Growth, Nutritional Status, and Dietary Intake Patterns Associated With Prolonged Breastfeeding in Young Korean Children: A Nationwide Cross-Sectional Study.

BACKGROUND: Although the optimal duration of breastfeeding remains unclear, breastfeeding is generally recommended exclusively for the first 6 months of life, which continues into late infancy. However, the awareness regarding the effects of long-term breastfeeding is relatively low compared with that of breastfeeding in early infancy. We aimed to investigate the growth and nutritional characteristics of the children with prolonged breastfeeding (PBF) over 1 year. METHODS: This cross-sectional study was based on the data of children aged 12 to 23 months from the National Health and Nutrition Examination Survey (2010-2020) conducted by the Korean Center for Disease Control and Prevention. Data on anthropometric measurements, dietary behavior, and food and nutrient intake were extracted, and the association between PBF and growth, nutritional status, and dietary patterns were analyzed. RESULTS: Of the 872 children with a birth weight of ≥ 2.5 kg in the final analysis, 34.2% continued breastfeeding over 12 months of age, and their median breastfeeding duration was 14.2 months. Children with PBF were more likely to have lower current body weight (P < 0.001) and weight gain (P < 0.001), lower daily protein (P = 0.012), calcium (P < 0.001), and iron (P < 0.001) intake per calorie compared with children weaned by 12 months of age or those who were never breastfed. Furthermore, they were started on complementary food at 6 months or later rather than 4-5 months (P < 0.001), consumed cow's milk earlier (P = 0.012), and consumed probiotics as dietary supplements (P < 0.001) significantly less commonly. When comparing the intake of food groups, children with PBF had a significantly higher intake of cereals and grains (P = 0.023) and fruits (P = 0.020) and a significantly lower intake of bean products (P = 0.020) and milk and dairy products (P = 0.003). CONCLUSION: Korean children who continued breastfeeding over 12 months of age showed distinct characteristics in terms of growth, nutritional status, and dietary patterns in the second year of life compared to children who did not. Long-term additional research on their growth and nutritional status may be needed; however, these findings are significant as important fundamental data for nutritional counseling to establish healthy PBF.

Breastfeeding and Red Meat Intake Are Associated with Iron Status in Healthy Korean Weaning-age Infants.

The present study investigated risk factors for iron deficiency (ID) and iron deficiency anemia (IDA) during late infancy, including feeding type and complementary feeding (CF) practice. Healthy term Korean infants (8-15 months) were weighed, and questionnaires regarding delivery, feeding, and weaning were completed by their caregivers. We also examined levels of hemoglobin, serum iron/total iron-binding capacity, serum ferritin, and mean corpuscular volume (MCV). Among 619 infants, ID and IDA were present in 174 infants (28.1%) and 87 infants (14.0%), respectively. The 288 infants with exclusively/mostly breastfeeding until late infancy (BFL) were most likely to exhibit ID (53.1%) and IDA (28.1%). The risk of ID was independently associated with BFL (adjusted odds ratio [aOR], 47.5; 95% confidence interval [CI], 18.3-122.9), male sex (aOR, 1.9; 95% CI, 1.2-2.9), fold weight gain (aOR, 2.6; 95% CI, 1.5-4.6), and perceived inadequacy of red meat intake (aOR, 1.7; 95% CI, 1.0-2.7). In addition to the risk factors for ID, Cesarean section delivery (aOR, 1.9; 95% CI, 1.1-3.2) and low parental CF-related knowledge (aOR, 2.8; 95% CI, 1.5-5.2) were risk factors for IDA. In conclusion, prolonged breastfeeding and perceived inadequacy of red meat intake may be among the important feeding-related risk factors of ID and IDA. Therefore, more meticulous education and monitoring of iron-rich food intake, such as red meat, with iron supplementation or iron status testing during late infancy if necessary, should be considered for breastfed Korean infants, especially for those with additional risk factors for ID or IDA.

Low-Level Toxic Metal Exposure in Healthy Weaning-Age Infants: Association with Growth, Dietary Intake, and Iron Deficiency.

Even low levels of toxic metal exposure (As, Cd, Hg, and Pb) in infancy might be harmful to children's development. This study investigated toxic metal exposure on healthy weaning-age infants and its relationship with growth, diet, and iron/anemia status. The weight, height, head circumference, whole blood levels of four toxic metals, hemoglobin, and serum ferritin of healthy infants was measured. Among 210 infants with a median age of 11.4 months (interquartile range: 10.5-12.0), the median levels of As, Cd, Hg, and Pb were 1.2 µg/L, 0.05 µg/L, 0.8 µg/L, and 0.83 µg/dL, respectively. In adjusted linear regression models, post-birth weight gain (Pb) and current head circumference (As, Pb) were negatively associated with toxic metal levels. In multiple linear regression or logistic regression analysis, the duration of breastfeeding (all four metals), perceived adequacy of rice-based food intake (As), regular fish intake (As, Hg), and iron deficiency with/without anemia (Cd, Pb) were associated with increased toxic metal levels. Although levels of toxic metals may not usually be high in this population, individual exposure risk may need to be assessed after considering the type of feeding or intake of complementary foods and the iron/anemia status while evaluating growth status during late infancy.