Vitamin A Concentration in Human Milk: A Meta-Analysis.

Humans require vitamin A (VA). However, pooled VA data in human milk is uncommon internationally and offers little support for dietary reference intake (DRIs) revision of infants under 6 months. As a result, we conducted a literature review and a meta-analysis to study VA concentration in breast milk throughout lactation across seven databases by August 2021. Observational or intervention studies involving nursing mothers between the ages of 18 and 45, with no recognized health concerns and who had full-term infants under 48 months were included. Studies in which retinol concentration was expressed as a mass concentration on a volume basis and determined using high-, ultra-, or ultra-fast performance liquid chromatography (HPLC, UPLC, or UFLC) were chosen. Finally, 76 papers involving 9171 samples published between 1985 and 2021 qualified for quantitative synthesis. Results from the random-effects model showed that the VA concentration of healthy term human milk decreased significantly as lactation progressed. VA (µg/L) with 95% CI at the colostrum, transitional, early mature and late mature stages being 920.7 (744.5, 1095.8), 523.7 (313.7, 733.6), 402.4 (342.5, 462.3) and 254.7 (223.7, 285.7), respectively (X2 = 71.36, p < 0.01). Subgroup analysis revealed no significant differences identified in VA concentration (µg/L) between Chinese and non-Chinese samples at each stage, being 1039.1 vs. 895.8 (p = 0.64), 505.7 vs. 542.2(p = 0.88), 408.4 vs. 401.2 (p = 0.92), 240.0 vs. 259.3 (p = 0.41). The findings have significant implications for the revision of DRIs for infants under six months.

Cohort profile: the Taicang and Wuqiang mother-child cohort study (TAWS) in China.

PURPOSE: The Taicang and Wuqiang cohort study (TAWS) was established to examine the association between early-life nutrition and children's health, and to explore the potential roles of maternal health, metabolites and microbiota in children's health in two different regions of China. PARTICIPANTS: A total of 7041 mother-child pairs were recruited during early pregnancy (n=4035, 57.3%) or delivery phase (n=3006, 42.7%) from health centres or hospitals in Taicang and Wuqiang. Mother-child pairs were followed up three times during pregnancy, once during delivery, and 7-10 times in the 3 years after delivery. Questionnaires were used to collect data on diet, supplementary intake, physical activity, depression scale, disease occurrence, feeding practice and development quotient of children. Anthropometric measurements of mothers and their children were assessed at each visit. Pregnancy outcomes were extracted from medical records. Biospecimens were collected and stored, including venous blood, cord blood, urine, stool, breast milk, cord and placenta. FINDINGS TO DATE: Data from the TAWS cohort showed different baseline characteristics of participants at the two sites of TAWS. Abnormal metabolism occurred among newborns whose mothers were diagnosed with gestational diabetes mellitus. Maternal serum folic acid above 14.5 ng/mL at early pregnancy was associated with a reduced risk of delivering small-for-gestational-age newborns. FUTURE PLANS: The association between maternal nutrition and the health of offspring will be examined at various follow-up visits. Biomarkers will be analysed to assess the associations between early-life nutrition and child development, immunity and health. Strategic recommendations for optimal infant feeding practices, obesity prevention and routine healthcare items will be developed and proposed based on the findings from the study. Children in this prospective cohort study will be followed up once a year until age 12 years to further examine the relationships between early-life nutrition and children's long-term development and health.

Human milk cholesterol is associated with lactation stage and maternal plasma cholesterol in Chinese populations.

BACKGROUND: Milk cholesterol concentrations throughout lactation were analyzed, and the relationship between maternal plasma cholesterol and milk cholesterol in various Chinese populations was examined. METHODS: A sub-sample of 1138 lactating women was randomly selected from a large cross-sectional study in China (n = 6481). Milk cholesterol concentrations were determined by HPLC, and concentrations of maternal plasma lipids were determined by an automated biochemical analyzer. RESULTS: The mean cholesterol concentrations were 200, 171, and 126 mg/L for colostrum, transitional milk, and mature milk, respectively. Cholesterol concentrations differed significantly between stages of lactation (colostrum vs. transitional milk, colostrum vs. mature milk, transitional milk vs. mature milk, all p < 0.001). Concentrations of maternal plasma total cholesterol (TC) (p = 0.02) and low-density lipoprotein cholesterol (LDL-C) (p = 0.03) were significantly associated with milk cholesterol. Milk cholesterol concentrations varied among different ethnicities (Tibetan vs. Hui: 164 vs. 131 mg/L, p = 0.027) but not among different geographic regions. CONCLUSIONS: The concentration of cholesterol in human milk changes dynamically throughout lactation. Milk cholesterol concentrations are significantly associated with maternal plasma concentrations of TC and LDL-C, and milk cholesterol concentrations vary across ethnicities in China. IMPACT: Concentrations of milk cholesterol were measured in various Chinese populations. Cholesterol concentrations differ significantly between stages of lactation. Maternal plasma total cholesterol and low-density lipoprotein cholesterol are associated with milk cholesterol. Milk cholesterol concentrations vary across ethnicities in China.

[Nutritional status of vitamin B_(12) and its influence factors in Chinese lactating women in 2013].

OBJECTIVE: To examine the vitamin B_(12) status of lactating women in China and to analyze the factors affecting the level of serum vitamin B_(12) in these subjects. METHODS: Participants were from the Chinese National Nutrition and Health Surveillance in 2013. By multi-stage stratified cluster randomly sampling method, 10 331 lactating women were selected from 55 counties of 30 provinces in China. Questionnaire was conducted to collect the basic information of lactating women and the dietary intake of them in the past one month was collected by food frequency questionnaire. A total of 20% of the total number of lactating women(a total of 1976) were randomly selected to analyze serum vitamin B_(12) by electro-chemiluminescence immunoassay method. Serum vitamin B_(12) deficiency was defined as a serum vitamin B_(12) level<200 pg/mL. The distribution of serum vitamin B_(12 )was lognormal, a generalized linear model was used to analyze the factors affecting the serum vitamin B_(12) level after logarithm transformation of it. RESULTS: The median of serum vitamin B_(12)(P25, P75) in lactating women was 469. 0(349. 0, 633. 5)pg/mL, the prevalence of vitaminB_(12) deficiency was 2. 7%(53/1976)and marginal deficiency rate was 12. 8%. With the increase of the education level of the lactating women the rate of vitamin B_(12) deficiency decreased gradually. The rate of vitamin B_(12 )deficiency of the lactating women presented regional differences and varied significantly among different regionals, education levels and the mothers who were breastfeeding or not. The value of serum vitamin B_(12 )was analyzed by generalized linear regression model showed that the levels of serum vitamin B_(12) in general rural counties and medium-sized or small cities were 1. 07 and 1. 13 times higher than those in poor rural areas, respectively. The serum vitamin B_(12) level of non-lactating women was 1. 08 times higher than that of lactating women. The serum vitamin B_(12 )level of the lactating women with junior high school level or below was significantly lower than that of the lactating women with college education and university education level, 88. 3% and 85. 0% of the lactating women with college education and university education, respectively. Serum vitamin B_(12) levels were positively correlated with intake of livestock meat, fish and seafood. CONCLUSION: The status of vitamin B_(12) in lactating women in China is good. Our findings suggest that some regionals, education levels, breastfeeding or not and livestock meat, fish meat and seafood supplement may be associated with serum vitamin B_(12 )in lactating women.

[Effect of pregnant serum folate concentration on newborn's birth weight].

OBJECTIVE: To study the effect of pregnant serum folate concentrations on the birth weight. METHODS: This study was a prospective cohort study. Pregnant women aged 18-45 who were examined and delivered in a county in Hebei Province from June 2016 to August 2018 and their newborns were included in the study. A total of 490 women were recruited and collected venous blood before the 20 th week of pregnancy. Basic information of women as well as their use of folic acid supplements was collected at the same time. Newborns' basic information, such as sex and birth weight, had been collected after delivery. The chemiluminescence method was used to determine the serum folate concentrations. Folate concentrations quartile were used as the cut-off point to divide subjects into four groups. The general linear model and multivariate unconditional Logistic regression analysis were used to study the effect of different serum folate concentrations on the infant birthweight. RESULTS: The age of 490 pregnant women was(27. 9±4. 1) years. The serum folate value P50(P25, P75) was 12. 3(9. 0, 14. 5) ng/mL and its' detection time was(13. 7±2. 6) weeks. 49. 3%(242/490) newborns were male. The average gestational age of the newborns was(39. 1±1. 0) weeks and the average birth weight was(3403±425) g. The birth weight of four groups' newborns were(3408±456) g, (3405±450) g, (3427±418) g and(3374±378) g, respectively. General linear model analysis showed that there was no significant difference in the effect of serum folate levels before the 20 th week of gestation on the birth weight(serum folate concentration<9. 0 ng/mL(ß=32. 24, P=0. 55), serum folate concentration 9. 0-12. 2(ß=18. 01, P=0. 74), serum folate concentration 12. 3-14. 4(ß=42. 27, P=0. 43)]. Multivariate unconditional Logistic regression analysis showed that the group with folate concentration above 14. 5 ng/mL can reduce the risk of small for gestational age(SGA) [(P=0. 02, OR=0. 08(95% CI 0. 01-0. 61)]. Comparing with ghe pregnant women whose serum folate concentration was in 9. 0-12. 4 ng/mL. Hovever, there was no significant difference between the pregnant serum folate levels and large for gestational age(LGA). CONCLUSION: There was no significant correlation between serum folate concentrations and the birth weight. But higher folate level may reduce the risk of SGA.

Effects of fish oil supplementation on glucose control and lipid levels among patients with type 2 diabetes mellitus: a Meta-analysis of randomized controlled trials.

BACKGROUND: Previous studies have yielded inconsistent findings on the role of fish oil in type 2 diabetes mellitus (T2DM). We systematically summarized the available evidence from randomized controlled trials (RCT) and aimed to investigate the effects of fish oil supplementation on glucose control and lipid levels among patients with T2DM. METHODS: A comprehensive literature search was performed in electronic databases (PubMed, ProQuest, Cochrane Library, CNKI, VIP, and Wanfang) to identify all relevant RCTs which were published up to May 31st, 2019. We used Modified Jadad Score system to evaluate the quality of each included RCT. The pooled effects were estimated using random-effects model and presented as standardized mean differences with 95% confidence intervals. RESULTS: A total of 12 RCTs were included in this meta-analysis. There was no significant difference in glucose control outcomes comparing fish oil supplementation to placebo. The effect size of fasting plasma glucose (FPG) was 0.13 (95% CI: - 0.03 to 0.28, p > 0.05). No marked change was observed in fasting insulin (FINS), glycosylated hemoglobin (HbA1c), and HOMA of insulin resistance (HOMA-IR) levels. Fish oil supplementation was associated with a decrease of triglyceride (TG) level by - 0.40 (95%CI: - 0.53 to - 0.28, p < 0.05), and an increase of high density lipoprotein (HDL) cholesterol level by 0.21 (95%CI: 0.05 to 0.37, p < 0.05). In subgroup analysis, HDL cholesterol level was higher among Asian and low-dose(< 2 g/d n-3 PUFA) subgroups compared to their counterparts (p < 0.05). TG level was lower in mid and long duration groups, along with an inconspicuous difference in short duration group. CONCLUSIONS: This meta-analysis shows that among patients with T2DM, fish oil supplementation leads to a favorable blood lipids profile but does not improve glucose control.

[Effects of vitamin D supplementation in early pregnancy on high-risk groups of gestational diabetes mellitus].

OBJECTIVE: To investigate the effect of vitamin D supplementation(VD) in early pregnancy on the serum 25-hydroxyvitamin D(25-OH-D) level and the risk of gestational diabetes mellitus(GDM). METHODS: From October to December 2017, a total of 101 pregnant women with high risk factors for GDM were enrolled in the first pregnancy consultation at the nutrition clinic of Haidian Maternal and Child Health Hospital, and were randomly divided into intervention group and control group. The intervention group was supplemented with 700 U VD and 100 mg of calcium at the beginning of pregnancy, and the control group was supplemented with 100 U VD and 100 mg of calcium at the same time, and the intervention time was until delivery. RESULTS: After intervention, the mean serum 25-OH-D level in the intervention group was(92. 08±29. 69) nmol/L, and that in the control group was(69. 99±25. 10) nmol/L. The serum levels of 25-OH-D in the pregnant women, gestational age and cord blood were higher than those in the control group(P<0. 05). The incidence of GDM in the intervention group was 18. 37%, and the incidence rate in the control group was 28. 85%(P>0. 05). Compared with the control group, the OR value of the risk of GDM in the intervention group was 0. 56(95% CI 0. 22-1. 42)( P<0. 05). CONCLUSION: The supplementation of VD in early pregnancy can significantly improve the VD nutrition level of pregnant women, but does not significantly reduce the incidence of GDM.

Concentration of Lactoferrin in Human Milk and Its Variation during Lactation in Different Chinese Populations.

BACKGROUND: Lactoferrin (Lf) is a multifunctional protein and one of the most abundant proteins in human milk. Various factors may affect its concentration in human milk, such as stage of lactation, ethnicity, and diet. OBJECTIVES: The objectives of the present study were to examine the dynamic change in milk Lf throughout the course of lactation and explore factors associated with milk Lf concentrations in various Chinese populations. METHODS: This investigation was a part of a large cross-sectional study conducted in 11 provinces/autonomous regions/municipalities (Beijing, Gansu, Guangdong, Guangxi, Heilongjiang, Inner Mongolia, Shandong, Shanghai, Xinjiang, Yunnan, and Zhejiang) across China between 2011 and 2013. Lactating women (n = 6481) within 0⁻330 days postpartum were recruited in the original study. A sub-sample of 824 women was randomly selected, and milk Lf concentrations were determined by UPLC/MS. RESULTS: The Lf concentration in milk from women delivering at term was 3.16 g/L, 1.73 g/L and 0.90 g/L for colostrum, transitional milk, and mature milk, respectively. Lf concentrations differed significantly between stages of lactation (colostrum vs. transitional milk, colostrum vs. mature milk, transitional milk vs. mature milk, all p < 0.001). Maternal BMI, age, mode of delivery, parturition, protein intake, and serum albumin concentration were not correlated with milk Lf concentration. However, milk Lf concentrations varied among different geographical regions (Guangdong (1.91 g/L) vs. Heilongjiang (1.44 g/L), p = 0.037; Guangdong (1.91 g/L) vs. Gansu (1.43 g/L), p = 0.041) and ethnicities (Dai (1.80 g/L) vs. Tibetan (0.99 g/L), p = 0.007; Han (1.62 g/L) vs. Tibetan (0.99 g/L), p = 0.002) in China. CONCLUSIONS: The concentration of Lf in human milk changes dynamically throughout lactation. Few maternal characteristics affect the milk Lf concentration, but it varies across different geographical regions and ethnicities in China.

[Association of vitamin A with bone mineral density in middle-aged and aged females].

OBJECTIVE: To find out the vitamin A intake in middle-aged and aged females, and to investigate the relationship between retinol intake and bone mineral density (BMD). METHODS: Two hundred and fifty women aged 45 to 66 were enrolled and received physical examination and BMD scanning, and their fasting blood samples and dietary records were collected. Serum retinol and beta-carotene were analyzed by HPLC. Assays for bone turnover markers (such as bone specific alkaline phosphatase, osteocalcin and 25-(OH) D3) in serum were performed by using commercially available kits. Subjects were divided into normal BMD group and low BMD group, and the dietary RE intakes and serum retinol were compared. RESULTS: The average RE intake was 455.8 microg (n = 169), which reached 65.1% of RNI. Serum retinol and beta-carotene in normal BMD group were a little bit higher than the low BMD group, but there was no statistic difference. Vitamin A intake of normal BMD group was 53.0 microg, which was lower than the low BMD group, and carotene intake of normal BMD group was 107.6 microg, which was higher than the low BMD group. The ratio of plant sourced retinol in normal BMD group was higher than the low BMD group. Bivariate correlation analysis on BMD and dietary RE intake showed no statistic correlation, but with a slight negative trend (P = 0.203, r = -0.140). There was a significantly difference in age, bone mineral contents, BMI and BSAP between low BMD group and normal BMD group (P < 0.001 or P < 0.01), and bivariate correlation analysis showed that the age (P < 0.001, r = -0.380), BMI (P < 0.001, r = 0.394) menopausal age (P < 0.05, r = 0.244) and body weight (P < 0.001, r = 0.434) were significantly correlated with BMD. The result of stepwise linear regression analysis showed that the age, menopausal years and BSAP were entered into the regression equation (R2 = 0.552, F = 24.661, P < 0.001), which indicated a strong connection with BMD. CONCLUSION: (a) RE intake did not reach RNI, and the use of supplements was not common (32.5%). (b) The intake of milk and milk products and beans and bean products was low, and the calcium intake did not reach 50% of AI. (c) Higher serum retinol in normal range might maintain BMD. (d) Too much RE intake might associate with decreased BMD, especially the BMD in femoral bone.

[Effects of ferrous sulfate supplementation on bone marrow hemopoiesis in rats].

OBJECTIVE: To explore the influences of different dosage ferrous sulfate supplements on bone marrow hemopoiesis in rats. METHODS: Female weaning Wistar rats were fed with an iron deficient diet (< 10 mg/kg diet) until the level of hemoglobin of rats was lower than 100 g/L. Rats (n = 50) were randomly divided into five groups according to the levels of hemoglobin and body weight, iron deficiency control (ID), daily low iron diet supplement (LDs), daily high iron diet supplement (HDs), weekly low iron supplement (LWs), and weekly high iron supplement (HWs). RESULTS: After 12 weeks, bone marrow stainable iron was seldom in ID group, and ample in supplement groups. The proportions of iron staining of bone marrow smear in supplement groups were more than 30%. Bone marrow cells in all rats were hyperplastic or active hyperplastic. CONCLUSIONS: Daily high iron supplement or once weekly high iron supplement were safe to bone marrow hemopoiesis in rats.

[Evaluation on glycine chelated iron (II) in improving nutritional anemia in rats].

OBJECTIVE: In order to evaluate the efficacy of glycine chelated iron (II) in improving nutritional anemia in rats. METHODS: After weaning wistar rats, weighing 50 - 60g, were fed the iron deficient diet for three weeks, whole blood was taken from rat's tail to measure Hb, then the rats were randomly divided into five groups by Hb, that is the control group fed with iron deficient diet, three groups fed the diets supplemented with different glycine chelated iron (II), and another group fed with the diet added with lactate iron. Each group was fed respective diets for four weeks and indicators related to iron-deficient nutritional anemia were evaluated. RESULTS: The addition of glycine chelated iron (II) did improve the growth and development of rats, increase the hemoglobin level and the iron retention in spleen, decrease free erythrocyte protoporphyrin (FEP) content in whole blood, and there was no significant difference between three supplemental groups with glycine chelated iron (II) and the group with lactate iron. CONCLUSION: glycine chelated iron (II) can be used as a reasonable iron supplement in improving iron-deficient nutritional anemia.

[Effect of selenium and zinc level in diet on bone development in rats exposed to lead].

OBJECTIVE: To explore the interaction role of selenium and zinc in diet on bone development in rats exposed to lead, and to observe the change of bone mineral content (BMC) and bone mineral density (BMD). METHODS: Wean male Wistar rats were fed with diet added with different levels of selenium, zinc and lead for 12 weeks. RESULTS: Long-term exposure to lead may inhibit the development of bone and reduce BMC and BMD, however, selenium and zinc in the diets could improve the inhibit effect of lead on weight and length, BMC and BMD of rat bone. CONCLUSION: The present study indicated that supplementing suitable amount of selenium or/and zinc could interact the side effect of lead, and increase the BMC and BMD of rat bone. The interaction mechanism of iron and zinc on bone exposed to lead in diets needs to be explore in further.

[Effect of iron and zinc levels in diet on development of bone in growing rats exposed to lead].

OBJECTIVE: The purpose of this paper was to explore the effect of iron and zinc in diet on development of bone in growing rats exposed to lead and observed the change of bone mineral content (BMC) and bone mineral density (BMD). METHODS: The growing rats were fed with diet added with different levels of iron, zinc and lead for 12 weeks. RESULTS: Long-term exposure to lead may inhibit the development of bone and reduce BMC and BMD, it can be improved the weight and length of bone and increased BMC and BMD following the increased in iron and zinc levels in the diets, but the lead level of bone increases. CONCLUSION: Supplementary suitable iron or/and zinc could improve the BMC and BMD, the mechanism of iron and zinc in diets on bone exposed to lead should be further research.

[Protection of zinc and selenium content of brain and blood on learning and memory exposed to lead in growing rats].

OBJECTIVE: The purpose of this paper was to explore the relations between lead levels of brain and blood on learning and memory, and to determine the antagonization of selenium and zinc on lead toxicity in brain and blood. METHODS: The growing rats were fed with diet added with different levels of selenium, zinc and lead for 12 weeks. RESULTS: (1) The lead levels of brain and blood of rats exposed to lead was higher than that of the control group; the lead levels of brain and blood administrated lead decreased following the increased in selenium and zinc levels in the diet. (2) Error frequencies and total time in water-maze significantly reduced in the groups exposed to lead. (3) Error frequencies and total time in water-maze and lead levels of brain and blood presented positive relation. CONCLUSION: The present study indicated that supplementary suitable zinc or/and selenium could alleviate the lead toxicity on the brain and blood of rats.

[Study on the effect of micronutrients supplementation on health status of children].

To study the effect of multi-micronutrients supplementation on nutritional status of children, 220 students aged 8-12 years were observed for 6 months. A half of them were given the supplements, another half placebo. The results showed that in comparison with the placebo, the supplemented children had a higher urine excretion of vitamin B2 and vitamin C after loading; a higher concentration of serum 25-OH-D3, a high content of hydroxy-proline and hydroxy-proline/creatinine ratio in fast urine, and a higher bone mineral content and bone mass density of the mid-ulna. The supplemented children performed significantly better than the placebo in reading speed, learning capacity and arithmetic examinations. It is concluded that micronutrients supplementation played a notable rule in resulting better nutritional status and learning ability of school children.