Selenium intakes and plasma selenium of New Zealand toddlers: secondary analysis of a randomised controlled trial.

Little is known about Se intakes and status in very young New Zealand children. However, Se intakes below recommendations and lower Se status compared with international studies have been reported in New Zealand (particularly South Island) adults. The Baby-Led Introduction to SolidS (BLISS) randomised controlled trial compared a modified version of baby-led weaning (infants feed themselves rather than being spoon-fed), with traditional spoon-feeding (Control). Weighed 3-d diet records were collected and plasma Se concentration measured using inductively coupled plasma mass spectrometry (ICP-MS). In total, 101 (BLISS n 50, Control n 51) 12-month-old toddlers provided complete data. The OR of Se intakes below the estimated average requirement (EAR) was no different between BLISS and Control (OR: 0·89; 95 % CI 0·39, 2·03), and there was no difference in mean plasma Se concentration between groups (0·04 µmol/l; 95 % CI -0·03, 0·11). In an adjusted model, consuming breast milk was associated with lower plasma Se concentrations (-0·12 µmol/l; 95 % CI -0·19, -0·04). Of the food groups other than infant milk (breast milk or infant formula), 'breads and cereals' contributed the most to Se intakes (12 % of intake). In conclusion, Se intakes and plasma Se concentrations of 12-month-old New Zealand toddlers were no different between those who had followed a baby-led approach to complementary feeding and those who followed traditional spoon-feeding. However, more than half of toddlers had Se intakes below the EAR.

Iodine Status of New Zealand Elderly Residents in Long-Term Residential Care.

In response to the re-emergence of iodine deficiency in New Zealand, in 2009 the government mandated that all commercially made breads be fortified with iodized salt. There has been no evaluation of the impact of the program on iodine status of the elderly, despite this population group being vulnerable to iodine deficiency or excess. The aim of this study was to describe the iodine status of elderly New Zealanders in residential aged-care homes following the implementation of the bread fortification program. A cross-sectional survey was conducted, involving 309 residents (median age 85 years) from 16 aged-care homes throughout NZ. Information on socio-demographic, anthropometric, dietary and health characteristics were collected. Casual spot urine samples were analysed for urinary iodine concentration (UIC). Blood samples were analysed for serum thyroglobulin, thyroglobulin antibodies, and other biochemical indices. The median UIC (MUIC) of the residents was 72 µg/L, indicating mild iodine deficiency, and 29% had a UIC < 50 µg/L. Median thyroglobulin concentration was 18 ng/mL and 26% had elevated thyroglobulin concentration (>40 ng/mL), suggesting iodine insufficiency. Diuretic use was associated with lower MUIC (p = 0.043). Synthetic thyroxine use was associated with lower odds of having a UIC < 50 µg/L (OR 0.32, p = 0.030)) and lower median thyroglobulin (-15.2 ng/mL, p = 0.001), compared with untreated participants. Frailty was associated with elevated thyroglobulin (p = 0.029), whereas anemia was associated with lower thyroglobulin (p = 0.016). Iodine insufficiency persists in New Zealanders residing in residential aged-care homes despite increasing iodine intake from fortified bread. Research is required to establish optimal iodine intake and status in the elderly.

Serum Zinc Is a Major Predictor of Anemia and Mediates the Effect of Selenium on Hemoglobin in School-Aged Children in a Nationally Representative Survey in New Zealand.

BACKGROUND: Zinc, selenium, and vitamin D status of New Zealand (NZ) school-aged children was examined in a national survey in 2002. To our knowledge, however, the role of these micronutrients as predictors of hemoglobin has not been explored despite plausible mechanisms for such relations. OBJECTIVE: We examined the relations of iron, zinc, selenium, and vitamin D status with hemoglobin and anemia in children of New Zealand European and other (NZEO) ethnicity enrolled in the 2002 Children's Nutrition Survey and explored whether zinc mediated the relation between selenium and hemoglobin. METHODS: Multivariate regression was performed to examine the relations of serum micronutrient biomarkers, acute inflammation, socioeconomic status, and body mass index (BMI) with hemoglobin and anemia of NZEO children aged 5-15 y (n = 503). A mediation analysis also investigated direct and indirect (through zinc) relations between selenium and hemoglobin. RESULTS: In total, 4.6% of the children were anemic, 3.2% had depleted iron stores, and none had iron deficiency anemia. The prevalence of low serum zinc (<8.7-10.1 µmol/L depending on age and sex), selenium (<0.82 µmol/L), and 25-hydroxyvitamin D (<50 nmol/L) was 14.1%, 22.9%, and 48.5%, respectively. Major predictors of hemoglobin were serum zinc, age, and BMI-for-age z score (P < 0.001); log ferritin and being female were also statistically significant (P < 0.05). Selenium had an indirect effect that was mediated by zinc, with a significant effect of selenium on zinc (P = 0.002) and zinc on hemoglobin (P < 0.001). Zinc was the only variable associated with anemia risk (OR: 5.49; 95% CI: 1.95, 15.46). CONCLUSIONS: Low serum zinc was an independent risk factor for anemia in NZEO school-aged children and mediated the effect of low selenium on hemoglobin. These findings emphasize the importance of considering multiple micronutrient deficiencies in addition to iron when interpreting anemia and of appreciating the mechanistic interactions that underlie these associations.

Effects of anemia at different stages of gestation on infant outcomes.

OBJECTIVES: Maternal anemia is a public health challenge worldwide. The present study aims to explore the effects of maternal anemia at different stages of gestation on postnatal growth and neurobehavioral development in infants. METHODS: A cohort of pregnant Indian women were followed from 13 to 22 wk gestation (i.e., second trimester; n = 211), 29 to 42 wk gestation (i.e., third trimester; n = 178); their infants were followed to ∼3 wk (n = 147) postpartum. Data collected included information on sociodemographic and health-related factors, including anemia (i.e., low hemoglobin status), maternal and infant anthropometric data, and infant neurobehavioral data. A mixed logistic regression model was used to examine the impact of anemia during pregnancy on maternal and infant outcomes (i.e., anthropometric growth parameters and infant neurobehavioral development). RESULTS: The prevalence of maternal anemia was 41% and 55% (P < 0.001), and iron deficiency anemia was 3.6% and 5.6%, respectively, in the second trimester and third trimester. Infants of pregnant women who were not anemic in the second trimester were 0.26 standard deviations (SD) heavier (P = 0.029), 0.50 SD taller (P = 0.001), and had 0.26 SD larger head circumference (P = 0.029) compared with infants of anemic pregnant women. Infants of pregnant women who were not anemic in the third trimester had orientation scores 3.88 higher (P = 0.004) than infants of women who were anemic. CONCLUSIONS: Our findings indicate that maternal anemia in the second trimester of gestation influences postnatal infant growth and underscores the necessity of alleviating anemia in young women in the early stages of gestation.

Dietary and non-dietary factors associated with serum zinc in Indian women.

Women in low-income settings, common in India, are at risk of inadequate zinc intake due to poor diet quality and low consumption of flesh foods rich in zinc. The aims of this study were to assess the prevalence of zinc status of non-pregnant rural and tribal women living in central India and to identify dietary and non-dietary factors associated with the biochemical zinc status of these women. Rural and tribal non-pregnant women 18-30 years of age were selected using proportion to population sampling near Nagpur, Maharashtra, India. Sociodemographic, biochemical (serum zinc), clinical, and dietary data (1-day interactive 24-h recall) were collected. The mean age of women (n = 109; rural = 52; tribal = 56) was 23.2 years and mean BMI was 17.9 kg/m(2). The majority of the participants identified as being non-vegetarian (72 %). The mean ± SD serum zinc concentration was 10.8 ± 1.6 µmol/L, and 52 % of participants had a low serum zinc concentration according to the International Zinc Nutrition Consultative Group (IZiNCG). The median (first and third quartile) energy, zinc intake, and phytate/zinc molar ratio was 5.4 (4.2, 6.7) MJ/day, 5.3 (3.8, 7.0) mg/day, and 26 (22, 28), respectively. Zinc intakes were well below IZiNCG recommendations for dietary zinc of 9 mg/day for non-pregnant women aged 14-18 years and 7 mg/day for non-pregnant women aged ≥ 19 years. Using linear regression analysis to identify non-dietary and dietary factors associated with serum zinc, a significant association was only found for current lactation (p = 0.012) and energy intake (p < 0.001). Diets low in energy with poor bioavailability of dietary zinc are likely to be the primary cause of the high proportion of Indian women with zinc deficiency.

Iron status of pregnant Indian women from an area of active iron supplementation.

OBJECTIVE: The aim of this study was to investigate the iron status of pregnant tribal women from Ramtek, Nagpur, Maharashtra, India using a combination of indices. METHODS: A community-based observational study was conducted to assess iron status using a convenience sample of pregnant Indian tribal women from Ramtek. Pregnant women were recruited at 13 to 22 wk gestation (first visit; n = 211) and followed to 29 to 42 wk gestation (second visit; n = 177) of pregnancy. Sociodemographic and anthropometric data; iron supplement intake; and blood samples for estimating hemoglobin (Hb), serum ferritin (SF), soluble transferrin receptor (sTfR), and C-reactive protein (CRP) were obtained. RESULTS: The mean (SD) Hb concentration at recruitment was 106 (15) g/L and 106 (14) g/L at the second visit; 41% of the women at recruitment and 55% at second visit were anemic (14% higher, P < 0.001). No women at recruitment and 3.7% at second visit had SF concentration < 15 ng/mL; and 3.3% at recruitment and 3.9% at the second visit had sTfR > 4.4 ng/mL (0.6% higher, P = 0.179). Almost 62% and 71% of pregnant women used iron supplements at both visits, respectively. Iron supplement intake > 7 d in the preceding month improved the Hb concentration by 3.23 g/L and reduced sTfR concentration by 13%; women who were breastfeeding at the time of recruitment had 11% higher SF concentration. CONCLUSIONS: The iron indices suggest that pregnant tribal women of central India, although anemic, had good iron status. Use of iron supplements > 7 d in the preceding month improved iron status; however, non-iron-deficiency anemia persisted in this group.

Influence of the glutathione peroxidase 1 Pro200Leu polymorphism on the response of glutathione peroxidase activity to selenium supplementation: a randomized controlled trial.

BACKGROUND: A genetic variant at codon 200 (Pro200Leu) of the gene encoding for glutathione peroxidase 1 (GPx1), a selenium-dependent enzyme, is associated with lower enzyme activity; however, the evidence is limited to in vitro and observational studies. OBJECTIVE: The objective was to determine whether the GPx1 Pro200Leu genetic variants modify the response of whole-blood glutathione peroxidase (GPx) activity to selenium supplementation in patients with coronary artery disease in New Zealand. DESIGN: The results from 2 parallel-design, double-blind trials were combined. Participants were randomly assigned to receive a daily supplement of 100 µg Se as l-selenomethionine (n = 129) or placebo (n = 126) for 12 wk. Plasma selenium and whole-blood GPx activity were measured at baseline and at week 12. Participants were genotyped for the GPx1 Pro200Leu polymorphism. RESULTS: Selenium supplementation increased whole-blood GPx activity by 5 (95% CI: 4, 7) U/g hemoglobin (P < 0.001); however, the magnitude of the increase did not differ by genotype (P = 0.165 for treatment-by-genotype interaction). In an exploratory analysis, a significant nutrient-gene interaction was apparent when baseline plasma selenium concentrations were included in the regression model (P = 0.006 for treatment-by-genotype × baseline selenium concentration interaction). Increases in GPx activity were 2-fold higher in Pro homozygotes than in participants carrying a Leu allele when baseline selenium concentrations were ≤1.15 µmol/L (P < 0.05). CONCLUSIONS: These results indicate that GPx1 Pro200Leu variants do not substantially modify the response of whole-blood GPx to selenium supplementation in individuals with relatively high plasma selenium concentrations. A nutrient-gene interaction was observed when the baseline selenium concentration was low, but this requires independent confirmation. This trial was registered at www.actr.org.au as ACTRN12605000412639 and ACTRN12606000197538.

A comprehensive assessment of urinary iodine concentration and thyroid hormones in New Zealand schoolchildren: a cross-sectional study.

BACKGROUND: Insufficient iodine in children's diets is of concern because thyroid hormones are needed for normal growth and development, particularly of the brain. This study aimed to carry out a comprehensive assessment of the iodine status of New Zealand schoolchildren using a range of biochemical indices suitable for populations (i.e. urinary iodine concentration) and individuals (i.e. thyroid hormones). METHODS: The New Zealand National Children's Nutrition Survey was a cross-‒sectional survey of a representative sample of schoolchildren aged 5-‒14 years. Children were asked to provide a casual urine sample for the determination of urinary iodine concentration (UIC) and a blood sample for the determination of thyroglobulin (Tg), Thyroid Stimulating Hormone (TSH), free thyroxine (fT4) and free triiodothyronine (fT3). RESULTS: The median UIC was 68 µg/L (n = 1153), which falls between 50-‒99 µg/L indicative of mild iodine deficiency. Furthermore, 29% of children had an UIC <50 µg/L and 82% had an UIC <100 µg/L. The median Tg concentration was 12.9 µg/L, which also falls between 10.0-‒19.9 µg/L indicative of mild iodine deficiency. The Tg concentration of children with an UIC <100 µg/L was 13.9 µg/L, higher than the 10.3 µg/L in children with an UIC >100 µg/L (P = 0.001). The mean TSH (1.7 mU/L), fT4 (14.9 pmol/L), and fT3 (6.0 pmol/L) concentrations for these mildly iodine deficient New Zealand children fell within normal reference ranges. CONCLUSIONS: The UIC and Tg concentration indicate that New Zealand schoolchildren were mildly iodine deficient according to WHO/UNICEF/ICCIDD, and both are suitable indices to assess iodine status in populations or groups. The normal concentrations of TSH, fT4 and fT3 of these children suggest that these thyroid hormones are not useful indices of mild iodine deficiency.

Plasma selenium concentrations in pregnant women in two countries with contrasting soil selenium levels.

PROJECT: Selenium has an important role in antioxidant defense and cell mediated immunity. Plasma selenium is a useful biomarker for comparing selenium status across populations, and influenced by selenium levels of soils and plants. PROCEDURE: This cross-sectional study compared plasma selenium (by electrothermal atomic absorption spectrophotometry) of women at 24 weeks gestation in Malawi (n=152) and the Philippines (n=301), countries with low and high soil selenium levels, respectively. Data on anthropometry, smoking, intakes of energy, nutrients and food groups (via 24-h recalls), hemoglobin, serum zinc, and C-reactive protein (CRP) were also collected. RESULTS: Mean (95% CI) plasma selenium was lower for Malawian than Filipino women (0.79, 0.77, 0.82 µmol/L vs. 1.44, 1.41, 1.47 µmol/L; p<0.001); 83% had concentrations below 1.0 µmol/L compared to 3% in the Filipinos. Cereals provided 78% and 67% of the energy in Malawi and the Philippines, respectively compared to 4% and 8.5%, respectively for cellular animal protein. Plasma selenium was correlated modestly with BMI (r=-0.138; p=0.096) and elevated CRP (>5.0 mg/L) (r=-0.143; p=0.084) in Malawi, and significantly with intake of cellular animal protein (g/d) (r=0.23; p=0.020) and serum zinc (r=0.13; p=0.044) in the Philippines. No comparable relationships were observed in either group for smoking, hemoglobin, or cereal intakes. CONCLUSION: Differences in plasma selenium paralleled reported trends in selenium concentrations in soils and staple cereals in Malawi and the Philippines. The biological significance of the lower plasma selenium for the Malawian women, and the extent to which they pose a risk for fetal and neonatal development, is uncertain.

The effect of maternal iodine status on infant outcomes in an iodine-deficient Indian population.

BACKGROUND: An adequate intake of iodine during pregnancy is essential for the synthesis of maternal thyroid hormones needed to support normal fetal development. This study aimed to assess the iodine status of pregnant tribal Indian women and their infants and to determine the impact of maternal iodine status on infant growth and behavior. METHODS: A prospective, observational study was undertaken to assess the iodine status of tribal pregnant Indian women living in Ramtek, northeast of Nagpur, India. Pregnant women were recruited at 13-22 weeks gestation (n=220), visited a second time at 33-37 weeks gestation (n=183), and again visited at 2-4 weeks postpartum with their infants. Sociodemographic, anthropometric, and biochemical data, including household salt, blood, and urine samples were obtained from pregnant women. Urine samples, anthropometric, and neonatal behavioral data were collected from infants. RESULTS: The median urinary iodine concentration (MUIC) at recruitment (mean gestation=17.5 weeks) of mothers was 106 µg/L, which declined to 71 µg/L at the second visit (mean gestation=34.5 weeks) similar to the postpartum MUIC of 69 µg/L, indicating that these women were iodine deficient. Infant (mean age=2.5 weeks) MUIC was 168 µg/L. Median maternal thyroid stimulating hormone (TSH) and free thyroxine (FT(4)) concentrations at first and second visits were 1.71 and 1.79 mIU/L and 14.4 and 15.4 pmol/L, respectively; 20.0% of women at first visit had TSH >97.5th percentile and 1.4% had FT(4) <2.5th percentile. Salt iodine concentration was a significant predictor of maternal UIC (p<0.001), and postpartum maternal UIC was a significant predictor of infant UIC (p<0.001). For every pmol/L increase in maternal FT(4) concentration at first visit, both infant weight-for-age Z-score and length-for-age Z-score increased by 0.05 units. There was no relationship between maternal UIC, FT(4), or TSH at first visit and neonatal behavior. CONCLUSIONS: Despite three quarters of the women in this study having access to adequately iodized salt (i.e., >15 ppm), these pregnant tribal Indian women were iodine deficient. Increasing the iodine content of salt deemed adequately iodized and iodine supplementation are two strategies that might improve the iodine status of these pregnant women and, consequently, the growth of their infants.

Minimal impact of excess iodate intake on thyroid hormones and selenium status in older New Zealanders.

OBJECTIVE: Iodine deficiency has re-emerged in New Zealand, while selenium status has improved. The aim of this study was to investigate the effects of excess iodine intake as iodate on thyroid and selenium status. METHODS: In a randomized controlled trial on older people (mean±s.d. 73±4.8 years; n=143), two groups received >50  mg iodine as iodate/day for 8 weeks because of supplement formulation error, either with 100  µg selenium (Se+highI) or without selenium (highI). Four other groups received 80  µg iodine as iodate/day with selenium (Se+lowI) or without selenium (lowI), selenium alone (Se+), or placebo. Thyroid hormones, selenium status, and median urinary iodine concentration (MUIC) were compared at weeks 0, 8, and 4 weeks post-supplementation. RESULTS: MUIC increased nine- and six-fold in Se+highI and highI groups, decreasing to baseline by week 12. Plasma selenium increased in selenium-supplemented groups (P<0.001). The level of increase in whole blood glutathione peroxidase (WBGPx) in the Se+highI group was smaller than Se+ (P=0.020) and Se+lowI (P=0.007) groups. The decrease in WBGPX in the highI group was greater than other non-selenium-supplemented groups, but differences were not significant. Ten of 43 participants exposed to excess iodate showed elevated TSH (hypothyroidism) at week 8. In all but two, TSH had returned to normal by week 12. In three participants, TSH decreased to <0.10  mIU/l (hyperthyroidism) at week 8, remaining low at week 12. CONCLUSIONS: Excess iodate induced hypothyroidism in some participants and hyperthyroidism in others. Most abnormalities disappeared after 4 weeks. Excess iodate reduced WBGPx activity and resulted in smaller increases in WBGPx after selenium supplementation.

Consumption of salmon v. salmon oil capsules: effects on n-3 PUFA and selenium status.

Salmon provides long-chain (LC) n-3 PUFA and Se, which are well recognised for their health benefits. The n-3 and Se status of the New Zealand population is marginal. The objective of the present study was to compare the effects of consuming salmon v. supplementation with salmon oil on LC n-3 and Se status. Healthy volunteers (n 44) were randomly assigned to one of four groups consuming 2 × 120 g servings of salmon/week or 2, 4 or 6 salmon oil capsules/d for 8 weeks. Linear regression analysis predictive models were fitted to the capsule data to predict changes in erythrocyte LC n-3 levels with intakes of LC n-3 from capsules in amounts equivalent to that consumed from salmon. Changes in Se status (plasma Se and whole-blood glutathione peroxidase) were compared between the groups consuming salmon and capsules (three groups combined). Salmon, 2, 4 and 6 capsules provided 0·82, 0·24, 0·47 and 0·69 g/d of LC n-3 fatty acids. Salmon provided 7 µg/d and capsules < 0·02 µg/d of Se. The predictive model (r(2) 0·31, P = 0·001) showed that increases in erythrocyte LC n-3 levels were similar when intakes of 0·82 g/d LC n-3 from salmon or capsules (1·92 (95 % CI 1·35, 2·49) v. 2·32 (95 % 1·76, 2·88) %) were consumed. Plasma Se increased significantly more with salmon than with capsules (12·2 (95 % CI 6·18, 18·12) v. 1·57 (95 % CI - 2·32, 5·45) µg/l, P = 0·01). LC n-3 status was similarly improved with consumption of salmon and capsules, while consuming salmon had the added benefit of increasing Se status. This is of particular relevance to the New Zealand population that has marginal LC n-3 and Se status.

Metabolism of L-selenomethionine and selenite by probiotic bacteria: in vitro and in vivo studies.

Since selenium supplements have been shown to undergo biotransformation in the gut, probiotic treatment in combination with selenium supplements may change selenium disposition. We investigated the metabolism of L-selenomethionine (SeMet) and selenite by probiotic bacteria in vitro and the disposition of selenium after probiotic treatment followed by oral dosing with SeMet and selenite in rats. When SeMet was incubated anaerobically with individual antibiotic-resistant probiotic strains (Streptococcus salivarius K12, Lactobacillus rhamnosus 67B, Lactobacillus acidophilus L10, and Bifidobacterium lactis LAFTI® B94) at 37°C for 24 h, 11-18% was metabolized with 44-80% of SeMet lost being converted to dimethyldiselenide (DMDSe) and dimethylselenide (DMSe). In similar incubations with selenite, metabolism was more extensive (26-100%) particularly by the lactobacilli with 0-4.8% of selenite lost being converted to DMSe and DMDSe accompanied by the formation of elemental selenium. Four groups of rats (n = 5/group) received a single oral dose of either SeMet or selenite (2 mg selenium/kg) at the time of the last dose of a probiotic mixture or its vehicle (lyoprotectant mixture used to maintain cell viability) administered every 12 h for 3 days. Another three groups of rats (n = 3/group) received a single oral dose of saline or SeMet or selenite at the same dose (untreated rats). Serum selenium concentrations over the subsequent 24 h were not significantly different between probiotic and vehicle treated rats but appeared to be more sustained (SeMet) or higher (selenite) than in the corresponding groups of untreated rats. Probiotic treated rats given SeMet also had selenium concentrations at 24 h that were significantly higher in liver and lower in kidney than untreated rats given SeMet. Thus, treatment with probiotics followed by SeMet significantly affects tissue levels of selenium.

Biotransformation of L-selenomethionine and selenite in rat gut contents.

L-selenomethionine (SeMet) and sodium selenite are widely used selenium nutritional supplements with potential benefit in preventing cancer. However, supplementation is not without risks of toxicity if intake is too high. The aim of the present study was to investigate SeMet and selenite metabolism in the gastrointestinal tract with particular focus on the formation of the volatile selenium excretion products, dimethylselenide (DMSe) and dimethyldiselenide (DMDSe). Adult male Wistar rats (n = 5) were euthanized, their intestinal tracts removed and the contents of jejunum, ileum, caecum and colon used to prepare 10% suspensions in saline. SeMet and selenite (0.5-0.6 mM) were then incubated with these suspensions at 37°C for 3 h. Caecum and colon contents were the most metabolically active towards SeMet with 30% and 15% metabolized over 3 h. DMDSe was the only volatile selenium metabolite detected accounting for 8.7 ± 1.3% of the selenium lost in caecum contents. Selenite was completely metabolized by caecum contents and 73% by colon contents under the same conditions forming DMSe (5.7 ± 0.9% of the selenium lost in caecum) and a precipitate of red amorphous elemental selenium. Based on previous literature and these results, we conclude that the gut microbiota contributes to the excretion of excess selenium through the production of methylated selenium compounds and elemental selenium.

Concurrent micronutrient deficiencies are prevalent in nonpregnant rural and tribal women from central India.

OBJECTIVE: The existence of concurrent micronutrient deficiencies in Indian women of reproductive age has received little attention. This study aimed to comprehensively assess the micronutrient status of nonpregnant rural and tribal women 18-30 y from central India. METHODS: Participants (n = 109) were randomly selected using a stratified (rural-tribal) proportionate-to-population size cluster sampling method from 12 subcenters in Ramtek block, Nagpur. Sociodemographic, anthropometric, dietary, and biochemical data, including blood and urine samples, were obtained. RESULTS: Tribal and rural women had similar sociodemographic characteristics and anthropometric status; 63% of women had a body mass index <18.5 kg/m(2). The median urinary iodine concentration was 215 µg/L (IQR: 127, 319). The mean (SD) concentration of hemoglobin, serum zinc, retinol, and folate was 112 (13) g/L, 10.8 (1.6) µmol/L, 1.2 (0.3) µmol/L, 18.4 (8.4) nmol/L, respectively, with a geometric mean serum vitamin B(12) concentration of 186 pmol/L. The percentage of women with low values for hemoglobin (<120 g/L), serum zinc (<10.7 µmol/L), vitamin B(12) (<148 pmol/L), retinol (<0.7 µmol/L), and folate (<6.8 nmol/L) was 66%, 52%, 34%, 4%, and 2%, respectively. Tribal women had a higher prevalence of zinc deficiency (58% versus 39%, P = 0.054) and concurrent deficiency of any two micronutrients (46% versus 26%; P = 0.034), including zinc and anemia (38% versus 21%, P = 0.024). CONCLUSION: Zinc, vitamin B(12), and iron constitute the principal micronutrient deficiencies in these women. Existing supplementation programs should be extended to include 18- to 30-y-old nonpregnant women as the majority of childbearing occurs within this timeframe.

Selenium and iodine supplementation: effect on thyroid function of older New Zealanders.

BACKGROUND: The New Zealand population has both marginal selenium status and mild iodine deficiency. Adequate intakes of iodine and selenium are required for optimal thyroid function. OBJECTIVE: The aim of the study was to determine whether low selenium and iodine status compromises thyroid function in an older New Zealand population. DESIGN: We investigated the effects of selenium and iodine supplementation in a double-blind, randomized, placebo-controlled trial in 100 Dunedin volunteers aged 60-80 y. Participants received 100 microg Se/d as l-selenomethionine, 80 microg I, 100 microg Se + 80 microg I, or placebo for 3 mo. Thyroid-stimulating hormone (TSH), free triiodothyronine (T(3)), free thyroxine (T(4)), thyroglobulin, plasma selenium, whole-blood glutathione peroxidase (GPx) activity, and urinary iodine concentrations (UICs) were measured. RESULTS: Plasma selenium (P < 0.0001) and whole-blood GPx activity (P<0.0001) increased from baseline to week 12 in the selenium and selenium plus iodine groups in comparison with the placebo group. Median UIC at baseline was 48 microg/L (interquartile range: 31-79 microg/L), which is indicative of moderate iodine deficiency. UIC increased in the iodine and selenium plus iodine groups and was significant only for the iodine group (P = 0.0014). Thyroglobulin concentration decreased by 24% and 13% of baseline in the iodine and selenium plus iodine groups in comparison with the placebo group (P = 0.009 and P = 0.108, respectively). No significant treatment effects were found for TSH, free T(3), free T(4), or ratio of T(3) to T(4). CONCLUSIONS: Additional selenium improved GPx activity but not the thyroid hormone status of older New Zealanders. Iodine supplementation alleviated the moderate iodine deficiency and reduced elevated thyroglobulin concentrations. No synergistic action of selenium and iodine was observed. The trial was registered at www.anzctr.org.au/registry/ as ACTRN012605000368639.

An improved HPLC method for the investigation of L-selenomethionine metabolism in rat gut contents.

Selenomethionine (SeMet) is a widely used nutritional supplement that has potential benefit for people living in selenium-deficient areas. Previous research has shown that selenium administered as SeMet undergoes significant enterohepatic recycling which may involve the gut microflora. In order to investigate this we have developed a simple method for the quantitation of l-SeMet in rat gut content suspensions prepared from jejunum, ileum, caecum and colon. After incubation of l-SeMet with gut content suspensions, samples were deproteinized with sulfosalicylic acid and derivatized with o-phthaldialdehyde (OPA) and N-acetyl-l-cysteine (NAC). Mass spectrometry confirmed the formation of a 1:1:1 derivative of l-SeMet with OPA and NAC. Samples were analysed by reversed-phase high-performance liquid chromatography with fluorescence detection. The assay was linear in the concentration range 0.5-100 microg/mL (r(2) = 0.9992) with a limit of detection of 0.025 microg/mL (signal-to-noise ratio of 5). Intra-day and inter-day accuracies were 91.1-92.8 and 91.7-95.5%, respectively with corresponding precisions as relative standard deviation of <5%. Incubation of l-SeMet with gut content suspensions from different parts of the rat intestine showed that l-SeMet metabolism occurs mainly in the caecum.

Iodine status in a Sherpa community in a village of the Khumbu region of Nepal.

OBJECTIVE: To assess the iodine status of Sherpa residents living in Kunde village, Khumbu region, Nepal. DESIGN: Prevalence of goitre was determined by palpation. Urinary iodine concentrations (UIC) were determined in casual morning samples, and thyroid-stimulating hormone (TSH) in finger-prick blood samples on filter paper. Dietary and demographic data were obtained via questionnaire, and selected foods analysed for iodine. SETTING: Khumbu region is an area of low soil iodine in Nepal, where the prevalence of goitre was greater than 90% in the 1960s prior to iodine intervention. SUBJECTS: Two hundred and fifteen of 219 permanent residents of Kunde were studied. RESULTS: Overall prevalence of goitre was 31% (Grade 1 goitre, 27.0%; Grade 2, 4.2%). When adjusted to a world population, goitre prevalence was 27% (95% CI 23, 32%); Grade 2 goitre prevalence was 2.8% (95% CI 1.0, 4.6%). Median UIC was 97 microg/l, but only 75 microg/l in women of childbearing age. Thirty per cent had UIC < 50 microg/l and 52% had UIC < 100 microg/l, while 31% of children aged <14 years had UIC > 300 microg/l. Ten per cent of participants had TSH concentrations >5 microU/ml. CONCLUSIONS: The prevalence of severe iodine deficiency has decreased since the 1960s, but mild iodine deficiency persists, particularly in women of childbearing age. The consumption of high-iodine uncooked instant noodles and flavour sachets by school-aged children contributed to their low prevalence of goitre and excessive UIC values. This finding may obscure a more severe iodine deficiency in the population, while increasing the risk of iodine-induced hyperthyroidism in children. Ongoing monitoring is essential.

Brazil nuts: an effective way to improve selenium status.

BACKGROUND: Brazil nuts provide a rich natural source of selenium, yet no studies have investigated the bioavailability of selenium in humans. OBJECTIVE: We investigated the efficacy of Brazil nuts in increasing selenium status in comparison with selenomethionine. DESIGN: A randomized controlled trial was conducted with 59 New Zealand adults. Participants consumed 2 Brazil nuts thought to provide approximately 100 mug Se, 100 mug Se as selenomethionine, or placebo daily for 12 wk. Actual intake from nuts averaged 53 mug Se/d (possible range: 20-84 mug Se). Plasma selenium and plasma and whole blood glutathione peroxidase (GPx) activities were measured at baseline and at 2, 4, 8, and 12 wk, and effects of treatments were compared. RESULTS: Plasma selenium increased by 64.2%, 61.0%, and 7.6%; plasma GPx by 8.3%, 3.4%, and -1.2%; and whole blood GPx by 13.2%, 5.3%, and 1.9% in the Brazil nut, selenomethionine, and placebo groups, respectively. Change over time at 12 wk in plasma selenium (P < 0.0001 for both groups) and plasma GPx activity in the Brazil nut (P < 0.001) and selenomethionine (P = 0.014) groups differed significantly from the placebo group but not from each other. The change in whole blood GPx activity was greater in the Brazil nut group than in the placebo (P = 0.002) and selenomethionine (P = 0.032) groups. CONCLUSION: Consumption of 2 Brazil nuts daily is as effective for increasing selenium status and enhancing GPx activity as 100 mug Se as selenomethionine. Inclusion of this high-selenium food in the diet could avoid the need for fortification or supplements to improve the selenium status of New Zealanders.

Carbohydrate loading and female endurance athletes: effect of menstrual-cycle phase.

This study compared 3 d of carbohydrate loading (CHOL; 8.4 g x kg(-1) x d(-1) carbohydrate) in female eumenorrheic athletes with 3 d of an isoenergetic normal diet (NORM; 5.2 g x kg(-1) x d(-1) carbohydrate) and examined the effect of menstrual-cycle phase on performance, muscle-glycogen concentration [glyc], and substrate utilization. Nine moderately trained eumenorrheic women cycled in an intermittent protocol varying in intensity from 45% to 75% VO2max for 75 min, followed by a 16-km time trial at the midfollicular (MF) and midluteal (ML) phases of the menstrual cycle on NORM and CHOL. Time-trial performance was not affected by diet (CHOL 26.10 +/- 1.04 min, NORM 26.16 +/- 1.35 min; P = 0.494) or menstrual-cycle phase (MF 26.05 +/- 1.10 min, ML 26.23 +/- 1.33 min; P = 0.370). Resting [glyc] was lowest in the MF phase after NORM (575 +/- 145 mmol x kg(-1) x dw(-1)), compared with the MF phase after CHOL (728 mmol x kg(-1) x dw(-1)) and the ML phase after CHOL and NORM (756 and 771 mmol x kg(-1) x dw(-1), respectively). No effect of phase on substrate utilization during exercise was observed. These data support previous observations of greater resting [glyc] in the ML than the MF phase of the menstrual cycle and suggest that lower glycogen storage in the MF phase can be overcome by carbohydrate loading.