The study published in the Molecular Nutrition & Food Research journal analyzed how epicatechin, a main flavanol in cocoa, abundant in dark chocolate, impacted insulin levels. It concluded that a diet rich in cocoa may help people manage diabetes.
No human tests
Dr Matthew Hobbs, head of research at Diabetes UK, said: “The implication that eating chocolate will help people with Type 2 diabetes to control their blood sugar is simply not a conclusion that can be drawn from this research.
“In this study the researchers used an extract of one compound that is found in chocolate and studied its effect on isolated liver cells grown in the lab. It did not test the effect in people.”
The study authors used a cocoa phenolic extract containing epicatechin to observe the impact on liver tissues, but did mention chocolate as a rich source of epicatechin in the paper.
Epicatechin dose too low
“The levels of these chemicals naturally found in chocolate would not be sufficient to have any beneficial effect in real life,” said Hobbs,
Dietitian Dr Carrie Ruxton added: “You are unlikely to get this dose in a bar of chocolate, particularly milk chocolate.”
There were 383.5 mg of polyphenols in the cocoa extract used in the study per 100 g with the concentration of epicatechin ranging from 13.2 nM to 132 nM.
Earlier research from the University of Milan , experimented with 45 g of dark chocolate with around 860 mg of polyphenols of which 58 mg were epicatechin.
The US Department of Agriculture says 100g of dark chocolate contains 41.5mg of epicatechin, which Ruxton said was more like the levels found in chocolate in shops.
Dangers outweigh benefits
Hobbs said that the extra fat, sugar and calories from chocolate would far outweigh any potential benefit from flavonoids.
Ruxton added: "Even a specialist ‘high flavonoid’ chocolate provided in portion of around 45g would give you 240 calories, 15g fat and 9g saturated fat. This is not really a healthy food for diabetics and may outweigh any benefits from the flavonoids. Better to drink tea."
Developments to boost flavanols
She said that diabetics would need to wait for pharmaceutical or nutraceutical developments and warned against assuming the benefits were already in commonly-consumed foods.
Biotech firm Lycotec recently developed an ingredient called Coco-Lycosome which is added at 1% at the melting stage to increase the bioavailability of epicatechin by 20 times in dark, milk and white chocolate.
Industry giant Barry Callebaut has developed a process called Acticoa , which maintains 80% of cocoa flavanols that are usually destroyed in chocolate manufacture.
Mol. Nutr. Food Res. 2013, 00, 1–12
‘Cocoa flavonoids improve insulin signalling and modulate glucose production via AKT and AMPK in HepG2 cells’
Authors: Isabel Cordero-Herrera, Marıa Angeles Martin, Laura Bravo, Luis Goya and Sonia Ramos