title: A moderate increase in dietary zinc reduces DNA strand breaks in leukocytes and alters plasma proteins without changing plasma zinc concentrations.
abstract: Food fortification has been recommended to improve a population's micronutrient status. Biofortification techniques modestly elevate the zinc content of cereals, but few studies have reported a positive impact on functional indicators of zinc status.
  
  
  
  We determined the impact of a modest increase in dietary zinc that was similar to that provided by biofortification programs on whole-body and cellular indicators of zinc status.
  
  
  
  Eighteen men participated in a 6-wk controlled consumption study of a low-zinc, rice-based diet. The diet contained 6 mg Zn/d for 2 wk and was followed by 10 mg Zn/d for 4 wk. To reduce zinc absorption, phytate was added to the diet during the initial period. Indicators of zinc homeostasis, including total absorbed zinc (TAZ), the exchangeable zinc pool (EZP), plasma and cellular zinc concentrations, zinc transporter gene expression, and other metabolic indicators (i.e., DNA damage, inflammation, and oxidative stress), were measured before and after each dietary-zinc period.
  
  
  
  TAZ increased with increased dietary zinc, but plasma zinc concentrations and EZP size were unchanged. Erythrocyte and leukocyte zinc concentrations and zinc transporter expressions were not altered. However, leukocyte DNA strand breaks decreased with increased dietary zinc, and the level of proteins involved in DNA repair and antioxidant and immune functions were restored after the dietary-zinc increase.
  
  
  
  A moderate 4-mg/d increase in dietary zinc, similar to that which would be expected from zinc-biofortified crops, improves zinc absorption but does not alter plasma zinc. The repair of DNA strand breaks improves, as do serum protein concentrations that are associated with the DNA repair process. This trial was registered at clinicaltrials.gov as NCT02861352.
authors.affiliation: Nutrition and Metabolism Center, Children's Hospital Oakland Research Institute, Oakland, CA.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Zyba
authors.affiliation: Nutrition and Metabolism Center, Children's Hospital Oakland Research Institute, Oakland, CA.
authors.forename: Swapna V
authors.identifier: 0000-0001-6769-1780
authors.initials: SV
authors.lastname: Shenvi
authors.affiliation: Nutrition and Metabolism Center, Children's Hospital Oakland Research Institute, Oakland, CA.
authors.forename: David W
authors.initials: DW
authors.lastname: Killilea
authors.affiliation: Nutrition and Metabolism Center, Children's Hospital Oakland Research Institute, Oakland, CA.
authors.forename: Tai C
authors.initials: TC
authors.lastname: Holland
authors.affiliation: Nutrition and Metabolism Center, Children's Hospital Oakland Research Institute, Oakland, CA.
authors.forename: Elijah
authors.initials: E
authors.lastname: Kim
authors.affiliation: Nutrition and Metabolism Center, Children's Hospital Oakland Research Institute, Oakland, CA.
authors.forename: Adrian
authors.initials: A
authors.lastname: Moy
authors.affiliation: Nutrition and Metabolism Center, Children's Hospital Oakland Research Institute, Oakland, CA.
authors.forename: Barbara
authors.initials: B
authors.lastname: Sutherland
authors.affiliation: Nutrition and Metabolism Center, Children's Hospital Oakland Research Institute, Oakland, CA.
authors.forename: Virginia
authors.identifier: 0000-0001-5257-4645
authors.initials: V
authors.lastname: Gildengorin
authors.affiliation: Nutrition and Metabolism Center, Children's Hospital Oakland Research Institute, Oakland, CA.
authors.forename: Mark K
authors.initials: MK
authors.lastname: Shigenaga
authors.affiliation: Nutrition and Metabolism Center, Children's Hospital Oakland Research Institute, Oakland, CA jking@chori.org.
authors.forename: Janet C
authors.identifier: 0000-0002-8484-7940
authors.initials: JC
authors.lastname: King
mesh_terms: D000328:Adult; D001798:Blood Proteins / Q000378:metabolism*; D001823:Body Composition; D015992:Body Mass Index; D027682:Cation Transport Proteins / Q000097:blood; D004249:DNA Damage / Q000187:drug effects*; D004032:Diet; D002523:Edible Grain / Q000737:chemistry; D005527:Food, Fortified; D006801:Humans; D007962:Leukocytes / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008668:Metallothionein / Q000097:blood; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects; D010833:Phytic Acid / Q000008:administration & dosage / Q000097:blood; D040901:Proteomics; D055815:Young Adult; D015032:Zinc / Q000008:administration & dosage* / Q000097:blood*
chemical_list: D001798:Blood Proteins; D027682:Cation Transport Proteins; C491053:MT2A protein, human; D010833:Phytic Acid; D008668:Metallothionein; D015032:Zinc
keywords: DNA repair; antioxidant; inflammation; zinc biomarkers; zinc fortification