The Truth About Dark Chocolate

There’s good news for chocolate lovers!

Consuming as little as a square of chocolate per day could help reduce the risk of hypertension and heart disease, according to a new study in the European Heart Journal.

Researchers analyzed data from over 19,000 middle-aged men and women in a study called the European Prospective Investigation into Cancer (EPIC).

The subjects were followed for an average of 8 years. Measurements- including blood pressure- were taken upon enrollment, and the participants were given dietary questionnaires.  They also completed questionnaires every two to three years reporting information about chronic disease and the incidence of both heart attack and stroke.

The data revealed some very good news for chocolate lovers.

Participants whose chocolate intake ranked among the highest 25 percent (an average of 7.5 grams per day of chocolate) had lower blood pressure and a significantly reduced risk of heart attack or stroke compared to subjects whose intake was lowest (average of 1.7 grams per day).

The difference in intake amounts to the equivalent of a single square of a 100 gram chocolate bar!

“Our hypothesis was that because chocolate appears to have a pronounced effect on blood pressure, therefore chocolate consumption would lower the risk of strokes and heart attacks, with a stronger effect being seen for stroke,” said lead researcher Dr. Brian Buijsse of the German Institute of Human Nutrition in Nuthetal. “People who ate the most amount of chocolate were at a 39% lower risk than those with the lowest chocolate intakes”

According to the researchers, if people in the group eating the least amount of chocolate increased their chocolate intake by six grams a day, 85 fewer heart attacks and strokes per 10,000 people could be expected to occur over a period of about ten years.  That may not sound like a lot- but if you’re one of the 85 people not having a heart attack or stroke, it’s pretty meaningful! And according to Buijsse, if the 39% reduction in risk were applied to the general population, the total number of avoidable heart attacks and strokes could be even higher.

So is it just that chocolate lowers blood pressure? Probably not. When the researchers statistically adjusted for blood pressure they found that lowered blood pressure only accounted for 12% of the association between chocolate consumption and fewer cardiovascular events. Current thinking is that the flavanols in cocoa improve  other cardiovascular risk factors besides blood pressure, such as endothelial and platelet function.

“Flavanols appear to be the substances in cocoa that are responsible for improving the bioavailability of nitric oxide from the cells that line the inner wall of blood vessels – vascular endothelial cells,” explained Dr Buijsse. “Nitric oxide is a gas that, once released, causes the smooth muscle cells of the blood vessels to relax and widen; this may contribute to lower blood pressure. Nitric oxide also improves platelet function, making the blood less sticky, and makes the vascular endothelium less attractive for white blood cells to attach and stick around.”

“Basic science has demonstrated quite convincingly that dark chocolate particularly, with a cocoa content of at least 70%, reduces oxidative stress and improves vascular and platelet function,” commented Professor of Cardiology Frank Ruschitzka, who is the Director of Heart Failure/Transplantation at the University Hospital Zurich, Switzerland, and a Fellow of the European Society of Cardiology. “However, before you rush to add dark chocolate to your diet, be aware that 100g of dark chocolate contains roughly 500 calories. As such, you may want to subtract an equivalent amount of calories, by cutting back on other foods, to avoid weight gain.”

Remember- this good news only applies to dark chocolate with a high cocoa content. Milk chocolate and garden-variety candy bars aren’t included- the healthy flavanols you get in cocoa just aren’t there.

Of all the “healthy eating prescriptions” you hear about, eating one square of delicious, high-quality dark chocolate with a 70% cocoa content has to be one of the easiest to follow. How hard is that?




  1. Chris Peacock

    Great post Jonny! 🙂 Green & Blacks 70% is one of my favorites.
    .-= Chris Peacock´s last blog ..THE EVENING RITUAL =-.

  2. Jeri Hurd

    I’m a bit confused—they ATE 7.5 gm per day, or that was the difference in what they ate? Is this saying you get the benefits from only 1/4 oz of dark chocolate per day? That seems a little low, but who can afford 3 oz. of chocolate a day, calorie wise, as lovely as that would be! : )

  3. Dr. Jonny


    the take home point was that as little as one square a day of high quality dark chocolate can make a difference.


  4. Jeri Hurd

    grin—I get that. I was trying to figure out a more accurate quantity, as I’ve seen bars with really big squares (a 3 oz. bar had six squares), and bars with about 24 squares per 3 oz.


  5. John

    I eat two squares of 85% cacao chocolate to finish off my evening meal of a protein (meat, fish or poultry), vegetable (broccolli, asparagus, brussel sprouts, or spinach usually) and a mixed green salad sprinkled with raw walnuts or almonds, tomatoes, garlic stuffed kalamata olives, extra virgin olive oil and a little crumbled danish blue cheese.

    The bitter chocolate is just enough and is very satisfying for a dessert.

  6. Maryann

    Hi Jonny,
    Always love all of the information that you share with us.
    I have occasional bouts of A fib. for which I take Atenolol.
    I was told never to have anything with caffein or any chocolate.
    Would you comment on this?
    Thanks so much.

  7. Dr. Jonny

    that’s a really good point and very interesting. I will have to check the actual study to see what amount they’re talking about in ounces. i assume the “standard” size in a high quality 70% cocoa bar, but it’s a good question


  8. Lou Meniketti

    I like to mix in 10-20 grams of 100-percent cacao nibs whenever I having some Greek-strained yogurt. Toss in a half or full scoop of something like DFH Whey Cool and a greens powder and you’re really cooking!

  9. doreen dahl

    off the subject of chocolate, but will you be commenting on the new Atkins book somewhere? I’ve read your original book on living the lowecarb life, but seems the new book has a few different twists? where can i get info on this new book compared to the old aTkins? thanks, doreen

  10. Kat Eden

    So if as little as one square makes a difference does it therefore stand to reason that the more we eat the healthier we become?! Just kidding 🙂

    My evening treat is a small bowl (like an olive pip bowl) in which I mix a couple teaspoons of coconut oil with some raw cacao. Zero sugar, zero carbs, 100% flavour!
    .-= Kat Eden´s last blog ..

  11. Dean

    Dark chocolate in moderation has many other health benefits as well, including improved blood circulation, lowered cholesterol, protection from cancer, improved brain function, protection against tooth decay, improved post-workout muscle recovery, and skin damage protection. These benefits are attributable to the high concentration of antioxidants in dark chocolate.

  12. joel

    i have added 1 square of 90% dark chocolate to my daily dose of food. It’s actually pretty good!

  13. Backyard Wrestling DVD

    Wow, this was a really high quality post. In theory I’d like to write like this too – taking time and actual effort to make a great post… but what can I say… I procrastinate alot and in no way appear to get something done.

  14. jstone626|nitric oxide

    Wow! I have just read this blog post! and it seems that this post is great! I have found many things by just simply reading it!! and the article were really great..because it is giving some advices…especially that it is talking about heart!! I should give thanks to this article!!

  15. Gluten Free

    There are other benefits though. If you are looking to reduce your body fat, especially the body fat in your abdominal region, then dark chocolate is a great way to do it. Excess abdominal fat is a contributor to heart disease, as well as heart attack.

  16. Gluten Free Pies

    Dark chocolate by far is one of the best additions for a healthy diet. It can be consumed in any form like cakes, pastries, and bars or even as beverages. However, the key for healthy diets always come in moderation.

  17. Gluten Free Biscuits

    Dark chocolate is healthy and a good for you treat! This is quite a relief to those of us who consider ourselves chocoholics. I admit I am a chocoholic. I love milk chocolate but it is full of sugar and we all know that consuming high levels of sugar is not good for you for many reasons.

  18. Anonymous

    I ate 100 grams of 85% chocolate today is that food or bad for my health

  19. Curran

    Great article!!! Thank you….also I love you 150 Healthiest Foods book.


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