Monday, August 6, 2012

Dark Chocolate: A Treat for Cardiovascular Health

I eat dark chocolate almost every day. Anyone who knows me well knows that my chocolate of choice is Ghirardelli’s Intense Dark 72% Cacao Twilight Delight – yum!

Thus, you can imagine that I was excited to stumble upon a CBS news article a couple weeks ago titled, “Daily dark chocolate good for the heart, study finds" (you can read the CBS news article here).

But what does that mean?

As a researcher, I was inspired to investigate further. The author cites a recent study (published in the British Medical Journal in May 2012) that examined dark chocolate consumption as a prevention therapy in people at high risk of cardiovascular (heart) disease. In short, these Australian researchers found that daily consumption of dark chocolate can reduce cardiovascular events (read the full study article here).

As I skimmed through the journal article, a few questions came to mind. I searched for answers (consulting other references when needed), summarized below:

1.      What was the study population?
The study population consisted of 2,013 people with high blood pressure who met the criteria for metabolic syndrome, with no history of cardiovascular disease and not receiving antihypertensive therapy. My first thought – this doesn’t apply to me.
2.      What is metabolic syndrome?
Metabolic syndrome is the name for a group of risk factors that occur together and increase the risk for coronary heart disease, stroke, and type 2 diabetes. It is present in individuals meeting 3 or more criteria for blood pressure, fasting blood sugar (glucose), waist circumference, HDL cholesterol, and/or triglycerides.
3.      The researchers found cardiovascular benefits with a daily consumption of 100 g (3.5 oz) of dark chocolate. How much is this?
Remember my Ghirardelli dark chocolate? Each Ghirardelli square is approximately 11 g, containing 55 calories, 5 g of fat, and 3 g of sugar. This means that I would need to eat 9 squares, for a total of 495 calories, 45 g of fat, and 27 g of sugar – in one day! Of course, this information led to my next question…   
4.      What about the adverse health effects from high calories, fat, and sugar?
Unfortunately, the researchers did not consider these effects specifically, citing it as a limitation to their study. However, they do recognize that while dark chocolate have been shown to generate beneficial metabolic, anti-inflammatory, and psychological effects (such as improved cholesterol levels, increased insulin sensitivity, reduced stress, and improved mood), it also imposes an additional caloric and glycemic load. These additional calories may need to be accounted for by changing other aspects of the diet to reduce the risk of weight gain. Yet, other studies have found that dark chocolate increases satiety, which may counteract this risk. Clearly, more research is needed to elaborate on this relationship, but I would highly recommend sticking to a small, more moderate portion until then!

Final thoughts:  First, I want to note that evidence to date suggests that the dark chocolate would need to be of at least 60-70% cocoa to produce any benefit – which is good news for me :) Second, I hope that one day we will find evidence of significant long-term health benefits of dark chocolate consumption in the more general population. For now, however, I will continue to indulge moderately and savor every bite!

Submitted By:
Angela Sberna
UTK Dietetic Intern

  1. Zomer E, Owen A, Magliano DJ, Liew D, Reid CM. The effectiveness and cost effectiveness of dark chocolate consumption as prevention therapy in people at high risk of cardiovascular disease: best case scenario analysis using a Markov model. BMJ. 2012;344:e3657.
  2. U.S. National Library of Medicine National Center for Biotechnology Information. Metabolic syndrome. PubMed Health Web site. Accessed June 13, 2012.

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