Zinc supplementation reduced DNA breaks in Ethiopian women

Abstract

Assessment of zinc status remains a challenge largely because serum/plasma zinc may not accurately reflect an individual’s zinc status. The comet assay, a sensitive method capable of detecting intracellular DNA strand breaks, may serve as a functional biomarker of zinc status. We hypothesized that effects of zinc supplementation on intracellular DNA damage could be assessed from samples collected in field studies in Ethiopia using the comet assay. Forty women, from villages where reported consumption of meat was less than once per month and phytate levels were high, received 20 mg zinc as zinc sulfate or placebo daily for 17 days in a randomized placebo-controlled trial. Plasma zinc concentrations were determined by inductively coupled plasma mass spectrometry (ICPMS). Cells from whole blood at the baseline and endpoint of the study were embedded in agarose, electrophoresed, and stained before being scored by an investigator blinded to the treatments. Although zinc supplementation did not significantly affect plasma zinc, mean (± SEM) comet tail moment measurement of supplemented women decreased from 39.7 ± 2.7 to 30.0 ± 1.8 (p<0.005) indicating a decrease in DNA strand breaks in zinc-supplemented individuals. These findings demonstrated that the comet assay could be used as a functional assay to assess the effects of zinc supplementation on DNA integrity in samples collected in a field setting where food sources of bioavailable zinc are limited. Furthermore, the comet assay was sufficiently sensitive to detect changes in zinc status as a result of supplementation despite no significant changes in plasma zinc.

A moderate increase in dietary zinc reduces DNA strand breaks in leukocytes and alters plasma proteins without changing plasma zinc concentrations

“…The comet assay has been used previously in several human-intervention trials to measure DNA single-strand breaks from peripheral blood cells ( 12 , 23 , 32 ). In a previous zinc depletion–zinc repletion study by our group, DNA damage increased significantly in healthy men after the consumption of a diet that provided 4 mg Zn/d for 6 wk, including a formula diet that provided 0.6 mg Zn/d during the first week.…”

“…Although PZCs did not change significantly during zinc depletion in that study, there was a negative correlation between PZCs and DNA damage in the 9 men. DNA strand breaks also declined significantly in a group of Ethiopian women who were given 20 mg supplemental zinc/d for 17 d ( 32 ). This change occurred without an overall increase in PZCs, but PZCs and DNA strand breaks were negatively correlated at the end of the study.…”

Zinc Supplementation in a Randomized Controlled Trial DecreasedZIP4andZIP8mRNA Abundance in Peripheral Blood Mononuclear Cells of Adult Women

“…Unlike the current study, zinc supplementation of adult women with a BMI range of 16.5–24.1 for 17 days with 20 mg zinc (as ZnSO 4 ) in rural Sidama, Ethiopia, did not result in significant change in plasma zinc concentration. 46 …”

Examining the effectiveness of consuming flour made from agronomically biofortified wheat (Zincol-2016/NR-421) for improving Zn status in women in a low-resource setting in Pakistan: study protocol for a randomised, double-blind, controlled cross-over trial (BiZiFED)

“…DNA fragmentation (measured using the Comet assay) has been shown to decrease following dietary Zn supplementation. 20 Whole blood was collected by venous blood draw. Duplicate samples of 50 µL of whole blood was mixed with 50 µL cryopreservation buffer (85% RPMI, 15% DMSO) in a cryovial and stored in a cryopreservation container in a fridge for up to 8 hours.…”