In late August 2018, headlines on websites and newspapers proclaimed the good news: “Three bars of chocolate a month can reduce chances of heart failure.” And, indeed, that’s what the researchers concluded, but it wasn’t all they found.
The researchers’ main finding was that people who eat a lot of chocolate (like on a daily basis) had a 17% greater risk of heart failure than people who ate no chocolate.
But then came the news that we all wanted to hear: “In contrast, moderate chocolate consumption may reduce the risk of heart failure” by 23%. The researchers—who presented these findings at the European Society of Cardiology Congress 2018 in Munich, Germany—categorized “moderate chocolate consumption” as one to three (not simply three) servings a month.
“I believe that chocolate is an important dietary source of flavonoids which are associated with reducing inflammation and increasing good cholesterol,” lead researcher Chayakrit Krittanawong, MD, Icahn School of Medicine at Mount Sinai, New York, NY, told The Telegraph. “However, chocolate may have high levels of saturated fats. I would say moderate dark chocolate consumption is good for health.”
Don’t be afraid of the dark
Take note that Dr. Krittanawong said “dark chocolate consumption is good for health.” That’s an important point. The compounds in chocolate that are believed to work wonders are flavanols, and dark chocolate contains up to two to three times more flavanols than milk chocolate. Flavanols are a type of polyphenol, a group of natural compounds found in plants, that have antioxidant and anti-inflammatory properties. Consuming flavanols appears to increase vasodilation, which lowers blood pressure and reduces cardiovascular events such as heart attacks and strokes.
The problem is that many studies on the subject (including Dr. Krittanawong’s) don’t distinguish between participants who ate dark chocolate vs those who ate milk chocolate. Perhaps that’s a big reason why there are some conflicting conclusions when it comes to the health benefits of chocolate.
For instance, a recent meta-analysis of more than 83,000 postmenopausal women who participated in the Women’s Health Initiative study found that eating chocolate provided no benefit against heart disease or stroke in those under 65 years old. In fact, the more chocolate they ate, the greater their risk.
On the other hand, another recent meta-analysis found that eating chocolate lowered the relative risk of heart failure, stroke, heart attack, and coronary heart disease. A dose-response analysis indicated that 45 g/week (almost exactly the size of a regular Hershey bar) was the most effective amount of chocolate to eat for reducing the risk of cardiovascular disease.
Importantly, a randomized trial showed that the more cocoa flavonoids that participants consumed, the greater was the beneficial effect on increasing vasodilation and lowering blood pressure.
Other beneficial effects
In addition to the heart, chocolate has also shown benefits in:
• The eyes. In a small trial, participants who ate a dark chocolate bar (but not a milk chocolate bar) had significantly improved contrast sensitivity and visual acuity for 2 hours after eating it. But, “the duration of these effects and their influence in real-world performance await further testing,” the investigators wrote.
• The brain. An 8-week clinical trial among elderly participants with no cognitive problems found that high doses of cocoa flavanols improved aspects of cognitive function, including cognitive processing and verbal fluency. Investigators also showed that high flavanol doses significantly improved insulin resistance, blood pressure, and lipid peroxidation. However, the highest dose had nearly 1,000 mg of cocoa flavanols (served in a chocolate drink). Compare that to about 50 mg of total flavanols in an average dark chocolate candy bar or about 7 mg in a milk chocolate bar. (This study was supported by Mars, Inc., which made the chocolate drink.)
Of course, eating more chocolate doesn’t necessarily result in more health benefits. Eating chocolate to excess (even dark chocolate, which still contains a good deal of sugar and fat) will negate the health benefits of flavanols and lead to the negative effects associated with high sugar and high fat consumption.