Dark chocolate gets pulses racing
heart health, and could actually increase pulse rates,
according to new research.
The research, published in The American Journal of Clinical Nutrition, examined the short terms effects of dark chocolate and cocoa on variables associated with neuropsychological functioning and cardiovascular health in healthy older adults. The researchers noted that in recent years there has been an increased interest in the potential health-related benefits of antioxidant and phytochemical-rich dark chocolate and cocoa. Indeed, the health benefits of antioxidant-rich chocolate have received much recognition in recent years, with positive findings from a number of studies impacting on consumer awareness. Chocolate manufacturers are using high cocoa content (over 70 per cent) as a means of differentiation, and cocoa has also received attention for its potential in functional food applications. However, whilst the investigation failed to support the predicted beneficial effects of short-term dark chocolate and cocoa on any of the neuropsychological or cardiovascular health-related variables in the study, consumption of dark chocolate and cocoa was "associated with significantly higher pulse rates at three and six week treatment assessments," stated the researchers from Virginia Polytechnic Institute and State University, Virginia Neuropsychology Associates, and the Free Clinic of Central Virginia. Study details and results According to the researchers a double blind, placebo-controlled, fixed-dose, parallel-group clinical trial was employed. One hundred and one healthy, cognitively intact, participants, aged 60 or over, were randomly assigned to receive a 37 g dark chocolate bar and 237ml (eight ounce) of an artificially sweetened cocoa drink, or placebos, on a daily basis for a six week period. The study, sponsored by The Hershey Company, used a chocolate bar with a proanthocyanin content of 397.3 mg per gram, and a cocoa beverage containing 357.41 mg proanthocyanins per gram. The placebo bar contained 0.2 mg of proanthrocyanins per gram. At the end of the study, no changes in any of the neuropsychological, haematological or blood pressure variables was observed in either the cocoa or placebo groups. However, the mid-point and end-of-treatment mean pulse rate assessments in the group taking the chocolate products were "significantly higher" that those at baseline and "significantly higher" than the mid-point and end-of-treatment rates in the control group. Conflicting results The results are at odds with an ever-growing body of science supporting health benefits, particularly for the heart, as a result of cocoa consumption. Only last year, results of the randomised, controlled, parallel-group trial, published in the Archives of Internal Medicine, suggested that a daily serving of dark chocolate containing 30 calories associated with a lowering of blood pressure. The prevalence of hypertension in the population declined from 86 to 68 per cent. Consumption of the polyphenol-rich dark chocolate led to measurable increases in blood polyphenol concentrations, and the blood pressure reduction was accompanied by a sustained increase of S-nitrosoglutathione, linking the effects to nitric oxide production in the cardiovascular system. Perceived health benefits have changed confectionery market Perceived health benefits associated with dark chocolate have lead to a market shift in the UK, according to Key Note Publications in their report Confectionery Market Report Plus 2008. The authors say that consumer preferences for healthier options have prompted a number of brands to move into dark chocolate ranges. In March 2008 global confectioner Nestle announced the establishment of a research development facility dedicated entirely to dark and premium chocolate. In December 2007, Nestle attributed a 5.4 per cent increase in sales for the first nine months of the 2007 tax year to the growing trend for premium dark chocolate bars such as Nestle Noir and Perugina Nero. Source: The American Journal of Clinical Nutrition April 2008, Volume 87, Number 4, Pages 872-880 "A double-blind, placebo-controlled, randomized trial of the effects of dark chocolate and cocoa on variables associated with neuropsychological functioning and cardiovascular health: clinical findings from a sample of healthy, cognitively intact older adults" Authors: W.D. Crews Jr, D.W. Harrison, J.W. Wright