Salivary iodine concentrations (SIC) and urinary iodine concentrations are correlated. This study aimed to verify the use of SIC as a biomarker for estimating iodine intake in pregnant and lactating women and to diagnose abnormal thyroid function. A cross-sectional study was conducted in northern Xinjiang, China. Participants provided venous blood, random urine, saliva and milk samples. A total of 607 pregnant and 171 lactating women volunteered to participate in the study. The average daily iodine intake was calculated for each participant. Pregnant women were divided according to trimester. The median daily iodine intake was 436·41 μg/d in the first trimester, 425·83 μg/d in the second trimester and 430·56 μg/d in the third trimester. The average daily iodine intake in lactating women was 416·16 μg/d. Different indicators were used to diagnose excessive iodine intake (> 500 μg/d). Among pregnant women, SIC had an AUC of 0·62 (P < 0·01), sensitivity of 51·75 % and specificity of 65 %. Among lactating women, SIC had an AUC of 0·63 (P = 0·03), sensitivity of 43·52 % and specificity of 85 %. SIC was an effective biomarker for diagnosing abnormal thyroid function (P = 0·03). In conclusion, this study demonstrated that SIC is a reliable biomarker for evaluating both iodine nutrition status and abnormal thyroid function in pregnant and lactating women.

EPA and DHA are essential for maternal and fetal health, but epidemiological data are sparse in China. We examined the trends of EPA alone and a combination of EPA plus DHA in pregnant and lactating women in three distinct geographic regions in China and explored their potential influencing factors. A total of 1015 healthy women during mid-pregnancy, late pregnancy or lactation were recruited from Weihai (coastland), Yueyang (lakeland) and Baotou (inland) cities of China between May and July of 2014. Maternal EPA and DHA concentrations (percentage of total fatty acids) in plasma and erythrocytes were measured by capillary GC. Adjusted EPA plus DHA concentrations in both plasma and erythrocytes significantly declined from mid-pregnancy (2·92 %, 6·95 %) to late pregnancy (2·20 %, 6·42 %) and lactation (2·40 %, 6·29 %) (P trend < 0·001); and both concentrations were highest in coastland, followed by lakeland, and lowest in inland (P < 0·001). Regarding EPA alone, the concentrations were higher in women during lactation or late pregnancy and in women in coastland and inland areas. Moreover, concentrations of EPA or EPA plus DHA were higher in women with older age, higher education, higher annual family income per capita and higher dietary intake of marine aquatic product and mutton. In lactating women, erythrocyte EPA concentration was higher in those having breast-feeding partially v. exclusively. In conclusion, maternal plasma and erythrocyte concentrations of EPA plus DHA or EPA alone differed with geographic regions, physiological periods and maternal characteristics, indicating a need of population-specific health strategies to improve fatty acids status in pregnant and lactating women.

Maternal dietary feeding practice is one of the proxy indicators of maternal nutrient adequacy and it improves outcomes for both mothers and their offspring. The minimum maternal dietary diversity score of lactating women is defined as when the mother ate at least four and above food groups from the nine food groups 24 h preceding the survey regardless of the portion size. Therefore, the present study aimed to determine the minimum dietary diversity score (MDDS) and its predictors among lactating mothers in the Pastoralist community, Ethiopia. A community-based cross-sectional study design was employed on 360 lactating mothers using a multi-stage sampling technique from 5 January 2020 to 10 February 2020. Data were collected using questionnaires and anthropometry measurements. Data were entered using EPI-data 4.6.02 and exported into SPSS version 25. Statistical significance was declared at P-value <0⋅05 at multivariable logistic regression. Only one in four lactating mothers met the MDDS. The majority of them consumed cereals in the preceding 24 h of data collection. The most important predictors were maternal meal frequency (adjusted odds ratio (AOR) 6⋅26; 95 % confidence interval (CI) (3⋅51, 11⋅15)), antenatal care (ANC) follow-up one to three times and four and above times (AOR: 2⋅58; 95 % CI (1⋅24, 5⋅36), 4⋅77 (1⋅90, 11⋅95), respectively) and secondary paternal education (AOR 2⋅97; 95 % CI (1⋅44, 6⋅11)). The MDDS among lactating mothers was low. Paternal education, maternal meal frequency and ANC follow-up were the significant predictors. Therefore, to improve maternal dietary diversity score emphasis should be given to those predictors.

The aim of this study was to investigate the association between daily Se intake and postpartum weight retention (PPWR) among Chinese lactating women, and the impact of their Se nutritional status on infants’ physical development. Se contents in breast milk and plasma collected from 264 lactating Chinese women at the 42nd day postpartum were analysed with inductively coupled plasma MS. Daily Se intake was calculated based on plasma Se concentration. The dietary data of 24-h records on three consecutive days were collected. Infant growth status was evaluated with WHO standards by Z-scores. Linear regression analyses and multinomial logistic regression were conducted to examine the impact of Se disequilibrium (including other factors) on PPWR and growth of infants, respectively. The results indicated that: (1) the daily Se intake of the subjects was negatively associated with their PPWR (B = −0·002, 95 % CI − 0·003, 0·000, P = 0·039); (2) both insufficient Se daily intake (B = −0·001, OR 0·999, 95 % CI 0·998, 1·000, P = 0·014) and low level of Se in milk (B = −0·025, OR 0·975, 95 % CI 0·951, 0·999, P = 0·021) had potential associations with their infants’ wasting, and low level of Se in milk (B = −0·159, OR 0·853, 95 % CI 0·743, 0·980, P = 0·024) had a significant association with their infants’ overweight. In conclusion, the insufficient Se nutritional status of lactating Chinese women was first found as one possible influencing factor of their PPWR as well as low physical development of their offspring.

Universal salt iodisation (USI) has been successfully implemented in China for more than 15 years. Recent evidence suggests that the definition of ‘adequate iodine’ (100–199 µg/l) be revised to ‘sufficient iodine’ (100–299 µg/l) based on the median urinary iodine concentration (MUI) in school-age children. The objective of this study was to determine the prevalence of thyroid dysfunction in populations after long-term salt iodisation and examine whether the definition of adequate iodine can be broadened to sufficient iodine based on the thyroid function in four population groups. A cross-sectional survey was conducted in six provinces in the northern, central and southern regions of China. Four population groups consisting of 657 children, 755 adults, 347 pregnant women and 348 lactating women were recruited. Three spot urinary samples were collected over a 10-d period and blood samples were collected on the 1st day. In the study, among the adults, pregnant women and lactating women, the prevalence rates of elevated thyroglobulin antibody and thyroid microsomal antibody levels were 12·4, 8·5 and 7·8 %, and 12·1, 9·1 and 9·1 %, respectively. Abnormally high thyroid dysfunction prevalence was not observed after more than 15 years of USI in China because the thyroid dysfunction rates were all <5 %. The recommended range should be cautiously broadened from adequate iodine to sufficient iodine according to the MUI of school-age children considering the high levels of hormones and antibodies in the other populations. Adults, particularly pregnant women positive for thyroid antibodies, should be closely monitored.

I deficiency is a worldwide public health problem. Median urinary I concentration in school-aged children has been used globally as a proxy for all populations. This study aims to determine whether median urinary I concentration of school-aged children is an appropriate indicator of I nutritional status in different adult populations. This is a secondary data analysis of two national I Deficiency Disorder surveys (2011, 2014) and two regional surveys (in coastal areas, 2009, and in high-risk areas, 2009–2014). Population groups included in these surveys were school-aged children (8–10 years), pregnant women, lactating women, women of childbearing age and adults (men and women, 18–45 years). All participants were self-reported healthy without history of thyroid diseases or were not using thyroid medicines. The median urinary I concentration of school-aged children was matched with that of the other population at the county level. The matched populations had similar iodised salt supply, food and water I, food composition and I content in salt. Weak or moderate correlation of median urinary I concentrations was observed between school-aged children and pregnant women and between children and lactating women. However, the agreement was stronger between children and women of childbearing age and between children and adult men and women. The results could be affected by cut-off values, data aggregation level and sample size. Using median urinary I concentration of school-aged children tends to overestimate that of pregnant women and lactating women. Median urinary I concentration of school-aged children can be used for assessing I nutrition in the adult population.

The way in which women accommodate for their increased nutritional needs during the lactation period is poorly investigated. In a cross-sectional study involving 220 lactating women (LW), equally distributed in economic quintiles (Q2, Q3, Q4), we investigated whether habitual dietary intake of LW differed from that of 200 pre-pregnant women (PPW) studied using the same methodology. Differences in dietary intake and nutrition sufficiency according to economic status were also investigated. Dietary intake data were collected using 2×24-h dietary recalls and FFQ. Energy, protein, Fe, Ca, Zn and vitamins A and C intakes were calculated utilising local food composition tables and were compared against Indonesian recommendations for adequacy. Energy and protein intakes <70 % of the recommendation and Fe, Ca, Zn and vitamins A and C intakes <77 % of the recommendation were considered insufficient. Except for Zn, dietary intakes of all studied nutrients were higher in LW compared with PPW. However, for all studied nutrients, dietary intake was insufficient in >25 % of LW. For Q2-LW, this proportion was >50 %, except for protein. LW across all studied economic quintiles approximately doubled their vegetable intake, and 71 % of LW indicated a belief that this enhances lactation performance. Biochemical status parameters were analysed in a subset of forty-five women. Anaemia as well as Fe, Zn and Se deficiencies were prevalent among LW, supporting the nutrient intake deficiency data. Despite increasing intakes in LW compared with PPW, habitual diets in the study area do not provide for daily nutrient requirements in substantial proportions for both LW and PPW across all investigated economic groups.

Areas with low, adequate and excessive I content in water co-exist in China. Limited data are currently available on I nutrition and thyroid disease in lactating women and their breast-fed infants with different I intakes. This study aimed to evaluate I nutrition in both lactating women and their infants and the prevalence of thyroid disease in areas with different levels of I in water. From January to June 2014, a total of 343 healthy lactating women (excluding those taking anti-thyroid drugs or I supplements within a year of the study, consuming seafood at the time of the study or those diagnosed with congenital thyroid disease) from Beihai in Guangxi province and Jiajiazhuang, Yangcheng, Jicun and Pingyao townships in Shanxi province were selected. Compared with the I-sufficient group, median urinary I concentrations in both lactating women and infants as well as breast milk I levels were significantly lower in the I-deficient group (P<0·001). The prevalence of thyroid disease in lactating women, particularly subclinical hypothyroidism, was higher in the I-excess group than in the I-sufficient group (P<0·05). In areas with excessive water I content, high thyroid peroxidase antibody and high thyroglobulin levels were risk factors for abnormal thyroid-stimulating hormone levels. Our data collectively suggest that excessive I intake potentially causes subclinical hypothyroidism in lactating women. Moreover, enhanced monitoring of I status is important to avoid adverse effects of I deficiency or excess, particularly in susceptible populations such as pregnant or lactating women and infants.

The main objective of the present study was to examine the association between dietary Fe intake and dietary predictors of Fe status and Hb concentration among lactating women in Bhaktapur, Nepal. We included 500 randomly selected lactating women in a cross-sectional survey. Dietary information was obtained through three interactive 24 h recall interviews including personal recipes. Concentrations of Hb and plasma ferritin and soluble transferrin receptors were measured. The daily median Fe intake from food was 17·5 mg, and 70 % of the women were found to be at the risk of inadequate dietary Fe intake. Approximately 90 % of the women had taken Fe supplements in pregnancy. The prevalence of anaemia was 20 % (Hb levels < 123 g/l) and that of Fe deficiency was 5 % (plasma ferritin levels < 15 μg/l). In multiple regression analyses, there was a weak positive association between dietary Fe intake and body Fe (β 0·03, 95 % CI 0·014, 0·045). Among the women with children aged < 6 months, but not those with older infants, intake of Fe supplements in pregnancy for at least 6 months was positively associated with body Fe (P for interaction < 0·01). Due to a relatively high dietary intake of non-haem Fe combined with low bioavailability, a high proportion of the women in the present study were at the risk of inadequate intake of Fe. The low prevalence of anaemia and Fe deficiency may be explained by the majority of the women consuming Fe supplements in pregnancy.