J Nutr. 2021 Dec 17:nxab425. doi: 10.1093/jn/nxab425. Online ahead of print.
ABSTRACT
BACKGROUND: Rice biofortification with Zinc (Zn) can improve the Zn status of rice-consuming populations. However, the metabolic impact in humans consuming Zn biofortified rice is unknown.
OBJECTIVE: To determine the effects of Zn biofortified rice on lipid metabolism in normolipidemic men.
DESIGN: The men consumed a rice-based diet containing 6 mg Zn/d and 1.5 g phytate (phytate:Zn ratio = 44) for 2 weeks (wk) followed by a 10 mg Zn/d diet without phytate for 4 wk. An ad libitum diet supplemented with 25 mg Zn/d was then fed for 3 wk. Fasting blood samples were taken at baseline and at the end of each metabolic period for measuring plasma zinc, glucose, insulin, triglyceride (TG), low- and high-density lipoprotein-cholesterol, fatty acids, oxylipins, and fatty acid desaturase activities. Statistical differences were assessed by linear mixed model.
RESULTS: FADS1 activity decreased by 29.1% (P = 0.007) when the 6 mg Zn/d diet was consumed for 2 wk. This change was associated with significant decreases in HDL-c and LDL-c. The alterations in FADS1, HDL-c and TG remained unchanged when Zn intakes were increased to 10 mg/d for 4 wk. Supplementation with 25 mg Zn/d for 3 wk normalized these metabolic changes and significantly increased LDL-c at the end of this metabolic period compared to baseline. FADS1 activity was inversely correlated with FADS2 (rmcorr = -0.52; P = 0.001) and TG (rmcorr = -0.55; P = 0.001) at all timepoints.
CONCLUSION: A low zinc, high phytate rice-based diet reduced plasma HDL-c concentrations and altered fatty acid profiles in healthy men within 2 wk. Consuming 10 mg Zn/d without phytate for 4 wk did not improve the lipid profiles, but a 25 mg Zn/d supplement corrects these alterations in lipid metabolism within 3 wk. Registration: Clinical Trials.gov: NCT02861352.
PMID:34919682 | DOI:10.1093/jn/nxab425
