Relationship between iron and vitamin a

The Relationship Between Iron and Vitamin C - Fergon

relationship between iron and vitamin a

In recent years, the relationship between vitamin A deficiency, iron, and anemia Indian children (6) indicated an association between serum retinol and. In the human body, nutrients interact with each other in different ways. Learn about the relationship between iron and vitamin C and absorption of both!. , INDEXING KEY WORDS vitamin A •iron interaction. A relationship between iron and vitamin effects of dietary vitamin A on liver iron.

Vitamin A, Iron, and Anemia: from observation to hypotheses

Other limitations of the study are lack of investigation of an inflammatory marker and other Fe parameters. There was no evidence of interactions between VA and Fe supplementation, assessed by Hb, ferritin, and retinol-binding protein RBP concentrations. There was insufficient power to assess if the supplementation regimens were modified by VA status at baseline.

Blood concentration of CRP was determined at baseline, but there was no subgroup analysis considering the influence of this inflammatory marker in adolescents with and without anemia. The authors did not assess Hb variants. Erythrocyte incorporation of Fe stable isotopes was measured 14 days after intake of maize porridge 2. The children were divided in two groups to receive the meals. Retinyl palmitate added to the labeled meal had no positive effect on erythrocyte incorporation of Fe, with Fe incorporation being significantly higher for meals not containing retinyl palmitate.

In fact, supplementation with retinyl palmitate decreased erythrocyte incorporation of Fe stable isotopes.

relationship between iron and vitamin a

At the end of the study, the children were supplemented with a single dose of VAIU and 3 weeks after supplementation the difference in Fe incorporation was no longer present, indicating a possible action of VA on the mobilization and availability of Fe, although the result was not statistically significant.

The difference in response to retinyl palmitate added to Fe-fortified maize porridge on erythrocyte incorporation of Fe before and after intake of the vitamin A capsule indicates, indirectly, changes in vitamin A status not measurable by the modified relative dose response MRDR technique.

Relationship between vitamin A and iron in the liver.

The lack of conclusive data on the effect of retinyl palmitate on Fe absorption indicates the complexity of the interactions between vitamin A status, dietary vitamin A and Fe metabolism. Vitamin A Supplementation in Pregnant and Lactating Women In a randomized, double-blind, placebo-controlled trial involving pregnant women from Indonesia, Suharno et al.

Mean serum retinol concentrations at baseline varied from 1. After 2 months of supplementation, the largest increase in Hb was observed for the group supplemented with VA and Fe, reaching a level of There were also statistically significant increases in serum ferritin and serum iron, and decreases in TIBC.

Relationship between vitamin A and iron in the liver.

Although the authors carefully evaluated the VA status at baseline, no inflammatory marker was considered. Transferrin receptor concentrations significantly increased in the three groups. Prevalence of VAD and mean plasma retinol concentration were respectively However, there were no differences between groups in relation to Hb and plasma retinol. Moreover, no impact was observed in the slope of the regression line between log erythropoietin and Hb.

Other factors could be associated with the lack of impact of VA supplementation in the pregnant women.

relationship between iron and vitamin a

Firstly, malaria is endemic in Malawi [ 23 ], and a recognized cause of anemia [ 24 ]. Secondly, Africa is a continent with high a prevalence of Hb variants [ 24 ]. These two epidemiologic and genetic characteristics are important confounders that were not considered in the analysis. In a study conducted by Tanumihardjo [ 16 ], 27 Indonesian women, 18—37 years of age, during the second trimester of gestation were divided into four groups to receive the following supplements: In this study an accurate method for assessment of VA status was used: MRDR modified relative dose response test.

However, the author did not investigate inflammatory markers. The women were allocated into the following groups: The supplements were administered seven days a week for two months, in a double-blind manner. The effect of the different supplementation regimes were analyzed by Hb increment, considering that only Hb was assessed at baseline.

The authors did not assess vitamin A concentrations at baseline, and no inflammatory marker.

relationship between iron and vitamin a

Prevalence of anemia in Asia is among the highest in the world. In a recent double-blind randomized trial conducted by Sun et al. The authors concluded that VA combined with Fe supplementation was more beneficial to improve iron status during pregnancy than iron alone.

The Influence of Vitamin A Supplementation on Iron Status

However, the authors did not consider inflammatory markers assessment and VA measurements at baseline. All the studies used randomization to allocate the subjects for supplementation or fortification. In spite of the methodological qualities, some of them did not use a placebo group [ 371415 ] and did not assess the VA status of the subjects at baseline [ 36711171820 ].

One study did not assess Fe parameters at baseline [ 20 ]. Only few studies included a reasonable number of iron parameters [ 11131415 ]. Another important limitation was the lack of assessment of Hb variants and malaria, especially in regions with a high prevalence of these problems [ 611121820 ]. This difficulty was more accentuated in studies where hemoglobin was the only parameter assessed [ 3617 ]. From 3—8 wk of age, rats were fed one of four purified diets that were either adequate or restricted in iron Fe and adequate or marginal in VA: Weight-matched rats fed adequate micronutrients were included to control for possible confounding effects of Fe deficiency on growth and feed efficiency.

Although marginal VA deficiency did not exacerbate indices of poor iron status during iron deficiency, iron deficiency was associated with lower plasma retinol and elevated liver VA concentrations. These results are consistent with an impaired mobilization of liver retinol during iron deficiency as well as multiple alterations in iron metabolism. In many parts of the world, iron deficiency coexists with deficiencies of other micronutrients, including vitamin A VA 3.

Although new cases of severe VA deficiency xerophthalmia still occur each year 3it is estimated that mild, or marginal, VA deficiency is far more prevalent, especially among children, pregnant and lactating women in the developing world, and may affect as many as million people worldwide 2. As early as the s, VA deficiency and anemia or other indices of low iron status were reported to be associated in humans and animals 4 — 6.

In observational studies, Mejia et al. In experimental studies conducted in adult men with very low VA intakes for — d, Hodges et al.

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These results suggested that iron stores were unavailable for hematopoiesis during VA deficiency, implying that VA plays a role in the release of iron from the liver. In general, there was no effect of VA supplementation on TIBC or serum ferritin, with the exception of a study in which serum ferritin was increased by VA supplementation The rat has been used since the s as a model in which to investigate the relationship between VA deficiency and iron deficiency 5.

Both Hb and Ht were lower in rats with either marginal 22 or more severe VA deficiency However, in other studies, hematologic signs of anemia during VA deficiency were not observed 14 Conversely, after VA supplementation of VA-deficient rats, plasma iron and TIBC increased, whereas iron concentrations in the liver, kidney, spleen and tibia decreased From these data, it has been hypothesized that VA deficiency promotes the sequestration of iron in tissues, making it unavailable for erythropoiesis, resulting eventually in anemia and abnormal iron indices.