title: Assessment of DNA damage using comet assay in middle-aged overweight/obese subjects after following a hypocaloric diet supplemented with cocoa extract.
abstract: Nutrient excess and unbalanced diets can result in overproduction of reactive oxygen species (ROS), which are associated with oxidative stress. Cocoa extract contains antioxidants that inhibit the harmful effects of ROS. This trial analysed the effect of cocoa extract consumption integrated as a bioactive compound into ready-to-eat meals, on oxidative stress at the level of DNA in overweight/obese subjects. Fifty volunteers [57.26(5.24) years, 30.59(2.33)kg/m(2)] participated in a 4-week double-blind, randomised, placebo-controlled parallel nutritional intervention. Half of the volunteers received meals supplemented with 1.4 g/day cocoa extract, while the other half received control meals, both within a 15% energy restriction diet. Lymphocytes were isolated and endogenous strand breaks, oxidised bases and resistance to H2O2-induced damage were measured by the comet assay. The intake of ready-to-eat meals supplemented with cocoa extract did not show relevant changes in the oxidative status of DNA. However, in the cocoa group, oxidised bases negatively correlated with methyl epicatechin-O-sulphate (r = -0.76; P = -0.007) and epicatechin sulphate (r = -0.61; P = -0.046). When volunteers of both groups were analysed together, a marginal decrease (P = 0.072) in oxidised bases was observed, which attributed to weight loss. Subjects who started the intervention with higher levels of damage showed a greater reduction in oxidised bases after 4 weeks (P = 0.040) compared to those who had lower baseline levels. In conclusion, even if 1.4 g of cocoa supplementation for 4 weeks did not show notable changes in terms of antioxidant status of DNA, the energy restriction showed a slightly decrease in oxidised bases and this was seen to a greater extent in subjects who started the intervention with higher levels of damage. On the other hand, the inverse associations found between oxidised bases and some cocoa-derived metabolites suggest that a protective effect might be seen in a longer period of time or in subjects with higher baseline DNA damage.
  
  
  BACKGROUND
  www.clinicaltrials.gov (NCT01596309).
authors.affiliation: Department of Nutrition, Food Science and Physiology, Nutrition Research Centre, University of Navarra, C/Irunlarrea 1, 31008 Pamplona, Navarra, Spain.
authors.forename: Idoia
authors.initials: I
authors.lastname: Ibero-Baraibar
authors.affiliation: Department of Pharmacology and Toxicology, University of Navarra, C/Irunlarrea 1, 31008 Pamplona, Spain and.
authors.forename: Amaya
authors.initials: A
authors.lastname: Azqueta
authors.affiliation: Department of Pharmacology and Toxicology, University of Navarra, C/Irunlarrea 1, 31008 Pamplona, Spain and.
authors.forename: Adela
authors.initials: A
authors.lastname: Lopez de Cerain
authors.affiliation: Department of Nutrition, Food Science and Physiology, Nutrition Research Centre, University of Navarra, C/Irunlarrea 1, 31008 Pamplona, Navarra, Spain, Physiopathology of Obesity and Nutrition, CIBERobn, Carlos III Health Research Institute, 28029 Madrid, Spain jalfmtz@unav.es.
authors.forename: J Alfredo
authors.initials: JA
authors.lastname: Martinez
authors.affiliation: Department of Nutrition, Food Science and Physiology, Nutrition Research Centre, University of Navarra, C/Irunlarrea 1, 31008 Pamplona, Navarra, Spain, Physiopathology of Obesity and Nutrition, CIBERobn, Carlos III Health Research Institute, 28029 Madrid, Spain.
authors.forename: M Angeles
authors.initials: MA
authors.lastname: Zulet
mesh_terms: D002099:Cacao / Q000737:chemistry*; D031204:Caloric Restriction / Q000009:adverse effects / Q000379:methods*; D020552:Comet Assay / Q000379:methods; D004249:DNA Damage / Q000235:genetics*; D019587:Dietary Supplements / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008214:Lymphocytes / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000178:diet therapy* / Q000473:pathology; D050177:Overweight / Q000178:diet therapy* / Q000473:pathology; D018384:Oxidative Stress / Q000235:genetics; D010936:Plant Extracts / Q000008:administration & dosage / Q000009:adverse effects*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D010936:Plant Extracts; D017382:Reactive Oxygen Species