Manuel Olivares

Iron status with different infant feeding regimens : relevance to screening and prevention of iron deficiency

The objective of this study was to evaluate the benefit of screening for anemia in infants in relation to their previous diet. The iron status of 854 nine-month-old infants on three different feeding regimens and on a regimen including iron dextran injection was determined by analysis of hemoglobin, serum ferritin, and erythrocyte protoporphyrin levels and of serum transferrin saturation. Infants were categorized as having iron deficiency if two or three of the three biochemical test results were abnormal and as having iron deficiency anemia if, in addition, the hemoglobin level was less than 110 gm/L. The prevalence of iron deficiency was highest in infants fed cow milk formula without added iron (37.5%), intermediate in the group fed human milk (26.5%), much lower in those fed cow milk formula with added iron (8.0%), and virtually absent in those injected with iron dextran (1.3%). The corresponding values for iron deficiency anemia were 20.2%, 14.7%, 0.6%, and 0%, respectively. The use of iron supplements is therefore justified in infants fed cow milk formula without added iron, even when there is no biochemical evidence of iron deficiency. The low prevalence of iron deficiency in the group fed iron-fortified formula appears to make it unnecessary to screen routinely for anemia in such infants. These results also support the recommendation that infants who are exclusively fed human milk for 9 months need an additional source of iron after about 6 months of age.

Anaemia and iron deficiency disease in children

Iron deficiency is the single most common nutritional disorder world-wide and the main cause of anaemia in infancy, childhood and pregnancy. It is prevalent in most of the developing world and it is probably the only nutritional deficiency of consideration in industrialised countries. In the developing world the prevalence of iron deficiency is high, and is due mainly to a low intake of bioavailable iron. However, in this setting, iron deficiency often co-exists with other conditions such as, malnutrition, vitamin A deficiency, folate deficiency, and infection. In tropical regions, parasitic infestation and haemoglobinopathies are also a common cause of anaemia. In the developed world iron deficiency is mainly a single nutritional problem. The conditions previously mentioned might contribute to the development of iron deficiency or they present difficulties in the laboratory diagnosis of iron deficiency.

Prevalence of Anemia in Latin America and the Caribbean

Background: In Latin America and the Caribbean, anemia has been a public health problem that affects mainly women of childbearing age and children under 6 years of age. However, the current prevalence of anemia in this region is unknown. Objective: To examine the latest available prevalence data on anemia in Latin America and the Caribbean. Methods: A systematic review was conducted in 2011 and updated in 2014. Studies determining the prevalence of anemia conducted in apparently healthy populations with national or regional representativeness were included in the review. Results: The lowest prevalence rates of anemia among children under 6 years of age were found in Chile (4.0%), Costa Rica (4.0%), Argentina (7.6%), and Mexico (19.9%). In Nicaragua, Brazil, Ecuador, El Panama, and Honduras, anemia was a moderate public health problem, with prevalence ranging Salvador, Cuba, Colombia, the Dominican Republic, Peru, from 20.1% to 37.3%. Anemia was a severe public health problem in Guatemala, Haiti, and Bolivia. The prevalence of anemia among women of childbearing age was lowest in Chile (5.1%). In Colombia, El Salvador, Costa Rica, Nicaragua, Ecuador, Mexico, Peru, Honduras, and Argentina, anemia was a mild public health problem, with prevalence ranging from 7.6% to 18.7%. In Guatemala, Brazil, the Dominican Republic, and Bolivia, anemia was a moderate public health problem, with prevalence ranging from 21.4% to 38.3%. Panama and Haiti had the highest reported prevalence rates (40.0% and 45.5%, respectively), and anemia was considered a severe public health problem in those countries. Conclusions: Anemia remains a public health problem in children under 6 years of age and women of childbearing age in most Latin America and Caribbean countries for which data are available.

Tumour necrosis factor‐α transcription in transferrin‐stimulated human blood mononuclear cells: is transferrin receptor involved in the signalling mechanism?

Summary. Transferrin (Tf) and tumour necrosis factor‐alpha (TNF‐α) participate in immune response regulation. We studied the capacity of Tf to modulate ‘in vitro’ TNF‐α secretion, membrane expression and transcription by human blood mononuclear cells (BMNC). Women 25–45u2003years of age with normal iron status (nu2003=u200320) or with iron deficiency (ID, nu2003=u200320) due to gynaecological bleeding were studied. BMNC were incubated with different proportions of Fe‐exempt and Fe‐saturated Tf (apo‐Tf:holo‐Tf). Apo‐Tf or holo‐Tf uniformly induced TNF‐α secretion in the cell supernatants from both groups. Nevertheless, cytokine levels were significantly lower in ID subjects. For all Tf‐Fe saturations assayed, mean TNF‐α levels varied between 1·4–1·6u2003ng/ml and 0·4–0·7u2003ng/ml for normal and ID women respectively (Pu2003<u20030·001). The addition of apo‐Tf enhanced TNF‐α secretion in a dose‐dependent manner, but the cytokine levels were lower in ID group. Tf did not induce pro‐TNF‐α expression in monocytes and lymphocytes from either group. Tf‐treated cells from normal individuals expressed approximately two to three times more TNF‐α mRNA than cells from ID subjects. Mean values ranged 96–110u2003atmol/ml in normal women and 24–31u2003atmol/ml in ID women for all Tf‐Fe saturation levels tested (Pu2003<u20030·001). These results show that Tf‐induced TNF‐α secretion is transcriptionally regulated. The impaired TNF‐α transcription in cells from ID subjects indicates that the quality of the immune response is linked to the Fe status of mononuclear cells.