There are multiple studies that all agree dark chocolate has health benefits, when eaten in moderation.

Benefits such as a lowered risk of preeclampsia in pregnancy1, lowered risk of cardiometabolic disorders2, lowered risk of calcified atherosclerotic plaque in the coronary arteries3, improved endothelial function in postmenopausal women4, reversed vascular dysfunction in diabetes5, acting as a prebiotic6, improved endothelial function7, and lower cholesterol8.

But the precise reason for all these benefits has been a mystery to science until now.

Researchers recently announced that bacteria in the stomach eat the chocolate, then ferment it to produce anti-inflammatory compounds good for the heart.

“We found that there are two kinds of microbes in the gut: the ‘good’ ones and the ‘bad’ ones,” said researcher Maria Moore “The good microbes, such as Bifidobacteriumand lactic acid bacteria, feast on chocolate. When you eat dark chocolate, they grow and ferment it, producing compounds that are anti-inflammatory."

The so-called bad microbes 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 Louisiana State University’s John Finley, Ph.D. and study leader.

This is the first study to investigate the effects of dark chocolate on the various types of bacteria in the stomach.

Chocolate’s Dark Side

It’s not all good news for chocolate lovers, though.

First of all, eating any energy-rich food like chocolate, without an increase in activity, increases your risk of obesity. Raw chocolate is high in cocoa butter, a fat which is removed during chocolate refining, then added back in varying proportions during the manufacturing process. Manufacturers may add other fats, sugars, and milk as well, all of which increase the caloric content of chocolate.

Chocolate absorbs lead from the environment during production. There is a slight concern of mild lead poisoning for some types of chocolate.

Research on elderly people suggests chocolate might cause osteoporosis9.

And there is even some evidence that chocolate may be addictive10. So don’t go overboard on the chocolates just yet.

Simulated Digestive Tract

Three cocoa powders were tested in the study.

The team used a model digestive tract, made of a series of modified test tubes, for simulating normal digestion. They then subjected the non-digestible materials to anaerobic fermentation using human fecal bacteria, according to Finley.

The study leader explained that cocoa powder, which is one of the ingredients of chocolate, contains several polyphenolic, or antioxidant, compounds such as catechin and epicatechin, plus a small amount of dietary fiber.

Both of these components are not digested well. When they reach the colon, the good 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,” Finley said.

Combining the fiber in cocoa with prebiotics would likely improve a person’s overall health and assist in converting polyphenolics in the stomach into anti-inflammatory compounds.

“When you ingest prebiotics, the beneficial gut microbial population increases and outcompetes any undesirable microbes in the gut, like those that cause stomach problems,” Finley said.

Prebiotics are carbohydrates found in foods like raw garlic and cooked whole wheat flour that humans can’t digest but that good bacteria like to eat. This food for your gut’s helpful inhabitants also comes in dietary supplements.

According to Finley, you could get even more health benefits if dark chocolate is combined with solid antioxidant-rich fruits like pomegranates and acai.

For More Information:

  1. Elizabeth W Triche, Laura M Grosso, Kathleen Belanger, Amy S Darefsky, Neal L Benowitz, Michael B Bracken Chocolate consumption in pregnancy and reduced likelihood of preeclampsia. Epidemiology. 2008 May;19(3):459-64

  2. Adriana Buitrago-Lopez, Jean Sanderson, Laura Johnson, Samantha Warnakula, Angela Wood, Emanuele Di Angelantonio, Oscar H Franco Chocolate consumption and cardiometabolic disorders: systematic review and meta-analysis. BMJ. 2011 ;343:d4488. Epub 2011 Aug 26

  3. Luc Djoussé, Paul N Hopkins, Donna K Arnett, James S Pankow, Ingrid Borecki, Kari E North, R Curtis Ellison Chocolate consumption is inversely associated with calcified atherosclerotic plaque in the coronary arteries Indian J Pharmacol. 2010 Dec;42(6):334-7

  4. Janice F Wang-Polagruto, Amparo C Villablanca, John A Polagruto, Luke Lee, Roberta R Holt, Heather R Schrader, Jodi L Ensunsa, Francene M Steinberg, Harold H Schmitz, Carl L Keen Chronic consumption of flavanol-rich cocoa improves endothelial function and decreases vascular cell adhesion molecule in hypercholesterolemic postmenopausal women Breast Cancer Res Treat. 2009 Sep;117(1):111-9.

  5. Jan Balzer, Tienush Rassaf, Christian Heiss, Petra Kleinbongard, Thomas Lauer, Marc Merx, Nicole Heussen, Heidrun B Gross, Carl L Keen, Hagen Schroeter, Malte Kelm Sustained benefits in vascular function through flavanol-containing cocoa in medicated diabetic patients a double-masked, randomized, controlled trial Leuk Res. 2009 Jun;33(6):823-8. Epub 2008 Nov 17

  6. Xenofon Tzounis, Ana Rodriguez-Mateos, Jelena Vulevic, Glenn R Gibson, Catherine Kwik-Uribe, Jeremy P E Spencer Prebiotic evaluation of cocoa-derived flavanols in healthy humans by using a randomized, controlled, double-blind, crossover intervention study Am J Clin Nutr. 2010 Nov 10. Epub 2010 Nov 10.

  7. Zubaida Faridi, Valentine Yanchou Njike, Suparna Dutta, Ather Ali, David L Katz Acute dark chocolate and cocoa ingestion and endothelial function: a randomized controlled crossover trial Am J Clin Nutr. 2008 Jul;88(1):58-63.

  8. Jaakko Mursu, Sari Voutilainen, Tarja Nurmi, Tiina H Rissanen, Jyrki K Virtanen, Jari Kaikkonen, Kristiina Nyyssönen, Jukka T Salonen Dark chocolate consumption increases HDL cholesterol concentration and chocolate fatty acids may inhibit lipid peroxidation in healthy humans. _Food Chem Toxicol._2008 Dec;46(12):3586-92.

  9. Hodgson, J.; Devine, A.; Burke, V.; Dick, I.; Prince, R. (2008). “Chocolate consumption and bone density in older women”. The American journal of clinical nutrition 87 (1): 175–180.

  10. Miller, Michael Craig (14 February 2013). “Can you become addicted to chocolate?”. Harvard Health Blog. Harvard University. Retrieved 14 April 2013

The Chocolate Therapist: A User’s Guide to the Extraordinary Health Benefits of Chocolate

Photo credits, top to bottom: Sarah Robinson, Raymond Bryson

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