The relationship between obesity and hypoferraemia in adults: a systematic review

Abstract

A growing number of studies suggest a potential link between obesity and altered iron metabolism. The purpose of this systematic review was to examine existing literature on iron status in obese populations. A comprehensive literature search was conducted. Included studies recruited participants ≥ 18 years with a body mass index ≥ 30 kg m(-2) and provided descriptive statistics for haemoglobin or ferritin at a minimum. There were 25 studies meeting all eligibility criteria, of these 10 examined iron status in free-living obese individuals and 15 reported baseline iron biomarkers from bariatric surgery candidates. Non-obese comparison groups were used by 10 (40%) articles. In these, seven obese groups reported higher mean haemoglobin concentration; six reported significantly higher ferritin concentration; and four significantly lower transferrin saturation. Due to insufficient data, it was not possible to make conclusions regarding mean differences for soluble transferrin receptor (sTfR), hepcidin or C-reactive protein. Existing evidence suggests a tendency for higher haemoglobin and ferritin concentration and lower transferrin saturation in obesity. Alternation of iron biomarkers in obese populations may be a result of obesity-related inflammation and/or related comorbidities. Further research incorporating measurement of inflammatory cytokines, sTfR and hepcidin is required to confirm the impact of obesity on iron status.

Association between serum ferritin levels and the incidence of obesity in Korean men: A prospective cohort study

“…In other words, a high level of serum ferritin represents a high level of iron accumulation in healthy individuals. However, some reports have shown that obesity is associated with iron deficiency [16][17][18]. Thus, the exact nature of the relationship between serum ferritin level and obesity remains unclear.…”

Iron status in obese women

“…Initially, iron deficiency in a population of obese people was linked to a low level of physical activity, poor dietary habits, and increased requirement of iron related to larger blood volume and obesity. Recently, depleted iron stores in obese subjects were linked to inflammation and hepcidin influence on iron influx into plasma through its down-regulating action on ferroportin-1 [4,5,6,7,8].…”

Micronutrient supplementation in gastric bypass surgery: prospective study on inflammation and iron metabolism in premenopausal women

“…Before surgery (at baseline), systemic lowgrade inflammation influenced the increase of ferritin levels; however, before and after surgery, ferritin values were determined by serum iron levels, iron intake, and hepcidin. In obesity, increased ferritin levels are associated with low transferrin saturation and hypoferremia, but those with obesity do not seem to be more prone to anemia, compared to eutrophic subjects (25,38). Most of these changes are related to the anemia of inflammation, in which mechanisms are stimulated by proinflammatory cytokines and hepcidin (16).…”

“…The minerals presented in the formula were chelated into an amino acid (glycine). The micronutrient supplementation of 2 RDAs (26) was suggested to be given daily for RYGB surgery in two doses (11,(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35). Adequate Intake (AI) (26) was used when the RDA was not established for the micronutrient (except for calcium).…”

“…Changes in iron metabolism associated with obesity and after bariatric surgery, as with the effect of micronutrient supplementation, need to be better elucidated (25). Therefore, this study aimed to assess the effect of two micronutrient supplementation schemes on inflammation and iron metabolism in premenopausal women who had undergone RYGB surgery.…”