Development and validation of a food frequency questionnaire to assess habitual iodine intake among women of childbearing age.

BACKGROUND: Adequate iodine status is critical for thyroid hormone synthesis, which is essential for foetal brain development. Suboptimal iodine status has been reported in young women across Europe. Although urinary iodine concentration (UIC) is a good indicator of recent exposure, it does not reflect habitual iodine intake. This study aimed to develop and validate an iodine-specific food frequency questionnaire (I-FFQ) to assess habitual intake in Irish women aged 18-50 years. METHODS: A 47-item interviewer-administered I-FFQ, informed by national food consumption data on Irish women aged 18-35 years, was developed and validated in a study of 100 nonpregnant women using a 4-day weighed food diary (FD) and UIC as the reference methods. Correlation, cross-classification and Bland-Altman analyses were used to assess agreement and bias between the I-FFQ and FD. Validity coefficients were calculated using the method of triads. RESULTS: Median (interquartile range [IQR]) UIC was 82 (49, 139) µg/L. Median (IQR) intakes were 161 (106, 217) and 133 (98, 182) µg/day for the I-FFQ and FD, respectively (p = 0.001). Estimates were moderately correlated (r = 0.434), and the I-FFQ classified 89% of participants into the same or adjacent tertile of intake as the FD. Validity coefficients for the I-FFQ, FD and UIC were 0.542, 0.800 and 0.228, respectively. Though repeatability analyses 10 weeks later (n = 69) showed slight differences in estimates of intake (I-FFQ1: 164 (104, 210) µg/day; I-FFQ2: 132 (67, 237) µg/day), intakes were highly correlated between administrations (r = 0.627, p = 0.001). CONCLUSIONS: The I-FFQ provides a reasonable estimate of habitual iodine intake in young women.

Poor Quality Diets Characterized by Low-Nutrient Density Foods Observed in One-Quarter of 2-Year-Olds in a High Resource Setting.

BACKGROUND: Young children have high nutritional requirements relative to their body size, making healthy diets critical for normal growth and development. OBJECTIVE: We aimed to integrate analysis of dietary patterns among 2-y-old children with indicators of dietary quality, micronutrient status, and body weight status. METHODS: Data from the 2-y follow-up of the Cork BASELINE Birth Cohort included dietary assessment using a 2-d weighed food diary, vitamin D and iron status biomarkers, and anthropometry (n = 468). K-means cluster analysis identified predominant dietary patterns based on energy contributions and associations with nutrient intakes and status and body weight were investigated. RESULTS: Four dietary patterns emerged: "Cows' milk" (unmodified cows' milk: 32% of total energy (TE)); "Traditional" (wholemeal breads, butter, fresh meat, fruit); "Low Nutrient Density (LND) foods" (confectionary, processed meat, convenience foods) and "Formula" (young child formula: 23%TE). The LND pattern was associated with excessive free sugar intake (14%TE) and salt intake (153% of daily limit). No differences in patterns of overweight were observed between the 4 groups; however, the LND group had 3-fold higher odds of being underweight [aOR (95% CI): 3.2 (1.2, 8.5)]. Children consuming >400ml/d of cows' milk or formula exhibited lower dietary variety, fewer family-type meals, and continued use of feeding bottles (75% and 81%, respectively, vs. 35-37% in the other groups). CONCLUSIONS: Unhealthy eating habits are common among young children. Dietary guidance to support families to provide healthy diets needs to maintain currency with eating habits and focus on food choices for meals, snacks, and beverages.

Iron, iodine and vitamin D deficiencies during pregnancy: epidemiology, risk factors and developmental impacts.

Micronutrient deficiency persists throughout the world, and although the burden is higher in low-resource settings, it is also prevalent in wealthy countries, a phenomenon termed 'hidden hunger'. Due to their high requirements for vitamins and minerals relative to their energy intake, young women and children are particularly vulnerable to hidden hunger. As they share several risk factors and impact on overlapping outcomes, we consider how deficiency of iron, iodine and vitamin D can have profound impacts on perinatal health and infant development. We review the epidemiology of these micronutrient deficiencies during pregnancy, including social, environmental and dietary risk factors. We identify the main challenges in defining nutritional status of these nutrients using validated diagnostic criteria linked with meaningful clinical outcomes. Public health strategies are urgently required to improve the overall health and nutritional status of women of reproductive age. Obesity prevention and early detection of malnutrition with standardised screening methods would detect pregnant women at increased risk of iron deficiency. Development of sensitive, individual biomarkers of iodine status is required to protect maternal health and fetal/infant brain development. Risk assessments of vitamin D requirements during pregnancy need to be revisited from the perspective of fetal and neonatal requirements. International consensus on standardised approaches to micronutrient assessment, analysis and reporting as well as sensitive, clinically validated infant and child neuro-behavioural outcomes will enable progression of useful observational and intervention studies.

Antenatal vitamin D exposure and childhood eczema, food allergy, asthma and allergic rhinitis at 2 and 5 years of age in the atopic disease-specific Cork BASELINE Birth Cohort Study.

BACKGROUND: Prospective studies of antenatal and infant vitamin D exposure and atopic disease from extensively characterised, disease-specific, maternal-infant cohorts with gold standard analysis of vitamin D status and clinically validated atopic outcomes are lacking. This study aimed to investigate associations between intrauterine vitamin D status and atopic outcomes in an extensively characterised, disease-specific, maternal-infant cohort. METHODS: Circulating 25-hydroxyvitamin D (25(OH)D) was measured in maternal sera at 15 weeks of gestation (n = 1537) and umbilical cord blood (n = 1050) using a CDC-accredited LC-MS/MS platform, and the association with clinically validated atopic disease outcomes (eczema, food allergy, asthma, allergic rhinitis) at 2 and 5 years was explored using multivariable logistic regression. RESULTS: Persistent eczema in the first 2 years of life was present in 5% of infants. Food allergy at 2 years was confirmed in 4%. The prevalence of aeroallergen sensitisation at 2 years was 8%. Asthma at 5 years was reported in 15% and allergic rhinitis in 5% of 5-year-olds. There were no significant differences in the distributions of maternal 25(OH)D at 15 weeks of gestation (mean [SD] 58.4 [26.2] and 58.5 [26.1] nmol/L) and cord 25(OH)D concentrations (mean [SD] 35.2 [17.8] and 35.4 [18.3] nmol/L) between children with and without atopic disease. Neither maternal (aOR [95% CI]: 1.02 [0.97, 1.08], P = 0.450) nor cord 25(OH)D (aOR [95% CI]: 1.00 [0.91, 1.09], P = 0.991) were significant predictors of atopic disease outcomes in fully adjusted models. CONCLUSION: These data in a disease-specific cohort with prospectively collected, validated atopic outcomes do not support an association between antenatal exposure to vitamin D and atopic disease outcomes in childhood.

Central haemodynamics in normal pregnancy: a prospective longitudinal study.

OBJECTIVE: To conduct a longitudinal evaluation of the central haemodynamic adaptations of normal pregnancy. METHODS: This was a prospective longitudinal study involving healthy, normotensive women who were having an uncomplicated, singleton pregnancy. Brachial and central SBP, DBP, mean arterial pressure (MAP), brachial and central pulse pressure (PP), aorta-to-brachial pulse pressure amplification (AMPA-B), heart rate (HR), augmentation index adjusted for HR (AIx75), carotid-femoral pulse wave velocity (cfPWV) and cardiac output (CO) were measured at a mean gestational age of 14, 24 and 36 weeks. RESULTS: One hundred women were followed prospectively throughout pregnancy. Brachial and central SBP, DBP and MAP decreased slightly in early gestation, followed by a significant increase in late gestation (P < 0.05). Brachial PP was lowest in the final trimester (P = 0.011) whereas central PP remained unchanged, resulting in a significant decrease in AMPA-B (P < 0.001). HR and AIx75 rose continuously throughout pregnancy (P < 0.001). A significant fall in cfPWV was observed mid-pregnancy, which remained significant after adjustment for MAP and HR (P < 0.05). CO rose mid-pregnancy, before returning to baseline values by week 36 of gestation (P < 0.05). CONCLUSION: To our knowledge, this is the largest prospective study to evaluate several central haemodynamic parameters in normotensive pregnancies, including adjusted-AIx and the gold-standard cfPWV. These data are a necessary foundation for the establishment of pregnancy-specific reference values and provide reference data for future trial design.

Interactions between Vitamin D Status, Calcium Intake and Parathyroid Hormone Concentrations in Healthy White-Skinned Pregnant Women at Northern Latitude.

Adverse effects of low vitamin D status and calcium intakes in pregnancy may be mediated through functional effects on the calcium metabolic system. Little explored in pregnancy, we aimed to examine the relative importance of serum 25-hydroxyvitamin D (25(OH)D) and calcium intake on parathyroid hormone (PTH) concentrations in healthy white-skinned pregnant women. This cross-sectional analysis included 142 participants (14 ± 2 weeks' gestation) at baseline of a vitamin D intervention trial at 51.9 °N. Serum 25(OH)D, PTH, and albumin-corrected calcium were quantified biochemically. Total vitamin D and calcium intakes (diet and supplements) were estimated using a validated food frequency questionnaire. The mean ± SD vitamin D intake was 10.7 ± 5.2 µg/day. With a mean ± SD serum 25(OH)D of 54.9 ± 22.6 nmol/L, 44% of women were <50 nmol/L and 13% <30 nmol/L. Calcium intakes (mean ± SD) were 1182 ± 488 mg/day and 23% of participants consumed <800 mg/day. The mean ± SD serum albumin-adjusted calcium was 2.2 ± 0.1 mmol/L and geometric mean (95% CI) PTH was 9.2 (8.4, 10.2) pg/mL. PTH was inversely correlated with serum 25(OH)D (r = -0.311, p < 0.001), but not with calcium intake or serum calcium (r = -0.087 and 0.057, respectively, both p > 0.05). Analysis of variance showed that while serum 25(OH)D (dichotomised at 50 nmol/L) had a significant effect on PTH (p = 0.025), calcium intake (<800, 800⁻1000, ≥1000 mg/day) had no effect (p = 0.822). There was no 25(OH)D-calcium intake interaction effect on PTH (p = 0.941). In this group of white-skinned women with largely sufficient calcium intakes, serum 25(OH)D was important for maintaining normal PTH concentration.

Estimation of the maternal vitamin D intake that maintains circulating 25-hydroxyvitamin D in late gestation at a concentration sufficient to keep umbilical cord sera ≥25-30 nmol/L: a dose-response, double-blind, randomized placebo-controlled trial in pregnant women at northern latitude.

Background: In the absence of dose-response data, Dietary Reference Values for vitamin D in nonpregnant adults are extended to pregnancy. Objective: The aim was to estimate vitamin D intake needed to maintain maternal 25-hydroxyvitamin D [25(OH)D] in late gestation at a concentration sufficient to prevent newborn 25(OH)D <25-30 nmol/L, a threshold indicative of increased risk of nutritional rickets. Design: We conducted a 3-arm, dose-response, double-blind, randomized placebo-controlled trial in Cork, Ireland (51.9oN). A total of 144 white-skinned pregnant women were assigned to receive 0, 10 (400 IU), or 20 (800 IU) µg vitamin D3/d from ≤18 wk of gestation. Vitamin D metabolites at 14, 24, and 36 wk of gestation and in cord sera, including 25(OH)D3, 3-epi-25(OH)D3, 24,25(OH)2D3, and 25(OH)D2 were quantified by liquid chromatography-tandem mass spectrometry. A curvilinear regression model predicted the total vitamin D intake (from diet and antenatal supplements plus treatment dose) that maintained maternal 25(OH)D in late gestation at a concentration sufficient to maintain cord 25(OH)D at ≥25-30 nmol/L. Results: Mean ± SD baseline 25(OH)D was 54.9 ± 10.7 nmol/L. Total vitamin D intakes at the study endpoint (36 wk of gestation) were 12.1 ± 8.0, 21.9 ± 5.3, and 33.7 ± 5.1 µg/d in the placebo and 10-µg and 20-µg vitamin D3 groups, respectively; and 25(OH)D was 24.3 ± 5.8 and 29.2 ± 5.6 nmol/L higher in the 10- and 20-µg groups, respectively, compared with placebo (P < 0.001). For maternal 25(OH)D concentrations ≥50 nmol/L, 95% of cord sera were ≥30 nmol/L and 99% were >25 nmol/L. The estimated vitamin D intake required to maintain serum 25(OH)D at ≥50 nmol/L in 97.5% of women was 28.9 µg/d. Conclusions: Thirty micrograms of vitamin D per day safely maintained serum 25(OH)D concentrations at ≥50 nmol/L in almost all white-skinned women during pregnancy at a northern latitude, which kept 25(OH)D at >25 nmol/L in 99% and ≥30 nmol/L in 95% of umbilical cord sera. This trial was registered at www.clinicaltrials.gov as NCT02506439.

Variation in iodine food composition data has a major impact on estimates of iodine intake in young children.

BACKGROUND/OBJECTIVES: The reliability of an estimate of iodine intake is largely dependent on the quality of the food composition data. We aimed to assess the impact of variations in food composition data for iodine and season on the estimates of iodine intake in young children. SUBJECTS/METHODS: Cross-sectional dietary intake study of Irish 2-year-olds participating in the Cork BASELINE Birth Cohort Study (n=468; 30% of the cohort at the 2-year follow-up) were used to assess the impact of variation in iodine food composition data on estimates of iodine intake, dietary adequacy and risk of exceeding the tolerable upper intake level (UL). RESULTS: Mean (SD) iodine intakes calculated using UK (147 (71)) and Irish (177 (93)) food composition data were significantly different (P < 0.001) (mean difference (95% confidence interval) = 30 (26-33) µg/day) and largely adequate (7-14% below the estimated average requirement). Intakes at the 95th percentile were 138% and 173% of the UL using UK and Irish food composition data, respectively, of which milk accounted for 106% and 150% of the UL. This translated into 22% and 35% of toddlers exceeding the UL, using UK and Irish composition data, respectively. The mean (SD) daily intake of cow's milk among the 91% of consumers was 309 (208) ml. Intakes of cow's milk at the 75th and 95th percentiles were 452 and 706 ml, respectively. Using Irish composition data for iodine in cows' milk, a daily intake of 450 ml could result in a toddler exceeding the UL from milk alone. CONCLUSIONS: Variability in food composition has a large impact on assessments of iodine intake, particularly among young children for whom milk contributes a large proportion of their daily nutrient intake. Although this is unlikely to result in long-term adverse effects, our study highlights the need for development of valid biomarkers of individual iodine status.

Development and evaluation of a concise food list for use in a web-based 24-h dietary recall tool.

Foodbook24 is a self-administered web-based 24-h dietary recall tool developed to assess food and nutrient intakes of Irish adults. This paper describes the first step undertaken in developing Foodbook24 which was to limit participant burden by establishing a concise list of food items for inclusion in the tool. The aim of the present study was to evaluate whether using a concise food list (as opposed to an extensive list) with generic composition data would influence the estimates of nutrient intakes in a nationally representative sample of Irish adults. A 2319-item food list generated from the Irish National Adult Nutrition Survey (NANS) (2008-2010) (n 1500) was used as the basis for a shortened food list for integration into the tool. Foods similar in nutritional composition were recoded with a generic type food code to produce a concise list of 751 food codes. The concise food list was applied to the NANS food consumption dataset and intake estimates of thirty-five nutrients were compared with estimates derived using the original extensive list. Small differences in nutrient intakes (<6 %) with limited effect size (Cohen's d < 0·1) were observed between estimates from both food lists. The concise food list showed strong positive correlations (rs 0·9-1·0, n 1500, P < 0·001) and a high level of agreement with the extensive list (80-97 % of nutrient intakes classified into the same tertile; >90% of intakes similarly categorised according to dietary reference values). This indicates that a concise food list is suitable for use in a web-based 24-h dietary recall tool for Irish adults.

The role of fortified foods and nutritional supplements in increasing vitamin D intake in Irish preschool children.

PURPOSE: There are limited data on the contribution of fortified foods and nutritional supplements to intakes of vitamin D in young children. Our objective was to examine the intake, adequacy, risk of excessive intake and sources of dietary vitamin D. METHODS: The nationally representative cross-sectional dietary survey of young children (aged 1-4 years) (n 500) was used to evaluate vitamin D intake and quantify the contribution of the base diet, fortified foods and nutritional supplements to total intake. RESULTS: Median (IQR) intakes of vitamin D were generally low in this young population, ranging from 2.0 (1.9) to 2.5 (4.9) µg/day. Ninety-three and 78 % of children had intakes below 10 and 5 µg/day, respectively. While vitamin D supplement users (17 %) had the highest intakes [6.7 (6.4) µg/day] (P < 0.001), 74 % had intakes below 10 µg/day. Vitamin D-fortified foods, consumed by 77 % of children [2.2 (2.0) µg/day], made nutritionally significant contributions to intake [0.8 (1.6) µg/day], particularly in younger children [1.5 (4.6) µg/day]. Children who did not use nutritional supplements or fortified foods had significantly (P < 0.001) lower intakes of vitamin D than the other groups [1.0 (0.8) µg/day]. Our analyses show the importance of milk and yoghurt, meat and fortified ready-to-eat cereals as sources of vitamin D in this age group. The use of nutritional supplements or fortified foods at current levels does not represent a risk of intakes exceeding the European Food Safety Authority (EFSA) tolerable upper intake level (UL) (50 µg/day), as intakes did not exceed or even approach the UL (P95: 22 % of UL). CONCLUSION: Intakes of vitamin D in preschool children in Ireland are generally low. Nutritional supplements and fortified foods make significant contributions to intakes of vitamin D, without risk of unacceptably high intakes. Though supplements are effective in raising intakes of vitamin D in users, uptake is low (17 %). Food fortification may represent a suitable public health approach to increasing vitamin D intakes. The national food consumption data of Irish preschool children provide the ideal starting point for modelling of fortification scenarios to identify which foods and levels of addition will ensure effective and safe increases in vitamin D intake.

Estimating safe maximum levels of vitamins and minerals in fortified foods and food supplements.

PURPOSE: To show how safe maximum levels (SML) of vitamins and minerals in fortified foods and supplements may be estimated in population subgroups. METHODS: SML were estimated for adults and 7- to 10-year-old children for six nutrients (retinol, vitamins B6, D and E, folic acid, iron and calcium) using data on usual daily nutrient intakes from Irish national nutrition surveys. RESULTS: SML of nutrients in supplements were lower for children than for adults, except for calcium and iron. Daily energy intake from fortified foods in high consumers (95th percentile) varied by nutrient from 138 to 342 kcal in adults and 40-309 kcal in children. SML (/100 kcal) of nutrients in fortified food were lower for children than adults for vitamins B6 and D, higher for vitamin E, with little difference for other nutrients. Including 25 % 'overage' for nutrients in fortified foods and supplements had little effect on SML. Nutritionally significant amounts of these nutrients can be added safely to supplements and fortified foods for these population subgroups. The estimated SML of nutrients in fortified foods and supplements may be considered safe for these population subgroups over the long term given the food composition and dietary patterns prevailing in the respective dietary surveys. CONCLUSIONS: This risk assessment approach shows how nutrient intake data may be used to estimate, for population subgroups, the SML for vitamins and minerals in both fortified foods and supplements, separately, each taking into account the intake from other dietary sources.

Estimation of the dietary requirement for vitamin D in white children aged 4-8 y: a randomized, controlled, dose-response trial.

BACKGROUND: Children in northern latitudes are at high risk of vitamin D deficiency during winter because of negligible dermal vitamin D3 production. However, to our knowledge, the dietary requirement for maintaining the nutritional adequacy of vitamin D in young children has not been investigated. OBJECTIVE: We aimed to establish the distribution of vitamin D intakes required to maintain winter serum 25-hydroxyvitamin D [25(OH)D] concentrations above the proposed cutoffs (25, 30, 40, and 50 nmol/L) in white Danish children aged 4-8 y living at 55°N. DESIGN: In a double-blind, randomized, controlled trial 119 children (mean age: 6.7 y) were assigned to 0 (placebo), 10, or 20 µg vitamin D3/d supplementation for 20 wk. We measured anthropometry, dietary vitamin D, and serum 25(OH)D with liquid chromatography-tandem mass spectrometry at baseline and endpoint. RESULTS: The mean ± SD baseline serum 25(OH)D was 56.7 ± 12.3 nmol/L (range: 28.7-101.4 nmol/L). Serum 25(OH)D increased by a mean ± SE of 4.9 ± 1.3 and 17.7 ± 1.8 nmol/L in the groups receiving 10 and 20 µg vitamin D3/d, respectively, and decreased by 24.1 ± 1.2 nmol/L in the placebo group (P < 0.001). A nonlinear model of serum 25(OH)D as a function of total vitamin D intake (diet and supplements) was fit to the data. The estimated vitamin D intakes required to maintain winter serum 25(OH)D >30 (avoiding deficiency) and >50 nmol/L (ensuring adequacy) in 97.5% of participants were 8.3 and 19.5 µg/d, respectively, and 4.4 µg/d was required to maintain serum 25(OH)D >40 nmol/L in 50% of participants. CONCLUSIONS: Vitamin D intakes between 8 and 20 µg/d are required by white 4- to 8-y-olds during winter in northern latitudes to maintain serum 25(OH)D >30-50 nmol/L depending on chosen serum 25(OH)D threshold. This trial was registered at clinicaltrials.gov as NCT02145195.

Phylloquinone Intakes and Food Sources and Vitamin K Status in a Nationally Representative Sample of Irish Adults.

BACKGROUND: Data from a nationally representative sample of 18- to 64-y-old Irish adults conducted in 1999 highlighted low phylloquinone intakes. That survey, however, did not include older adults (aged ≥65 y), a subgroup that is potentially at higher risk of low phylloquinone intakes, or a biomarker of vitamin K status. OBJECTIVES: The objectives of this work were to measure the phylloquinone intake and its adequacy and the serum percentage of undercarboxylated osteocalcin (%ucOC), a vitamin K status biomarker, in a nationally representative sample of Irish adults aged 18-90 y, and to compare these newer data on dietary phylloquinone in adults aged 18-64 y with those from the previous survey. METHODS: Data and biobanked serum samples from the National Adult Nutrition Survey, a randomly selected sample of Irish adults aged 18-90 y (N = 1500), were accessed. Phylloquinone intakes were estimated from 4-d food diary data and were compared across age groups (18-35, 36-50, 51-64, and ≥65 y). Serum %ucOC was assessed by immunoassay (n = 692). RESULTS: The mean ± SD intake of phylloquinone from all sources was 85.2 ± 59.1 µg/d, 99% of which was derived from food. Phylloquinone intakes and serum %ucOC were significantly (P < 0.05) lower (14-25%) and higher (27-39%), respectively, in the 18- to 35-y age group than in the 36- to 50-y, 51- to 64-y, and ≥65-y age groups (no differences between these 3 groups; P > 0.2 in all cases). Mean phylloquinone intakes had increased (P < 0.01) modestly (6 µg/d) in 18-64-y-olds across a decade. Of the total study population, 55% had phylloquinone intakes below the United Kingdom recommended intake of 1 µg ⋅ kg body weight-1 ⋅ d-1 CONCLUSION: Our study shows that younger adults (aged 18-35 y) appear to be at higher risk of inadequate vitamin K intake and lower vitamin K status, the health implications of which are unclear and warrant further investigation.

Estimation of the dietary requirement for vitamin D in adolescents aged 14-18 y: a dose-response, double-blind, randomized placebo-controlled trial.

BACKGROUND: Adolescents are a population group at high risk of low vitamin D status, yet the evidence base for establishing dietary vitamin D requirements remains weak. OBJECTIVE: The aim was to establish the distribution of vitamin D intakes required to maintain serum 25-hydroxyvitamin D [25(OH)D] concentrations above proposed cutoffs (25, 30, 40, and 50 nmol/L) during winter in white males and females (14-18 y of age) in the United Kingdom (51°N). DESIGN: In a dose-response trial, 110 adolescents (aged 15.9 ± 1.4 y; 43% males) were randomly assigned to receive 0, 10, or 20 µg vitamin D3 supplements/d for 20 wk during winter. A nonlinear regression model was fit to total vitamin D intake and postintervention serum 25(OH)D concentrations, and regression-predicted values estimated the vitamin D intakes required to maintain serum 25(OH)D concentrations above specific cutoffs. RESULTS: Mean ± SD serum 25(OH)D concentrations increased from 49.2 ± 12.0 to 56.6 ± 12.4 nmol/L and from 51.7 ± 13.4 to 63.9 ± 10.6 nmol/L in the 10- and 20-µg/d groups, respectively, and decreased in the placebo group from 46.8 ± 11.4 to 30.7 ± 8.6 nmol/L (all P ≤ 0.001). Vitamin D intakes required to maintain 25(OH)D concentrations >25 and >30 nmol/L in 97.5% of adolescents were estimated to be 10.1 and 13.1 µg/d, respectively, and 6.6 µg/d to maintain 50% of adolescents at concentrations >40 nmol/L. Because the response of 25(OH)D reached a plateau at 46 nmol/L, there is uncertainty in estimating the vitamin D intake required to maintain 25(OH)D concentrations >50 nmol/L in 97.5% of adolescents, but it exceeded 30 µg/d. CONCLUSION: Vitamin D intakes between 10 and ∼30 µg/d are required by white adolescents during winter to maintain serum 25(OH)D concentrations >25-50 nmol/L, depending on the serum 25(OH)D threshold chosen. This trial was registered at clinicaltrials.gov as NCT02150122 and as International Standard Randomized Controlled Trial Number ISRCTN40736890.

Impact of voluntary food fortification practices in Ireland: trends in nutrient intakes in Irish adults between 1997-9 and 2008-10.

Because of the discretionary nature of voluntary food fortification in the European Union, there is a need to monitor fortification practices and consumption of fortified foods in order to assess the efficacy and safety of such additions on an ongoing basis. The present study aimed to investigate the nutritional impact of changes in voluntary fortification practices in adults aged 18-64 years using dietary intake data from two nationally representative cross-sectional food consumption surveys, the North/South Ireland Food Consumption Survey (NSIFCS) (1997-9) and the National Adult Nutrition Survey (NANS) (2008-10). The supply of fortified foods increased between 1997-9 and 2008-10, resulting in a higher proportion of adults consuming fortified foods (from 67 to 82 ) and a greater contribution to mean daily energy intake (from 4.6 to 8.4%). The overall nutrient profile of fortified foods consumed remained favourable, i.e. higher in starch and dietary fibre and lower in fat and saturated fat, with polyunsaturated fat, sugars and Na in proportion to energy. Women, particularly those of childbearing age, remained the key beneficiaries of voluntary fortification practices in Ireland. Continued voluntary fortification of foods has increased protection against neural tube defect-affected pregnancy by folic acid and maintained the beneficial impact on the adequacy of Fe intake. Increased consumption of fortified foods did not contribute to an increased risk of intakes exceeding the tolerable upper intake level for any micronutrient. Recent increases in voluntary fortification of foods in Ireland have made a favourable nutritional impact on the diets of adults and have not contributed to an increased risk of adverse effects.

The impact of voluntary food fortification on micronutrient intakes and status in European countries: a review.

This review aims to assess the efficacy and safety of voluntary fortification as an option to address the occurrence of inadequate micronutrient intakes in population subgroups in Europe. Although legislation is harmonised across the European Union, fortification practices and patterns of consumption of fortified foods vary considerably between countries. While the proportion of children consuming fortified foods is greater than adults, the proportion of dietary energy obtained from fortified foods is generally low (<10% in Ireland, where fortified foods are widely consumed). There are a few systematic studies on the overall nutritional impact of voluntary fortification, but there are several studies on the impact of fortified ready-to-eat breakfast cereals. The available evidence indicates that voluntary fortification can reduce the risk of sub-optimal intakes of a range of micronutrients at a population level and can also improve status for selected micronutrients (e.g. folate, vitamin D and riboflavin) in children and adults. Although concerns have been raised regarding the potential of food fortification to lead to unacceptably high micronutrient intakes, particularly for those consuming higher amounts of fortified foods, data from national surveys on total micronutrient intakes (including fortified foods) in Europe show that small proportions of the population, particularly children, may exceed the upper intake level (UL) for some micronutrients. The risk of adverse effects occurring in these individuals exceeding the UL by modest amounts is low. In conclusion, voluntary fortification practices have been shown to improve intake and status of key micronutrients in European Union population groups and do not contribute appreciably to risk of adverse effects.