19 randomized controlled trials: Dark chocolate could benefit cardiovascular health
To the tantalizing delight of chocolate lovers everywhere, a number of recent studies employing various methods have suggested that compounds in cocoa called flavanols could benefit cardiovascular health. Now a systematic review and meta-analysis of 19 randomized controlled trials (RCTs) of cocoa consumption reveals some further pieces of supporting evidence.
The meta-analysis in the Journal of Nutrition, an assessment of the combined evidence from all 19 RCTs, focused on whether consumption of flavanol-rich cocoa products was associated with improvements in specific circulating biomarkers of cardiometabolic health as compared to consuming placebos with negligible cocoa flavanol content. In all, 1,139 volunteers were involved in these trials.
"Our meta-analysis of RCTs characterizes how cocoa flavanols affect cardiometabolic biomarkers, providing guidance in designing large, definitive prevention trials against diabetes and cardiovascular disease in future work," said corresponding author Dr. Simin Liu, professor and director of the Center for Global Cardiometabolic Health at Brown University who worked with epidemiology graduate student and lead author Xiaochen Lin. "We found that cocoa flavanol intake may reduce dyslipidemia (elevated triglycerides), insulin resistance and systemic inflammation, which are all major subclinical risk factors for cardiometabolic diseases."
Liu noted some limitations in the trials. All studies were small and of short duration, not all of the biomarkers tracked in these studies changed for the better, and none of the studies were designed to test directly whether cocoa flavanol consumption leads to reduced cases of heart attacks or type 2 diabetes.
But taking into account some of these heterogeneities across studies, the team's meta-analysis summarizing data from 19 trials found potential beneficial effects of flavanol-rich cocoa on cardiometabolic health. There were small-to-modest but statistically significant improvements among those who ate flavanol-rich cocoa product vs. those who did not.
The greatest effects were seen among trial volunteers who ate between 200 and 600 milligrams of flavanols a day (based on their cocoa consumption). They saw significant declines in blood glucose and insulin, as well as another indicator of insulin resistance called HOMA-IR. They also saw an increase in HDL, or "good," cholesterol. Those consuming higher doses saw some of the insulin resistance benefits and a drop in triglycerides, but not a significant increase in HDL. Those with lower doses of flavanols only saw a significant HDL benefit.
In general, Lin said, where there were benefits they were evident for both women and men and didn't depend on what physical form the flavanol-rich cocoa product was consumed in -- dark chocolate vs. a beverage, for example.
"The treatment groups of the trials included in our meta-analysis are primarily dark chocolate -- a few were using cocoa powder-based beverages," Lin said. "Therefore, the findings from the current study apparently shouldn't be generalized to different sorts of chocolate candies or white chocolates, of which the content of sugar/food additives could be substantially higher than that of the dark chocolate."
The authors therefore concluded, "Our study highlights the urgent need for large, long-term RCTs that improve our understanding of how the short-term benefits of cocoa flavanol intake on cardiometabolic biomarkers may be translated into clinical outcomes."
Eating chocolate daily linked to lowered heart disease and stroke risk
To the tantalizing delight of chocolate lovers everywhere, a number of recent studies employing various methods have suggested that compounds in cocoa called flavanols could benefit cardiovascular health. Now a systematic review and meta-analysis of 19 randomized controlled trials (RCTs) of cocoa consumption reveals some further pieces of supporting evidence.
The meta-analysis in the Journal of Nutrition, an assessment of the combined evidence from all 19 RCTs, focused on whether consumption of flavanol-rich cocoa products was associated with improvements in specific circulating biomarkers of cardiometabolic health as compared to consuming placebos with negligible cocoa flavanol content. In all, 1,139 volunteers were involved in these trials.
"Our meta-analysis of RCTs characterizes how cocoa flavanols affect cardiometabolic biomarkers, providing guidance in designing large, definitive prevention trials against diabetes and cardiovascular disease in future work," said corresponding author Dr. Simin Liu, professor and director of the Center for Global Cardiometabolic Health at Brown University who worked with epidemiology graduate student and lead author Xiaochen Lin. "We found that cocoa flavanol intake may reduce dyslipidemia (elevated triglycerides), insulin resistance and systemic inflammation, which are all major subclinical risk factors for cardiometabolic diseases."
Liu noted some limitations in the trials. All studies were small and of short duration, not all of the biomarkers tracked in these studies changed for the better, and none of the studies were designed to test directly whether cocoa flavanol consumption leads to reduced cases of heart attacks or type 2 diabetes.
But taking into account some of these heterogeneities across studies, the team's meta-analysis summarizing data from 19 trials found potential beneficial effects of flavanol-rich cocoa on cardiometabolic health. There were small-to-modest but statistically significant improvements among those who ate flavanol-rich cocoa product vs. those who did not.
The greatest effects were seen among trial volunteers who ate between 200 and 600 milligrams of flavanols a day (based on their cocoa consumption). They saw significant declines in blood glucose and insulin, as well as another indicator of insulin resistance called HOMA-IR. They also saw an increase in HDL, or "good," cholesterol. Those consuming higher doses saw some of the insulin resistance benefits and a drop in triglycerides, but not a significant increase in HDL. Those with lower doses of flavanols only saw a significant HDL benefit.
In general, Lin said, where there were benefits they were evident for both women and men and didn't depend on what physical form the flavanol-rich cocoa product was consumed in --dark chocolate vs. a beverage, for example.
"The treatment groups of the trials included in our meta-analysis are primarily dark chocolate -- a few were using cocoa powder-based beverages," Lin said. "Therefore, the findings from the current study apparently shouldn't be generalized to different sorts of chocolate candies or white chocolates, of which the content of sugar/food additives could be substantially higher than that of the dark chocolate."
The authors therefore concluded, "Our study highlights the urgent need for large, long-term RCTs that improve our understanding of how the short-term benefits of cocoa flavanol intake on cardiometabolic biomarkers may be translated into clinical outcomes."
Eating chocolate daily linked to lowered heart disease and stroke risk
Eating up to 100 g of chocolate every day is
linked to lowered heart disease and stroke risk, finds research
published online in the journal Heart.
They base their findings on almost 21,000 adults taking part in the EPIC-Norfolk study, which is tracking the impact of diet on the long term health of 25,000 men and women in Norfolk, England, using food frequency and lifestyle questionnaires.
The researchers also carried out a systematic review of the available international published evidence on the links between chocolate and cardiovascular disease, involving almost 158,000 people--including the EPIC study participants.
The EPIC-Norfolk participants (9214 men and 11 737 women) were monitored for an average of almost 12 years, during which time 3013 (14%) people experienced either an episode of fatal or non-fatal coronary heart disease or stroke.
Around one in five (20%) participants said they did not eat any chocolate, but among the others, daily consumption averaged 7 g, with some eating up to 100 g.
Higher levels of consumption were associated with younger age and lower weight (BMI), waist: hip ratio, systolic blood pressure, inflammatory proteins, diabetes and more regular physical activity --all of which add up to a favourable cardiovascular disease risk profile.
Eating more chocolate was also associated with higher energy intake and a diet containing more fat and carbs and less protein and alcohol.
The calculations showed that compared with those who ate no chocolate higher intake was linked to an 11% lower risk of cardiovascular disease and a 25% lower risk of associated death.
It was also associated with a 9% lower risk of hospital admission or death as a result of coronary heart disease, after taking account of dietary factors.
And among the 16,000 people whose inflammatory protein (CRP) level had been measured, those eating the most chocolate seemed to have an 18% lower risk than those who ate the least.
The highest chocolate intake was similarly associated with a 23% lower risk of stroke, even after taking account of other potential risk factors.
Of nine relevant studies included in the systematic review, five studies each assessed coronary heart disease and stroke outcome, and they found a significantly lower risk of both conditions associated with regular chocolate consumption.
And it was linked to a 25% lower risk of any episode of cardiovascular disease and a 45% lower risk of associated death.
This is an observational study so no definitive conclusions about cause and effect can be drawn. And the researchers point out that food frequency questionnaires do involve a certain amount of recall bias and underestimation of items eaten.
Reverse causation--whereby those with a higher cardiovascular disease risk profile eat less chocolate and foods containing it than those who are healthier--may also help to explain the results, they say.
Nevertheless, they add: "Cumulative evidence suggests that higher chocolate intake is associated with a lower risk of future cardiovascular events."
And they point out that as milk chocolate, which is considered to be less 'healthy' than dark chocolate, was more frequently eaten by the EPIC-Norfolk participants, the beneficial health effects may extend to this type of chocolate too.
"This may indicate that not only flavonoids, but also other compounds, possibly related to milk constituents, such as calcium and fatty acids, may provide an explanation for the observed association," they suggest.
Chocolate fights diabetes,
obesity, cardiovascular disease, and cancer
Eating high levels of flavonoids including anthocyanins and
other compounds (found in berries, tea, and chocolate) could offer protection
from type 2 diabetes - according to research from the University of East Anglia
(UEA) and King's College London.
Findings published January 2014 in the Journal of Nutrition reveal that high intakes of these dietary
compounds are associated with lower insulin resistance and better blood glucose
regulation.
A study of almost 2,000 people also found that these food
groups lower inflammation which, when chronic, is associated with diabetes,
obesity, cardiovascular disease, and cancer.
Prof Aedin Cassidy from UEA's Norwich Medical School led the
research. She said: "Our research looked at the benefits of eating certain
sub-groups of flavanoids. We focused on flavones, which are found in herbs and
vegetables such as parsley, thyme, and celery, and anthocyanins, found in
berries, red grapes, wine and other red or blue-coloured fruits and vegetables.
"This is one of the first large-scale human studies to
look at how these powerful bioactive compounds might reduce the risk of
diabetes. Laboratory studies have shown these types of foods might modulate
blood glucose regulation – affecting the risk of type 2 diabetes. But until now
little has been know about how habitual intakes might affect insulin
resistance, blood glucose regulation and inflammation in humans."
Researchers studied almost 2,000 healthy women volunteers
from TwinsUK who had completed a food questionnaire designed to estimate total
dietary flavonoid intake as well as intakes from six flavonoid subclasses.
Blood samples were analysed for evidence of both glucose regulation and
inflammation. Insulin resistance, a hallmark of type 2 diabetes, was assessed
using an equation that considered both fasting insulin and glucose levels.
"We found that those who consumed plenty of
anthocyanins and flavones had lower insulin resistance. High insulin resistance
is associated with Type 2 diabetes, so what we are seeing is that people who
eat foods rich in these two compounds – such as berries, herbs, red grapes,
wine– are less likely to develop the disease.
"We also found that those who ate the most anthocyanins
were least likely to suffer chronic inflammation – which is associated with
many of today's most pressing health concerns including diabetes, obesity,
cardiovascular disease, and cancer.
"And those who consumed the most flavone compounds had
improved levels of a protein (adiponectin) which helps regulate a number of
metabolic processes including glucose levels.
"What we don't yet know is exactly how much of these
compounds are necessary to potentially reduce the risk of type 2
diabetes," she added.
Prof Tim Spector, research collaborator and director of the
TwinsUK study from King's College London, said: "This is an exciting
finding that shows that some components of foods that we consider unhealthy
like chocolate or wine may contain some beneficial substances. If we can start
to identify and separate these substances we can potentially improve healthy
eating. There are many reasons including genetics why people prefer certain
foods so we should be cautious until we test them properly in randomised trials
and in people developing early diabetes."
A Serving a Day of Dark
Chocolate Might Keep the Doctor Away
Chocolate, considered by some to be the “food of the gods,”
has been part of the human diet for at least 4,000 years; its origin thought to
be in the region surrounding the Amazon basin. Introduced to the Western world
by Christopher Columbus after his fourth voyage to the New World in 1502,
chocolate is now enjoyed worldwide. Researchers estimate that the typical
American consumes over 10 pounds of chocolate annually, with those living on
the west coast eating the most. Wouldn’t it be great if only chocolate were
considered healthy?
In fact, chocolate is a great source of myriad substances that
scientists think might impart important health benefits. For instance, it
contains compounds called “flavanols” that appear to play a variety of bodily
roles including those related to their potent antioxidant and anti-inflammatory
actions. Many large-scale human studies have documented a statistical
correlation between flavanol intake and risk for cardiovascular disease. And
animal studies suggest that this relationship may be due to the physiologic
effects that flavanols have on chronic inflammation, blood vessel health, and
circulating lipid levels. However, few controlled human intervention studies
have been conducted to test the direct effect of chocolate consumption on these
variables.
To help fill this knowledge gap, researchers at San Diego
State University tested their hypothesis that chocolate, in particular dark
chocolate which contains higher levels of flavanols than milk chocolate, may
protect against the risk of cardiovascular disease by lowering blood pressure,
blood flow, and improving blood lipid levels. In this prospective, controlled
human intervention study, 31 fortunate subjects were assigned randomly to
consume either a daily serving (50 grams) of either regular dark chocolate (70%
cocoa), dark chocolate (70% cocoa) that had been overheated or “bloomed,” or
white chocolate (0% cocoa). The subjects were asked to consume the chocolate
for 15 days. Blood pressure, forearm skin blood flow, circulating lipid
profiles, and blood glucose levels were recorded at the beginning and end of
the study.
When compared to participants assigned to the white
chocolate group, those consuming either form of dark chocolate had lower blood
glucose and low-density lipoprotein cholesterol (LDL, the “bad” form) levels
coupled with higher high-density lipoprotein cholesterol (HDL, the “good”
form).
The researchers concluded that dark chocolate may reduce the
risk of cardiovascular disease by improving glucose levels and lipid profiles.
However, they cautioned that—although habitual dark chocolate consumption may
benefit one’s health by reducing the risk of cardiovascular disease—it must be
eaten in moderation because it can easily increase daily amounts of saturated
fat and calories. Indeed, the authors commented, "We had great compliance
with our study subjects because everybody wanted to eat chocolate. We actually
had to tell them not to eat more than 50 grams a day.
Cocoa Health Benefits
Norman Hollenberg,
professor of medicine at Harvard Medical School has spent years studying the
benefits of cocoa drinking on the Kuna people in Panama. He found that the risk
of 4 of the 5 most common killer diseases: stroke, heart failure, cancer and
diabetes, is reduced to less then 10% in the Kuna. They can drink up to 40 cups
of cocoa a week. Natural cocoa has high levels of epicatechin.
'If these
observations predict the future, then we can say without blushing that they are
among the most important observations in the history of medicine,' Hollenberg
says. ‘We all agree that penicillin and anaesthesia are enormously important.
But epicatechin could potentially get rid of 4 of the 5 most common diseases in
the western world, how important does that make epicatechin?... I would say
very important’
Nutrition expert
Daniel Fabricant says that Hollenberg’s results, although observational, are so
impressive that they may even warrant a rethink of how vitamins are defined.
Epicatechin does not currently meet the criteria. Vitamins are defined as
essential to the normal functioning, metabolism, regulation and growth of cells
and deficiency is usually linked to disease. At the moment, the science does
not support epicatechin having an essential role. But, Fabricant, who is vice
president scientific affairs at the Natural Products Association, says: 'the
link between high epicatechin consumption and a decreased risk of killer
disease is so striking, it should be investigated further. It may be that these
diseases are the result of epicatechin deficiency,' he says.
-->
Eating chocolate
daily linked to lowered heart disease and stroke risk
Eating up to 100 g of chocolate every day is linked to
lowered heart disease and stroke risk, finds research published online in the
journal Heart.
They base their findings on almost 21,000 adults taking part in the EPIC-Norfolk study, which is tracking the impact of diet on the long term health of 25,000 men and women in Norfolk, England, using food frequency and lifestyle questionnaires.
The researchers also carried out a systematic review of the available international published evidence on the links between chocolate and cardiovascular disease, involving almost 158,000 people--including the EPIC study participants.
The EPIC-Norfolk participants (9214 men and 11 737 women) were monitored for an average of almost 12 years, during which time 3013 (14%) people experienced either an episode of fatal or non-fatal coronary heart disease or stroke.
Around one in five (20%) participants said they did not eat any chocolate, but among the others, daily consumption averaged 7 g, with some eating up to 100 g.
Higher levels of consumption were associated with younger age and lower weight (BMI), waist: hip ratio, systolic blood pressure, inflammatory proteins, diabetes and more regular physical activity --all of which add up to a favourable cardiovascular disease risk profile.
Eating more chocolate was also associated with higher energy intake and a diet containing more fat and carbs and less protein and alcohol.
The calculations showed that compared with those who ate no chocolate higher intake was linked to an 11% lower risk of cardiovascular disease and a 25% lower risk of associated death.
It was also associated with a 9% lower risk of hospital admission or death as a result of coronary heart disease, after taking account of dietary factors.
And among the 16,000 people whose inflammatory protein (CRP) level had been measured, those eating the most chocolate seemed to have an 18% lower risk than those who ate the least.
The highest chocolate intake was similarly associated with a 23% lower risk of stroke, even after taking account of other potential risk factors.
Of nine relevant studies included in the systematic review, five studies each assessed coronary heart disease and stroke outcome, and they found a significantly lower risk of both conditions associated with regular chocolate consumption.
And it was linked to a 25% lower risk of any episode of cardiovascular disease and a 45% lower risk of associated death.
This is an observational study so no definitive conclusions about cause and effect can be drawn. And the researchers point out that food frequency questionnaires do involve a certain amount of recall bias and underestimation of items eaten.
Reverse causation--whereby those with a higher cardiovascular disease risk profile eat less chocolate and foods containing it than those who are healthier--may also help to explain the results, they say.
Nevertheless, they add: "Cumulative evidence suggests that higher chocolate intake is associated with a lower risk of future cardiovascular events."
And they point out that as milk chocolate, which is considered to be less 'healthy' than dark chocolate, was more frequently eaten by the EPIC-Norfolk participants, the beneficial health effects may extend to this type of chocolate too.
"This may indicate that not only flavonoids, but also other compounds, possibly related to milk constituents, such as calcium and fatty acids, may provide an explanation for the observed association," they suggest.
Bacteria in the stomach gobble the chocolate and ferment it into
anti-inflammatory compounds
The health benefits of eating dark chocolate have
been extolled for centuries, but the exact reason has remained a mystery ––
until now. Researchers report that certain bacteria in the stomach gobble the
chocolate and ferment it into anti-inflammatory compounds that are good for the
heart.
Their findings were unveiled at the 247th
National Meeting & Exposition of the American Chemical Society (ACS) in
March 2014.
"We found that there are two kinds of
microbes in the gut: the 'good' ones and the 'bad' ones," explained Maria
Moore, an undergraduate student and one of the study's researchers.
"The good microbes, such as Bifidobacterium
and lactic acid bacteria, feast on chocolate," she said. "When you
eat dark chocolate, they grow and ferment it, producing compounds that are
anti-inflammatory." The other bacteria in the gut are associated with
inflammation and can cause gas, bloating, diarrhea and constipation. These
include some Clostridia and some E. coli.
"When these compounds are absorbed by the
body, they lessen the inflammation of cardiovascular tissue, reducing the
long-term risk of stroke," said John Finley, Ph.D., who led the work. He
said that this study is the first to look at the effects of dark chocolate on
the various types of bacteria in the stomach. The researchers are with Louisiana
State University.
The team tested three cocoa powders using a
model digestive tract, comprised of a series of modified test tubes, to
simulate normal digestion. They then subjected the non-digestible materials to
anaerobic fermentation using human fecal bacteria, according to Finley.
He explained that cocoa powder, an ingredient in
chocolate, contains several polyphenolic, or antioxidant, compounds such as
catechin and epicatechin, and a small amount of dietary fiber. Both components
are poorly digested and absorbed, but when they reach the colon, the desirable
microbes take over. "In our study we found that the fiber is fermented and
the large polyphenolic polymers are metabolized to smaller molecules, which are
more easily absorbed. These smaller polymers exhibit anti-inflammatory
activity," he said.
Dark chocolate helps restore flexibility to arteries
Dark chocolate helps restore flexibility to
arteries while also preventing white blood cells from sticking to the walls of
blood vessels. Both arterial
stiffness and white blood cell adhesion are known factors that play a
significant role in atherosclerosis. What's more, the scientists also found
that increasing the flavanol content of dark chocolate did not change this
effect. This discovery was published in the March 2014 issue of The FASEB Journal.
"We provide a more complete picture of the
impact of chocolate consumption in vascular health and show that increasing
flavanol content has no added beneficial effect on vascular health," said
Diederik Esser, Ph.D., a researcher involved in the work from the Top Institute
Food and Nutrition and Wageningen University, Division of Human Nutrition in
Wageningen, The Netherlands. "However, this increased flavanol content
clearly affected taste and thereby the motivation to eat these chocolates. So
the dark side of chocolate is a healthy one."
To make this discovery, Esser and colleagues
analyzed 44 middle-aged overweight men over two periods of four weeks as they
consumed 70 grams of chocolate per day. Study participants received either
specially produced dark chocolate with high flavanol content or chocolate that
was regularly produced. Both chocolates had a similar cocoa mass content.
Before and after both intervention periods, researchers performed a variety of
measurements that are important indicators of vascular health. During the
study, participants were advised to refrain from certain energy dense food
products to prevent weight gain. Scientists also evaluated the sensory
properties of the high flavanol chocolate and the regular chocolate and
collected the motivation scores of the participants to eat these chocolates
during the intervention.
"The effect that dark chocolate has on our
bodies is encouraging not only because it allows us to indulge with less guilt,
but also because it could lead the way to therapies that do the same thing as
dark chocolate but with better and more consistent results," said Gerald
Weissmann, M.D., Editor-in-Chief of The FASEB Journal. "Until the 'dark
chocolate drug' is developed, however, we'll just have to make do with what
nature has given us!"
Chocolate: A sweet method for stroke prevention in men?
Eating a moderate amount of chocolate each week
may be associated with a lower risk of stroke in men, according to a new study
published in the August 29, 2012, online issue of Neurology®, the medical journal of the American Academy of
Neurology.
"While other studies have looked at how
chocolate may help cardiovascular health, this is the first of its kind study
to find that chocolate, may be beneficial for reducing stroke in men,"
said study author Susanna C. Larsson, PhD, with the Karolinska Institute in
Stockholm, Sweden.
For the study, 37,103 Swedish men ages 49 to 75
were given a food questionnaire that assessed how often they consumed various
foods and drinks and were asked how often they had chocolate. Researchers then
identified stroke cases through a hospital discharge registry. Over 10 years,
there were 1,995 cases of first stroke.
Men in the study who ate the largest amount of
chocolate, about one-third of a cup of chocolate chips (63 grams), had a lower
risk of stroke compared to those who did not consume any chocolate. Those
eating the highest amount of chocolate had a 17-percent lower risk of stroke,
or 12 fewer strokes per 100,000 person-years compared to those who ate no
chocolate. Person-years is the total number of years that each participant was
under observation.
In a larger analysis of five studies that
included 4,260 stroke cases, the risk of stroke for individuals in the highest
category of chocolate consumption was 19 percent lower compared to
non-chocolate consumers. For every increase in chocolate consumption of 50
grams per week, or about a quarter cup of chocolate chips, the risk of stroke
decreased by about 14 percent.
"The beneficial effect of chocolate
consumption on stroke may be related to the flavonoids in chocolate. Flavonoids
appear to be protective against cardiovascular disease through antioxidant,
anti-clotting and anti-inflammatory properties. It's also possible that
flavonoids in chocolate may decrease blood concentrations of bad cholesterol
and reduce blood pressure," said Larsson.
"Interestingly, dark chocolate has
previously been associated with heart health benefits, but about 90 percent of
the chocolate intake in Sweden, including what was consumed during our study,
is milk chocolate," Larsson added.
Dark Chocolate, Cocoa Compounds, May Reduce Blood Pressure
Compounds in
cocoa may help to reduce blood pressure, according to a new systematic review
in The Cochrane Library. The
researchers reviewed evidence from short-term trials in which participants were
given dark chocolate or cocoa powder daily and found that their blood pressure
dropped slightly compared to a control group.
Cocoa contains
compounds called flavanols, thought to be responsible for the formation of
nitric oxide in the body. Nitric oxide causes blood vessel walls to relax and
open wider, thereby reducing blood pressure. The link between cocoa and blood
pressure stems from the discovery that the indigenous people of San Blas Island
in Central American, who drink flavanol-rich cocoa drinks every day, have
normal blood pressure regardless of age. However, flavanol concentrations in
cocoa and chocolate products vary according to cocoa processing procedures and
types of chocolate, so it is difficult to establish the optimal dosage for an
effect.
To investigate
the effect of flavanols on blood pressure, the researchers reviewed data from
trials in which people consumed dark chocolate or cocoa powder containing
between 30-1080 mg of flavanols in 3-100 g of chocolate each day. Altogether,
856 people were involved in 20 trials lasting 2-8 weeks, or in one case, 18
weeks. Flavanol-rich chocolate or cocoa powder reduced blood pressure on
average by 2-3 mm Hg.
“Although we
don’t yet have evidence for any sustained decrease in blood pressure, the small
reduction we saw over the short term might complement other treatment options
and might contribute to reducing the risk of cardiovascular disease,” said lead
researcher Karin Ried of the National Institute of Integrative Medicine in
Melbourne, Australia, who worked with colleagues at the University of Adelaide.
In
a subset of trials, when chocolate or cocoa powder was compared to flavanol-free-products
as controls, the beneficial effects were more pronounced (3-4 mm Hg), whereas
the researchers found no significant effect on blood pressure in the second
subset with low-flavanol products as control. It is possible that low-flavanol
products also have a small effect on blood pressure, so that it was harder to
observe differences between high and low-flavanol products in these trials.
However, results of these subsets of trials may have been influenced by trial
length and blinding of participants, as trials using flavanol-free control
products tended to be of shorter duration with participants knowing their
allocated group.
“We’ll also need
to see long term trials, including effects on the risk of stroke and
cardiovascular disease, before we can come to conclusions regarding clinical
outcomes and potential side effects of long-term consumption,” said Ried.
“These trials should use flavanol-free products in the control groups to
eliminate any potential effects of low-dose flavanol on blood pressure.”
Dark Chocolate May Reduce Cardiovascular Events
Good news for chocolate lovers! Eating dark chocolate on a daily basis
can reduce cardiovascular events, including heart attacks and strokes in people
with metabolic syndrome, i.e. a combination of factors that increase the risk
of developing heart disease and diabetes.
The study was published in British Medical Journal (BMJ) June 1, 2012.
Worldwide, cardiovascular disease is the highest cause of
mortality. Dark chocolate with a cocoa solid content of at least 60% is rich in
flavonoids that are known to protect the heart. However, the protecting effects
have so far only been assessed in short-term studies. To predict the long-term
effects, Australian researchers from Melbourne used a mathematical model to
predict the long-term health effects and economic effectiveness of eating dark
chocolate on a daily basis. For their study, the researchers recruited 2,013
people who were high-risk candidates for heart disease.
All participants were hypertensive and met the criteria for
metabolic syndrome, yet they had no previous history of heart disease or
diabetes and did not take medication to lower their blood pressure. The
best-case scenario, i.e. a compliance of 100% meant that eating dark chocolate
on a daily basis would be able to prevent 70 non-fatal and 15 fatal
cardiovascular events per 10,000 people over a 10-year duration.
By reducing the compliance rate to 80%, they could
potentially prevent 55 non-fatal and 10 fatal events respectively, which is
still a substantial reduction and effective intervention.
According to the model, governments would be able to spend
$A40 (£25; €31; $42) per person per year cost effectively on dark chocolate
prevention strategies. This saving could be used for advertising, educational
campaigns, or subsidizing dark chocolate in this high-risk population.
The researchers point out that their study only assessed
non-fatal stroke and non-fatal heart attacks, and that further tests are
required to evaluate the potential impact on other cardiovascular events like
heart failure.
They also stress that these protective effects only apply to
dark chocolate with a cocoa content of at least 60-70% cocoa, an not to milk or
white chocolate. This could be because of the fact that dark chocolate has a
much higher level of flavonoids.
Chocolate Consumption Reduces Risk of Stroke in Women
Ample evidence
indicates that chocolate may have beneficial effects on the cardiovascular
system. Chocolate consumption has been shown to reduce systolic and diastolic
blood pressure in short-term randomized feeding trials (1), and has been
demonstrated to improve endothelial and platelet function and to ameliorate
insulin resistance (2). Moreover, flavonoids in chocolate possess strong
antioxidant activity and can suppress oxidation of low-density lipoprotein
cholesterol (3).
In the autumn of
1997, 39,227 women completed a questionnaire that included approximately 350
items concerning diet and other lifestyle factors (4). We excluded women with a
missing national identification number, those with implausible values for total
energy intake, and those with a history of cancer, stroke, coronary heart
disease, or diabetes mellitus before baseline. That left 33,372 women, age 49
to 83 years, for analysis. The study was approved by the Ethical Review Board
at the Karolinska Institutet (Stockholm, Sweden). Chocolate consumption was
assessed using a self-administered food-frequency questionnaire. Women were
asked to indicate how often on average they had consumed chocolate and 95 other
foods during the previous year. There were 8 pre-defined consumption categories
ranging from never to ≥3 times a day. In the 1990s, approximately 90% of
chocolate consumption in Sweden was milk chocolate, containing approximately
30% cocoa solids (5).
Our findings are
broadly consistent with those from previous smaller studies, which observed
either a statistically significant (136 stroke cases) (6) or a nonsignificant
(111 or 469 stroke cases) (5,7) inverse association between chocolate
consumption and total stroke. In the present study, only women in the highest
quartile of chocolate consumption (median 66.5 g/week) had a significantly
reduced risk of stroke, suggesting that higher intakes are necessary for a
potential protective effect. The reason for the stronger association observed
for hemorrhagic stroke than for cerebral infarction is unclear.
In summary,
results from this cohort of women suggest that a high chocolate consumption is
associated with a lower risk of stroke.
Chocolate reduces the risk of
cardiovascular disease and stroke
A number of recent studies have shown that eating chocolate has a
positive influence on human health due to its antioxidant and anti-inflammatory
properties. This includes reducing blood pressure and improving insulin
sensitivity (a stage in the development of diabetes).
However, the evidence about how eating chocolate affects your heart
still remains unclear. So, Dr Oscar Franco and colleagues from the University
of Cambridge carried out a large scale review of the existing evidence to
evaluate the effects of eating chocolate on cardiovascular events like heart
attack and stroke.
They analysed the results of seven studies, involving over 100,000
participants with and without existing heart disease. For each study, they
compared the group with the highest chocolate consumption against the group
with the lowest consumption. Differences in study design and quality were also
taken into account to minimise bias.
Five studies reported a beneficial link between higher levels of
chocolate consumption and the risk of cardiovascular events and they found that
the "highest levels of chocolate consumption were associated with a 37%
reduction in cardiovascular disease and a 29% reduction in stroke compared with
lowest levels." No significant reduction was found in relation to heart
failure.
The studies did not differentiate between dark or milk chocolate and
included consumption of chocolate bars, drinks, biscuits and desserts.
The authors say the findings need to be interpreted with caution, in
particular because commercially available chocolate is very calorific (around
500 calories for every 100 grams) and eating too much of it could in itself
lead to weight gain, risk of diabetes and heart disease.
Moderate chocolate consumption
linked to lower risks of heart failure
Study highlights:
• Eating moderate amounts of chocolate is linked to lower risks of heart
failure among middle-aged and older women, compared to eating no chocolate at
all.
• Experts warn Americans that the potential for heart health benefits
from chocolate must be carefully weighed against the negative risks including
excess calories and fat.
• This is the first study to examine long-term effects of eating
chocolate on heart failure rates.
Middle-aged and elderly Swedish women who regularly ate a small amount
of chocolate had lower risks of heart failure risks, in a study reported in Circulation: Heart Failure, a journal of
the American Heart Association.
The nine-year study, conducted among 31,823 middle-aged and elderly
Swedish women, looked at the relationship of the amount of high-quality
chocolate the women ate, compared to their risk for heart failure. The quality
of chocolate consumed by the women had a higher density cocoa content somewhat
like dark chocolate by American standards. In this study, researchers found:
- Women who ate an average of one to two servings of the high-quality
chocolate per week had a 32 percent lower risk of developing heart failure.
- Those who had one to three servings per month had a 26 percent lower
risk.
- Those who consumed at least one serving daily or more didn’t appear to
benefit from a protective effect against heart failure.
The lack of a protective effect among women eating chocolate every day
is probably due to the additional calories gained from eating chocolate instead
of more nutritious foods, said Murrray Mittleman, M.D., Dr.P.H., lead
researcher of the study.
“You can’t ignore that chocolate is a relatively calorie-dense food and
large amounts of habitual consumption is going to raise your risks for weight
gain,” said Mittleman, director of the Cardiovascular Epidemiology Research
Unit at Harvard Medical School’s Beth Israel Deaconess Medical Center in
Boston. “But if you’re going to have a treat, dark chocolate is probably a good
choice, as long as it’s in moderation.”
High concentration of compounds called “flavonoids” in chocolate may
lower blood pressure, among other benefits, according to mostly short-term
studies. However, this is the first study to show long-term outcomes related
specifically to heart failure, which can result from ongoing untreated high
blood pressure.
In the observational study, researchers analyzed self-reported
food-frequency questionnaire responses from participants 48-to-83-years-old in
the Swedish Mammography Cohort. Combining the results with data from national
Swedish hospitalization and death registries between 1998 through 2006, the
researchers used multiple forms of statistical modeling to reach their
conclusions on heart failure and chocolate consumption.
Mittleman said differences in chocolate quality affect the study’s
implications for Americans. Higher cocoa content is associated with greater
heart benefits. In Sweden, even milk chocolate has a higher cocoa concentration
than dark chocolate sold in the United States.
Although 90 percent of all chocolate eaten across Sweden during the
study period was milk chocolate, it contained about 30 percent cocoa solids.
U.S. standards only require 15 percent cocoa solids to qualify as dark
chocolate. So, by comparison, American chocolate may have fewer heart benefits
and more calories and fat per equivalent amounts of cocoa content compared to
the chocolate eaten by the Swedish women in the study.
Also, the average serving size for Swedish women in the study ranged
from 19 grams among those 62 and older, to 30 grams among those 61 and younger.
In contrast, the standard American portion size is 20 grams.
“Those tempted to use these data as their rationale for eating large
amounts of chocolate or engaging in more frequent chocolate consumption are not
interpreting this study appropriately,” said Linda Van Horn, Ph.D., R.D.,
immediate past chair of the American Heart Association Nutrition Committee and
professor in the Department of Preventive Medicine at Northwestern University’s
Feinberg School of Medicine in Chicago. “This is not an ‘eat all you want’
take-home message, rather it’s that eating a little dark chocolate can be
healthful, as long as other adverse behaviors do not occur, such as weight gain
or excessive intake of non-nutrient dense ‘empty’ calories.”
Dark chocolate lowers blood
pressure
For people with hypertension, eating dark chocolate can significantly
reduce blood pressure. Researchers writing in the open access journal BMC Medicine combined the results of 15
studies into the effects of flavanols, the compounds in chocolate which cause
dilation of blood vessels, on blood pressure.
Dr Karin Ried worked with a team of researchers from the University of
Adelaide, Australia, to conduct the analysis. She said, "Flavanols have
been shown to increase the formation of endothelial nitric oxide, which
promotes vasodilation and consequently may lower blood pressure. There have,
however, been conflicting results as to the real-life effects of eating
chocolate. We've found that consumption can significantly, albeit modestly,
reduce blood pressure for people with high blood pressure but not for people
with normal blood pressure".
The pressure reduction seen in the combined results for people with
hypertension, 5mm Hg systolic, may be clinically relevant – it is comparable to
the known effects of 30 daily minutes of physical activity (4-9mm Hg) and could
theoretically reduce the risk of a cardiovascular event by about 20% over five
years. The researchers are cautious, however, "The practicability of
chocolate or cocoa drinks as long-term treatment is questionable", said Dr
Ried.
Does chocolate reduce blood
pressure? A meta-analysis
Karin Ried, Thomas Sullivan,
Peter Fakler, Oliver R Frank and Nigel P Stocks
BMC Medicine 2010, 8:39
doi:10.1186/1741-7015-8-39
Dark Chocolate May Guard
Against Brain Injury From Stroke
Researchers at Johns Hopkins have discovered that a compound in dark
chocolate may protect the brain after a stroke by increasing cellular signals
already known to shield nerve cells from damage.
Ninety minutes after feeding mice a single modest dose of epicatechin, a
compound found naturally in dark chocolate, the scientists induced an ischemic
stroke by essentially cutting off blood supply to the animals' brains. They
found that the animals that had preventively ingested the epicatechin suffered
significantly less brain damage than the ones that had not been given the
compound.
While most treatments against stroke in humans have to be given within a
two- to three-hour time window to be effective, epicatechin appeared to limit
further neuronal damage when given to mice 3.5 hours after a stroke. Given six
hours after a stroke, however, the compound offered no protection to brain
cells.
Sylvain Dore, Ph.D., associate professor of anesthesiology and critical
care medicine and pharmacology and molecular sciences at the Johns Hopkins
University School of Medicine, says his study suggests that epicatechin
stimulates two previously well-established pathways known to shield nerve cells
in the brain from damage. When the stroke hits, the brain is ready to protect
itself because these pathways - Nrf2 and heme oxygenase 1 - are activated. In
mice that selectively lacked activity in those pathways, the study found,
epicatechin had no significant protective effect and their brain cells died after
a stroke.
The study appeared online in the Journal
of Cerebral Blood Flow and Metabolism.
Eventually, Dore says, he hopes his research into these pathways could
lead to insights into limiting acute stroke damage and possibly protecting
against chronic neurological degenerative conditions, such as Alzheimer's
disease and other age-related cognitive disorders.
The amount of dark chocolate people would need to consume to benefit
from its protective effects remains unclear, since Dore has not studied it in
clinical trials. People shouldn't take this research as a free pass to go out
and consume large amounts of chocolate, which is high in calories and fat. In
fact, people should be reminded to eat a healthy diet with a variety of fruits
and vegetables.
Scientists have been intrigued by the potential health benefits of
epicatechin by studying the Kuna Indians, a remote population living on islands
off the coast of Panama. The islands' residents had a low incidence of
cardiovascular disease.
Scientists who studied them found nothing striking in the genes and
realized that when they moved away from Kuna, they were no longer protected
from heart problems. Researchers soon discovered the reason was likely
environmental: The residents of Kuna regularly drank a very bitter cocoa drink,
with a consistency like molasses, instead of coffee or soda. The drink was high
in the compound epicatechin, which is a flavanol, a flavanoid-related compound.
But Dore says his research suggests the amount needed could end up being
quite small because the suspected beneficial mechanism is indirect.
"Epicatechin itself may not be shielding brain cells from free radical
damage directly, but instead, epicatechin, and its metabolites, may be
prompting the cells to defend themselves," he suggests. The epicatechin is
needed to jump-start the protective pathway that is already present within the
cells. "Even a small amount may be sufficient," Dore says.
Not all dark chocolates are created equally, he cautions. Some have more
bioactive epicatechin than others.
"The epicatechin found in dark chocolate is extremely sensitive to
changes in heat and light" he says. "In the process of making
chocolate, you have to make sure you don't destroy it. Only few chocolates have
the active ingredient. The fact that it says 'dark chocolate' is not
sufficient."
Chocolate reduces blood
pressure and risk of heart disease
Chocolate may be good for you – at least in small quantities and
preferably if it's dark chocolate – according to research that shows just one
small square of chocolate a day can lower your blood pressure and reduce your
risk of heart disease. The study was published online Wednesday 31 March 2010
in the European Heart Journal [1].
Researchers in Germany followed 19,357 people, aged between 35 and 65,
for at least ten years and found that those who ate the most amount of
chocolate – an average of 7.5 grams a day – had lower blood pressure and a 39%
lower risk of having a heart attack or stroke compared to those who ate the
least amount of chocolate – an average of 1.7 grams a day. The difference
between the two groups amounts to six grams of chocolate: the equivalent of
less than one small square of a 100g bar.
Dr Brian Buijsse, a nutritional epidemiologist at the German Institute
of Human Nutrition, Nuthetal, Germany, who led the research said: "People
who ate the most amount of chocolate were at a 39% lower risk than those with
the lowest chocolate intakes. To put it in terms of absolute risk, if people in
the group eating the least amount of chocolate (of whom 219 per 10,000 had a
heart attack or stroke) increased their chocolate intake by six grams a day, 85
fewer heart attacks and strokes per 10,000 people could be expected to occur
over a period of about ten years. If the 39% lower risk is generalised to the
general population, the number of avoidable heart attacks and strokes could be
higher because the absolute risk in the general population is higher."[2]
However, he warned that it was important people ensured that eating
chocolate did not increase their overall intake of calories or reduce their
consumption of healthy foods. "Small amounts of chocolate may help to
prevent heart disease, but only if it replaces other energy-dense food, such as
snacks, in order to keep body weight stable," he said.
The people in the study were participants in the Potsdam arm of the
European Prospective Investigation into Cancer (EPIC). They received medical
checks, including blood pressure, height and weight measurements at the start
of the study between 1994-1998, and they also answered questions about their
diet, lifestyle and health. They were asked how frequently they ate a 50g bar
of chocolate, and they could say whether they ate half a bar, or one, two or
three bars. They were not asked about whether the chocolate was white, milk or
dark chocolate; however, the researchers asked a sub-set of 1,568 participants
to recall their chocolate intake over a 24-hour period and to indicate which
type of chocolate they ate. This gave an indication of the proportions that
might be expected in the whole study. In this sub-set, 57% ate milk chocolate,
24% dark chocolate and 2% white chocolate.
In follow-up questionnaires, sent out every two or three years until
December 2006, the study participants were asked whether they had had a heart
attack or stroke, information which was subsequently verified by medical
records from general physicians or hospitals. Death certificates from those who
had died were also used to identify heart attacks and strokes.
The researchers allocated the participants to four groups (quartiles)
according to their level of chocolate consumption. Those in the top quartile,
eating around 7.5g of chocolate a day, had blood pressure that was about 1mm Hg
(systolic) and 0.9mm Hg (diastolic) lower than those in the bottom quartile.
[3]
"Our hypothesis was that because chocolate appears to have a
pronounced effect on blood pressure, therefore chocolate consumption would
lower the risk of strokes and heart attacks, with a stronger effect being seen
for stroke," explained Dr Buijsse.
This is, in fact, what the study found. During the eight years there
were 166 heart attacks (24 fatal) and 136 strokes (12 fatal); people in the top
quartile had a 27% reduced risk of heart attacks and nearly half the risk (48%)
of strokes, compared with those in the lowest quartile.
The researchers found lower blood pressure due to chocolate consumption
at the start of the study explained 12% of the reduced risk of heart attacks
and strokes, but even after taking this into account, those in the top quartile
still had their risk reduced by a third (32%) compared to those in the bottom quartile
over the duration of the study.
Although more research needs to be carried out, the researchers believe
that flavanols in cocoa may be the reason why chocolate seems to be good for
people's blood pressure and heart health; and since there is more cocoa in dark
chocolate, dark chocolate may have a greater effect.
"Flavanols appear to be the substances in cocoa that are
responsible for improving the bioavailability of nitric oxide from the cells
that line the inner wall of blood vessels – vascular endothelial cells,"
said Dr Buijsse. "Nitric oxide is a gas that, once released, causes the
smooth muscle cells of the blood vessels to relax and widen; this may
contribute to lower blood pressure. Nitric oxide also improves platelet
function, making the blood less sticky, and makes the vascular endothelium less
attractive for white blood cells to attach and stick around."
The authors of the study conclude: "Given these and other promising
health effects of cocoa, it is tempting to indulge more in chocolate. Small
amounts of chocolate, however, may become part of a diet aimed to prevent CVD
[cardiovascular disease] only after confirmation by other observational studies
and particularly by randomized trials."
Commenting on the research on behalf of the European Society of
Cardiology (ESC), Frank Ruschitzka, Professor of Cardiology, Director of Heart
Failure/Transplantation at the University Hospital Zurich, Switzerland, and a
Fellow of the ESC, said: "Basic science has demonstrated quite convincingly
that dark chocolate particularly, with a cocoa content of at least 70%, reduces
oxidative stress and improves vascular and platelet function. However, before
you rush to add dark chocolate to your diet, be aware that 100g of dark
chocolate contains roughly 500 calories. As such, you may want to subtract an
equivalent amount of calories, by cutting back on other foods, to avoid weight
gain."
Notes:
[1] "Chocolate consumption in
relation to blood pressure and risk of cardiovascular disease in German adults."
European Heart Journal. doi:10.1093/eurheartj/ehq068.
[2] Examples of absolute risk are given here to help with understanding
the findings; however, the study itself only reports relative risk.
[3] mm Hg = millimetres of mercury (the measure for blood pressure).
Systolic = when the heart's ventricles contract.
Diastolic = when the ventricles relax.
The normal blood pressure for a healthy adult is around 120/80.
Chocolate could lower risk of
stroke
Giving chocolates to your Valentine may help lower their risk of stroke
based on a preliminary study from researchers at St. Michael's Hospital. The
study, presented at the American Academy of Neurology in April, 2010, also
found that eating chocolate may lower the risk of death after suffering a stroke.
"Though more research is needed to determine whether chocolate is
the contributing factor to lowering stroke risk, it is rich in anti-oxidants
and that may have a protective effect against stroke," explains Dr.
Gustavo Saposnik, a neurologist at St. Michael's Hospital.
Chocolate is rich in antioxidants called flavonoids which may help lower
the risk of strokes.
Authored by Sarah Sahib, the research analyzed three studies involving
chocolate consumption and stroke risk. One showed there was no association
between flavonoid intake and risk of stroke or death. In contrast, a second
study found an association with stroke for chocolate consumption once a week as
opposed to none per week. The third study suggested flavonoid intake from
eating chocolate weekly lowered death caused by a stroke.
"We are continuing to investigate the correlation between chocolate
and the risk of stroke," says Dr. Saposnik. "The preliminary data is
interesting but we need to determine whether consumption truly lowers the risk
of a stroke or whether the benefit is biased based on those who are on average
healthier than the general population when enrolling in a clinical trial."
A
little dark chocolate = less blood pressure
Consumption of small amounts of dark chocolate associated
with reduction in blood pressure
Eating about 30 calories a day of dark chocolate was
associated with a lowering of blood pressure, without weight gain or other
adverse effects, according to a study in JAMA.
Previous research has indicated that consumption of high
amounts of cocoa-containing foods can lower blood pressure (BP), believed to be
due to the action of the cocoa polyphenols (a group of chemical substances
found in plants, some of which, such as the flavanols, are believed to be
beneficial to health). “A particular concern is that the potential BP reduction
contributed by the flavanols could be offset by the high sugar, fat and calorie
intake with the cocoa products,” the authors write. The effect of low cocoa
intake on BP is unclear.
Dirk Taubert, M.D., Ph.D., of University Hospital of
Cologne, Germany, and colleagues assessed the effects of low regular amounts of
cocoa on BP. The trial, conducted between January 2005 and December 2006,
included 44 adults (age 56 through 73 years; 24 women, 20 men) with untreated
upper-range prehypertension (BP 130/85 – 139/89) or stage 1 hypertension (BP
140/90 – 160/100). Participants were randomly assigned to receive for 18 weeks
either 6.3 g (30 calories) per day of dark chocolate containing 30 mg
polyphenols or matching polyphenol-free white chocolate.
The researchers found that from baseline to 18 weeks, dark
chocolate intake reduced average systolic BP by −2.9 (1.6) mm Hg and diastolic
BP by −1.9 (1.0) mm Hg without changes in body weight, plasma levels of lipids
or glucose. Hypertension prevalence declined from 86 percent to 68 percent.
Systolic and diastolic BP remained unchanged throughout the treatment period
among those in the white chocolate group. Dark chocolate consumption resulted
in the short-term appearance of cocoa phenols in plasma and increased
vasodilatory S-nitrosoglutathione. There was no change in plasma biomarkers in
the white chocolate group.
“Although the magnitude of the BP reduction was small, the
effects are clinically noteworthy. On a population basis, it has been estimated
that a 3-mm Hg reduction in systolic BP would reduce the relative risk of
stroke mortality by 8 percent, of coronary artery disease mortality by 5
percent, and of all-cause mortality by 4 percent,” the authors write.
“The most
intriguing finding of this study is that small amounts of commercial cocoa
confectionary convey a similar BP-lowering potential compared with
comprehensive dietary modifications that have proven efficacy to reduce
cardiovascular event rate. Whereas long-term adherence to complex behavioral
changes is often low and requires continuous counseling, adoption of small
amounts of flavanol-rich cocoa into the habitual diet is a dietary modification
that is easy to adhere to and therefore may be a promising behavioral approach
to lower blood pressure in individuals with above-optimal blood pressure.
Future studies should evaluate the effects of dark chocolate in other
populations and evaluate long-term outcomes,” the authors conclude.
Dark chocolate: Half a bar per week to keep at bay the risk
of heart attack
An Italian study,
the first outcome of a large epidemiological investigation, finds new
beneficial effects of chocolate in the prevention of cardiovascular disease
6.7 grams of
chocolate per day represent the ideal amount for a protective effect against
inflammation and subsequent cardiovascular disease.
The findings,
published in the Journal of Nutrition,
official journal of the American Society of Nutrition, come from one of the
largest epidemiological studies ever conducted in Europe, the Moli-sani
Project, which has enrolled 20,000 inhabitants of the Molise region so far. By
studying the participants recruited, researchers focused on the complex
mechanism of inflammation. It is known how a chronic inflammatory state
represents a risk factor for the development of cardiovascular disease, from
myocardial infarction to stroke, just to mention the major diseases. Keeping
the inflammation process under control has become a major issue for prevention
programs and C reactive protein turned out to be one of the most promising
markers, detectable by a simple blood test.
"We started
from the hypothesis- says Romina di Giuseppe, 33, lead author of the study-
that high amounts of antioxidants contained in the cocoa seeds, in particular
flavonoids and other kinds of poly-phenols, might have beneficial effects on
the inflammatory state. Our results have been absolutely encouraging: people
having moderate amounts of dark chocolate regularly have significantly lower
levels of C-reactive protein in their blood. In other words, their inflammatory
state is considerably reduced." The 17% average reduction observed may appear
quite small, but it is enough to decrease the risk of cardiovascular disease
for one third in women and one fourth in men. It is undoubtedly a remarkable
outcome".
Chocolate amounts
are critical. "We are talking of a moderate consumption. The best effect is
obtained by consuming an average amount of 6.7 grams of chocolate per day,
corresponding to a small square of chocolate twice or three times a week.
Beyond these amounts the beneficial effect tends to disappear".
From a practical
point of view, as the common chocolate bar is 100 grams, the study states that
less than half a bar of dark chocolate consumed during the week may become a
healthy habit. What about the milk chocolate? "Previous studies- the young
investigator continues- have demonstrated that milk interferes with the
absorption of polyphenols. That is why our study considered just the dark
chocolate".
Researchers wanted
to sweep all the doubts away. They took into account that chocolate lovers
might consume other healthy food too, as wine, fruits and vegetables. Or they
might exercise more than others people do. So the observed positive effect
might be ascribed to other factors but not to cocoa itself. "In order to
avoid this - researcher says - we "adjusted" for all possible "confounding"
parameters. But the beneficial effect of chocolate still remained and we do
believe it is real".
Cocoa could prevent intestinal pathologies such as colon cancer
A new study on
living animals has shown for the first time that eating cocoa (the raw material
in chocolate) can help to prevent intestinal complaints linked to oxidative
stress, including colon carcinogenesis onset caused by chemical substances.
The growing
interest amongst the scientific community to identify those foods capable of
preventing diseases has now categorized cocoa as a 'superfood'. It has been
recognised as an excellent source of phytochemical compounds, which offer
potential health benefits.
Headed by
scientists from the Institute of Food Science and Technology and Nutrition
(ICTAN) and recently (January, 2012) published in the Molecular Nutrition & Food Research journal, the new study
supports this idea and upholds that cacao consumption helps to prevent
intestinal complaints linked to oxidative stress, such as the onset of
chemically induced colon carcinogenesis.
"Being
exposed to different poisons in the diet like toxins, mutagens and
procarcinogens, the intestinal mucus is very susceptible to pathologies,"
explains María Ángeles Martín Arribas, lead author of the study and researcher
at ICTAN. She adds that "foods like cocoa, which is rich in polyphenols,
seems to play an important role in protecting against disease."
The study on
live animals (rats) has for the first time confirmed the potential protection
effect that flavonoids in cocoa have against colon cancer onset. For eight
weeks the authors of the study fed the rats with a cocoa-rich (12%) diet and
carcinogenesis was induced.
Doctor Martín
Arribas outlines that "four weeks after being administered with the
chemical compound azoxymethane (AOM), intestinal mucus from premalignant
neoplastic lesions appeared. These lesions are called 'aberrant crypt foci' and
are considered to be good markers of colon cancer pathogenesis.
The results of
the study showed that the rats fed a cocoa-rich diet had a significantly
reduced number of aberrant crypts in the colon induced by the carcinogen.
Likewise, this sample saw an improvement in their endogenous antioxidant
defences and a decrease in the markers of oxidative damage induced by the toxic
compound in this cell.
The researchers
conclude that the protection effect of cocoa can stop cell-signalling pathways
involved in cell proliferation and, therefore, subsequent neoplasty and tumour
formation. Lastly, the animals fed with the cocoa-rich diet showed an increase
in apoptosis or programmed cell death as a chemoprevention mechanism against
the development of the carcinogenesis.
Although more
research is required to determine what bioactive compounds in cocoa are
responsible for such effects, the authors conclude that a cocoa-rich diet seems
capable of reducing induced oxidative stress. It could also have protection
properties in the initial stages of colon cancer as it reduces premalignant
neoplastic lesion formation.
Cocoa is one of
the ingredients in chocolate. It is one of the richest foods in phenolic
compounds, mainly in flavonoids like procyanidins, catechins and epicatechins,
which have numerous beneficial biological activities in the prevention of
cardiovascular diseases and cancer (mainly colorectal cancer).
In fact, compared
to other foods with a high flavonoid content, cocoa has a high level of
procyanidins with limited bioavailability. These flavonoids are therefore found
in their highest concentrations in the intestine where they neutralise many
oxidants.
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