Enteral iron supplementation in preterm infants is recommended to supply sufficient iron for growth and development without increasing the risk of iron overload. However, the current recommendations ...date from 2010 and are based on limited evidence.
This systematic review aimed to investigate the effects of enteral iron supplementation on iron status, growth, neurological development, and adverse clinical outcomes in preterm (<37 weeks' gestation) and low-birth-weight (LBW, <2500 g) infants.
The PubMed/Medline and Cochrane Library databases were searched to 31 October 2018.
Of the 684 records identified, 27 articles, describing 18 randomized controlled trials (RCTs) plus 4 nonrandomized interventions, were included. Using the Cochrane Collaboration's criteria, study quality was found to be poor to fair overall.
Most articles (23/27) reported iron status indices; supplementation for ≥8 weeks resulted in increased hemoglobin and ferritin concentrations and a reduction in iron deficiency and anemia. No article reported on iron overload. Growth-related parameters reported in 12 articles were not affected by supplementation. Among the 7 articles on neurological development, a positive effect on behavior at 3.5 and 7 years was observed in one Swedish RCT. No association was found between supplementation and adverse clinical outcomes in the 9 articles reporting on studies in which such data was collected.
Long-term iron supplementation appears to result in improved iron status and a reduction in iron deficiency and anemia in preterm and LBW infants. However, high-quality evidence regarding the long-term effects of supplementation on functional health outcomes is lacking. Iron overload has largely been ignored. Well-designed, long-term, dose-response RCTs are required to ascertain the optimal dose and delivery method for the provision of dietary iron in preterm infants, with consideration of short- and long-term health effects.
PROSPERO registration no. CRD42018085214.
A global move toward consumption of diets from sustainable sources is required to protect planetary health. As this dietary transition will result in greater reliance on plant-based protein sources, ...the impact on micronutrient (MN) intakes and status is unknown.
Evaluate the evidence of effects on intakes and status of selected MNs resulting from changes in dietary intakes to reduce environmental impact. Selected MNs of public health concern were vitamins A, D, and B12, folate, calcium, iron, iodine, and zinc.
We systematically searched 7 databases from January 2011 to October 2022 and followed the PRISMA guidelines. Eligible studies had to report individual MN intake and/or status data collected in free-living individuals from the year 2000 onward and environmental outcomes.
From the 10,965 studies identified, 56 studies were included, mostly from high-income countries (n = 49). Iron (all 56) and iodine (n = 20) were the most and least reported MNs, respectively. There was one randomized controlled trial (RCT) that also provided the only biomarker data, 10 dietary intake studies, and 45 dietary modeling studies, including 29 diet optimization studies. Most studies sought to reduce greenhouse gas emissions or intake of animal-sourced foods. Most results suggested that intakes of zinc, calcium, iodine, and vitamins B12, A, and D would decrease, and total iron and folate would increase in a dietary transition to reduce environmental impacts. Risk of inadequate intakes of zinc, calcium, vitamins A, B12 and D were more likely to increase in the 10 studies that reported nutrient adequacy. Diet optimization (n = 29) demonstrated that meeting nutritional and environmental targets is technically feasible, although acceptability is not guaranteed.
Lower intakes and status of MNs of public health concern are a potential outcome of dietary changes to reduce environmental impacts. Adequate consideration of context and nutritional requirements is required to develop evidence-based recommendations.
This study was registered prospectively with PROSPERO (CRD42021239713).
Associations between vitamin D and pregnancy outcomes have been inconsistent.
We described the distribution of 25-hydroxyvitamin D3 25(OH)D3, 3-epi-25(OH)D3, and 25(OH)D2 in early pregnancy and ...investigated associations with pre-eclampsia and small-for-gestational-age (SGA) birth, which are indicative of uteroplacental dysfunction.
The SCOPE (Screening for Pregnancy Endpoints) Ireland prospective pregnancy cohort study included 1768 well-characterized low-risk, nulliparous women resident at 52°N. Serum 25(OH)D3, 3-epi-25(OH)D3, and 25(OH)D2 were quantified at 15 wk of gestation with the use of a CDC-accredited liquid chromatography-tandem mass spectrometry method.
The mean ± SD total 25(OH)D concentration was 56.7 ± 25.9 nmol/L, and 17% and 44% of women had 25(OH)D concentrations <30 and <50 nmol/L, respectively. The prevalence of pre-eclampsia was 3.8%, and 10.7% of infants were SGA. There was a lower risk of pre-eclampsia plus SGA combined (13.6%) at 25(OH)D concentrations >75 nmol/L (adjusted OR: 0.64; 95% CI: 0.43, 0.96). The main predictors of 25(OH)D were the use of vitamin D-containing supplements (adjusted mean difference: 20.1 nmol/L; 95% CI: 18.5, 22.7 nmol/L) and summer sampling (adjusted mean difference: 15.5 nmol/L; 95% CI: 13.4, 17.6 nmol/L). Non-Caucasian ethnicity (adjusted mean difference: -19.3 nmol/L; 95% CI: -25.4, -13.2 nmol/L) and smoking (adjusted mean difference: -7.0 nmol/L; 95% CI: -10.5, -3.6 nmol/L) were negative predictors of 25(OH)D. The mean ± SD concentration of 3-epi-25(OH)D3, which was detectable in 99.9% of samples, was 2.6 ± 1.6 nmol/L. Determinants of 3-epi-25(OH)D3 were 25(OH)D3 (adjusted mean difference: 0.052 nmol/L; 95% CI: 0.050, 0.053 nmol/L) and maternal age (adjusted mean difference: -0.018 nmol/L; 95% CI: -0.026, -0.009 nmol/L). The mean ± SD concentration of 25(OH)D2 was 3.1 ± 2.7 nmol/L, which was present in all samples. No adverse effects of 25(OH)D concentrations >125 nmol/L were observed.
In the first report to our knowledge of CDC-accredited 25(OH)D data and pregnancy outcomes from a large, clinically validated, prospective cohort study, we observed a protective association of a 25(OH)D concentration >75 nmol/L and a reduced risk of uteroplacental dysfunction as indicated by a composite outcome of SGA and pre-eclampsia. Well-designed, adequately powered randomized controlled trials are required to verify this observation. The SCOPE pregnancy cohort was registered at www.anzctr.org.au as ACTRN12607000551493.
Vitamin D deficiency can lead to musculoskeletal diseases such as rickets and osteomalacia, but vitamin D supplementation may also prevent extraskeletal diseases such as respiratory tract infections, ...asthma exacerbations, pregnancy complications and premature deaths. Vitamin D has a unique metabolism as it is mainly obtained through synthesis in the skin under the influence of sunlight (i.e., ultraviolet-B radiation) whereas intake by nutrition traditionally plays a relatively minor role. Dietary guidelines for vitamin D are based on a consensus that serum 25-hydroxyvitamin D (25OHD) concentrations are used to assess vitamin D status, with the recommended target concentrations ranging from ≥25 to ≥50 nmol/L (≥10-≥20 ng/mL), corresponding to a daily vitamin D intake of 10 to 20 μg (400-800 international units). Most populations fail to meet these recommended dietary vitamin D requirements. In Europe, 25(OH)D concentrations <30 nmol/L (12 ng/mL) and <50 nmol/L (20 ng/mL) are present in 13.0 and 40.4% of the general population, respectively. This substantial gap between officially recommended dietary reference intakes for vitamin D and the high prevalence of vitamin D deficiency in the general population requires action from health authorities. Promotion of a healthier lifestyle with more outdoor activities and optimal nutrition are definitely warranted but will not erase vitamin D deficiency and must, in the case of sunlight exposure, be well balanced with regard to potential adverse effects such as skin cancer. Intake of vitamin D supplements is limited by relatively poor adherence (in particular in individuals with low-socioeconomic status) and potential for overdosing. Systematic vitamin D food fortification is, however, an effective approach to improve vitamin D status in the general population, and this has already been introduced by countries such as the US, Canada, India, and Finland. Recent advances in our knowledge on the safety of vitamin D treatment, the dose-response relationship of vitamin D intake and 25(OH)D levels, as well as data on the effectiveness of vitamin D fortification in countries such as Finland provide a solid basis to introduce and modify vitamin D food fortification in order to improve public health with this likewise cost-effective approach.
Iron is essential for the functioning of all cells and organs, most critically for the developing brain in the fundamental neuronal processes of myelination, energy and neurotransmitter metabolism. ...Iron deficiency, especially in the first 1000 days of life, can result in long-lasting, irreversible deficits in cognition, motor function and behaviour. Pregnant women, infants and young children are most vulnerable to iron deficiency, due to their high requirements to support growth and development, coupled with a frequently inadequate dietary supply. An unrecognised problem is that even if iron intake is adequate, common pregnancy-related and lifestyle factors can affect maternal–fetal iron supply in utero, resulting in an increased risk of deficiency for the mother and her fetus. Although preterm birth, gestational diabetes mellitus and intrauterine growth restriction are known risk factors, more recent evidence suggests that maternal obesity and delivery by caesarean section further increase the risk of iron deficiency in the newborn infant, which can persist into early childhood. Despite the considerable threat that early-life iron deficiency poses to long-term neurological development, life chances and a country's overall social and economic progress, strategies to tackle the issue are non-existent, too limited or totally inappropriate. Prevention strategies, focused on improving the health and nutritional status of women of reproductive age are required. Delayed cord clamping should be considered a priority. Better screening strategies to enable the early detection of iron deficiency during pregnancy and early-life should be prioritised, with intervention strategies to protect maternal health and the developing brain.
Associations of vitamin D with perinatal outcomes are inconsistent and few studies have considered the wider calcium metabolic system.
We aimed to explore functional vitamin D deficiency in pregnancy ...by investigating associations between vitamin D status, parathyroid hormone (PTH), and perinatal outcomes.
SCOPE (Screening for Pregnancy Endpoints) Ireland is a prospective cohort study of low-risk, nulliparous pregnant women. We measured serum 25-hydroxyvitamin D 25(OH)D and PTH at 15 wk of gestation in 1754 participants.
Mean ± SD 25(OH)D was 56.6 ± 25.8 nmol/L (22.7 ± 10.3 ng/mL) and geometric mean (95% CI) PTH was 7.84 pg/mL (7.7, 8.0 pg/mL) 0.86 pmol/L (0.85, 0.88 pmol/L). PTH was elevated in 34.3% of women who had 25(OH)D <30 nmol/L and in 13.9% of those with 25(OH)D ≥75 nmol/L. Whereas 17% had 25(OH)D <30 nmol/L, 5.5% had functional vitamin D deficiency, defined as 25(OH)D <30 nmol/L with elevated PTH. Elevated mean arterial pressure (MAP), gestational hypertension, pre-eclampsia, and small-for-gestational-age (SGA) birth were confirmed in 9.2%, 11.9%, 3.8%, and 10.6% of participants, respectively. In fully adjusted regression models, neither low 25(OH)D nor elevated PTH alone increased the risk of any individual outcome. The prevalence of elevated MAP (19.1% compared with 9.7%) and SGA (16.0% compared with 6.7%) were highest (P < 0.05) in those with functional vitamin D deficiency compared with the reference group 25(OH)D ≥75 nmol/L and normal PTH. The adjusted prevalence ratio (PR) and RR (95% CIs) for elevated MAP and SGA were 1.83 (1.02, 3.27) and 1.53 (0.80, 2.93), respectively. There was no effect of functional vitamin D deficiency on the risk of gestational hypertension (adjusted RR: 1.00; 95% CI: 0.60, 1.67) or pre-eclampsia (adjusted RR: 1.17; 95% CI: 0.32, 4.20).
The concept of functional vitamin D deficiency, reflecting calcium metabolic stress, should be considered in studies of vitamin D in pregnancy.The SCOPE pregnancy cohort is registered at http://www.anzctr.org.au as ACTRN12607000551493.
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.
The iodine‐specific food frequency questionnaire (I‐FFQ), designed to capture habitual iodine intake in women aged 18–50 years, was validated against a 4‐day weighed food record and urinary iodine concentration. The I‐FFQ demonstrated reasonable validity and good repeatability and effectively identified individuals at risk of low or high intakes.
Key points
A food frequency questionnaire to measure habitual iodine intake (I‐FFQ iodine‐specific food frequency questionnaire) in Irish women of childbearing age was developed and validated in an online study against a 4‐day weighed food diary (FD) and urinary iodine concentration.
Although I‐FFQ intake estimates were higher than the FD (mean (SD standard deviation) difference = 13 (72) µg/day), there was good agreement between the methods. The I‐FFQ demonstrated reasonable validity (ρQT = 0.54) and good repeatability (r = 0.63), highlighting potential applications in clinical research.
One in five women in this study had inadequate iodine intakes, and median UIC was low in the cohort (84 µg/L), indicating the need for future studies of iodine intake and status in Irish women.
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