Attention chocolate lovers! Did you see chocolate flurries
falling from the virtual sky around the middle of June? If you did, that’s because
the journal Heart published an article about the relationship between
regular consumption of chocolate and the risk of cardiovascular disease.(1) The paper is called “Habitual chocolate consumption and risk of cardiovascular
disease among healthy men and women.” The journal also issued a press-release
about the paper. Both the paper and the press-release are available
electronically for journal subscribers - I don’t have access. I did what I
could and read the abstract of the paper. The abstract was written by the
researchers and summarizes what they did, how they did it, and their
conclusions. This week, I write about chocolate.
 |
| Chocolate https://www.flickr.com/photos/gemsling/542272611/ |
What's with all the fuss about chocolate?
Besides tasting good, why do researchers keep investigating chocolate?
It’s all about cacao beans. Chocolate and cocoa are made from cacao beans. Cacao beans are rich
with plant chemicals (phytochemicals) called polyphenols. Flavonoids are a class
of polyphenols. Cacao beans contain numerous flavonoids including catechin,
epicatechin and procyanidin. (3,4) I ran a quick search of “chocolate” at ClinicalTrials.gov
on July 6, 2015 and found 254 studies listed. Of these, 33 studies are actively recruiting or are just about to start recruiting participants. We are going to hear more
about chocolate for years to come.
At this point, research suggests that flavonoids may function to improve heart health, lower
blood pressure and reduce the risk of cardiovascular disease. Flavonoids are
suspected to work by reducing oxidative damage (they act as antioxidants),
promoting relaxation of the arteries, and triggering signaling pathways that reduce
inflammation. (3,4) It is still unclear exactly how flavonoids from
cacao beans work in the body and if flavonoids work together or individually to exert
an impact. Researchers continue to work on finding answers to these questions
and many others I can’t imagine.
According to a 2012 paper, consuming 50 grams of powdered cocoa daily may have
a modest effect on lowering high blood pressure.(2) However, cocoa has only been shown to lower high blood pressure 1-3 mmHg and appears to be less effective in people over 45 years. Evidence doesn’t support
adding cocoa or chocolate to an existing blood pressure therapy because
the potential effect is minimal and it introduces your body to additional sugar,
saturated fat and calories. (2,4)
News coverage about the paper “Habitual chocolate consumption”
On June 19, 2015, about two days after the paper was
electronically published, National Public Radio aired a story on Morning Edition. The title of the story overstated the results made by the researchers. The
news story itself was more balanced than the title.
CBS news and Science Daily
also issued reports about the research. The contents of their reports were remarkably
similar and I assume – but don’t know for sure – that they were written off of the
same press-release.
All three of these news pieces included strengths and weaknesses of the research. They also indicated
that the research did not prove cause and effect, that people should not change
their diet as a result of the research and that other factors may have influenced
the results (such as memory recall about foods that were previously consumed,
body composition, etc.). By reading the news articles, I learned that people who consumed the most
chocolate were regularly eating up to 100 grams of chocolate a day. That is
equivalent to about 2.5 chocolate bars each day. That is a lot of chocolate,
sugar, calories and fat!
A unique finding of this study, according to the
news articles, is that participants ate a lot of milk chocolate (rather than
dark chocolate). Milk chocolate contains lower levels of flavonoids compared to
dark chocolate. Research has focused on flavonoids, but other factors in milk chocolate may have contributed to the association researchers found – perhaps
milk proteins may have played a role. We just don’t know.
The news reports all emphasize that a take home message from the “Habitual chocolate consumption...” paper is that people concerned about heart
health may not need to avoid chocolate.
My take home message is that science worthy ≠
news worthy.
What did the research study reveal?
The researchers asked whether a relationship existed between
regular chocolate intake and the risk of developing cardiovascular problems like
heart attack and stroke later in life.(3) To answer their question, the
research group examined data obtained as part of the the European Prospective Investigation into
Cancer (EPIC)-Norfolk study. They were able to assess information from more than 20,900
adults. They learned about the foods people ate using a survey tool called food frequency questionnaire (FFQ).
- FFQs are a good way to assess the types of foods people eat because foods are organized into categories.
- FFQs also assess the frequency and quantity of different food categories a person eats over the course of a given period of time, like six months or a year. As you can imagine, memory recall can be a problem.
- It can be hard to understand how to fit foods into categories. FFQs are useful and important tools for nutrition research, but they aren’t perfect – nothing is.
After collecting baseline information, researchers followed up with the participants to
find out about what types of cardiovascular disease events may have developed over the years. They analyzed data and assessed whether an association existed between regular chocolate consumption and cardiovascular disease events. Their results revealed that
- people who ate the most chocolate were less likely to have coronary heart disease than people who ate the least amount of chocolate; and
- people who ate the most chocolate were less likely to have a stroke compared to people who the least amount of chocolate.
Final thoughts
This study contributes to the growing body of research about
the potential benefits of chocolate and cocoa, but the researchers did not reveal breakthrough
information that will impact lives today. Physicians are not going to make
recommendations for patients based on this study. This paper is valuable for flavonoid, chocolate and cocoa researchers. Most research does not lead to brilliant, breakthrough and life changing information. It contributes to a body of knowledge that leads to bigger moments in science and better health care decisions.
More research is needed to understand what the results of this research
study mean and how cocoa and chocolate may work in the body to impact heart
health.
Chocolate contains flavonoids, sugar, fat, and calories. If
you like chocolate and there is no medical reason you must avoid it, enjoy it as part of a balanced, varied diet. Remember to make room for it in your eating plan and that evidence
doesn’t support consuming chocolate to prevent or treat disease.
If there is
any magic, it is in moderation.
References
1. Kwok CS, Boekholdt SM, Lentjes MA et al. (2015) Habitual chocolate
consumption and risk of cardiovascular disease among healthy men and women. Heart.
2.
Fogleman CD (2013) Effect of cocoa on blood pressure. Am Fam Physician 87,
484.
3.
Linus Pauling Institute: Phytochemicals - Flavonoids. website. http://lpi.oregonstate.edu/mic/dietary-factors/phytochemicals/flavonoids.
Accessed July 6, 2015.
4.
Mayo Clinic: Supplements - Chocolate. website. http://www.mayoclinic.org/drugs-supplements/chocolate/background/hrb-20058898.
Accessed July 6, 2015.
#chocolate4health
#chocolate
