Dietary Zinc Intake and the Association of Insulin Level and HOMA-IR with Telomere Shortening in Mexican Children

The relationship between dietary zinc (Zn) intake, metabolic diseases, and telomere length has been little explored in the children population. This observational cross-sectional study assesses the association between obesity (OB), cardiometabolic traits, telomere length, and dietary Zn intake in children with normal weight (NW) and OB from Mexico City.

Anthropometric data, blood pressure, biochemical measurements, the homeostatic model assessment of insulin resistance (HOMA-IR) and leucocyte telomere length (determined by quantitative-PCR) were analyzed in 171 children with NW and 172 with OB. Furthermore, dietary Zn intake was evaluated in 117 children NW and 120 with OB.

Telomere shortening was associated with fasting plasma insulin (FPI) and HOMA-IR in NW (beta coefficient [β]_FPI = -0.022 ± 0.008, p = 0.009; β_HOMA-IR = -0.096 ± 0.040, p = 0.020) and OB (β_FPI = -0.007 ± 0.002, p = 0.003; β_HOMA-IR = -0.034 ± 0.012, p = 0.005) children. Dietary Zn intake resulted negatively associated with FPI (β = -2.418 ± 0.764, p = 0.002) and HOMA-IR (β = -0.399 ± 0.014, p = 0.009) in children with OB. Then, in children with OB, the association between FPI, HOMA-IR, and telomere shortening was evaluated separately in groups of low, medium, and high dietary Zn intake (according to tertiles). The association between FPI, HOMA-IR, and telomere shortening was not significant in the high Zn intake group (P_FPI = 0.633; P_HOMA-IR = 0.567).

Our results suggest that a high Zn intake may ameliorate the telomere shortening related to high FPI and HOMA-IR.