A Moderate Interleukin‐6 Reduction, Not a Moderate Weight Reduction, Improves the Serum Iron Status in Diet‐Induced Weight Loss with Fish Oil Supplementation

Abstract

Fish oil is ineffective as an adjunct for weight or fat loss but has beneficial effects on preserving the lean body mass. A significant improvement in the iron status is only observed in those with moderate loss of serum IL-6 supplemented with fish oil.

Can diet‐induced weight loss improve iron homoeostasis in patients with obesity: A systematic review and meta‐analysis

“…In total, 879 subjects who were OW or obese (mean BMI: 31.8 ± 4.17 kg/m 2 , 82% females) were included, of which 660 were adults (mean BMI: 32.9 ± 4.23 kg/m 2 ) and 219 were children and adolescents (mean BMI: 25.2 ± 3.83 kg/m 2 ). Eight studies 15,21,22,24,33–36 (57.1%) were RCTs and six studies 14,16,17,19,20,23 (42.9%) were longitudinal studies. In adults, 10 studies (10/11) employed hypocaloric diet‐induced weight loss, with the exception of one study that used exercise as a stand‐alone weight‐loss programme 36 .…”

“…The majority of studies reported baseline and endpoint values of serum ferritin (14/14), serum iron (12/14), %TS (11/14), Hb (11/14), BW (13/14) and BMI (11/14). However, only four studies reported serum hepcidin (4/14) and IL‐6 (4/14) concentrations 15–17,24 . The range of the intervention duration was 1.5–24 months (adults: 1.5 to 24 months, children: 6 to 12 months), and the ranges of reductions in BW and BMI were −14.9 to 4.7 kg (adults: −14.9 to −0.15 kg, children: −3.8 to 4.7 kg) and −4.5 to 0.4 kg/m 2 (adults: −4.5 to −0.51 kg/m 2 , children: −3.4 to 0.4 kg/m 2 ), respectively.…”

“…F I G U R E 1 Plasma flowchart illustrating the study selection process 15,21,22,24,[33][34][35][36] (57.1%) were RCTs and six studies 14,16,17,19,20,23 14,16,17,19,20,23 (42.9%) were longitudinal studies. In adults, 10 studies (10/11) employed hypocaloric diet-induced weight loss, with the exception of one study that used exercise as a stand-alone weightloss programme.…”

“…However, only four studies reported serum hepcidin (4/14) and IL-6 (4/14) concentrations. [15][16][17]24 The range of the intervention duration was 1.…”

“…For several decades, a hypocaloric diet or the combination of a hypocaloric diet and exercise/physical activity has been used in practice to induce weight loss, and >5% of initial body weight (BW) loss is known to improve cardiometabolic profiles and reduce proinflammatory cytokines and hepcidin. [14][15][16][17] It was suggested that a healthy mode of weight loss is accompanied by reductions in inflammatory biomarkers and hepcidin levels, which, in turn, may help re-establish physiological iron homoeostasis in patients who were OW or obese through improving intestinal iron absorption and intracellular iron efflux. 4 Currently, data on the effects of hypocaloric diet-induced weight loss on the body's iron status are scarce, and results are inconsistent.…”