The Impact of Linoleic Acid on Infant Health in the Absence or Presence of DHA in Infant Formulas.

Both linoleic acid (LA) and α-linolenic acid (ALA) are essential dietary fatty acids, and a balanced dietary supply of these is of the utmost importance for health. In many countries across the globe, the LA level and LA/ALA ratio in breast milk (BM) are high. For infant formula (IF), the maximum LA level set by authorities (e.g., Codex or China) is 1400 mg LA/100 kcal ≈ 28% of total fatty acid (FA) ≈ 12.6% of energy. The aims of this study are: (1) to provide an overview of polyunsaturated fatty acid (PUFA) levels in BM across the world, and (2) to determine the health impact of different LA levels and LA/ALA ratios in IF by reviewing the published literature in the context of the current regulatory framework. The lipid composition of BM from mothers living in 31 different countries was determined based on a literature review. This review also includes data from infant studies (intervention/cohort) on nutritional needs regarding LA and ALA, safety, and biological effects. The impact of various LA/ALA ratios in IF on DHA status was assessed within the context of the current worldwide regulatory framework including China and the EU. Country averages of LA and ALA in BM range from 8.5-26.9% FA and 0.3-2.65% FA, respectively. The average BM LA level across the world, including mainland China, is below the maximum 28% FA, and no toxicological or long-term safety data are available on LA levels > 28% FA. Although recommended IF LA/ALA ratios range from 5:1 to 15:1, ratios closer to 5:1 seem to promote a higher endogenous synthesis of DHA. However, even those infants fed IF with more optimal LA/ALA ratios do not reach the DHA levels observed in breastfed infants, and the levels of DHA present are not sufficient to have positive effects on vision. Current evidence suggests that there is no benefit to going beyond the maximum LA level of 28% FA in IF. To achieve the DHA levels found in BM, the addition of DHA to IF is necessary, which is in line with regulations in China and the EU. Virtually all intervention studies investigating LA levels and safety were conducted in Western countries in the absence of added DHA. Therefore, well-designed intervention trials in infants across the globe are required to obtain clarity about optimal and safe levels of LA and LA/ALA ratios in IF.

Nutritional complexity in children with ADHD related morbidities in China: A cross-sectional study.

BACKGROUND AND OBJECTIVES: To assess the general and nutritional health of children with attention deficit/ hyperactivity disorder (ADHD). METHODS AND STUDY DESIGN: The National Multicenter Sleep Research Database for 23791 school-age children in grades 1-6 from 9 cities in China was accessed. Children with a specialist diagnosis of ADHD or not (non-ADHD) in 2005 were studied. National anthropometric growth standards for children aged 2-18 years classified children as underweight, wasted, stunted (short stature presumed nutritional), or overweight/obesity. Independent variables were preterm birth, sleep quality and prior disease and ADHD was the dependent variable. Binary logistic regression models were developed along with interaction analyses for associated disorder or disease on overweight/obesity, and stunted. RESULTS: Some 18731 records were analyzed for 808 children with ADHD. The comparative prevalences for ADHD with non-ADHD children were stunted 9.8% vs 5.9% (p<0.001) and overweight/ obesity (32.6% vs 29.6%, p=0.002) respectively. ADHD boys were more often underweight (7.5% vs 5.3%, p=0.027), but not in girls. ADHD likelihood Odds Ratios, ORs (with 95%CI) were for premature birth 1.838, (1.393-2.423), allergic diseases 1.915 (1.526-2.399), otitis media 1.54 (1.118- 2.146), tonsillar or adenoid hypertrophy1.662 (1.348-2.050), gastroesophageal reflux 3.008(1.792-1.792-5.049), and sleep disorder 2.201(1.847-2.623) were ADHD risk factors. Only poor sleep quality and ADHD exhibited an interaction for stunted with OR=0.409 (0.233-0.719). CONCLUSIONS: Compromised and complex nutritional health in ADHD children challenges clinical nutrition with a range of health problems, albeit coherent with the needed nutritional emphasis in the 'first 1000 days'.

Reduced Occurrence of Gastrointestinal Symptoms in Chinese Infants Fed Minimally Processed Commercially Available Formula: A Cross-Sectional Observational Study.

Healthy Chinese infants consuming one of four commercially available infant formulas (IF) were assessed on the occurrence of gastrointestinal symptoms associated with suboptimal digestion of processed milk proteins. The IF differed in blocked lysine (BL) levels, a proxy indicator of heat processing as well as the nutritional quality of milk. A cross-sectional, observational study of one week was conducted in healthy, term, exclusively formula-fed Chinese infants (n = 452) fed with one of four commercially available IF (IF A n = 106, BL 9%; IF B n = 119, BL 12%; IF C n = 113, BL 11%; IF D n = 114 BL 20%). Parents/caretakers were requested to report feeding quantity, gastrointestinal symptoms, crying behavior, and stool characteristics daily using subject dairy and Amsterdam Infant Stool Scale (AISS). Infants fed with IF A reported less "hard" and "watery" stools and more "soft/formed" stools. Higher percentages of score I (yellow/golden) or II (orange) and less green (score III) coloured stools were noted for IF A-fed infants compared to all other formulas according to AISS. Night time crying was also significantly lower in the IF A groups compared to all other formulas. Furthermore, a higher percentage of parents/caretakers of IF A-fed infants reported absence or no complaints of abdominal distension, burping, flatulence, diarrhea, and constipation. Results suggest lower occurrence of GI symptoms and lower crying time at night in infants fed with minimally processed formula (indexed by BL levels). Future studies are required to confirm the association between minimal processing of milk formula and improved gut comfort in healthy infants.

Reduced crying and favourable stool characteristics in Chinese infants fed milk fat-based formula.

BACKGROUND AND OBJECTIVES: Chinese infants consuming four different commercially-available infant formulas were evaluated on gut comfort and stool consistency parameters. METHODS AND STUDY DESIGN: Gut comfort characteristics were evaluated during a 7-day cross-sectional observational study in 409 healthy, term, exclusively formula-fed infants via questionnaires and fecal parameters. RESULTS: The stool consistency and color scores were different between the infants consuming one of the four commercially-available infant formulas including different fat sources, i.e. one milk fat-based (IF1), two structured vegetable fat blend-based (IF2 and IF4) and one palm oil-free vegetable fat blend-based (IF3). The scoring pattern showed more 'soft-formed' stools for IF1- consuming infants compared to infants consuming IF2, IF3 or IF4. In addition, a lower amount of green feces was observed in combination with an increase in golden-colored feces for IF1-consuming infants compared to the other groups. Furthermore, IF1-consuming infants reported less fussy/crying time during the night and less gut discomfort. Infants consuming milk fat-based IF1 showed significantly lower fatty acid soaps compared to palmoil free IF3-fed infants. CONCLUSIONS: Infants consuming milk fat-based IF1 experienced less gut discomfort compared to infants consuming other commercially-available infant formula. Lower fecal fatty acid soap levels, fussy/crying time during the night and gut discomfort were observed. These findings contribute to the current understanding of the association between lipid structure and gut comfort parameters. However, the suggested benefits noted cannot be fully linked to the effect of fat blend differences since formulas differ in ingredient-sourcing and processing. Future research should confirm the added benefit of milk fat-based infant formulas to improve gut comfort parameters.

Comparison of the effects of different growth standards on infants in Urban Shanghai: a cluster-randomized controlled trial.

BACKGROUND: The Shanghai growth standards are higher than World Health Organization (WHO) growth standards, which may influence the feeding practices of the caregivers and increase the risk of overweight in these infants. This study aimed to compare the effects of different growth standards on childhood obesity in Shanghai metropolitan area. METHODS: This was a cluster-randomized controlled trial conducted in 2 downtown areas with 19 community health service centers in Shanghai from November 2013 to December 2015. Randomization was done at the level of the community. Infants (health newborns) were assessed and monitored by the Shanghai growth standards (S-group) and the 2006 WHO growth standards (W-group), respectively. Measurements were taken at 1.0, 2.0, 4.0, 6.0, 9.0 and 12.0 months of age during follow-up period. Based on the values of length and weight measurements, according to the group's growth standards, doctors provided the caregivers with corresponding clinical consultation. Changes in weight-for-age z-score (WAZ), length-for-age z-score (LAZ), and weight-for length z-score (WLZ) between 2 groups were assessed using mixed regression models. Overweight was compared between 2 group at all follow-up measurements. RESULTS: A total of 6509 infants (52.1% were boys) were in the W-group, and 8510 infants (51.4% were boys) were in the S-group. The overweight ratios between two groups were distinct at 9 months of age (3.4% in W-group and 4.3% in S-group) and 12 months of age (2.2% in W-group and 3.8% in S-group), and the differences were statistically significant (P = 0.020 and P < 0.001, respectively). Compared to W-group, the increase in WAZ (coefficient = 0.04, P = 0.004) and WLZ (coefficient = 0.09, P < 0.001) were significantly greater, and the LAZ was lower (coefficient = -0.04, P = 0.047) in S-group (W-group values were used as reference in mixed regression models). CONCLUSION: Compared to the Shanghai growth standards, the adoption of WHO 2006 growth standards would reduce the risk of infant overweight in Shanghai metropolitan area up to 1 year of age. TRIAL REGISTRATION NUMBER: ChiCTR1800015371, http://www.chictr.org.cn/ Chinese Clinical Trial Registry.

[Establishment of a rat model of oral food allergy].

OBJECTIVE: To establish a food allergy model in Brown Norway (BN) rats by gavage of ovalbumin (OVA) without any adjuvant, and to evaluate this model. METHODS: A total of 20 male BN rats aged 3 weeks were randomly divided into allergy group and control group (n=10 each). BN rats in the allergy group were given OVA 1 mg per day by gavage, and all the rats were treated for 41 days continuously. On day 42, the rats in the allergy group were given OVA 100 mg by gavage for challenge. The rats in the control group were given normal saline of the same volume by gavage. Differences in body length, body weight, and food intake were compared between the two groups on days 7, 14, 21, 28, 35, and 42. ELISA was used to measure the serum OVA-IgE level and plasma histamine level after challenge on day 42, and the changes in rats' appearance and fecal properties were observed. The model of food allergy was considered successful when the serum OVA-IgE level in the allergy group was no less than the mean serum OVA-IgE level + 3 standard deviation in the control group. RESULTS: There were no significant differences in body length, body weight or food intake between the allergy and control groups at all time points (P>0.05). On day 21, the control group had a significantly higher food intake than the allergy group (P<0.05). On day 42 after challenge, the allergy group showed significantly higher serum OVA-IgE and plasma histamine levels than the control group (P<0.05). The sensitization rate (rate of successful modeling) was 90%. The fecal properties showed no significant differences between the two groups. CONCLUSIONS: OVA by gavage without any adjuvant can successfully establish the model of food allergy in BN rats and has a high success rate. Food allergy induced by OVA may reduce food intake within a short period of time, but no influence on rats' body length or body weight has been observed.

Vitamin D Insufficiency and Its Association with Biochemical and Anthropometric Variables of Young Children in Rural Southwestern China.

BACKGROUND: With recognition of the important roles of Vitamin D (VitD) in various physiological processes, increasing attention has been drawn to the status of VitD in early life. However, the VitD status of young children and the related factors in rural areas of Southwestern China remain unclear. This study aimed to explore VitD status and its seasonal variation in 18-month-old children living in rural Southwestern China. The association of VitD with biochemical and anthropometric variables was also investigated. METHODS: A total of 177 18-month-old children in a rural area of Yunnan Province, Southwestern China, were enrolled. Serum concentrations of 25-hydroxy Vitamin D (25(OH)D) were measured through high-performance liquid chromatogram-tandem mass spectrometry. Parathyroid hormone (PTH) levels were measured with a chemiluminescence assay. Serum concentrations of calcium, phosphorus, and alkaline phosphatase (ALP) were also measured. Anthropometric data and the outdoor activity time of each participant were collected. RESULTS: The serum 25(OH)D concentration was 26.61 ± 7.26 ng/ml; concentrations lower than 30 ng/ml accounted for 70.6% of the participants and concentrations lower than 20 ng/ml accounted for 16.4%. The level of serum 25(OH)D was not significantly different among four seasons (P >0.05). A positive relationship was found between 25(OH)D concentration and the time of outdoor activities (r = 0.168, P < 0.05). Serum PTH concentration was negatively correlated with 25(OH)D concentration (r = -0.163, P < 0.05). A positive relationship was found between the serum concentrations of 25(OH)D and calcium (r = 0.154, P < 0.05). No significant association was observed between 25(OH)D and ALP, phosphorus, or anthropometric variables. CONCLUSIONS: The prevalence of VitD insufficiency is high among young children in the rural Southwestern China regardless of the seasons. VitD supplementation is still essential to maintain VitD sufficiency for children living in rural area.

Association between feeding practices and weight status in young children.

BACKGROUND: Inappropriate feeding practices during infancy may lead to overweight. The aims of this study are to investigate the growth of children in the first 18 months of life; to evaluate the feeding practices of caregivers using developed Young Child Feeding Questionnaire; and to investigate caregivers' feeding attitudes and behaviors associated with infants' weight status. METHODS: Six month-old infants and their main caregivers entering the Kongjiang Community Health Center for a routine well-child check were recruited for this study and followed up every 6 months for 12 months. Questionnaire survey was carried out through on-site face-to-face interview at each visit with the main caregivers of children using Young Child Feeding Questionnaire, which included caregivers' feeding attitudes and behaviors. The weight and length of children were measured at each visit. RESULTS: Among 197 children who completed the investigation at 18 months of age, 64 (32.49%) children were overweight (BMI-for-age z scores > +1). The increases in weight-for-age z scores and BMI-for-age z scores from birth to 6 months, 12 to 18 months and birth to 18 months in overweight children were significantly higher than those in normal weight children (P < 0.001). In normal weight children, caregivers worried more about children's being "underweight" and "eating less" (P = 0.001), whereas caregivers with overweight children worried more about children's "eating too much" and being "overweight" (P < 0.001). In 64 overweight infants, the scores of "concern about child's food intake" were significantly correlated with increase in BAZ between 12 and 18 months (Bata = 0.293, P = 0.029). CONCLUSIONS: Young Child Feeding Questionnaire is a valid tool for evaluating feeding practice of caregivers. The rapid BMI gain in overweight children may be associated with some inappropriate feeding attitudes and behaviors of caregivers.

[Research advances in the role of fecal calprotectin in intestinal development and diseases among children].

Calprotectin is a calcium- and zinc-binding protein of the S100 family expressed mainly by neutrophils with important extracellular activity. This paper reviews current findings concerning the relationship between faecal calprotectin and intestinal development among children, influencing factors of fecal calprotectin and the implication of faecal calprotectin in the diagnosis, follow-up, assessment of relapses, and response to treatment in pediatric intestinal diseases, such as necrotizing enterocolitis, inflammatory bowel disease, intestinal infection, celiac disease and allergy. Further studies are required to provide insights into the actual role of calprotectin in physiological and pathological processes in pediatrics.

Meat as complementary food for older breastfed infants and toddlers: a randomized, controlled trial in rural China.

BACKGROUND: Because of its contribution to dietary diversity and to favorable intakes of micronutrients, including iron and zinc, meat is hypothesized to be a valuable complementary food for the infant and young child. However, the evidence base remains limited. OBJECTIVE: To compare the difference in anthropometric measurements of rural Chinese infants and toddlers 6 to 18 months of age who received a daily supplement of meat or cereal for 12 months. METHODS: This cluster-randomized, controlled study provided a daily supplement of either meat (n = 514, 20 clusters) or cereal (n = 957, 40 clusters) starting as a first complementary food at 6 months of age. Anthropometric measurements were assessed longitudinally. RESULTS: After 12 months of intervention, the meat group (δ13.01 ± 1.9 cm) had greater (p = .01) linear growth than the cereal group (δ12.75 ± 1.8 cm) and a smaller decrease in length-for-age z-score (LAZ) over time (-0.43 ± 0.72 in the meat group vs. -0.54 ± 0.67 in the cereal group), after adjustment for baseline length, LAZ, maternal education, work status, and maternal height and weight. CONCLUSIONS: Linear growth was modestly greater in the meat group than in the cereal group. LAZ was substantially negative at 6 months, and the intervention did not prevent ongoing decline over the course of the study.

Fecal calprotectin levels are higher in rural than in urban Chinese infants and negatively associated with growth.

BACKGROUND: Fecal calprotectin (FC) is an established simple biomarker of gut inflammation. To examine a possible relationship between linear growth and gut inflammation, we compared fecal calprotectin levels in 6 month old infants from poor rural vs affluent urban families. METHODS: The project was a cross-sectional comparison of FC from rural and urban populations in China. The relationship between length-for-age Z-score (LAZ) and FC concentrations were also compared. Single fecal samples were assayed for FC using EK-CAL ELISA kits. RESULTS: The age of subjects for both locations was 6.1 ± 0.2 mo; all were apparently healthy. The mean ± SD of the LAZ for the rural and urban infants were -0.6 ± 0.9 and 0.4 ± 0.9, respectively. FC had a non-normal distribution. The median FC of 420.9 and 140.1 µg/g for rural and urban infants, respectively, were significantly different (P < 0.0001). For the rural group, linear regression analysis showed that an increase in FC of 100 µg/g was associated with a decrease of 0.06 in LAZ. CONCLUSION: FC levels were significantly elevated in the rural infants and high concentrations accounted for approximately one-third of the low LAZ scores of these infants.

Feeding and growth of normal birth weight infants during the first year of life in Shanghai.

AIM: This study aimed to explore the relationship between infant feeding practices and growth outcomes in the first 12 months of life. DESIGN: Investigators completed 262 questionnaires, which included infant feeding patterns, feeding environment, feeding beliefs/attitudes and caregivers' feeding behaviors through on-site face-to-face interviews with the main caregivers of infants at 12 months of age. The infant's weight and length at ages 6 and 12 months were measured. SETTING: The study was conducted in urban Shanghai, China. SUBJECTS: This study included 262 healthy normal birth weight full-term singleton 6-month-old infants and their main caregivers. RESULTS: Among 262 infants, 86 (32.82%) infants were overweight [BMI-for-age z scores (BAZ)>+1] at 12 months. Compared with normal weight infants, the overweight infants had higher birth weights (P=0.009). Furthermore, the overweight infants gained significantly more weight (P<0.001) in the first year of life. In normal weight infants, caregivers worried more about infants being "underweight" and "eating less" (P<0.001) whereas caregivers with overweight infants worried more about infants being "overweight" (P<0.001). Consequently, the total score of caregivers' over-feeding behaviors was significantly higher in normal weight infants (P=0.029). However, in overweight infants, the scores of "fed quickly within 10 min" (r=0.223, P=0.039) and "feeding was the best way to stop the infant's fussiness" (r=0.285, P=0.008) were positively correlated with BAZ. CONCLUSIONS: Overweight in early life is associated with carelessness about excessive appetite and some particular infant feeding behaviors of caregivers in Shanghai.

A summary index of infant and child feeding practices is associated with child growth in urban Shanghai.

BACKGROUND: Recently, an infant and child feeding index (ICFI) constructed on brief recalls of breastfeeding, feeding frequency and food diversification was assumed to provide long-term prediction about child feeding practices. The aim of this study was to investigate the association between the cross-sectional ICFI (CS-ICFI) or longitudinal ICFI (L-ICFI) and child anthropometric indices in downtown Shanghai, China. METHODS: The prospective cohort study included 180 infants aged 5-7 mo with their main caregivers who were visited 3 times every 6 months over 12 months. A CS-ICFI was constructed for each visit by using data on feeding practices based on 24-h and 7-d recalls. An L-ICFI was constructed with use of the 3 CS-ICFIs. The associations between ICFI and length-for-age z score (LAZ), weight-for-age z score (WAZ), and weight-for-length z score (WLZ) were examined. The stability of the CS-ICFI was assessed by using repeatability coefficient (RC). RESULTS: The L-ICFI was positively associated with LAZ and WAZ at Visit 3(beta = 0.151, P = 0.040 and beta = 0.173, P = 0.024, respectively). Moreover, the CS-ICFI at Visit 1 was positively associated with LAZ, WAZ and WLZ (beta = 0.160, P = 0.029; beta = 0.191, P = 0.009; beta = 0.176, P = 0.020) at Visit 3, and the CS-ICFI at Visit 3 was also positively associated with LAZ (beta = 0.176, P = 0.016). Stability of the CS-ICFI was shown by the value of 0.14 (95% CI: 0.07, 0.31) of the RC, which differed significantly from 0 (P < 0.05). CONCLUSIONS: The ICFI constructed on brief recalls based on cross-sectional studies can be used to evaluate the effects of child feeding practice on child growth.

[Intestinal inflammation-induced child growth failure: immunologic and endocrine mechanisms].

Faltering linear growth is commonly encountered in children with intestinal inflammation. Growth hormone (GH) and insulin-like growth factor-1 (IGF-1) are important regulators of postnatal longitudinal bone growth. Inhibition of GH/IGF axis will result in growth failure in young children. Pro-inflammatory cytokines such as interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) abnormally increase in children with intestinal inflammation, and may affect linear growth both systemically and locally at the level of the growth plate though disturbing the GH/IGF axis.

The use of dysprosium to measure endogenous zinc excretion in feces eliminates the necessity of complete fecal collections.

The secretion of endogenous zinc (Zn) into the gut and subsequent excretion in the feces is understood to play a major role in maintaining Zn homeostasis in humans. Therefore, the measurement of endogenous Zn losses in the feces (EFZ) can be an important aspect of the study of Zn metabolism and homeostasis. The methods currently used to measure EFZ have the disadvantage of requiring complete fecal collections over multiple days. We have investigated the use of dysprosium (Dy), a nonabsorbable rare earth metal, in a method of determining EFZ that does not require complete fecal collections and permits the measurement of EFZ from several fecal samples. The method was evaluated using data from a study of free-living adult females in which Dy was administered 3-4 times/d over a period of 5 or 6 d to monitor completeness of fecal collections. The results did not differ from those obtained using an established isotope dilution method. We found that the measurement of the sample Dy:Zn ratio was useful for selecting samples for measurement. We conclude that the Dy method of determining EFZ is a valid and less burdensome alternative to current techniques.

[Key parameters and formulas for approximate average height and weight of normal Chinese children under 7 years of age].

OBJECTIVE: In order to understand the normal physical growth of Chinese children, data of children aged from 0 to 7 years from urban and rural areas of nine Chinese cities in 2005 were analyzed. METHODS: The original data of height and weight were drawn into growth curves charts by Graphpad Prism 5.0 software according to the different age groups. The children were classified into five age groups: 0-3 months, 4-6 months, 7-12 months, 13-24 months, and 2-7 years. RESULTS: The average birth weight was 3.3 kg and the height averaged 50 cm. The average monthly weight gain was 1.0-1.2 kg and the average monthly increase of height was 4 cm in the 0-3 months group. By 3 months of age, the weight and height averaged 6.6 kg and 62 cm, respectively. In the 4-6 months group, the growth rate was reduced to a half of the 0-3 months group, with an average monthly weight and height gain was 0.5-0.6 kg and 2 cm respectively. The growth rate in the 7-2 months group was a half of the 4-6 months group. By 12 months of age, the weight and height average 9.9 kg and 75 cm, respectively. The average monthly weight and height gain in the 13-24 months group was 0.2 kg and 1 cm respectively, with an average weight and height of 12 kg and 87 cm respectively by 24 months of age. A steady growth was found in the 2-7 years group, with a yearly average weight and height increment of about 2 kg and 7 cm respectively. The formulas for approximate average weight and height in children between 2 and 7 years were as follows: age (yr)*2+8 (kg) (weight); age (yr)*7+75 (cm) (height). CONCLUSIONS: The approximate weight and height of normal Chinese children under 7 years of age can be evaluated by the key parameters and formulas above mentioned.

Measurement of zinc absorption from meals: comparison of extrinsic zinc labeling and independent measurements of dietary zinc absorption.

BACKGROUND: Extrinsic labeling techniques are typically used to measure fractional absorption of zinc (FAZ(extrinsic)) but none have been adequately evaluated. OBJECTIVE: To compare determination of the quantity of zinc absorbed (TAZ(extrinsic)) using measurements of FAZ(extrinsic) with results of simultaneous determinations of dietary zinc absorbed (TAZ(metabolic)) that are not dependent on labeling ingested food with an extrinsic tracer (modified metabolic balance technique). DESIGN: (70)Zn was administered orally with all meals for 6 consecutive days to 21 healthy, free-living adult women consuming a constant diet. (68)Zn and (67)Zn were administered intravenously. FAZ(extrinsic) was measured using a dual isotope tracer ratio technique and multiplied by dietary zinc to give TAZ(extrinsic). TAZ(metabolic) was determined by addition of net absorption of zinc and endogenous fecal zinc, the latter determined by an isotope dilution technique. RESULTS: TAZ(extrinsic) and TAZ(metabolic) were 3.0 +/- 1.1 mg/day and 3.1 +/- 1.1 mg/day respectively, paired t-test p = 0.492. The correlation coefficient for TAZ(extrinsic) and TAZ(metabolic) was 0.91, and for FAZ(extrinsic) and FAZ(metabolic) was 0.95. A Bland Altman analysis indicated a bias of 0.07, and the limits of agreement of -0.86 to 1.01 for TAZ(extrinsic) and TAZ(metabolic). CONCLUSION: These results from two independent methods provide reasonable validation of our extrinsic labeling technique for a wide range of composite diets.

Major variables of zinc homeostasis in Chinese toddlers.

BACKGROUND: Measurement of the major variables of zinc homeostasis is an essential prerequisite for estimating human zinc requirements, which currently require a factorial approach. The data required for this approach have not been available for toddlers, whose requirements have been estimated by extrapolation from other age groups. OBJECTIVE: The objective of the study was to measure key variables of zinc homeostasis in rural and small-town Chinese toddlers. DESIGN: Zinc stable-isotope tracers were administered intravenously and orally with all meals for 1 d to 43 toddlers. Subsequent metabolic collections in the homes included duplicate diets, quantitative fecal collections, and spot urine sampling. Fractional absorption of zinc (FAZ) was measured by a dual-isotope tracer ratio technique, and endogenous fecal zinc (EFZ) was measured by an isotope dilution technique. RESULTS: No group or sex differences were found. Therefore, results were combined for 43 toddlers aged 19-25 mo whose major food staple was white rice. Selected results (x+/- SD) were 1.86 +/- 0.55 mg total dietary Zn/d; 0.35 +/- 0.12 FAZ; 0.63 +/- 0.24 mg total absorbed Zn/d; 0.67 +/- 0.23 mg EFZ/d; and 65.0 +/- 8.3 microg plasma Zn/dL. The molar ratio of dietary phytate to zinc was 2.7:1. CONCLUSIONS: The mean intake and absorption of zinc in this population are low in comparison with estimated average dietary and physiologic requirements for zinc, and plasma zinc values are consistent with zinc deficiency. Intestinal losses of endogenous zinc exceed previous estimates for toddlers, and only modest evidence exists of conservation in response to low zinc intake and absorption.

Dysprosium as a nonabsorbable fecal marker in studies of zinc homeostasis.

BACKGROUND: Dysprosium is a nonabsorbable rare earth element that has had successful application as a marker for fecal excretion of unabsorbed zinc. OBJECTIVE: Our goals were 1) to evaluate the efficacy of administering dysprosium with all meals over several days as a method of determining the completeness of fecal collections, 2) to determine the similarity of gastrointestinal transit kinetics and excretion patterns of dysprosium and zinc tracer administered simultaneously over several days, and 3) to evaluate alternative methods of using the data for fecal excretion of orally administered zinc tracer and dysprosium to measure the fractional absorption of zinc. DESIGN: 70Zn and dysprosium were administered orally with all meals for 5 consecutive days to 7 healthy, free-living adults consuming a constant diet based on habitual intake. Additional tracers, 67Zn and 68Zn, were administered intravenously. Urine and fecal samples were collected during tracer administration and for 8 d after the last dose. Isotope ratios were measured in urine and feces, and total zinc and dysprosium were measured in fecal samples. RESULTS: The mean recovery of dysprosium was 101.3 +/- 2.4%. The zinc oral tracer and dysprosium had similar fecal excretory patterns; the correlation coefficient for 70Zn and dysprosium in fecal samples exceeded 0.99 (P < 0.0001) for each subject. Fractional zinc absorption measurements using various dysprosium methods correlated well (r > 0.95) with those from the fecal monitoring and dual-isotope-tracer ratio methods. CONCLUSION: Administration of dysprosium is a useful means of determining the completeness of fecal collections and of measuring zinc absorption.