title: Influence of tea drinking on manganese intake, manganese status and leucocyte expression of MnSOD and cytosolic aminopeptidase P.
abstract: OBJECTIVE
  Since black tea contains high levels of manganese (Mn), we investigated the relationship between dietary Mn intake, circulating Mn levels and leucocyte expression of two Mn-dependent enzymes in tea drinkers and non-tea drinkers.
  
  
  METHODS
  We assessed Mn intakes (food frequency questionnaire), fasting whole blood and plasma Mn levels, and quantitative expression of peripheral blood mononuclear cell Mn-dependent superoxide dismutase (MnSOD) and cytosolic aminopeptidase-P (cAP-P).
  
  
  METHODS
  In total, 24 tea drinkers (> or = 1 l black tea/day) and 28 non-tea drinkers were recruited from the staff and students of King's College London by circular email.
  
  
  RESULTS
  Dietary Mn intakes (mean (range)) were significantly lower (P < 0.0001) in non tea drinkers (3.2 mg/day (0.5-6.5)) than tea drinkers (5.5 mg/day (2-12) or 10 mg/day (5-20) depending upon the value used for Mn levels of black tea). Whole blood, plasma Mn levels and expression of MnSOD and cAP-P did not differ between the groups. In a continuous analysis, whole blood Mn levels and expression of MnSOD correlated inversely but no other parameters associated with each other.
  
  
  CONCLUSIONS
  Tea drinking is a major source of dietary Mn and intakes commonly exceed proposed adequate intake values of 1.8-2.3 mg Mn/day and, on occasion, exceed upper limits of 10-11 mg/day. Dietary Mn intake has little influence on markers of Mn status or expression of Mn-dependent enzymes. Fasting whole blood Mn levels and leucocyte expression of MnSOD could, together, be further investigated as markers of Mn status.
authors.affiliation: WRc-NSF Ltd, Henley Road, Medmenham, Marlow, Buckinghamshire, UK.
authors.forename: S- J
authors.initials: S
authors.lastname: Hope
authors.forename: K
authors.initials: K
authors.lastname: Daniel
authors.forename: K L
authors.initials: KL
authors.lastname: Gleason
authors.forename: S
authors.initials: S
authors.lastname: Comber
authors.forename: M
authors.initials: M
authors.lastname: Nelson
authors.forename: J J
authors.initials: JJ
authors.lastname: Powell
mesh_terms: D000328:Adult; D000626:Aminopeptidases / Q000378:metabolism*; D001628:Beverages; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008345:Manganese / Q000008:administration & dosage* / Q000097:blood / Q000378:metabolism*; D008875:Middle Aged; D018673:Nutrition Policy; D009752:Nutritional Status; D013482:Superoxide Dismutase / Q000378:metabolism*; D011795:Surveys and Questionnaires; D013662:Tea / Q000737:chemistry*; D006113:United Kingdom
chemical_list: D013662:Tea; D008345:Manganese; D013482:Superoxide Dismutase; D000626:Aminopeptidases; C022750:X-Pro aminopeptidase