Higher selenium was associated with higher risk of diabetes: Consistent evidence from longitudinal and cross-sectional studies based on nail and serum selenium measures.

Although the association between selenium (Se) and diabetes has been well-discussed in recent years, few studies have focused on the effects of long-term natural Se exposure and rarely concerned the effects of different Se biomarkers. To address this question, we carried out a 7-year longitudinal study on older adults aged over 65 and another cross-sectional study on middle-aged and older adults aged 40 and above from Chinese soil Se-deplete and Se-optimum areas. Cox proportional hazard models were used to evaluate the associations between nail Se levels and incidence risk of diabetes. Unconditional logistic regression models and analysis of variance models were used to examine the associations between serum Se levels and the prevalence risk of diabetes. The nail and serum Se levels were 0.47 ± 0.20 µg/g and 111.09 ± 55.01 µg/L for the two study populations, respectively. For both of the independent studies, higher Se levels were observed to be associated with a higher risk of diabetes and prediabetes. Compared with the Second nail Se quartile (Q2), the adjusted hazard ratios (HRs) and 95 % confidence intervals (95 % CIs) of diabetes for Q1, Q3 and Q4 were 1.24(0.70, 2.21), 1.53(0.98, 2.39) and 1.31(0.76, 2.26), respectively, and the adjusted HRs (95 % CIs) of prediabetes were 1.47(0.77, 2.81), 1.38(0.83, 2.30), and 1.97(1.13, 3.44), respectively. Compared with the first serum Se quintile (Q1), the adjusted odds ratios (ORs) and 95 % CIs of diabetes for higher quintiles were 1.12(0.75, 1.66), 1.05(0.71, 1.57), 1.09(0.73, 1.62) and 1.51(1.02, 2.19), and the adjusted ORs (95 % CIs) of prediabetes were 1.27(0.77, 2.09), 1.70(1.05, 2.74), 1.94(1.21, 3.11) and 1.67(1.03, 2.71). Our findings consistently suggest that higher Se status is associated with a higher risk of diabetes in adults.

Physiologic requirement for iron in pregnant women, assessed using the stable isotope tracer technique.

BACKGROUND: Knowledge of the physiologic requirement for iron, the core index for the formulation of a dietary reference intake (DRI), is of great importance for the health of a pregnant woman and her fetus, and can help a mother accurately plan her iron supplementation. However, direct measurements of the physiologic requirement for iron during pregnancy are still lacking. METHOD: Eleven women of reproductive age from Hebei Province, China, who planned to become pregnant in the near future, were enrolled between January and March 2015 and included in the final analysis. Subjects participated in a 2-week metabolic trial in which they consumed 50 mg of the stable isotope 58Fe, and were then followed for ~ 2 years. The abundance of 58Fe and the total iron concentration in the circulation were measured using Multi-collector Inductively-Coupled Plasma Mass Spectrometry and Atomic Absorption Spectroscopy, respectively. The physiologic requirement for iron during pregnancy was then calculated by the formula derived from our previously published work. RESULTS: The mean physiologic requirement for iron in the 11 subjects, across their entire pregnancies, was 3.05 mg.d- 1 in total and 44.0 µg.kg- 1.d- 1 after adjustment for body mass. The physiologic requirements for iron in the first, second, and third trimesters were 2.04 mg.d- 1, 3.26 mg.d- 1, and 4.13 mg.d- 1, respectively. When adjusted for body mass, the physiologic requirements for iron in different trimesters were 32.3 µg.kg- 1.d- 1, 46.9 µg.kg- 1.d- 1, and 55.7 µg.kg- 1.d- 1, respectively. CONCLUSION: We preliminarily explored the physiologic requirement for iron in pregnant women. The data demonstrated that pregnant women needed about twice iron than non-pregnant women. This research may be helpful for the design of future studies and the modification of iron DRIs. TRIAL REGISTRATION: ChiCTR, ChiCTR-OCH-14004302. Registered 14 February 2014, http://www.chictr.org.cn/showproj.aspx?proj=5267.

Evaluation of median urinary iodine concentration cut-off for defining iodine deficiency in pregnant women after a long term USI in China.

BACKGROUND: The WHO/UNICEF/ICCIDD define iodine deficiency during pregnancy as median urinary iodine concentration (MUIC) ≤ 150 µg/L. China implemented universal salt iodization (USI) in 1995, and recent surveillance showed nationwide elimination of iodine deficiency disorders (IDD). Data from 2014 showed that the MUIC in 19,500 pregnant women was 154.6 µg/L and 145 µg/L in 9000 pregnant women in 2015. However, symptoms of iodine deficiency were absent. Our study sought to evaluate whether MUIC below 150 µg/L affects thyroid function of Chinese pregnant women and their newborns in Chinese context. METHODS: We screened 103 women with normal thyroid function and MUIC lower than 150 µg/L during week 6 of pregnancy at Peking Union Medical College Hospital. Patient demographics and dietary salt intake were recorded. Subjects were followed at 12, 24, and 32 gestational weeks. At each visit, a 3-day dietary record, drinking water samples, and edible salt samples were collected and analyzed for total dietary iodine intake. Additionally, 24-h urine iodine and creatinine were measured. Blood tests assessed thyroid function in both mothers and newborns. RESULTS: Of 103 pregnant women enrolled, 79 completed all follow-up visits. Most subjects maintained normal thyroid function throughout pregnancy. However, 19 had thyroid dysfunction based on thyroid stimulating hormone and free thyroxine levels. The median serum iodine was 71 µg/L (95% CI: 44, 109). The median thyroglobulin was < 13 µg/L. values above this level indicate iodine deficiency in pregnant women. The median dietary iodine intake during pregnancy, derived from the 3-day record and measures of water and salt, was 231.17 µg/d. Assuming 90% urinary iodine excretion (UIE), 200.11 µg/d UIE means the 222.34 µg iodine loss per day, suggesting that subjects had a positive iodine balance throughout pregnancy. All neonatal blood samples showed TSH levels lower than 10 mIU/L, indicating normal thyroid function. No significant difference was found among gestational weeks for urinary iodine, and the MUIC in subjects who completed 3 follow-up visits was 107.41 µg/L. CONCLUSION: Twenty years after implementing USI, expectant Chinese mothers with MUIC of 107.4 µg/L, less than the WHO's 150 µg/L benchmark, maintained thyroid function in both themselves and their newborn babies.

Physiological requirements for iron in women of reproductive age assessed by the stable isotope tracer technique.

BACKGROUND: Iron nutrition is important for the health of women of reproductive age, and defining the physiologic requirement for iron can help them accurately plan the iron intake. However, research on the physiologic requirement for iron in women is insufficient worldwide. This study aimed to further improve the methodology and get more precise data for the physiological requirements for iron in women of reproductive age on the basis of our previous study. METHOD: Sixty-one women of reproductive age who had not been pregnant before and during the whole study were included from Hebei province, China in 2015. Each subject participated in a 2-week metabolic trial with consuming 50 mg of the stable isotope 58Fe, and were then followed for ~ 800 days. The abundance of 58Fe and the total iron concentration in the circulation were measured using multi-collector inductively-coupled plasma mass spectrometry and atomic absorption spectroscopy. The physiologic requirement for iron in women of reproductive age was then calculated. RESULTS: The average iron circulation rate was 80.4%, and the steady period started from about 1 year. The average physiological requirement for iron of 21 subjects obtained by formula calculation was 1.55 mg/d and 23.63 µg.kg- 1.d- 1 after adjustment for body mass, and that of 33 subjects obtained by linear regression was 1.29 mg/d, 20.98 µg.kg- 1.d- 1 after adjustment for body mass. The results by two methods showed no significant difference. The EAR and RNI calculated from this results was 11-13 mg/d and 15-18 mg/d, respectively, both of which were slightly lower than the recommended value in Chinese Dietary Reference Intake (2013). CONCLUSION: The physiological requirements for iron in women of reproductive age were in accordance with other studies, while the EAR and RNI calculated from which were slightly lower than Chinese present recommended value. TRIAL REGISTRATION: ChiCTR, ChiCTR-OCH-14004302. Registered 14 February 2014, http://www.chictr.org.cn/enindex.aspx.

Prevalence and Risk Factors for Anemia in Non-pregnant Childbearing Women from the Chinese Fifth National Health and Nutrition Survey.

Anemia is a public health issue for developing countries, especially for women of childbearing age. The aim of this study was to assess the anemia status and analyze the risk factors for anemia in Chinese childbearing women aged 18-49 years. Hemoglobin concentration was measured by the HiCN method in the Fifth Chinese National Nutrition and Health Survey (CNNHS) in 2010-2012. Age, region type, ethnicity, bodyweight, height, education, season and smoke habit were recorded in unified questionnaires. Latitude was divided by China's Qinling Mountains and Huaihe River. Childbearing women (28,289) from the CNNHS 2010-2012 were included in this study. The median hemoglobin concentration was 136.2(126.6-145.0) g/L, and it was significantly higher than in CNNHS 2002 (132.5 (122.3-141.6) g/L). The prevalence of anemia was 15.0%, and it was significantly lower than 10 years ago. The logistic regression analysis showed anemia in Chinese childbearing women was specifically related to 30-39 age group (P = 0.004), in spring (P < 0.0001) or in winter (P = 0.006), small and medium-sized cities (P = 0.044) and middle school education level (P = 0.027). The results showed that anemia status among childbearing women was greatly improved over 10 years since 2002, but it was still more severe than the rest of the populations. The nutrition propaganda and education is recommended for childbearing women to help them to improve the nutritional status on their own.

Prevalence of Anemia in Chinese Children and Adolescents and Its Associated Factors.

In this study, we assessed the hemoglobin levels and anemia status of Chinese children and adolescents from the Chinese National Nutrition and Health Survey (CNNHS) in 2010⁻2012 and analyzed the factors associated with anemia. The hemoglobin concentration and prevalence of anemia for children and adolescents aged 6⁻17 years from both CNNHS 2010⁻2012 and CNNHS 2002 were analyzed. Multi-variable logistic regression analysis was used to assess the factors associated with anemia. The mean hemoglobin concentration increased among Chinese children and adolescents, from 135.2 ± 13.9g/L in CNNHS 2002 to 141.2 ± 15.8 g/L in CNNHS 2010⁻2012, with the prevalence of anemia decreasing from 12.6% to 6.6% (p<0.0001). Anemia was specifically related to girls (p < 0.0001);children aged 6⁻8 years (p = 0.0175), 12⁻14 years (p = 0.0007), and 15⁻17 years (p < 0.0001);ordinary rural areas (p = 0.0009) and poor rural areas (p < 0.0001);spring (p < 0.0001), autumn (p < 0.0001), and winter (p < 0.0001);underweight individuals (p < 0.0001); and an annual average income per capita of less than 20,000 RMB (p < 0.0001).The prevalence of anemia in Chinese children and adolescents has improved significantly in comparison to 10 years prior; however, it remains a public health problem in this population. Further research is required to understand the determinants of iron status, which could then lead to strategies to alleviate iron deficiency for Chinese children and adolescents, especially for girls, those living in rural areas, underweight individuals, and those with a low family income.

Basal energy expenditure, resting energy expenditure and one metabolic equivalent (1 MET) values for young Chinese adults with different body weights.

BACKGROUND AND OBJECTIVES: Accurately assessing energy expenditure (EE) of people with different body weight is essential to facilitate weight management. The aim of this study was to measure basal energy expenditure (BEE), resting energy expenditure (REE) and to explore the true 1 MET value for young Chinese adults with different body weight. METHODS AND STUDY DESIGN: A total of 251 young Chinese adults were divided into three groups: the normal weight group, the overweight group and the obese group. Their BEE, REE and 1 MET values were measured by Cortex Metamax 3B (MM3B). Multiple linear regressions and correlation analysis were used to examine factors that influence EE in Chinese population. RESULTS: The mean measured BEE and REE of young Chinese adults with normal weight, overweight and obesity was 1429, 1609, 1778 kcal/day and 1522, 1712, 1885 kcal/day, respectively. The EE per kilogram body weight decreased with the increasing body weight. The mean oxygen consumption in the three group was 3.78, 3.47, 3.21 mL/kg/min respectively. There was no significant difference in BEE and REE after adjustment for fat-free mass (FFM). The significant influencing factors were body mass index (BMI) and sex in BEE, FFM and BMI in REE in Chinese population. CONCLUSIONS: BEE and REE were significantly different for different body weights while these differences disappeared after adjustment for FFM, and people with different body weights may have different 1 MET values. Further studies should be conducted to obtain more accurate daily energy requirement and 1MET value for specific Chinese populations.

[Relationship of diabetes mellitus in older Han adults in China with leptin receptor gene rs1137100 and rs1137101 polymorphrism].

OBJECTIVE: To explore the relationship of diabetes in older Han adults with leptin receptor gene rs1137100 and rs1137101 single nucleotide polymorphism( SNP). METHODS: A total of 511 older Han adults were selected for this study and divided into diabetes and control groups, with 241 and 270 people in each group. The genotypes of rs1137100 and rs1137101 and the allele frequency were determined by Taqman method. The correlations between genotypes of leptin receptor gene SNPs with diabetes wereanalyzed. Blood concentrations of lipids, fasting serum glucose( FBG), leptin and insulin were also measured. RESULTS: The distribution of GG, GA and AA genotypes in rs1137100 in the diabetes group and the healthy group was 73. 0%, 24. 5%, 2. 5% and 68. 9%, 28. 9%, 2. 2%, respectively. The difference was not significant between the two groups( χ~2= 1. 27, P = 0. 53). There was no significance in the difference of the frequency of "A"allele in rs1137100 in the two groups, with 14. 7% and 16. 7% in each group( χ~2= 0. 72, P = 0. 40). In rs1137101, the distribution of GG, GA and AA genotypes in the diabetes group and the healthy group was 77. 6%, 21. 2%, 1. 2% and 77. 8%, 21. 1%, 1. 1%, respectively. The difference was not significant between the two groups( χ~2= 0. 02, P = 0. 99). There was no significance in the difference of the frequency of"A"allele in rs1137101 in the two groups, with 11. 8% 11. 7% in each group( χ~2=0. 01, P = 0. 94. The Logistic analysis showed that GA and AA genotypes carriers in rs1137100 had similar risk for diabetes when comparing with the GG genotypes( OR =1. 06, 95% CI 0. 34-3. 34, OR = 0. 80, 95% CI 0. 54-1. 19). The GA and AA genotypes carriers in rs1137101 had similar risk for diabetes when comparing with the GG genotypes, and the OR values were 1. 12( 95% CI 0. 22-5. 63) and 1. 01( 95% CI0. 66-1. 54), respectively. CONCLUSION: The rs1137100 and rs1137101 polymorphism are not significantly associated with the prevalence of diabetes in older Han adults.

[Association of leptin receptor gene polymorphrism with metabolic syndrome in older Han adults from major cities in China].

OBJECTIVE: To investigate the relationship of leptin receptor gene rs1137100 and rs1137101 single nucleotide polymorphrism (SNP) with metabolic syndrome (MS) in older Han adults from major cities in China. METHODS: A total of 2082 older Han adults were selected from 18 major cities including 15 provinces/municipalities of China National Nutrition and Health Survey in 2002. According to the MS definition proposed by Joint Interim Statement (JIS), the subjects were divided into MS and control groups. Plasma leptin and insulin levels were measured. The genotypes of rs1137100 and rs1137101 were detected by Taqman method. Association of genotypes of leptin receptor gene SNPs with MS was investigated. RESULTS: The MS group showed higher body mass index (BMI), waist circumference, fasting serum glucose, systolic blood pressure (SBP) and diastolic blood pressure (DBP), triglycerides (TG), serum total cholesterol (TC), insulin, homeostasis model of assessment for insulin resistence index (HOMA-IR) and leptin levels than those of control individuals, while the high density lipoprotein cholesterol (HDL-c) was significantly lower than the control group. The, GG, AA, GA genotypes distribution and the A allele frequency of rs1137100 and rs1137101 were similar between the two groups. The DBP and SBP level were obviously higher in AA genotype. The HDL-c concentration Was significantly lower in AA and GA + AA genotype. The AA and GA genotypes carriers in rs1137100 had similar risk for MS when comparing with the GG genotypes, and the OR values were 1.23 (95% CI 0.90-1.67) and 2.23 (95% CI 0.83-6.44), respectively. The AA and GA genotypes carriers in rs1137101 had similar risk for MS when comparing with the GG genotypes, and the OR values were 1.23 (95% CI 0.90-1.67) and 2.23 (95% CI 0.83-6.44), respectively. CONCLUSION: Leptin receptor genes rs1137100 and rs1137101 are not associated with pathogenesis of MS in older Han adults, but it may relate with hypertension or lipid abnormality.

The effect of recombinant human lactoferrin from the milk of transgenic cows on Salmonella enterica serovar typhimurium infection in mice.

Lactoferrin (LF) is a multifunctional protein with antibacterial and immunomodulatory activities. Given this beneficial effect, transgenic approaches have been used to produce lactoferrin. The aim of the current study was to investigate the in vivo effect of recombinant human lactoferrin (rhLF) from the milk of transgenic cows on Salmonella enterica serovar typhimurium (ST) infection in mice. Two hours before the infection with 0.3 ml at 2 × 10(5) CFU ml(-1) of ST, each animal in the ST + rhLF group received 0.3 ml of rhLF with 20 mg ml(-1) concentration while the ST group received PBS as placebos with the same volume through oral gavage. The mice were infected with ST once only on the first day. After the infection, the mice received 0.3 ml of rhLF with 20 mg ml(-1) (6 mg d(-1)) concentration or PBS, respectively, for 7 days. Mortality and weight were monitored daily. Bacterial enumeration in the blood, liver, and spleen and histopathological analysis of the liver, spleen, kidney and intestine were conducted. The results showed that rhLF decreased the bacterial load in the liver and spleen of mice, reduced the degree of mice hepatomegaly and splenomegaly, and attenuated infectious inflammation with less histopathological abnormalities in the liver, spleen and kidney of mice in the ST infection. This study showed that rhLF with 6 mg per day had antibacterial activity of alleviating the infection caused by ST bacteria, which indicated that rhLF could be used as a supplement in special products.

[Basal metabolic rate of overweight and obese adults in Beijing].

OBJECTIVE: To detect the basal metabolic rate( BMR) of overweight and obese adults in Beijing, to investigate the correlation of BMR with body composition and to find a better BMR estimated equation for overweight and obese adults in China. METHODS: The BMR and body composition were detected with indirect calorimetry and dual-energy Xray absorptiometry. The correlations of BMR with body composition were used by Pearson correlation test. The measured BMR data were compared with the estimated values of commonly used equations. RESULTS: The study involved 85 adults. The BMR of overweight and obese adults were significantly more than those of normal BMI( P < 0. 001). The BMR of obese people were significantly more than overweight( P = 0. 036). The measured BMR was significantly correlated with lean body mass( r = 0. 865; r = 0. 784) in overweight and obese adults. The measured BMR was negatively correlated with fat mass in overweightpeople, but not among the normal BMI and obese people. The BMR average bias of HENRY equation and LIU equation were less than 2%, respectively, the difference was not significant( P > 0. 05). CONCLUSION: The BMR of overweight and obese people is higher than normal healthy people. The important factor affect BMR is lean body mass. The impact of fat mass on BMR is uncertain. HENRY equation and LIU( ≥18) equation are suitable for predicting BMR of overweight and obese people.

Effect of NaFeEDTA-fortified soy sauce on zinc absorption in children.

NaFeEDTA has been applied in many foods as an iron fortificant and is used to prevent iron deficiency in Fe-depleted populations. In China, soy sauce is fortified with NaFeEDTA to control iron deficiency. However, it is unclear whether Fe-fortified soy sauce affects zinc absorption. To investigate whether NaFeEDTA-fortified soy sauce affects zinc absorption in children, sixty children were enrolled in this study and randomly assigned to three groups (10 male children and 10 female children in each group). All children received daily 3 mg of (67)Zn and 1.2 mg of dysprosium orally, while the children in the three groups were supplemented with NaFeEDTA-fortified soy sauce (6 mg Fe, NaFeEDTA group), FeSO4-fortified soy sauce (6 mg Fe, FeSO4 group), and no iron-fortified soy sauce (control group), respectively. Fecal samples were collected during the experimental period and analyzed for the Zn content, (67)Zn isotope ratio and dysprosium content. The Fe intake from NaFeEDTA-fortified and FeSO4-fortified groups was significantly higher than that in the control group (P < 0.0001). The daily total Zn intake was not significantly different among the three groups. There were no significant differences in fractional Zn absorption (FZA) (P = 0.3895), dysprosium recovery (P = 0.7498) and Zn absorption (P = 0.5940) among the three groups. Therefore, NaFeEDTA-fortified soy sauce does not affect Zn bioavailability in children.

[Study on no-fusion expression and purification of Glycine max dehydration-responsive element-binding protein (GmDREB1) expressed in E. coli].

OBJECTIVE: To obtain enough GmDREB1 protein comparable with native protein for further safety assessment of the protein. METHODS: The GmDREB1 gene was cloned into no-fusion expression vector pBV220 and the recombinant vector pBV220-GmDREB1 was obtained. The constructed vector was transformed into expression host E. coli DH5a. The protein expression was optimized by improving the codon, induced expression conditions and selecting the appropriate vector. The protein was obtained by cation exchange chromatography and gel filtration chromatography and identified by N-terminal amino acid sequencing, western blotting and activity determination. RESULTS: The soluble protein was expressed efficiently in E. coli DH5a containing the optimized target gene by 42 degrees C induction for 3 hours and the purified protein consistent with the native protein was obtained through the chromatography. CONCLUSION: The results of this study illustrated that the GmDREB1 protein could be acquired through prokaryotic host expression which had comparable N-terminal amino acid sequences, immunogenicity and biological activities with those of native GmDREB1 protein.

[Isolation and purification of recombinant human lactoferrin (rhLF) from transgenic rice and its antibacterial activities].

OBJECTIVE: To study the isolation and purification of recombinant human lactoferrin (rhLF) from transgenic rice, and to check its antibacterial activities. METHODS: After isolated rhLF from transgenic rice via saturated ammonium sulfate precipitation, then purified it through CM Sepharose FF-exchange chromatography and molecular sieve chromatography Sephadex G25. The inhibition effects under different concentrations of rhLF (0.25, 0.5, 1.0, 2.0, 4.0, and 5.0 mg/ml) against Salmonella typhimurium, Staphyloccocus aureus, Bacillus cereus, Listeria monocytogenes were observed, using broth microdilution method. RESULTS: The rhLF was obtained at a higher purity (about 90%) through successful isolation and purification. After Coomassie blue staining, Westernblot and mass spectrometer analysis, it was identified as the purpose protein with the molecular weight of approximately 79 kDa. The antibacterial experiments showed that 5 mg/ml and 4 mg/ml rhLF could inhibite Salmonella typhimurium and Staphylococcus aureus persistently, 2 mg/ml and 1 mg/ml rhLF showed a significant inhibitory effects in the later period; while 0.5 mg/ml or lower concentration, showed no inhibitory effects. As to Bacillus cereus, only 5 mg/ml and 4 mg/ml rhLF exhibited certain inhibitory effects within 18 hours. Listeria monocytogenes was inhibited within 18 hours just at 5 mg/ml rhLF. CONCLUSION: The rhLF could be successfully separated and purified from transgenic rice, and the purified protein still has significant antibacterial activities.

[Large-scale purification and acute toxicity of cowpea trypsin inhibitor].

OBJECTIVE: To provide the acute toxicity data of cowpea trypsin inhibitor (CpTI) using recombinant protein purified from E. coli. METHODS: Recombinant CpTI protein was expressed and purified from E. coli. Bacterial recombinant plasmid was transformed into E. coli and the transformed cells were induced with IPTG. The expressed CpTI protein was purified by hydrophobic interaction chromatography and anion exchange chromatography. Sixty mice, randomly assigned to 6 groups, were administrated 10.0, 4.64, 2.15 and 1.00 g/kg BW of CpTI or 5.00 g/kg BW of BSA control protein or sterile water respectively by oral gavage. RESULTS: All animals survived with no significant change in body weight and food consumption throughout the study. Macroscopic necropsy examination on day 15 revealed no gross pathological lesions in any of the animals. The maximum tolerated dose (MTD) of CpTI was more than 10.0 g/kg body weight in mice. CONCLUSION: No toxicity of CpTI protein was found in ICR mice model.