Effects Of Vitamin A Intervention Trial On Nutritional Status Of Serum Vitamin A And Iron In Healthy Adults

Objective: The purpose of this study was to understand the food nutritional statusand dietary pattern among health adults in Jining area, Shandong Province; study theeffect of vitamin A intervention trial on nutritional status of serum vitamin A and iron.Methods: With the help of the village doctors, healthy adults aged33to55years oldwere recruited. After the informed agreement was signed and Health examination waschecked,115healthy adults were enrolled and divided randomly into four groups,with28or29adults in each group. They were given a4-month intervention of VAsupplement with different doses of retinyl acetate in capsules. The equivalent doses ofsupplemented retinyl acetate were600μg/d,400μg/d,200μg/d and0μg/d (control) ofretinol, respectively. The capsules were administered orally by double blind method.During the experiment, the subjects kept their usual dietary pattern but avoided highVA or pre-VA carotenoids foods from their diets. A24-h dietary recall was carried outmonthly on every subject. Before and after the intervention, the fast blood sampleswere collected from each subject, and were determined for hemoglobin concentration, levels of serum retinol, iron, ferritin and transferritin receptor. The dietary nutrientswas calculated by the Nutrition calculator which was designed according to ChinaFood Composition2002by our research group. Software Stata10.0was used forstatistic analysis.Results: Total108subjects finished the experiment, with27,28,27and26personsleft in group A, B, C and D, respectively. The daily diets of the subjects were simple,the dietary intakes of energy nutrients, carbohydrate, lipid and many micronutrientswas insufficient. However，the intake of the high quality protein was only reached40percent. The dietary intakes of energy nutrients, VA and iron (both were P>0.05)among each group during the experimental period had no difference. The serumretinol concentration of subjects from group A increased from1.63±0.55μmol/L ofbaseline to1.93±0.52μmol/L at the end of the experiment (P<0.05); the elevatedvalue of serum retinol for group B and C were0.29μmol/L and0.14μmol/L (bothwere P<0.05); there was no difference before and after the experiment for controlgroup D (P>0.05). There was no significant difference on Hb concentration beforeand after the experiment as well as between groups (all were P>0.05). In subjects ofgroup A, serum iron concentration increased (P<0.05) and serum ferritin andtransferritin receptor concentration decreased significantly (both were P<0.05) afterVA supplement intervention; No such changes were observed in group B and C(P<0.05).Conclusion: The intakes of some nutrients were not enough, and the nutritioneducation should be strengthened among the subjects. It seems that the intervention ofVA supplement with relative high dose of retinol at dietary level could enhance theiron status further in no-anemic healthy adults even without dietary ironsupplementation.