Impact of Diet and Weight Loss on Iron and Zinc Status in Overweight and Obese Young Women

飲食和減重對過重和肥胖年輕女性鐵和鋅狀況之影響

Hoi Lun Cheng ； Hayley J Griffin ； Christian E Bryant ； Kieron B Rooney ； Katharine S Steinbeck ； Helen T O'Connor

《Asia Pacific Journal of Clinical Nutrition》 預刊文章 Pp. 29-37

摘要

Young overweight women are at risk of iron and zinc deficiency. This study assessed iron, zinc and inflammatory status during a 12-month weight loss trial in young women (18-25 y; BMI ≥27.5 kg/m^2) randomised to a higherprotein (HP: 32% protein; 12.2 mg/day iron; 11.7 mg/day zinc) or lower-protein (LP: 20%; 9.9 mg/day; 7.6 mg/day respectively) diet with contrasting haem iron and zinc content. In completers (HP: n=21; LP: n=15), HP participants showed higher median ferritin (52.0 vs 39.0 μg/L; p=0.021) and lower median soluble transferrin receptor-ferritin index (sTfR-F; 0.89 vs 1.05; p=0.024) although concentrations remained within normal range for both diets. Median C-reactive protein (CRP; HP: 3.54; LP: 4.63 mg/L) and hepcidin (HP: 5.70; LP: 8.25 ng/mL) were not elevated at baseline, and no longitudinal between-diet differences were observed for zinc and CRP. Compared to those with ＜5% weight loss, HP participants losing ≥10% weight showed lower median sTfR-F (0.76 vs 1.03; p=0.019) at six months. Impact of ≥10% weight loss on iron was more apparent in LP participants who exhibited greater mean serum iron (20.0 vs 13.5 μmol/L; p=0.002), transferrin saturation (29.8% vs 19.4%; p=0.001) and lower sTfR (1.24 vs 1.92 mg/L; p=0.034) at 12 months. Results show normal iron and zinc status can be maintained during 12 months of energy restriction. In the absence of elevated baseline inflammation and hepcidin, a more favourable iron profile in those with ≥10% weight loss may reflect stronger compliance or the potential influence of iron regulatory mechanisms unrelated to inflammatory hepcidin reduction.

關鍵字

肥胖 ； 體重減少 ； 年輕成人 ； 鐵 ； 鋅

並列摘要

Young overweight women are at risk of iron and zinc deficiency. This study assessed iron, zinc and inflammatory status during a 12-month weight loss trial in young women (18-25 y; BMI ≥27.5 kg/m^2) randomised to a higherprotein (HP: 32% protein; 12.2 mg/day iron; 11.7 mg/day zinc) or lower-protein (LP: 20%; 9.9 mg/day; 7.6 mg/day respectively) diet with contrasting haem iron and zinc content. In completers (HP: n=21; LP: n=15), HP participants showed higher median ferritin (52.0 vs 39.0 μg/L; p=0.021) and lower median soluble transferrin receptor-ferritin index (sTfR-F; 0.89 vs 1.05; p=0.024) although concentrations remained within normal range for both diets. Median C-reactive protein (CRP; HP: 3.54; LP: 4.63 mg/L) and hepcidin (HP: 5.70; LP: 8.25 ng/mL) were not elevated at baseline, and no longitudinal between-diet differences were observed for zinc and CRP. Compared to those with ＜5% weight loss, HP participants losing ≥10% weight showed lower median sTfR-F (0.76 vs 1.03; p=0.019) at six months. Impact of ≥10% weight loss on iron was more apparent in LP participants who exhibited greater mean serum iron (20.0 vs 13.5 μmol/L; p=0.002), transferrin saturation (29.8% vs 19.4%; p=0.001) and lower sTfR (1.24 vs 1.92 mg/L; p=0.034) at 12 months. Results show normal iron and zinc status can be maintained during 12 months of energy restriction. In the absence of elevated baseline inflammation and hepcidin, a more favourable iron profile in those with ≥10% weight loss may reflect stronger compliance or the potential influence of iron regulatory mechanisms unrelated to inflammatory hepcidin reduction.

並列關鍵字

obesity ； weight loss ； young adult ； iron ； zinc