Yumei Zhang

Micronutrient inadequacy remains a nutritional problem in Chinese children. However, the associations between dietary diversity and inadequate micronutrient intake have not been extensively studied. A total of 2012 children aged 3–17 years from the China Health and Nutrition Survey were included for analysis. Dietary diversity score (DDS) and food variety scores (FVS) were assessed based on three 24-h recall periods. The nutrient adequacy ratio (NAR) was used to determine the micronutrient adequacy of the diet. The mean adequacy ratio (MAR, %) was defined as the sum of each NAR divided by the number of involved micronutrients. Overall micronutrient inadequacy (OMI) was defined as having a MAR below 0.75. Micronutrient inadequacy was defined as the proportion of individuals whose nutrient intake was less than the estimated average requirement. After adjustment confounders, DDS and FVSs were positively associated with MAR and NAR of most nutrients except sodium (p < 0.05). A higher DDS was negatively associated with the prevalence of inadequate intake of vitamin A, riboflavin, vitamin C, iron, zinc, selenium, niacin, phosphorus, magnesium and OMI. Similar results were found for FVSs. In conclusion, this study indicates that poor dietary diversity and food variety in Chinese children are directly associated with inadequate micronutrient intake.

Micronutrient malnutrition affects the well-being of both adults and children. Dietary diversity score (DDS) is a useful evaluation index with a relatively well-developed guideline by FAO. It’s meaningful to assess and predict inadequate micronutrient intakes using DDS in Chinese children, after ruling out the risk of obesity coming with more dietary diversity. Data for evaluation were extracted from the Nutrition Study of Preschool Children and School Children, which is a cross-sectional study covering 8 cities of China, including 1694 children in kindergartens and primary schools. This study applied DDS to Chinese children to test the validity for micronutrient inadequacy, and then explored the relationship between dietary diversity and obesity. It reveals that dietary diversity varied with age and place of residence; the older ones and the ones living in rural areas tend to have poorer dietary diversity. Another discovery is that DDS is positively correlated with indicators of micronutrient adequacy, with a score of 6–8 indicating the lowest risk of micronutrient inadequacy in different groups of children. In our study population, dietary diversity is not related with obesity. Dietary diversity score is a valid indicator to evaluate micronutrient inadequacy in Chinese children, though there is still room for improvement of the method. Besides, the relationship between increase of dietary diversity and risk of obesity should be treated circumspectly.

Human breast milk (BM) amino acid (AA) composition may be impacted by lactation stage or factors related to geographical location. The present cross-sectional study is aimed at assessing the temporal changes of BMAA over lactation stages in a large cohort of urban mothers in China. Four hundred fifty BM samples, collected in three Chinese cities covering eight months of lactation were analyzed for free (FAA) and total (TAA) AA by o-phthalaldehyde/ fluorenylmethylchloroformate (OPA/FMOC) derivatization. Concentrations and changes over lactation were aligned with previous reports. Both the sum and the individual TAA values significantly decreased during the first periods of lactation and then generally leveled off. Leucine and methionine were respectively the most and the least abundant indispensable amino acids across all the lactation stages, whereas glutamic acid + glutamine (Glx) was the most and cystine the least abundant dispensable AA. The contribution of FAA to TAA levels was less than 2%, except for free Glx, which was the most abundant FAA. In conclusion, the AA composition of the milk from our cohort of urban Chinese mothers was comparable to previous studies conducted in other parts of the world, suggesting that this is an evolutionary conserved trait largely independent of geographical, ethnic, or dietary factors.

Human breast milk (BM) protein composition may be impacted by lactation stage or factors related to geographical location. The present study aimed at assessing the temporal changes of BM major proteins over lactation stages and the impact of mode of delivery on immune factors, in a large cohort of urban mothers in China. 450 BM samples, collected in three Chinese cities, covering 8 months of lactation were analyzed for α-lactalbumin, lactoferrin, serum albumin, total caseins, immunoglobulins (IgA, IgM and IgG) and transforming growth factor (TGF) β1 and β2 content by microfluidic chip- or ELISA-based quantitative methods. Concentrations and changes over lactation were aligned with previous reports. α-lactalbumin, lactoferrin, IgA, IgM and TGF-β1 contents followed similar variations characterized by highest concentrations in early lactation that rapidly decreased before remaining stable up to end of lactation. TGF-β2 content displayed same early dynamics before increasing again. Total caseins followed a different pattern, showing initial increase before decreasing back to starting values. Serum albumin and IgG levels appeared stable throughout lactation. In conclusion, BM content in major proteins of urban mothers in China was comparable with previous studies carried out in other parts of the world and C-section delivery had only very limited impact on BM immune factors.

Breastfed infants tend to be less prone to infections and may have improved cognitive benefits compared to formula-fed infants. Human milk oligosaccharides (HMO) are the third most abundant component of human milk, but are absent from formulae. They may be partially responsible for the benefits of breastfeeding. In this cross-sectional observational study, the HMO composition of milk from Chinese mothers was studied to determine the impact of stage of lactation, mode of delivery and geographical location. The content of 10 HMO was measured by HPLC in 446 milk samples from mothers living in three different cities in China. Around 21% of the samples contained levels of 2′-fucosyllactose (2′-FL) below the limit of quantification, which is similar to the frequency of fucosyltransferase-2 non-secretors in other populations, but 2′-FL was detected in all samples. Levels of most of the HMO studied decreased during the course of lactation, but the level of 3-fucosyllactose increased. Levels of 2′-FL and 3-fucosyllactose seem to be strongly correlated, suggesting some sort of mechanism for co-regulation. Levels of 6′-sialyllactose were higher than those of 3′-sialyllactose at early stages of lactation, but beyond 2–4 months, 3′-sialyllactose was predominant. Neither mode of delivery nor geographical location had any impact on HMO composition.