TABLE 3.
Studies on the impact of weight loss interventions on iron status, inflammation, and hepcidin1
| Author | Year | Population | Relevant primary measurements | Key findings |
| Ausk et al. (107) | 1997 | Severely obese women (n = 43) on 3 different very low-energy diets: lowest calorie, middle calorie supplemented with iron (27 mg/dL), and highest calorie (United States) | BMI, body composition (fat mass and fat-free mass), and iron status (Tsat, ferritin, Hb, HCT) | Initially, Tsat decreased by 30% in all groups, but only the iron-supplemented group had an increase in iron status back to normal levels. |
| Di Toro et al. (110) | 1997 | Obese children and adolescents (n = 55) on a 13-wk hypocaloric diet (n = 22) or a 10-wk (n = 33) protein sparing modified fast diet (Italy) | Ideal body weight (IBW), arm fat area, arm muscle area, iron status (sFe, Tsat, ferritin), dietary intake (24-h recall) | There was weight loss with both diets but no change in iron status. |
| Anty et al. (111) | 2008 | Morbidly obese women (n = 178) undergoing bariatric surgery with a 6-mo follow-up (n = 55) (France) | BMI, iron status (plasma iron, Tsat, ferritin, Hb), CRP | At baseline, there was a high prevalence of iron deficiency (53%, Tsat <20%), and 6% of the subjects were anemic (Hb < 12 g/dL). Six months after bariatric surgery there was a decrease in CRP and an increase in Tsat, from 18% to 25%. |
| Amato et al. (61) | 2010 | Obese children (n = 15) undergoing a 6-mo calorie-restricted diet (Italy) | BMI, iron status (sFe, Tsat, ferritin), iron absorption (iron load test), serum hepcidin, IL-6, and leptin | There was a decrease in BMI, serum hepcidin, and leptin and a trend for decrease in IL-6. Also, iron status (sFe, Tsat) and iron absorption increased after weight loss. Hepcidin was positively correlated with serum leptin. |
| Tussing-Humphreys et al. (47) | 2010 | Premenopausal obese women undergoing bariatric surgery (n = 20) with a 6-mo follow-up (United States) | BMI, waist circumference, iron status (sFe, Tsat, sTfR, ferritin, Hb, HCT), serum hepcidin, CRP, IL-6, dietary iron | At baseline, iron deficiency was seen in 45% of subjects (sTfR >28.1 nmol/L). There was a decrease in BMI, CRP, serum hepcidin, and sTfR. There were increases in Hb and HCT. Change in hepcidin was not associated with change in BMI. |
| Tussing-Humphreys et al. (71) | 2011 | Obese (n = 17) and lean (n = 19) premenopausal women. Outcomes were also measured in obese group 6-mo after bariatric surgery (United States) | BMI, waist circumference, iron status (sTfR, Hb), serum hepcidin, CRP, IL-6. Cytokine production (IL-6, IL-10, IL-22, IFN-γ, TNF-α) by WBC after stimulation with LPS or ZY | At baseline, cytokine production (IL-6, IFN-γ, and TNF-α) after stimulation with LPS or ZY was lower in the obese vs. lean women. After weight loss, IL-6 and TNF-α production in the obese group increased and became equal to the nonobese group. At baseline, IFN-γ ex vivo production in the obese group correlated negatively with serum hepcidin and positively with sTfR. |
1
AT, adipose tissue; CRP, C-reactive protein; Hb, hemoglobin; HCT, hematocrit; LPS, lipopolysaccharide; sFe, serum iron; sTfR; soluble transferrin receptor; TIBC, total iron binding capacity; Tsat, transferrin saturation; WBCs, white blood cells; ZY, zymosan.