Monday, 19 December 2011

A Holiday Treat (From: Science)

Well my friends, its that time of year again!  Regardless of what holiday you celebrate, I think it is safe to say that most of our diets take a little bit of a dive in the month of December.

Take me for instance; yesterday I ate cookies and milk for breakfast followed by leftover chips and cheeses for lunch.  Then, logically enough, I consumed chips, cheese and cookies for dinner while watching this movie.  A classic film for a classic holiday season diet.

All of these treats reminded me of something my mom always used to tell me growing up (and still does to this day), "chocolate is good for you."  Yes, when I felt completely full and unable to ingest more Christmas chocolate, my mom would cheer me on with encouraging phrases such as, "eat it, it's good for you," or "it's cocoa, eat it."  So I would.  

Was she right all along?  I decided I had to go to the literature and find out.


In my search I came across this study published in 2008 in the American Journal of Clinical Nutrition.  Luckily for all of you, this one is available in full text for free online-it's a Christmas miracle!  Enjoy this nice holiday read as a gift from me to you!

One of the historically accepted benefits of chocolate involves its impact on the cardiovascular system.  Specifically, the active ingredient within cocoa (flavanoids) are thought to improve endothelial function.  What is endothelial function?  Well, the endothelium is the internal layer of your blood vessels.  If it is functioning well, you will be less likely to have high blood pressure, and less likely to experiencing blood clotting.

So, by having an impact on your endothetlial function, the flavanoids in cocoa could potentially decrease your blood pressure and the odds of developing a clot - that is what this study looked at.

How it was done:

In the study, there were two phases. During each phase, subjects were randomly assigned to consume either:

  • 74g chocolate containing 22g of cocoa
  • 74g placebo chocolate containing 0g cocoa
  • 22g of sugar free cocoa
  • 22g of sugared cocoa
  • placebo (no cocoa)
Then, the researchers measured parameters including blood pressure (BP) and flow-mediated dilation (FMD).  FMD is essentially a measure of the diameter of the blood vessel and therefore one way of measuring endothelial function.

What they found:

Here are the main conclusions the researchers reached: 

  1.  FMD and BP improved after eating chocolate compared to the placebo group in Phase 1.
  2.  FMD improved after eating both the sugared and sugarless cocoa compared to the placebo group in Phase 2.
  3. BP improved after eating the sugarless cocoa compared to the placebo group in Phase 2.
What does this mean?

My mom was right.  Again.

But really, I thought this study was fascinating.  With ingestion of chocolate containing cocoa, or pure cocoa itself, the subjects consistently showed better endothelial function.  The researchers attributed these changes to the cocoa flavanoids rising in concentration within the blood.  This study also shows that while both sugared and sugar free cocoa can have a positive impact on endothelial function, the sugar free option has an even more significant impact.

Nevertheless, there are a few things you should keep in mind when analyzing these results.  First of all, these changes were measured only once, not over a period of time.  So, even though these benefits were seen at the initial point of measurement, that does not mean they will persist days or even hours later.  Secondly, it is also important to keep in mind that these measurements were taken after eating cocoa once.  Perhaps the vascular response would not have been as profound if the individuals consumed cocoa on a regular basis.   

Either way, this study does show that a one time episode of cocoa ingestion will have an acute, positive impact on endothelial function.  Based on that, you can enjoy your dark chocolate a little more guilt free!

Happy Holidays!

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