Download Correlation between chocolate consumption and Life expectancy

Correlation between chocolate consumption and Life expectancy, Coronary artery disease
and Alzheimer’s disease.
Institute where work was performed:
Department of Physiology, College of Medicine, University of Dammam, Dammam, Kingdom
of Saudi Arabia
Correspondence address
Department of Physiology
College of Medicine, Building 65
University of Dammam, Dammam
Kingdom of Saudi Arabia
Cell: +966 0596 212 648
Email: [email protected]
[email protected]
Running title: Chocolate, Life expectancy, Coronary artery disease and Alzheimer’s disease.
1
Title: Correlation between chocolate consumption and Life expectancy, Coronary artery
disease and Alzheimer’s disease.
Abstract
Background: This non experimental correlational study was planned to study the association
between chocolate consumption, Life expectancy, Coronary artery disease and Alzheimer’s
disease.
Methods: Data on per capita yearly chocolate consumption, life expectancy, Number of deaths
per 100, 000 populations due to Coronary artery disease and Alzheimer’s disease were obtained
from
http://onegoldenticket.blogspot.com/2011/01/chocolate-consumption-statistics.html,
wikipedia
http://en.wikipedia.org/wiki/List_of_countries_by_life_expectancy
and
http://www.worldlifeexpectancy.com/ respectively.
Results: No significant correlation was found when yearly chocolate consumption was
compared with any of the variables like Coronary artery disease, Alzheimer’s disease and life
expectancy.
Conclusion: Yearly Chocolate consumption is not related to life expectancy, deaths due to
coronary artery disease and Alzheimer’s disease.
Key words: Chocolate, Life expectancy, Coronary artery disease, Alzheimer’s disease.
Introduction
Growing evidence suggest that by adhering to an active life-style and balanced diet high in
antioxidants such as the cocoa poly-phenols, the life expectancy of a healthy human may be
extended by 5-10 years. Coronary Artery Disease (CAD) is the top most leading cause of the
death in United States1 and worldwide. Numerous studies propose that CAD may be avoidable
by lifestyle modifications, such as exercise and nutrition.2,3,4 Moreover, the American Heart
Association and the U.S. Preventive Services Task Force both have endorsed the expected
consequences of diet for the prevention of CAD.5,6
Evidence is accumulating that some forms of cocoa and chocolate, may have the potential to
reduce the risk of CAD due to their high levels of stearic acid and antioxidant flavonoids.7 The
flavonoids improve endothelial function by activation of the nitric oxide synthase system8,9 and
decrease blood clotting by inhibiting platelet activation.10 An epidemiological study has
discovered low prevalence of atherosclerosis, type 2 diabetes, and hypertension in Kuna island
dwellers due to raw cocoa intake daily on regular basis.11 It has been suggested that an intake of
50 g/day of dark chocolate is associated with 10.5 % reduction of CAD risk.12
Alzheimer’s disease (AD) is an irreversible neurodegenerative disorder associated with
progressive cognitive decline and dementia. Its pathogenesis is multifactorial with a complex
combination of genetic and nongenetic components. One of the nongenetic components is food
micronutrients.13 The role of micronutrients in AD is being increasingly studied.14,15,16 A
significant inverse relationship between dementia or cognitive impairment and the intake of
chocolate/cocoa has been reported.17 Cocoa brings about an increase in cerebral blood flow and
might be advantageous in conditions such as dementia and stroke.18,19 It also has been shown to
improve several cognitive abilities in a dose dependent manner.20
2
Keeping in mind large number of epidemiological and observational studies touting
chocolate/cocoa’s ability to reduce the risk of CAD7,21,22 and to improve the cognitive function,
23,24
we found it essential to establish chocolate’s association with CAD and AD. Since chocolate
consumption could hypothetically improve CAD risk factors and cognitive function, we
wondered whether there would be a correlation between a country’s level of chocolate
consumption and its population’s life expectancy, deaths due to CAD and AD. We predicted a
a. Negative or inverse relationship between chocolate consumption (year/kg/capita) and
CAD and AD in the populations.
b. Positive or direct relationship between chocolate consumption (year/kg/capita) and life
expectancy
Methods
Data on per capita yearly chocolate consumption in 23 countries was obtained from
http://onegoldenticket.blogspot.com/2011/01/chocolate-consumption-statistics.html. Data on life
expectancy
was
downloaded
from
wikipedia
http://en.wikipedia.org/wiki/List_of_countries_by_life_expectancy. Number of deaths per 100,
000
populations
due
to
CAD
and
AD
was
downloaded
from
http://www.worldlifeexpectancy.com/ (Table 1).
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Table 1: Data of chocolate consumption, Life expectancy, Coronary artery disease and
Alzheimer’s disease
Statistical analysis
Statistical analysis was carried out by using SPSS-13. Mean (± Standard Deviation) was
calculated. Pearson correlation was used to find out the relation between chocolate consumption
(kg/year/per capita) and life expectancy, CAD; and AD (Table 2).
Variables
Life expectancy
Coronary Artery
Disease
Alzheimer's Disease
Mean ± SD
78.37 ± 3.39
84.18 ±
51.68
12.20 ± 8.83
r
0.315
0.124
0.327
p
value
0.143
0.572
0.128
Table 2: Pearson correlation between chocolate consumption and Life expectancy, Coronary
artery disease and Alzheimer’s disease
Results
No significant correlation was found when yearly chocolate consumption was compared with
any of the variables like Coronary artery disease, Alzheimer’s disease and life expectancy
(Figure 1, 2 and 3). An inverse relationship was seen between chocolate consumption and
deaths/100,000 population due to CAD however it was statistically insignificant.
4
/
Figure 1: Chocolate consumption and Life expectancy
5
Figure 2: Chocolate consumption and Coronary Artery Disease
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Figure 3: Chocolate consumption and Alzheimer’s disease
Discussion
The principal finding of this study is a lack of correlation between chocolate intake
(kg/year/capita) and the life expectancy, deaths/100,000 population due to CAD and AD in
various countries. This is in contrast to the claims made by the chocolate industry and studies
available on net. This discrepancy might be due to the fact that most of the research on
chocolate/cocoa has been funded/carried out by biased sources having personal interests in it.25
Moreover, most of the studies have used raw/pure cocoa extracts such as epicatechin,
procyanidine or the products containing much higher polyphenol contents than most of the
commercially available chocolate.25,26 Commercial chocolate may vary widely in flavonoid
contents due to variations in processing technique which leads to the loss of flavonoids.27,28
Bayard compared the death rate of CVD and cancer among island-dwelling Kuna and those
living in the mainland and found statistically significant lower rated in island-dwelling Kuna just
because they drank locally grown flavonol rich cocoa, as their major fluid whereas commercially
processed cocoa used in mainland was flavonol poor.29
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Another reason for absence of health beneficial effects of chocolate at population level might be
the use of milk chocolate because Dark chocolate contains considerably higher amounts of
flavonoids than milk chocolate.30 Milk may slow down the intestinal absorption of flavonoids31
by forming secondary bonds with chocolate flavonoids,32 hence negating the potential health
benefits of chocolate.
Third reason could be that the people who consumed more chocolate did not then pay off for the
additional calories by increasing the amount of daily exercise or reducing caloric intake of other
fats, sweets, or carbohydrates to prevent obesity and the metabolic and cardiovascular risks
related to it; therefore they were not able to enjoy health benefits of Chocolate.
A recent study published in New England Journal of Medicine contradicts our results. Messerli
showed surprisingly strong correlation between chocolate intake per capita and the number of
Nobel laureates in various countries.33 The reverse causation theory may justify the opposite
results of Messerli from our study, that is, persons with better cognition are likely to eat more
chocolate because they are more aware of the health benefits of the flavanols in dark chocolate.
Also there could be confounding variables like socioeconomic, geoghraphic and climatic factor
that could possibly drive both chocolate consumption and the number of Nobel laureates over
many years.
There are many limitations of our study. First the present data are based on country averages, and
the specific chocolate intake of individuals who are/were genetically at high risk of CAD, AD
due to other causes remains unknown. Secondly there may be many other confounding variables
like better prognosis or a lower incidence of these illnesses in a particular country, individual
factors such as type of diet, physical activity, stress and genetic factors; it was beyond the scope
of this research to cater each and every confounding variable. Third data for country per capita
chocolate consumption may be erroneous as there is no clear mechanism to determine how much
of a country's chocolate is consumed by locals and how much by foreigners.
Future Recommendation:
1. Researchers and Pharmaceutical industries all over the world should try to discover
the ways/processing technique to retain maximum flavonols in commercially
available chocolate so that modern day world could also fully benefit from
Theobroma Cocoa “drink of the Gods”.
2. Most of the research on chocolate/cocoa has been funded/carried out by biased
sources having personal interests in it.25 Extra observational/ interventional studies
from non-biased sources are required.
Conflict of interest:
Author declares that there is no conflict of interest.
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