Claims About Cocoa

1. Chocolate is often used in decadent desserts, but scientists have been trying to determine if chocolate also has health benefits and what those benefits might be. The idea that chocolate might be good for you stems from studies of the Guna, a group of people who live on islands off the coast of Panama. They have a low risk of cardiovascular disease or high blood pressure given their weight and salt intake. Researchers realised that genes weren’t the reason: those who moved away from the islands developed high blood pressure and heart disease at typical rates. Something in their island environment must have kept their blood pressure from rising.
2. ‘What was particularly striking about their environment was the amount of cocoa they consume, which was easily ten times more than most of us would get in a typical day,’ says Dr Brent M. Egan, researcher at the Medical University of South Carolina who studies the effect of chocolate on blood pressure.
3.  But the cocoa of the Guna is a far cry from the chocolate that most of us eat. The Guna make a drink with dried, ground cocoa beans (the seeds of the cocoa tree) with a little added sweetener. The chocolate we tend to eat, on the other hand, is made from cocoa beans that are roasted and processed in various other ways, and then combined with ingredients like whole milk.
4. Processing can extract two main components from cocoa beans: cocoa solids and cocoa butter. Powdered cocoa is made using the solids. Chocolate is made from a combination of cocoa solids and cocoa butter. The colour of the chocolate depends partly on the amount of cocoa solids and added ingredients, such as milk. In general, though, the darker the chocolate, the more cocoa solids it contains. Researchers think the solids are where the healthy compounds are.
5.  Over the years there have been many studies on the health effects of chocolate. ‘We have good science on chocolate, especially about dark chocolate on blood pressure,’ says Dr Luc Djoussé of Harvard Medical School and Brigham and Women’s Hospital. His research team found an overall drop in blood pressure among people who eat more chocolate. ‘The results suggest that chocolate may, in fact, lower blood pressure,’ Djoussé says. ‘This effect was even stronger among people with high blood pressure to begin with.’
6. .Laboratory studies have uncovered several mechanisms that might explain chocolate’s benefits for heart health. However, it’s hard to prove if the chocolate that most Americans eat actually has those effects on the human body. Controlling how much chocolate people eat and tracking them over long periods is not an easy task. 
7. ‘The clinical trials that have been done in people have all been fairly short,’ says Dr Ranganath Muniyappa, a staff clinician at America’s National Institutes of Health (NIH) who studies diabetes and cardiovascular health. These studies, he explains, look at cardiovascular risk ‘markers’—factors related to heart health, such as blood pressure—but not actual long-term outcomes like heart disease and stroke.
8. Chocolate contains high levels of compounds thought to help prevent cancer, too. But Dr Joseph Su, an NIH expert in diet and cancer, says that direct evidence for this is similarly hard to come by. Since cancer can take many years to develop, it’s difficult to prove that eating chocolate can affect the disease. Instead, researchers look to see if factors linked to cancer change when chocolate is consumed.
9.  ‘Right now, some studies show really a remarkable modification of those markers,’ Su says. But the evidence that chocolate can reduce cancer or death rates in people is still weak. ‘There are a few studies that show some effect,’ Su says, ‘but the findings so far are not consistent.
10.  What might be responsible for many of chocolate’s beneficial effects? Scientists believe it might be compounds called flavanols, which are also found in tea, wine, fruits and vegetables. Different chocolates can vary greatly in their flavanol content. Cocoa beans naturally differ in their flavanol levels. A large portion of flavanols may also be removed during processing. In fact, companies often remove these compounds intentionally because of their bitter taste. The end result is that there’s no way to know if the chocolate products you’re looking at contain high flavanol levels.
11. Although studies of flavanol are promising, scientists agree that you shouldn’t increase your chocolate intake just yet. ‘The science doesn’t allow us to make recommendations because the evidence is just not there,’ says Muniyappa. 

  Adapted from NIH News in Health, ‘Claims About Cocoa’