Effect of breastfeeding on serum zinc levels and growth in healthy infants

Association of serum and erythrocyte zinc levels with breastfeeding and complementary feeding in preterm and term infants

Zinc is an important nutrient involved in cell division, physical growth, and immune system function. Most studies evaluating the nutritional status related to zinc and prematurity were conducted with hospitalized preterm infants. These studies show controversial results regarding the prevalence of deficiency, clinical implications, and the effect of zinc supplementation on mortality, infectious diseases, and growth in these groups. This study aimed to compare serum and erythrocyte zinc levels in a group of preterm and full-term infants after 9 months of age, and related the zinc levels to dietary intake and anthropometric indicators in both groups. This cross-sectional study compared 43 preterm infants (24 to 33 weeks) aged 9-24 months to 47 full-term healthy infants. Outcome measures: anthropometric indicators and dietary intake. Blood sample for serum and erythrocyte zinc levels (ICP-MS, Inductively Coupled Plasma Mass Spectrometry). There was no difference between the groups regarding the mean of serum and erythrocyte zinc. Variables associated with higher serum zinc levels were breastfeeding at evaluation (β = 20.11 µg/dL, 95% CI 9.62-30.60, p < 0.001) and the later introduction of solid foods (β = 6.6 µg/dL, 95% CI 5.3-11.4, p < 0.001). Breastfeeding was also associated with higher erythrocyte zinc levels. The zinc levels were adequate in both groups, there was no association with anthropometric indicators or dietary intake and were slightly influenced by breastfeeding and time of solid food introduction.

The Effect of Zinc Administration in Short Adolescent Mothers who Breastfeed on Zinc Level, Insulin-1 Growth Factors, and Infant Growth

BACKGROUND: Zinc is an important nutrient for humans at all stages of life, whose needs increase during pregnancy and lactation. Zinc concentrations in breast milk are considered adequate for the first 6 months of life, despite an increase in the volume of milk consumed, zinc in breast milk is likely to be sufficient if there is no diet. weaning (9). Zinc levels in breast milk cannot compensate for the increased zinc requirements of the premature neonate due to higher than normal zinc requirements, small liver size with reduced zinc stores and a shortened digestive system. AIM:This study aims to measure serum zinc levels, IGF-1, and growth of infants aged 6 months in short adolescent mothers who are breastfeeding and have been intervened with zinc supplementation. MATERIAL AND METHOD: This study is a quantitative study using a quasi-experimental design, and a pretest-posttest approach with a control group. The sampling technique used purposive sampling with inclusion criteria, namely: infants from breastfeeding mothers aged <19 years, history of SEZ, maternal height <150 cm, so that the total sample size was 60 respondents (30 control samples and 30 intervention samples). Analysis of the data collected in the study was processed analytically with the Independent Sample T-Test and Paired T-Test tests. RESULT: From this study, it was found that the Paired Sample T Test results obtained p value < 0.001 indicating that there was a difference before and after the intervention, so it can be concluded that there was an effect of giving zinc supplementation on serum zinc and IGF-1 levels of infants in the intervention group. And through the Independent T test, the value of p = 0.001 < = 0.05. This shows that there is an effect of zinc supplementation on serum zinc and IGF-1 levels in infants. While the results of the Z-Score test for body weight and Z-Score values for body length obtained p <0.001. This illustrates that there is a difference between the intervention group and the control group, so it can be concluded that there is an effect of zinc supplementation on the growth of infants aged 6 months. CONCLUSSION: There was a significant difference between before and after the intervention in the two groups, so that zinc supplementation was effective in influencing serum zinc levels, IGF-1 and infant growth.

Trajectory of vitamin D, micronutrient status and childhood growth in exclusively breastfed children

This study aimed to compare the trajectory of serum 25(OH)D, micronutrient levels, and anthropometric measurements between exclusively breastfed and mixed-fed children. This is a prospective cohort study. Anthropometric measurements of the children were obtained during scheduled clinical visits. Tests for 25(OHD), ferritin, zinc and complete blood count were performed yearly until 3 years of age. Clinical records and questionnaires on dietary habits were obtained. The results showed that despite official recommendations on vitamin D/iron supplements for breastfed children, less than 10% of our exclusively breastfed children received regular supplements. Thus, after 1 year, the odds for having iron deficiency anemia and vitamin D insufficiency were 9 [95% CI, 4-19] and 6 [95% CI, 2-16], respectively. Longitudinal follow-up showed the prevalence of iron deficiency to decrease from 34% at 1 year to 2% at age 3 years. However, the prevalence of vitamin D insufficiency remained persistently high throughout the first three years of life (60% at 1 to 44% at 3 years). Very few children had zinc deficiency. Anthropometric measurements showed exclusively breastfed children to have lower mean z-scores for body weight and height when compared to mixed-fed children after 12 months. In conclusion, children who were exclusively breastfed for longer than 4 months without proper supplement were more likely to have transient iron deficiency anemia and persistent vitamin D insufficiency. Their growth became relatively slower after infancy. Whether this was associated with underlying inadequate serum vitamin D and iron level remains an important issue to be explored.

Zinc concentrations in human milk and infant serum during the first six months of lactation

Normal supply of zinc to the newborn via milk is essential for normal development. Using ICP-OES, we analyzed changes in the level of Zn in milk and infant serum in the neonatal period (Day 1 and Day 28 post partum) and at 6 months after delivery, in the cohort of 60 mothers and exclusively breastfed babies. Zn level in the serum showed increase (significant at 6 months) during this period (mg/mL): Day 1: 0.52±0.12; Day 28: 0.59±0.19; 6 months: 0.68±0.28. The concentration of Zn in the milk showed an opposite (decreasing) trend during the follow up: Day 1: 4.70±1.74mg/L; Day 28: 2.65±1.06; 6 months: 0.46±0.36. A significant negative correlation was established between serum and milk [Zn] at day 28 (R=-0.338; p=0.008), whereas a positive correlation was found at 6 months between these parameters (R=0.306; p=0.018). There was no significant correlation between [Zn] in the milk and serum and infants' body mass, mothers' age and mass at delivery. The level of Zn in the milk at 6 months of lactation is not sufficient to meet the recommended values. This implies that in Serbian population, Zn supplementation might be needed in the later phase of lactation.

Same-sex twins are taller and heavier than opposite-sex twins (but only if breastfed): Possible evidence for sex bias in human breast milk

Recent studies show that human and other mammalian breast milk may be tailored for the sex of the offspring. Such sex bias suggests that opposite-sex twins, who receive breast milk that cannot simultaneously be tailored for both sexes, may be at a disadvantage for growth compared with same-sex twins. An analysis of data from the National Longitudinal Study of Adolescent Health (Add Health) shows that, controlling for sex, age, birth weight, and zygosity, breastfed same-sex twins are, on average, about 1 inch taller and 12 pounds heavier than their opposite-sex counterparts through adolescence and early adulthood. In contrast, never-breastfed same-sex twins tend to be shorter and lighter than their opposite-sex counterparts. These results may be potential evidence for sex bias in human breast milk and its long-term effects.