“Challenge accepted”, right?
Sadly, it’s not quite that easy. The verdict come from a study published in Nature Neuroscience in November 2014, which saw volunteers ingest increased quantities of flavanols; chemicals which naturally occur in cocoa, red wine and teas.
The positive effect of tea containing these and related chemicals has been long extolled, and though there have been no proven benefits to human health, studies have shown that ageing mice fed on plant-derived flavanol rich diets have enhanced physiological processes and elevated brain activity, improving blood flow to the brain in addition to boosting memory retention. This small study aimed to investigate whether the same applies to larger mammals, us humans.
18 volunteers consumed supplements of only 10 milligrams of flavanols each day across two weeks, while across the same time period another 19 consumed 900 milligrams of flavanols. The dose was delivered in two drinks per day, mixed with water or milk, in addition to a regime of aerobic exercise.
At the end of the three month study, both of the improvements reported in the study involving mice were investigated. All the volunteers underwent MRI scans, which revealed that those taking the higher dose of flavanols had 20% higher blood flow rates to a given region of the brain than those in the other group.
Further, flavanols appear to have improved volunteer’s memories. Both before and after the trail, all 37 people were asked to complete a memory test involving identifying abstract shapes they’ve already been shown from a selection twice the size. The high dose group, on average, reacted to each shape 630 milliseconds faster than the low dose group.
These results confirm what we already know – that ingestion of cocoa flavanols improves vasodialation and blood flow to both the peripheries of the body and the brain, which it does so by acting on the synthesis and degradation of vital nitric oxide compounds. In 2014, the European Food Safety Authority even approved the ability for cocoa products containing over 200 milligrams of flavanols to claim they “maintain the elasticity of blood vessels, which contributes to normal blood flow”. Some flavanols, eliciting this improved blood flow, have even been linked to reducing the risk of coronary heart disease. The changes seen in this study, however, have even more exciting implications.
The region of increased blood flow, the dentate gyrus, has been previously linked to age-related memory loss, and it is suggested that increasing reaction times in memory based tasks has the potential to give older people elements of brain function that they possessed decades ago.
Sadly though, increasing your consumption of regular chocolate cannot bring you these benefits.
Not only – to quote Scott Small, one of the study’s authors – would you have to consume a volume of chocolate so large as to be damaging to your health to obtain these benefits, peer-reviewed medical journal The Lancet has further warnings. An editorial from 2007 actively discouraged against increasing your intake of dark chocolate even slightly above the normal, because of the trade off with increased fat, sugar and calories, as well as the possibility that any flavanols may have been removed anyway, to reduce bitterness.
Authors in the field seem to be keenly aware of the emotionally charged debated and self-professed slight hilarity that surrounds investigating the health benefits of chocolate, especially in the context of media excitement at the prospect – searching for “Is chocolate good for you?” will bring you over 200 million results.
Answers to that question so far seem positive, with the potential to improve countless lives. Investigation into exact the length and magnitude of the effects that flavanols have is still needed, as well as the reminder that, sadly, you likely can’t use these benefits to justify that extra Twix, either.