Exposure to Vitamin D Fortification Policy in Prenatal Life and the Risk of Childhood Asthma: Results From the D-Tect Study

Importance of diet in children and adolescents with obesity and asthma

Both obesity and asthma are increasingly being diagnosed in the childhood population. Obesity is linked to a greater asthma morbidity, and it increases the risk of severity of the disease course. The association between these 2 disorders has not yet been fully elucidated; however, several putative factors have been proposed related to mechanical and inflammatory aspects of obesity. Diet is an important adjustable element in obesity and asthma management. An unhealthy diet based on processed food is likely to promote chronic inflammation in both conditions; hence, appropriate nutrition should be an integral part of the children's therapy. This review discusses dietary models that have a positive impact on patient health.

Benefits and Harms of Edible Vegetable Oils and Fats Fortified with Vitamins A and D as a Public Health Intervention in the General Population: A Systematic Review of Interventions

This systematic review aims to assess whether edible vegetable oils and fats fortified with vitamin A and/or D are effective and safe in improving vitamin intake and ameliorating deficiency states in the general population. In November 2022, we systematically searched MEDLINE, Cochrane CENTRAL, Scopus, Global Index Medicus, ClinicalTrials.gov, and WHO ICTRP (International Clinical Trials Registry Platform) for randomized controlled trials (RCT) and non-randomized studies of interventions (NRSI) investigating the fortification of edible vegetable oils and fats with either vitamin A or vitamin D or both as compared to the same vegetable oils and/or fats without vitamin A and D fortification or no interventions, in the general population, without age restriction. We assessed the methodological quality of included RCTs using Cochrane's risk of bias tool 2.0 and of NRSIs using ROBINS-I tool. We performed random-effects meta-analysis and assessed certainty of evidence using GRADE. We included eight studies. Available evidence showed no significant effect of fortification with vitamin A on serum retinol levels (RCTs: MD 0.35 µmol/L, 95% CI -0.43 to 1.12; two trials; 514 participants; low-certainty evidence; CCTs: MD 0.31 µmol/L, 95% CI -0.18 to 0.80; two trials; 205 participants; very low-certainty evidence) and on subclinical vitamin A deficiency. Low-certainty evidence showed no effect of vitamin D fortification on serum 25-hydroxy vitamin D concentration (MD 6.59 nmol/L, 95% CI -6.89 to 20.07; one trial; 62 participants). In conclusion, vitamin A-fortified vegetable oils and fats may result in little to no difference in serum retinol levels in general populations. The dose of vitamin A used in the trials may be safe but may not be sufficient to reduce subclinical vitamin A deficiency. Further, the evidence suggests that vitamin D fortification results in little to no difference in serum 25-hydroxy vitamin D concentration. Several aspects of providing fortified oils and fats to the general population as a public health intervention should be further investigated, including optimal fortification dose, effects on vitamin D deficiency and its clinical symptoms and potential adverse effects.

Perspective: School Meal Programs Require Higher Vitamin D Fortification Levels in Milk Products and Plant-Based Alternatives-Evidence from the National Health and Nutrition Examination Surveys (NHANES 2001-2018)

Poor vitamin D status impairs bone growth and immune defense in school-aged children and adolescents, particularly in minorities. Vitamin D insufficiency/deficiency increases the risk of acute viral respiratory infection, underscoring the need for adequate vitamin D intakes during school sessions when viral exposure may be greatest. We studied available vitamin D-related survey data and published findings based on NHANES (2001-2018) to assess the dependency of vitamin D status {25-hydroxyvitamin D [25(OH)D]; in nmol/L} on vitamin D intake (μg/d) in elementary school-aged children (4-8 y), middle school children (9-13 y), and high school adolescents (14-18 y). We sought evidence supporting the need for school programs to facilitate vitamin D adequacy. Usual vitamin D intakes from food and beverages by children/adolescents (NHANES 2015-2018) examined at the 50th percentile intake by race/ethnicity (non-Hispanic White, non-Hispanic Black, Hispanic) showed all age groups consumed less than half of the Estimated Average Requirement (EAR) for vitamin D (10 μg/d), independent of race/ethnicity. NHANES (2001-2010) analyses show evidence of lower vitamin D status in school-aged children that is linked to lower intakes of fortified milk varying over race/ethnicity and age. Adolescents had lower vitamin D status and milk intake than younger children. A total of 22-44% of vitamin D intakes occurred away from home, with larger percentages of total intakes at breakfast and lunch, at times consistent with school meals. Ever-present inadequate vitamin D intakes with a large percentage consumed away from home together with well-established benefits to growth, bone, and immune defense from enriched vitamin D-fortified milk in school intervention trials provide strong justification to require enriched vitamin D-fortified foods in school meals. An easy to implement plan for improving vitamin D intakes is possible through the FDA's amendment allowing higher vitamin D fortification levels of dairy and plant-based milk alternatives that could increase vitamin D intakes beyond the EAR with just 2 daily servings.

Cord blood 25(OH)D3, cord blood total immunoglobulin E levels, and food allergies in infancy: A birth cohort study in Chongqing, China

Background

Food allergy (FA) in infants has become a common disease worldwide. There are many controversies surrounding the relationships among levels of cord blood 25-hydroxy vitamin D3 [25(OH)D3], total immunoglobulin E (IgE), and FA.

Methods

In this study, we recruited pregnant women in the third trimester undergoing obstetric examination in Chongqing City, Western China. Healthy full-term singleton births between May to August 2018 and November 2018 to January 2019 were included in the summer-birth and winter-birth cohorts, respectively. Questionnaires on vitamin D status in pregnancy and family allergies were used to investigate the pregnant women. The levels of <12 ng/mL, 12～20 ng/mL, and >20 ng/mL 25(OH)D3 in cord blood detected by liquid chromatography tandem mass spectrometry were considered deficient, insufficient, and sufficient, respectively. The electrochemiluminescence method was used to detect the total lgE levels in cord blood, classified into low-IgE (<0.35 IU/mL) and high-IgE (≥0.35 IU/mL) levels, respectively. Within postnatal 6 months, allergic symptoms in infants were investigated using questionnaire during the infants' monthly physical examinations. Suspected cases of FA underwent a history inquiry, skin prick test, food elimination test, and open-food challenge for diagnosis of FA. Multivariate logistic regression was used to analyze the risk factors of FA in infants.

Results

In this study, we recruited 741 pairs of pregnant women and infants, including 343 infants in the summer-birth cohort and 398 infants in the winter-birth cohort. The incidence of FA within postnatal 6 months was 6.88%, showing significantly higher incidence of FA in the winter-birth cohorts than in the summer-birth cohorts (10.3% vs. 2.9%, χ2 = 15.682, P = 0.000). Among the 741 infants, 47.1%, 27.5%, and 13.8% of infants had deficient, insufficient, and sufficient 25(OH)D3, respectively, in the cord blood; 81.5% and 18.5% of infants had total low-IgE and total high-IgE levels, respectively, in the cord blood. No significant correlation was found between the 25(OH)D3 and IgE levels (r = -0.038, P = 0.300). Logistic regression analysis showed that winter birth [odds ratio (OR) 95% confidence interval (CI): 4.292 (2.003～8.359)] compared with infants in summer birth group, and sufficient (>20 ng/mL) 25(OH)D3 levels in cord blood [OR (95% CI): 2.355 (1.129～4.911) compared with infants in the deficient group (<12 ng/mL) and 3.782 (1.680～8.514) compared with infants in the insufficient group (12～20 ng/mL)] were independent risk factors for FA in infants within postnatal 6 months.

Conclusions

Winter birth and sufficient 25(OH)D3 levels in infant cord blood were independent risk factors for FA in infants. 25(OH)D3 and total IgE levels in cord blood cannot be used as predictors of FA in early infancy.

Pediatric Obesity-Related Asthma: The Role of Nutrition and Nutrients in Prevention and Treatment

Childhood obesity rates have dramatically risen in numerous countries worldwide. Obesity is likely a factor in increased asthma risk, which is already one of the most widespread chronic respiratory pathologies. The pathogenic mechanism of asthma risk has still not yet been fully elucidated. Moreover, the role of obesity-related inflammation and pulmonary overreaction to environmental triggers, which ultimately result in asthma-like symptoms, and the importance of dietary characteristics is well recognized. Diet is an important adjustable element in the asthma development. Food-specific composition of the diet, in particular fat, sugar, and low-quality nutrients, is likely to promote the chronic inflammatory state seen in asthmatic patients with obesity. An unbalanced diet or supplementation as a way to control asthma more efficiently has been described. A personalized dietary intervention may improve respiratory symptoms and signs and therapeutic response. In this narrative review, we presented and discussed more recent literature on asthma associated with obesity among children, focusing on the risk of asthma among children with obesity, asthma as a result of obesity focusing on the role of adipose tissue as a mediator of systemic and local airway inflammation implicated in asthma regulation, and the impact of nutrition and nutrients in the development and treatment of asthma. Appropriate early nutritional intervention could possibly be critical in preventing and managing asthma associated with obesity among children.

Assessing Health Consequences of Vitamin D Fortification Utilizing a Societal Experiment Design: Methodological Lessons Learned from the D-Tect Project

By utilizing historical changes in Danish legislation related to mandatory vitamin D fortification of margarine, which was implemented in the mid 1930s and abruptly abandoned in June 1985, the studies in the D-tect project investigated the effects of vitamin D on health outcomes in individuals, who during gestation were exposed or unexposed to extra vitamin D from fortified margarine. This paper reviews and narratively summarizes the analytic approaches alongside the results of the societal fortification experiment studies from the D-tect project and addresses the challenges in designing societal experiment studies and evaluating their results. The latter are discussed as lessons learned that may be useful for designers of similar studies, expected to be extensively utilized while researching the health consequences of the COVID-19 pandemic by comparing individuals born before and after the epidemic. In the D-tect project, 16 articles based on the societal fortification experiment were published analyzing 10 different outcomes and using different statistical approaches. Lessons learned included the detail of the analysis of the historical information on the exposure, availability and validity of the outcome data, variety of analytical approaches, and specifics concerning vitamin D effect evaluation, such as consideration of the influence of sunshine or season. In conclusion, the D-tect project clearly demonstrated the cost-effectiveness and research potential of natural- or societal-experiment-based studies.

Exposure to the Danish Mandatory Vitamin D Fortification Policy in Prenatal Life and the Risk of Developing Coeliac Disease-The Importance of Season: A Semi Ecological Study

Few studies have examined the role of maternal diet in relation to development of coeliac disease (CD). In Denmark, cancellation of mandatory vitamin D fortification of margarine in June 1985 provided this opportunity. This study examined if season of birth or prenatal exposure to extra vitamin D from food fortification were associated with developing CD later in life. A strength of this study is the distinctly longer follow-up of patients (30 years). This register-based study has a semi-ecological design. Logistic regression analysis was used to estimate odds ratios and to calculate 95% confidence intervals. The odds ratio for developing CD was 0.81 (95% CI 0.66; 1.00 p = 0.054), comparing those with fetal exposure to mandatory vitamin D fortification policy of margarine to those without after adjusting for gender and season of birth. There was a statistically significant season effect particularly for children born in autumn (OR 1.6 95% CI 1.16; 2.21) and born in summer (OR 1.5 95% CI 1.1; 2.1) when compared to children born in winter. Although this study did not find evidence to support the premise that prenatal exposure to small extra amounts of vitamin D from a mandatory food fortification policy lowered risk of developing CD, the small number of CD cases and observed association between season of birth and CD suggest that environmental exposure ought to be further explored.