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Iron, oxidative stress, and Stearoyl‐CoA Desaturase activity: An Analysis from the National Health and Nutrition Examination Survey 2003–04
Author(s) -
Wu Yue,
Baylin Ana,
Colacino Justin
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.788.6
Subject(s) - medicine , biomarker , national health and nutrition examination survey , ferritin , oxidative stress , cotinine , waist , interquartile range , physiology , endocrinology , body mass index , biology , population , biochemistry , environmental health , nicotine
Stearoyl‐coa desaturase (SCD) is a key enzyme in fatty acid metabolism, and elevated SCD activity is associated with multiple adverse health outcomes, including heart disease, cancer, and diabetes. Diet, hormones, and environmental exposures are potential factors affecting SCD activity. However, less is known about the relationship between intake of micronutrients, such as iron, and SCD activity. Iron is an essential element for human as it participates in various metabolic activities. It is also well known to be associated with oxidative stress, which can attenuate lipid synthesis and induce abnormal lipogenesis. Using NHANES 2003–04 data, the association between levels of serum ferritin, a biomarker of circulating iron levels, and the Δ9 desaturase index (the ratio between plasma palmitoleic acid and palmitic acid), a biomarker of SCD activity, was investigated among female subjects (N=447) aged from 20–49 years old with various race/ethnicity backgrounds (Mexican American: n=88; Hispanic: n=13; non‐Hispanic White: n=232; non‐Hispanic Black: n=92; Other: n=22). Since women have higher iron requirements during pregnancy, stratification analysis were performed to compare Δ9 desaturase index levels among women who were at different points in life (pregnant: n=78; non‐pregnant: n=363). The multivariate analyses were performed utilizing generalized linear modeling and adjusting for potential confounders, including waist circumference, age, race, and cotinine levels. Kenny's 4‐step mediation method was applied to test whether this association was mediated through gamma‐glutamyl transpeptidase (GGT), a biomarker of oxidative stress. Results showed an interquartile range increase in serum ferritin corresponded to 4% (95% CI: 1%, 7%) higher Δ9 desaturase index (p=0.04). We observed a significant positive association between waist circumference (p<0.0001) and cotinine (p=0.025) with higher Δ9 desaturase index. Non‐Hispanic Blacks, on average, had a significantly lower Δ9 desaturase index (p<0.0001) compared with non‐Hispanic Whites (the reference group). After stratifying pregnancy status, an interquartile range increase in serum ferritin corresponded to 4% (95% CI: 2%, 6%) higher Δ9 desaturase index among non‐pregnant women (p=0.041). In sensitivity analysis, we compared the Δ9 desaturase activity between iron overloaded (ferritin ≥ 150 ng/ml) and non‐iron overloaded individuals. Iron overloading was associated with 16.2% higher Δ9 desaturase activity (p=0.116). This association was not fully mediated via GGT. Given the current emphasis on iron‐fortified foods and iron supplements, identifying the negative impact of iron overloading can help researchers and health providers to give adjusted nutrition recommendations to populations with lower iron requirements, such as hemochromatosis patients, women after menopause and non‐active older men. Combined graphChange of delta‐9 desaturase index with increased ferritin (A), change of GGT with increased ferritin (B), change of delta‐9 desaturase index with increased GGT (C).