacao
Percentages, 2014).

The term “moderate” in dark chocolate
consumption. It was observed that the term moderate
dark chocolate consumption differed across the several studies. It is
essential to understand what is meant by the term moderate, so that the benefits of this intervention can be enjoyed
by many. Too little dark chocolate a day can be ineffective at controlling
cardiovascular risk factor levels, although too much dark chocolate may still
reduce some risk factors like blood pressure and high cholesterol but still has
the ability to bring about other cardiovascular disease risk factors such as
obesity, which again, opens the doors for additional harmful risk factors. According
to randomized control trials conducted by Destch, Eitel & Schuler (2010)
and Latham, Hensen & Minor (2013), the correct amount of dark chocolate a
person should be having a day is 25-50 grams. Faridi, Dutta & Katz (2008)
and Allen, Evans & Erdman (2007) however, states that a good amount of dark
chocolate a day would be exactly 22 grams but Abdullah Al-Faris (2008)
administered up to 100 grams in her study. After close review of 33 articles,
it was found that the approximate average of the daily consumption of dark
chocolate should be around 50-100 grams.

The bioavailability of dark chocolate on an
individual. “Bioavailability refers to the maximum amount of a substance that
is absorbed into the body, and how quickly that maximum amount becomes
available to the body” (Weber, 2008). Chocolate flavonoids have depicted a good
dose response bioavailability in humans (Ding, Hutfless & Girotra, 2006).
This simply means that most of what is ingested is absorbed and used by the
body in a very quick manner, leaving very little leftover to be free and excreted.
A persons bioavailability to a substance or drug may differ from one to another
because it is also dependent on factors such as age, weight and height,
metabolic rate and gender to name a few (Le, 2014). It is essential to note the
bioavailability of a substance on the body, in this case chocolate, because
although the intervention group may all be receiving the same dose of dark
chocolate a day, their reactions and biological outcomes of it may differ because
they are not all the same with regard to the factors mentioned above. Bioavailability
is a crucial tool in pharmaceuticals, if future studies prove the health
benefits of chocolate then it may even stimulate the opportunity for
development of medicinal chocolate, in which bioavailability will be used to
calculate the required dosage (Stone, 2014).


and Synthesis of the Data


    This paper spoke in detail about the dark
chocolate and the health benefits the flavonoids in it display, but now it will
discuss exactly what those benefits are in context with the literature and the
three specific cardiovascular risk factors it is targeted at; hypertension,
insulin resistance and high cholesterol.




is increased blood pressure, which simply means the pressure of the blood in
the body’s blood vessels is higher than what is should be, putting extra strain
on the body’s cardiovascular system. According to the Center for Disease
Control and Prevention (2014), sixty seven million U.S adults (1 in 3 people)
have hypertension and as much as 53% of those affected, do not have their
condition under control. These are shocking figures as hypertension is the
biggest risk factor to cardiovascular disease, and is highly modifiable and
dependent on he individual’s actions and behaviors (World Heart Federation,


RESULTS: According to Allen et al.,
(2008), moderate dark chocolate consumption significantly reduced blood
pressure in a 4-8 week randomized control trial of 650 participants. The consumption
of small dark chocolate bars reduced both systolic and diastolic blood pressure
by about 8,2%, although this change seemed to only be evident from the fourth
week of administering it. It is also useful to note that in this study, over
the given period of time, the body weight of the subjects did not change from
the baseline data collected. This is a great advantage as it shows the benefits
of moderate dark chocolate consumption without it adding any harmful factors to
the body if done correctly. Another randomized control trial conducted by
Almoosawi, Fyfe & Clement (2009), also depicted a significant reduction in
blood pressure from baseline to around week 5 of the intervention. This study
linked the reduction in blood pressure directly to enhanced vascular function
from ingesting the chocolate.


DISCUSSION: The relationship between
blood pressure and CVD is continuous and the smallest reductions in blood
pressure can substantially decrease CVD around the globe. Latham et al.,
(2014), talks about the link between these variables involving a substance known
as endothelial nitric oxide (NO). It goes on to say that the intake of cocoa
flavonoids increases the NO generation, which in turn prevents leukocyte
adhesion, platelet adhesion and smooth muscle cell proliferation leading to
vasodilation and lastly a beneficial reduction in blood pressure.


Insulin Resistance

to the National Diabetes Information Clearinghouse (2014), “insulin resistance
is a condition in which the body produces insulin but does not use it
effectively.” Instead of being absorbed up by the cells, glucose in the body
builds up in the blood, and as a result may lead to diabetes, which is also a
great risk factor of cardiovascular disease and can be life-threatening.


RESULTS: Grassi, Desideri & Ferri
(2013) conducted a study to measure the effects of flavonoid rich chocolate on
hypertension and insulin resistance. Results suggest that when the participants
were given flavonoid rich chocolate, their insulin resistance decreased by
0.31%. Although this is small reduction, it was observed that those who
received a placebo containing no
flavonoids showed no decrease in
insulin resistance at all. The study also showed that insulin sensitivity had
increased over a short-term period of dark chocolate consumption and was
measured using an insulin sensitivity index. This resulted in the insulin
responses to glucose in the body being significantly improved, ultimately
reducing the blood glucose levels up to 1.6%. Shrime et al., (2011), also
displays results that 100mg of flavonoid rich chocolate a day can reduce
insulin resistance by 0.94%.


to Latham et al., (2014), the impairment of insulin-stimulated NO production
contributes to the body’s metabolic insulin resistance and therefore, by
enhancing the NO bioavailability by consumption of dark chocolate, insulin
resistance will decrease and insulin sensitivity increase. This makes it much
easier for the body to break down and metabolize the glucose in the body and
significantly reduces cardiovascular risk. Majority of the studies measuring
these variables made use of a specific tool of measurement; the homeo- stasis
model assessment of insulin resistance (HOMA-IR).  This tool estimates steady state beta cell
function (%B) and insulin sensitivity (%S), as percentages of a normal
reference population (University of Oxford, 2014).

High Cholesterol

is a waxy substance that is found within the lipids (fats) of the body,
although the body requires this to build healthy cells, high cholesterol can
result in a build up of fatty deposits in and around the blood vessels, which
significantly increases the probability of suffering from heart disease (Mayo
Clinic, 2014).


RESULTS: Fraga, Keen & Goretta
(2005), investigated the regular consumption of flavonoid rich diets on
cardiovascular disease risk and reports results that 105 grams of dark
chocolate daily has proved to decrease plasma cholesterol up to 11%, and LDL
cholesterol up to as much as 15%. Ding et al., (2006) found that as little as
31 grams of dark chocolate a day can increase HDL cholesterol. This is highly
beneficial as LDL cholesterol is what is known as the ‘bad’ cholesterol as it
leads to plaque build-up and atherosclerosis, while HDL cholesterol is the
‘good’ cholesterol and helps remove the LDL cholesterol (American Heart
Association, 2014). By reducing LDL cholesterol and increasing HDL cholesterol
significantly reduces the risk of cardiovascular disease.


rich substances like dark chocolate lower LDL cholesterol by inhibiting
cholesterol absorption in the digestive tract and inhibiting LDL cholesterol
production (Latham et al., 2014). If there is too much LDL cholesterol in the
body, the cardiovascular system works extra hard to pump the blood around as
atherosclerosis has reduced the size of the blood vessels. This increases the
blood pressure drastically, putting a person at high risk of CDD and it is
therefore very beneficial to keep LDL cholesterol at a low.

Gaps Within
the Literature

the research, a number of gaps in knowledge were identified. In order to
understand and explore the topic of moderate dark chocolate consumption and its
cardioprotective effect more, it is of utmost importance to address these gaps
in the near future. Some of the pitfalls include:

·      The high
probability of confounding variables. Due to the nature of this topic,
measuring cardiovascular risk, there will always be other factors contributing
to the positive or negative outcomes in the body such as age, sex, weight and
height as well as hereditary characteristics. This makes it a little more
difficult to find an accurate causal relationship as results may be altered in
one or more ways depending on the factors mentioned above.

·      Although
some of the study samples were quite large, majority of them were not. Some
studies even used as little as 10-20 participants. Small sample sizes make it
difficult to generalize the findings to the population.

·      Even
though several studies have been conducted over the past decade and more on
this topic, it is still difficult to state the exact amount of dark chocolate
needed to enjoy the maximum benefits of it as the articles all differ from one
another. All dark chocolate isn’t the same as well, making it even harder to
give a proper estimate.

·      Although
the average person may read articles in things like magazines or newspapers on
this topic, scientific, evidence-based data and articles are not easily
accessible to them as they could benefit greatly from knowing the facts about
the topic and by putting it into practice.


the Gaps

suggested checklist to improve the above-mentioned gaps in future research

·      Conducting
randomized control trials where possible as it is one of the most scientifically
sound ways of investigation.

·      Attempt
to publish all literature whether it is positive or null discoveries so that
the wider public can learn more on the topic.

·      Use well-defined
cocoa and chocolate, and if possible for industry to allow similar
cocoa/chocolate to be available for independent researchers for future
studies/repeating work.

·      Ensure
bioavailability of the dark chocolate within its environment.

·      Use an
appropriate control for non-flavonoid chocolate.

·      Use a
daily dose of chocolate that can readily be implemented into the diet.

·      Use much
larger sample size to explore the relationship between the variables.

·      Ensure
participants within the sample are similar as possible to one another so that
other factors contribute less to the outcome.



diseases, the category that accounts for the most deaths in the world, can be
prevented and managed in many differed ways, as most of its risk factors are
highly modifiable. Dark chocolate consumption in moderation has been linked to
cardioprotective effects in the body with relation to many CVD risk factors,
over and above the ones mentioned in this paper. In conclusion, moderate dark
chocolate consumption does lower blood pressure, fight insulin resistance and
reduce LDL cholesterol, putting an individual at a lowered risk of developing
CVD. Future studies need to be conducted to explore this topic further as it
can be regarded as fairly new in the health research industry.


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