Dietary Zinc Intake and Urinary Zinc Excretion in Diabetic Nephropathy

Abstract. Zinc deficiency and altered myocardial adenylate cyclase activity commonly occur in diabetes. To determine whether the zinc intake of the animal can account for the altered β-adrenergic receptor activity in the diabetic heart, we determined the β-adrenergic receptor number and isoproterenol-, NaF- and forskolin-stimulated adenylate cyclase activity in diabetic and control rats maintained on low, normal and high zinc diets for 3 weeks. Scatchard analysis of [125I]iodocyanopindolol binding to control heart membrane preparations revealed a binding capacity of 17.3 ± 1.3 fmol/mg protein with a Kd of 35 ± 1.0 pmol/l. Neither the diabetic state nor the zinc status altered these binding parameters. The isoproterenol-stimulated adenylate cyclase acticity was significantly lower in diabetic rats on low zinc diets compared with controls. The NaF- (65.1 ± 5.4 vs 60.8 ± 6.4 pmol cAMP·mg protein−1·min−1) and forskolin-stimulated adenylate cyclase activities (161 ± 9.3 vs 154 ± 21.2 pmol cAMP·mg protein−1· min−1) were not significantly altered in diabetic rats. Low dietary zinc intake compared with high zinc diet significantly increased NaF- and forskolin-stimulated adenylate cyclase activity both in diabetic rats and controls. The effect of dietary zinc content on isoproterenol-stimulated adenylate cyclase was significant in control rats only. Thus zinc intake appears to be an important determinant of cardiac adenylate cyclase activity level. Additional factors peculiar to the diabetic state are involved in the modulation of β-adrenergic responsiveness of the diabetic heart.

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U-shaped Association Between Dietary Zinc Intake and New-onset Diabetes: A Nationwide Cohort Study in China

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/clinem/dgab636 ◽

2021 ◽

Author(s):

Panpan He ◽

Huan Li ◽

Mengyi Liu ◽

Zhuxian Zhang ◽

Yuanyuan Zhang ◽

...

Keyword(s):

Chinese Adults ◽

Dietary Zinc ◽

Nutrition Survey ◽

Zinc Intake ◽

Health And Nutrition ◽

Onset Diabetes ◽

Household Food Inventory ◽

Diagnosed Diabetes ◽

New Onset

Abstract Aims We aimed to investigate the relationship of dietary zinc intake with new-onset diabetes among Chinese adults. Materials and Methods A total of 16 257 participants who were free of diabetes at baseline from the China Health and Nutrition Survey were included. Dietary intake was measured by 3 consecutive 24-hour dietary recalls combined with a household food inventory. Participants with self-reported physician-diagnosed diabetes, or fasting glucose ≥ 7.0 mmol/L, or glycated hemoglobin ≥ 6.5% during the follow-up were defined as having new-onset diabetes. Results A total of 1097 participants developed new-onset diabetes during a median follow-up duration of 9.0 years. Overall, the association between dietary zinc intake and new-onset diabetes followed a U-shape (P for nonlinearity < 0.001). The risk of new-onset diabetes was significantly lower in participants with zinc intake < 9.1 mg/day (per mg/day: hazard ratio [HR], 0.73; 95% CI, 0.60-0.88), and higher in those with zinc intake ≥ 9.1 mg/day (per mg/day: HR, 1.10; 95% CI, 1.07-1.13). Consistently, when dietary zinc intake was assessed as deciles, compared with those in deciles 2-8 (8.9 -<12.2 mg/day), the risk of new-onset diabetes was higher for decile 1 (<8.9 mg/day: HR, 1.29; 95% CI, 1.04-1.62), and deciles 9 to 10 (≥12.2 mg/day: HR, 1.62; 95% CI, 1.38-1.90). Similar U-shaped relations were found for plant-derived or animal-derived zinc intake with new-onset diabetes (all P for nonlinearity < 0.001). Conclusions There was a U-shaped association between dietary zinc intake and new-onset diabetes in general Chinese adults, with an inflection point at about 9.1 mg/day.

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