A comprehensive understanding of the nutritional composition and active components of human milk are important for promoting infant health. However, in the design and implementation of scientific research on human milk, the lack of standardized research and implementation methods have led to the collection, storage, and testing processes of human milk samples being largely based on reference literature and practical experience. This has resulted in variability in the representativeness of human milk samples and differences in the comparability of research results between different studies. This article summarizes the principles and guidelines for the " Specification for collection and storage of human milk samples for research", published by the Chinese Nutrition Society on December 30, 2022, and discusses the feasibility and importance of standardized management in the process of scientific research on human milk.

This article is a summary of the Second China Breast Milk Science Conference, which was held in Beijing from August 5 to 7, 2022, with the theme of "Data sharing, method sharing and science sharing". The purpose of the conference is to summarize the latest progress in breast milk research, identify the unresolved issues, and jointly discuss the direction of future breast milk research. Firstly, we summarize the contents and purpose of breast milk scientific research and prospect of breast milk science. The second part focuses on the research status of breast milk composition and its health effects, and puts forward the future research direction. The third section focuses on the health effects of breastfeeding and scientific support and key aspects of breastfeeding promotion actions. The fourth part elaborates the specific methods of current scientific research of breast milk and emphasize the importance of method standardization and the idea of future methodological research. The fifth part consists of the strategy of feeding infants with medical conditions and ways to better promote the growth and development of these infants. The last part introduces the innovation, deficiencies, and future research directions of infant formula production technology in China. This conference demonstrate the importance of multidisciplinary communication, discussions and collaborations in clinical medicine, nutrition, perinatal health, food science, and policy-making in the scientific research of breast milk, and provides guidance for future multidisciplinary research on the physiology of lactation, the composition of breast milk, breastfeeding, and infants and young children nutrition.

Objective:To explore the relationship between vegetarian diets and vitamin B 12 levels in Chinese pregnant women. Methods:A cross-sectional survey was used to explore the relationship between vegetarian diets and vitamin B 12 levels in Chinese pregnant women based on data from the Chinese National Nutrition and Health Surveillance (2015-2017). Maternal serum vitamin B 12 concentration was determined by electrochemiluminescence. Background and diet information of all subjects were collected using general and food frequency questionnaires. General Linear Model was used to analyze the difference in serum vitamin B 12 levels between vegetarian and non-vegetarian pregnant women and multivariate logistic regression for examining the relationship between vegetarian diets and vitamin B 12 deficiency (vitamin B 12<150 pmol/L) in pregnant women. Results:A total of 8 366 pregnant women were included in the analysis, and vegetarians accounted for 1.2% (102/8 366). The median serum vitamin B 12 concentrations were 155.8(93.6-212.4) pmol/L and 187.2(127.4-267.6) pmol/L ( Z=－4.22, P<0.001), and the vitamin B 12 deficiency rates were 48.0% (49/102) and 35.0% (2 896/8 264) in vegetarian and non-vegetarian women, respectively. The vitamin B 12 deficiency rate in vegetarian women was 0.89-fold higher than in non-vegetarians (95% CI: 1.24-2.89). Among the vegetarian and non-vegetarian pregnant women, vitamin B 12 deficiency rates during the first, second, and third trimesters were 34.8%(16/46), 54.3%(19/35), 66.7%(14/21), and 20.4%(521/2 559), 32.6%(941/2 886), 50.9%(1 430/2 807), noting for an increasing trend ( Z=23.54 and 2.57, P=0.010 and P<0.001). Conclusions:Vegetarian pregnant women are at high risk of vitamin B 12 deficiency. Compared with non-vegetarian women, vegetarian pregnant women in China have lower vitamin B 12 levels and a higher risk of vitamin B 12 deficiency. Moreover, the risk of vitamin B 12 deficiency will gradually increase during pregnancy.

Objective:To compare the efficacy and safety of unilateral biportal endoscopy (UBE) and microendoscopic discectomy (MED) in the treatment of lumbar spinal stenosis by Meta-analysis.Methods:PubMed, Web of Science, CNKI and Wanfang Data were searched from their establishment to January 2021 for all the studies on UBE and MED in the treatment of lumbar spinal stenosis. The data extracted were authors, year of publication, study design, subject characteristics, sample size, surgical protocol, age, sex ratio, duration of surgery, length of hospital stay, complications, visual analogue scale (VAS), and Oswestry Disability Index (ODI). The Meta-analysis was conducted with software Revman 5.3 to analyze the operation time, hospital stay, complication rate, waist and lower extremity VAS scores and ODI scores at preoperation, early postoperation and the last follow-up. The quality of the case-control studies included was evaluated using the Newcastle Ottawa Scale (NOS) while the methodological quality and risk of bias of the randomized controlled studies (RCT) included were evaluated using the Cochrane Bias Risk Assessment Tool.Results:Finally, 7 studies were included, 6 in English and one in Chinese. There were 2 RCTs and 5 case-control studies. There were 251 patients in the UBE group and 224 patients in the MED group. Compared with the MED group, the UBE group had a significantly shorter hospital stay ( MD=-2.28, 95% CI: -3.42 to -1.14, P<0.001), and a significantly lower VAS score for early postoperative low back pain ( MD=-0.80, 95% CI:-1.44 to -0.16, P=0.01). There were no significant differences between the 2 groups in operation time, complication rate, waist VAS scores at preoperation or the last follow-up, lower extremity VAS or ODI scores at preoperation, early postoperation or the last follow-up, or dural dilatation area ( P>0.05). Conclusions:In the treatment of lumbar spinal stenosis, compared with MED, UBE is superior in early relief of low back pain and hospital stay after operation, but shows no significant difference in long-term efficacy or safety.

Objective:To analyze effects of parity on women′s nutrition and health status.Methods:This study was based on the data bank of "Chinese Nutrition and Health Surveillance of Children and Adolescents Aged 0-17 years old and Lactating Mothers from 2016 to 2017". Using a multi-stage stratified random sampling method, 17 771 women at 0 to 24 months postpartum from 31 provinces in Mainland China were included in this study. Questionnaires were used to collect data on women′s general demographic characteristics, parity, mode of delivery, pre-pregnancy weight, pre-delivery weight, diseases before and during pregnancy, postpartum hemorrhage. Current body height, body weight, waist circumference, and blood pressure were measured. Blood hemoglobin, blood glucose and blood lipids were detected. Pre-pregnancy BMI, gestational weight gain, postpartum weight retention, postpartum BMI, the rates of anemia, hypertension, diabetes, and dyslipidemia were calculated. Survey sample weights were calculated according to the sampling design and number of children under 2 years old from the sixth population census data of China. Effects of parity on the observational indicators after adjusting for confounding factors were analyzed by multivariate linear regression and multivariate logistic regression.Results:The age of 17 771 women was (29.5±5.0) years old, 12.2% (2 172) were over 35 but less than 40 years old, and 3.2% (563) were over 40 years old; the women with one parity, two parities, and three parities accounted for 47.3% (8 413), 48.5% (8 620) and 4.2% (738), respectively; urban women accounted for 49.9% (8 875), and rural women accounted for 50.1% (8 896). The results from multivariate linear regression showed that the pre-pregnancy BMI of women with two and three parities was 0.55 kg/m 2 and 0.76 kg/m 2 higher than women with one parity, respectively; the results of multivariate logistic regression showed that the OR(95% CI) of pre-pregnancy anemia was 1.45(1.04-2.02) for women with three parities compared with women with one parity, and the OR(95% CI) of anemia during pregnancy for women with two parities was 1.20(1.06-1.35) compared with women with one parity. Conclusion:Parity is associated with pre-pregnancy BMI and risk of anemia before and during pregnancy in women of reproductive age.

Objective:To analyze effects of parity on women′s nutrition and health status.Methods:This study was based on the data bank of "Chinese Nutrition and Health Surveillance of Children and Adolescents Aged 0-17 years old and Lactating Mothers from 2016 to 2017". Using a multi-stage stratified random sampling method, 17 771 women at 0 to 24 months postpartum from 31 provinces in Mainland China were included in this study. Questionnaires were used to collect data on women′s general demographic characteristics, parity, mode of delivery, pre-pregnancy weight, pre-delivery weight, diseases before and during pregnancy, postpartum hemorrhage. Current body height, body weight, waist circumference, and blood pressure were measured. Blood hemoglobin, blood glucose and blood lipids were detected. Pre-pregnancy BMI, gestational weight gain, postpartum weight retention, postpartum BMI, the rates of anemia, hypertension, diabetes, and dyslipidemia were calculated. Survey sample weights were calculated according to the sampling design and number of children under 2 years old from the sixth population census data of China. Effects of parity on the observational indicators after adjusting for confounding factors were analyzed by multivariate linear regression and multivariate logistic regression.Results:The age of 17 771 women was (29.5±5.0) years old, 12.2% (2 172) were over 35 but less than 40 years old, and 3.2% (563) were over 40 years old; the women with one parity, two parities, and three parities accounted for 47.3% (8 413), 48.5% (8 620) and 4.2% (738), respectively; urban women accounted for 49.9% (8 875), and rural women accounted for 50.1% (8 896). The results from multivariate linear regression showed that the pre-pregnancy BMI of women with two and three parities was 0.55 kg/m 2 and 0.76 kg/m 2 higher than women with one parity, respectively; the results of multivariate logistic regression showed that the OR(95% CI) of pre-pregnancy anemia was 1.45(1.04-2.02) for women with three parities compared with women with one parity, and the OR(95% CI) of anemia during pregnancy for women with two parities was 1.20(1.06-1.35) compared with women with one parity. Conclusion:Parity is associated with pre-pregnancy BMI and risk of anemia before and during pregnancy in women of reproductive age.

Human milk is the optimal food for infants. We described the history of human milk research both in China and abroad, the gap between domestic and international research, and the future direction in this area. Human milk needs to be studied as a biological system in the future. Reference values for human milk components of Chinese healthy mother-infant dyad should be established. Factors associated with human milk components variations and relationships between human milk components and maternal and child health also need to be investigated to achieve the best nutrition and health status for mother and child pairs.

Objective To study the function of Deptor gene on the regulation of diabetes mellitus in suc-cessfully constructed and identified islet β-cell conditionally DEPTOR knockout mice model. Method By cross-breeding Deptorflox/floxmice with Cre mice expressed conditional specifically in pancreatic β-cell,Deptorflox/+Cre+/-mice were acquired and their genotypic identification was then performed. As the mice model of this study, Deptorflox/floxCre+/-mice were generated by crossing Deptorflox/+Cre+/-mice with Deptorflox/floxmice.Genotypic identifica-tion was performed by PCR at the age of 3 weeks. Tamoxifen was administered through intraperitoneal injection to induce the activation of the Cre recombination in islet beta cells of 8 weeks mice.Double immunofluorescence label-ing was then applied to identify the knockout effect of DEPTOR gene. Results Ten Islets Deptor knockout mice models were successfully acquired after 10-month cross-breeding. Validated genotype by PCR analysis were Deptorflox/floxCre+/- and double immunofluorescence labeling showed a significant difference between knockout mice and rodent controls. Conclusion Our study successfully constructs the islets conditionally Deptor deleted mice model by using Cre-loxp recombination system,providing a promising appliable animal model for study of dia-betes mellitus pathogenetic mechanism.

Objective: To examine the status and related factors for gestational weight gain of Chinese pregnant women at different trimesters in 2010-2012. Methods: Participants were from Chinese National Nutrition and Health Surveillance in 2010-2012. Using a multi-stage stratified cluster random sampling method, we recruited 2 805 singleton pregnant women with gestational age 13 weeks or more from 31 provinces of China. A standard questionnaire was used to collect general information and pre-pregnancy weight; body weight and height of pregnant women were measured using a unified weighing scale and stadiometer, dietary intake during the previous year was collected using a food frequency questionnaire. A multiple logistic regression was used to analyze potential factors associated with appropriate gestational weight gain. Results: Among 2 805 pregnant women, 1 441 were in the second (13-27 weeks) and 1 364 in the third trimesters (≥28 weeks) . In the 2^nd trimester, 229 cases (15.9%), 440 cases (30.5%) and 772 cases (53.6%) were insufficient gestational weight gain, appropriate gestational weight gain and excessive gestational weight gain respectively. So were 256 cases (18.8%), 474 cases (34.8%), 634 cases (46.5%) in the 3^rd trimester respectively. In the multivariate unconditional logistic model, less fruit intake was associated with insufficient weight gain for women in the 2^nd trimester (OR (95%CI): 1.58 (1.06-2.34)). Pregnant women with Han ethnicity who live in the small/medium city had lower risk of insufficient weight gain in the 3^rd trimester (OR (95%CI): 0.58 (0.34-0.98)). Those pregnant women with physical activity <1 hour/day had a higher risk of excessive weight gain (OR (95%CI): 1.33 (1.02-1.73)). Conclusion The prevalence of appropriate gestational weight gain was low in China. Our study suggests that pregnant weight gain is associated with fruit intake, types of residential area and physical activity.

Objective: To analyze the status of gestational weight gain (GWG) among Chinese mothers who gave singleton and full-term births, and to look at optimal GWG ranges. Methods: In 2013, using the multi-stage stratified and population proportional cluster sampling method, we investigated 8 323 mother-child pairs at their 0-24 months postpartum from 55 counties (cities/districts) of 30 provinces (except Tibet) in mainland China. Questionnaire was used to collect data on body weight before pregnancy and delivery, diseases during gestation, hemorrhage or not at postpartum, child birth weight and length, and other information about pregnant outcomes. We measured mother's body weight and height, and child's body weight and length. Based on 'Chinese Adult Body Weight Standard’, we divided mothers into four groups according to their body weight before pregnancy: low weight (BMI<18.5 kg/m²), normal weight (BMI 18.5-23.9 kg/m²), overweight (BMI 24.0-27.9 kg/m²) and obesity (BMI≥28.0 kg/m²). The status of GWG was assessed by IOM optimal GWG guidelines. Chinese optimal GWG ranges were calculated according to the association of GWG with pregnant outcomes and anthropometry of mothers and children, and according to P25-P75 of GWG among mothers who had good pregnant outcomes and good anthropometry, and whose children had good anthropometry. The status of GWG was assessed by the new optimal ranges. Results: P50 (P25-P75) of GWG among the 8 323 mothers was 15.0 (10.0-19.0) kg. According to the proposed optimal GWG ranges of IOM, the proportions of inadequate, optimal and excessive GWG accounted for 27.2% (2 263 mothers), 36.2% (3 016 mothers) and 36.6% (3 044 mothers). The optimal GWG ranges for low weight, normal weight, overweight and obesity were 11.5-18.0, 10.0-15.0, 8.0-14.0 and 5.0-11.5 kg. Based on these optimal GWG ranges established in this study, the rates of inadequate, optimal and excessive GWG were 15.7% (1 303 mothers), 45.0% (3 744 mothers) and 39.3% (3 276 mothers), and these rates were significantly different from that defined by the IOM standards (χ2=345.36, P<0.001). Conclusion The median of GWG among Chinese mothers is 15.0 kg, which is at a relatively higher level. This study suggests the optimal GWG ranges for Chinese women who give singleton and full-term babies, which appears lower than IOM's.