Individual participant data (IPD)-level meta-analysis of randomised controlled trials with vitamin D-fortified foods to estimate Dietary Reference Values for vitamin D

Vitamin D for the Prevention of Disease: An Endocrine Society Clinical Practice Guideline

BACKGROUND

Numerous studies demonstrate associations between serum concentrations of 25-hydroxyvitamin D (25[OH]D) and a variety of common disorders, including musculoskeletal, metabolic, cardiovascular, malignant, autoimmune, and infectious diseases. Although a causal link between serum 25(OH)D concentrations and many disorders has not been clearly established, these associations have led to widespread supplementation with vitamin D and increased laboratory testing for 25(OH)D in the general population. The benefit-risk ratio of this increase in vitamin D use is not clear, and the optimal vitamin D intake and the role of testing for 25(OH)D for disease prevention remain uncertain.

OBJECTIVE

To develop clinical guidelines for the use of vitamin D (cholecalciferol [vitamin D3] or ergocalciferol [vitamin D2]) to lower the risk of disease in individuals without established indications for vitamin D treatment or 25(OH)D testing.

METHODS

A multidisciplinary panel of clinical experts, along with experts in guideline methodology and systematic literature review, identified and prioritized 14 clinically relevant questions related to the use of vitamin D and 25(OH)D testing to lower the risk of disease. The panel prioritized randomized placebo-controlled trials in general populations (without an established indication for vitamin D treatment or 25[OH]D testing), evaluating the effects of empiric vitamin D administration throughout the lifespan, as well as in select conditions (pregnancy and prediabetes). The panel defined "empiric supplementation" as vitamin D intake that (a) exceeds the Dietary Reference Intakes (DRI) and (b) is implemented without testing for 25(OH)D. Systematic reviews queried electronic databases for publications related to these 14 clinical questions. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology was used to assess the certainty of evidence and guide recommendations. The approach incorporated perspectives from a patient representative and considered patient values, costs and resources required, acceptability and feasibility, and impact on health equity of the proposed recommendations. The process to develop this clinical guideline did not use a risk assessment framework and was not designed to replace current DRI for vitamin D.

RESULTS

The panel suggests empiric vitamin D supplementation for children and adolescents aged 1 to 18 years to prevent nutritional rickets and because of its potential to lower the risk of respiratory tract infections; for those aged 75 years and older because of its potential to lower the risk of mortality; for those who are pregnant because of its potential to lower the risk of preeclampsia, intra-uterine mortality, preterm birth, small-for-gestational-age birth, and neonatal mortality; and for those with high-risk prediabetes because of its potential to reduce progression to diabetes. Because the vitamin D doses in the included clinical trials varied considerably and many trial participants were allowed to continue their own vitamin D-containing supplements, the optimal doses for empiric vitamin D supplementation remain unclear for the populations considered. For nonpregnant people older than 50 years for whom vitamin D is indicated, the panel suggests supplementation via daily administration of vitamin D, rather than intermittent use of high doses. The panel suggests against empiric vitamin D supplementation above the current DRI to lower the risk of disease in healthy adults younger than 75 years. No clinical trial evidence was found to support routine screening for 25(OH)D in the general population, nor in those with obesity or dark complexion, and there was no clear evidence defining the optimal target level of 25(OH)D required for disease prevention in the populations considered; thus, the panel suggests against routine 25(OH)D testing in all populations considered. The panel judged that, in most situations, empiric vitamin D supplementation is inexpensive, feasible, acceptable to both healthy individuals and health care professionals, and has no negative effect on health equity.

CONCLUSION

The panel suggests empiric vitamin D for those aged 1 to 18 years and adults over 75 years of age, those who are pregnant, and those with high-risk prediabetes. Due to the scarcity of natural food sources rich in vitamin D, empiric supplementation can be achieved through a combination of fortified foods and supplements that contain vitamin D. Based on the absence of supportive clinical trial evidence, the panel suggests against routine 25(OH)D testing in the absence of established indications. These recommendations are not meant to replace the current DRIs for vitamin D, nor do they apply to people with established indications for vitamin D treatment or 25(OH)D testing. Further research is needed to determine optimal 25(OH)D levels for specific health benefits.

Strategic food vehicles for vitamin D fortification and effects on vitamin D status: A systematic review and meta-analysis of randomised controlled trials

There has been growing interest in the potential of vitamin D food fortification in Europe as a means of addressing low vitamin D status. The WHO-FAO suggest that choosing a suitable food vehicle and ensuring the combination of the food vehicle and the fortificant will be efficacious and effective are of key importance to a successful food fortification programme. Our key objective was to conduct a systematic review and meta-analysis to investigate the effect of various animal- and plant-based food vehicles fortified with vitamin D (as D3 or D2) on circulating 25-hydroxyvitamin D [25(OH)D] concentrations. A list of prioritised food vehicles was established and we searched PubMed, Embase, Scopus and Web of Science for randomised controlled trials (RCTs) which used these vehicles individually, and which met prespecified criteria. The searches identified 49 papers which described suitable RCTs using vitamin D-fortified bread/savoury biscuits (n = 5), orange juice (n = 5), UV-mushrooms (n = 8), cheese (n = 3), yogurt (n = 5), fluid milk (n = 13), powdered milk (n = 5), eggs (n = 2), edible oils (n = 4), or breakfast cereal (n = 1). No suitable RCTs were identified for rice, maize flour, butter, margarine or dairy spreads, plant-based milk or yogurt alternatives. Random-effects meta-analyses of each food vehicle individually indicated weighted mean differences (WMD) in 25(OH)D in the range ∼9-35 nmol/L (3-15 RCT arms, depending on vehicle), and all statistically significant (P < 0.01-0.0001), with the exception of UV-mushrooms (P = 0.06). Heterogeneity was variable (I2 =33-99%, depending on vehicle), but subgroup analysis based on vitamer and dose reduced it in some instances. Sub-group analysis on the basis of whether the food vehicles were from plant-based or animal-based origin showed no significant difference in WMD (15.2 versus 15.9 nmol/L, respectively; P = 0.48). These results support the use of various animal- and plant-based food vehicles for vitamin D fortification to improve circulating 25(OH)D concentrations in populations. This work was registered with PROSPERO as CRD42023439883.

Vitamin D: determinants of status, indications for testing and knowledge in a convenience sample of Irish adults

Vitamin D deficiency is common in Irish adults, though there is limited research on its determinants, knowledge of vitamin D or indications for testing. We aimed to explore the determinants of vitamin D status in adults and examine knowledge and reasons for testing. The study population comprised adults who had serum 25-hydroxyvitamin D tested by general practitioners request at a Dublin Hospital in 2020. Questionnaires detailing dietary intake, sun exposure, ethnicity, biophysical factors and vitamin D knowledge were sent to a sample stratified by age, sex and vitamin D status. In total, there were 383 participants, mean age 56·0 (sd 16·6) years. Wintertime deficiency disproportionally affected non-white v. white (60 % v. 24 %, P < 0·001). The greatest predictors of deficiency were low vitamin D intake (< 10 μg/d) (P < 0·001) and non-white ethnicity (P = 0·006), followed by sun avoidance (P = 0·022). It was also more prevalent in those with lower body exposure when outdoors. The majority (86 %) identified vitamin D as important for bone health. However, 40 % were tested for non-clinical indications and half were not aware of the recommended daily allowance (RDA). Low vitamin D intake was the most important determinant of deficiency, but ethnicity and sun exposure habits were also significant predictors. The majority had no clear indication for testing and were not aware of the RDA. Public health policies to improve knowledge and vitamin D intake, especially for those of non-white ethnicity and with reduced sun exposure, should be considered.

Meta-Analysis of European Clinical Trials Characterizing the Healthy-Adult Serum 25-hydroxyvitamin D Response to Vitamin D Supplementation

To obtain reliable data that allow health authorities to re-evaluate recommendations for oral vitamin D uptake, we conducted a meta-analysis to investigate the impact of supplementation on serum 25-hydroxyvitamin D (25(OH)D) levels in healthy adults in Europe. Of the publications identified (n = 4005) in our literature search (PUBMED, through 2 January 2022), 49 primary studies (7320 subjects, 73 study arms) were eligible for inclusion in our meta-analysis. The risk of bias was assessed using the Cochrane RoB tool based on seven categories, according to which each study is rated using three grades, and overall was rated as rather low. The median duration of intervention was 136.78 days (range, 1088 days); the mean weighted baseline 25(OH)D concentration and mean age were 33.01 vs. 33.84 nmol/L and 46.8 vs. 44.8 years in the vitamin D and placebo groups, respectively. Using random-effects models, 25(OH)D levels were increased by 36.28 nmol/L (95% CI 31.97-40.59) in the vitamin D group compared to the placebo, with a relative serum increment of 1.77 nmol/L per 2.5 μg of vitamin D daily. Notably, the relative serum 25(OH)D increment was affected by various factors, including the dosage and baseline serum 25(OH)D concentration, decreasing with increasing vitamin D doses and with increasing baseline serum levels. We estimate that supplementation in all healthy adults in Europe with appr. 25 μg of vitamin D (1000 IU) daily would raise serum 25(OH)D levels in 95% of the population to ≥50 nmol/L. Our work provides health authorities with reliable data that can help to re-evaluate recommendations for oral vitamin D supplementation.

Fortification of Staple Foods for Household Use with Vitamin D: An Overview of Systematic Reviews

Vitamin D deficiency is a global public health concern with significant implications for bone health and chronic disease prevention. Our aim was to summarize the evidence from Cochrane and other systematic reviews evaluating the benefits or harms of vitamin D fortification of staple foods for household use. In April 2023, we systematically searched Ovid MEDLINE, Embase, Epistemonikos and the Cochrane Database of Systematic Reviews for systematic reviews investigating the effects of vitamin D fortification of food in general populations of any age. We used Cochrane methodology and assessed the methodological quality of included studies using AMSTAR (A MeaSurement Tool to Assess Systematic Reviews). We assessed the degree of overlap among reviews. All outcomes included in systematic reviews were assessed. The protocol is registered in PROSPERO (registration number: CRD42023420991). We included 27 systematic reviews out of 5028 records for analysis. Overall, 11 out of 12 systematic reviews calculating pooled estimates reported a significant increase in serum 25(OH)D concentrations. The mean change in serum 25(OH)D concentrations per additional 100 units of vitamin D ranged from 0.7 to 10.8 nmol/L. Fortification of food with vitamin D showed a reduction in the prevalence of vitamin D deficiency based on high-certainty evidence. Parathormone (PTH) levels were described to decrease, bone mineral density to increase, while the effects on other bone turnover markers were inconsistent. Fortification did not significantly impact most anthropometric parameters, but it seemed to positively influence lipid profiles. In summary, fortification of food with vitamin D results in a reduction of vitamin D deficiency and might increase serum 25(OH)D concentrations, to varying extents depending on the fortified vehicle and population characteristics. Additionally, fortification may have a positive impact on bone turnover and lipid metabolism but may only have a limited effect on anthropometric parameters.

Increased Serum Total and Free 25-Hydroxyvitamin D with Daily Intake of Cholecalciferol-Fortified Skim Milk: A Randomized Controlled Trial in Colombian Adolescents

BACKGROUND

The efficacy of cholecalciferol (vitamin D3) food fortification in low- and middle-income countries near the Equator is unknown.

OBJECTIVES

We examined the effects of providing cholecalciferol-fortified skim milk to adolescents and their mothers on serum total 25(OH)D, free 25(OH)D, and vitamin D-binding protein (DBP) concentrations in a randomized controlled trial.

METHODS

We randomly assigned 80 Colombian families each with a child aged 12-14.5 y and their mother 1 L of skim milk daily, either fortified with 2400 IU (60 μg) cholecalciferol or unfortified, for 6 wk. We prescribed 500 mL of milk daily to adolescents; mothers consumed the remainder ad libitum. We estimated intent-to-treat effects as the between-arm difference in the change in serum total and free 25(OH)D and DBP concentrations from baseline to the end of follow-up. Secondary analyses included stratification by baseline characteristics and per-protocol comparisons.

RESULTS

Among adolescents, fortification effects (95% CI) on serum total 25(OH)D, free 25(OH)D, and DBP concentrations were 5.4 nmol/L (2.1, 8.8 nmol/L), 0.6 pmol/L (-0.2, 1.4 pmol/L), and -416 nmol/L (-944, 112 nmol/L), respectively. Effects on total 25(OH)D were stronger in adolescents with lower DBP concentrations, darker skin, less sunlight exposure, and higher compliance than in their respective counterparts. Fortification increased free 25(OH)D concentrations in high compliers. Among mothers, the effects (95% CI) on total 25(OH)D and DBP concentrations were 4.0 nmol/L (0.6, 7.5 nmol/L) and -128 nmol/L (-637, 381 nmol/L), respectively. There were no adverse events.

CONCLUSIONS

Provision of cholecalciferol-fortified skim milk increases serum total 25(OH)D concentrations in Colombian adolescents and adult women.

Low socioeconomic status predicts vitamin D status in a cross-section of Irish children

Vitamin D is essential for bone and muscle health with adequate status in childhood crucial for normal skeletal development. We aimed to investigate vitamin D status in a convenience sample (n = 1226) of Irish children (aged 1-17 years) who had serum 25-hydroxyvitamin D (25(OH)D) tested by request of their GP at a Dublin Hospital between 2014 and 2020. We examined predictors including age, sex, season and socioeconomic status (SES). Vitamin D deficiency (<30 nmol/l) was prevalent affecting 23 % and was more common in disadvantaged areas (34 %) and in those aged >12 v. ≤12 years (24 % v. 16 %, P = 0⋅033). The greatest predictor was SES (disadvantaged v. affluent, OR 2⋅18, CI 1⋅34, 3⋅53, P = 0⋅002), followed by female sex (OR 1⋅57, CI 1⋅15, 2⋅14, P = 0⋅005) and winter season (October to February, OR 1⋅40, CI 1⋅07, 1⋅84, P = 0⋅015). A quarter of our sample of children were deficient, rising to one-third in those in disadvantaged areas. Females and those aged over 12 years had a higher prevalence of deficiency. Public health strategies to improve vitamin D status in Irish children, including systematic food fortification may need to be considered to address this issue.

Individual participant data (IPD)-level meta-analysis of randomised controlled trials to estimate the vitamin D dietary requirements in dark-skinned individuals resident at high latitude

CONTEXT AND PURPOSE

There is an urgent need to develop vitamin D dietary recommendations for dark-skinned populations resident at high latitude. Using data from randomised controlled trials (RCTs) with vitamin D₃-supplements/fortified foods, we undertook an individual participant data-level meta-regression (IPD) analysis of the response of wintertime serum 25-hydroxyvitamin (25(OH)D) to total vitamin D intake among dark-skinned children and adults residing at ≥ 40° N and derived dietary requirement values for vitamin D.

METHODS

IPD analysis using data from 677 dark-skinned participants (of Black or South Asian descent; ages 5-86 years) in 10 RCTs with vitamin D supplements/fortified foods identified via a systematic review and predefined eligibility criteria. Outcome measures were vitamin D intake estimates across a range of 25(OH)D thresholds.

RESULTS

To maintain serum 25(OH)D concentrations ≥ 25 and 30 nmol/L in 97.5% of individuals, 23.9 and 27.3 µg/day of vitamin D, respectively, were required among South Asian and 24.1 and 33.2 µg/day, respectively, among Black participants. Overall, our age-stratified intake estimates did not exceed age-specific Tolerable Upper Intake Levels for vitamin D. The vitamin D intake required by dark-skinned individuals to maintain 97.5% of winter 25(OH)D concentrations ≥ 50 nmol/L was 66.8 µg/day. This intake predicted that the upper 2.5% of individuals could potentially achieve serum 25(OH)D concentrations ≥ 158 nmol/L, which has been linked to potential adverse effects in older adults in supplementation studies.

CONCLUSIONS

Our IPD-derived vitamin D intakes required to maintain 97.5% of winter 25(OH)D concentrations ≥ 25, 30 and 50 nmol/L are substantially higher than the equivalent estimates for White individuals. These requirement estimates are also higher than those currently recommended internationally by several agencies, which are based predominantly on data from Whites and derived from standard meta-regression based on aggregate data. Much more work is needed in dark-skinned populations both in the dose-response relationship and risk characterisation for health outcomes.

TRAIL REGISTRATION

PROSPERO International Prospective Register of Systematic Reviews (Registration Number: CRD42018097260).

Vitamin D Status and Health Outcomes in School Children in Northern Ireland: Year One Results from the D-VinCHI Study

(1) Background: Vitamin D status has never been investigated in children in Northern Ireland (UK). (2) Methods: Children (4-11 years) (n = 47) were recruited from November 2019 to March 2020 onto the cross-sectional study. Anthropometry was assessed. Plasma 25-hydroxyvitamin D (25(OH)D) was analysed. Vitamin D intake, parental knowledge and perceptions, participant habits, physical activity and sedentary behaviour were established via questionnaire. Muscle strength was assessed via isometric grip strength dynamometry and balance via dominant single-leg and tandem stance. Parathyroid hormone, bone turnover markers (OC, CTX and P1NP), glycated haemoglobin and inflammatory markers (CRP, IFN-γ, IL-10, IL-12p70, IL-13, IL-1β, IL-2, IL-4, IL-6, IL-8 and TNF-α) were analysed. (3) Results: Mean (SD) 25(OH)D was 49.17 (17.04) nmol/L (n = 47); 44.7% of the children were vitamin D sufficient (25(OH)D >50 nmol/L), 48.9% were insufficient (25-50 nmol/L) and 6.4% were deficient (<25 nmol/L). 25(OH)D was positively correlated with vitamin D intake (µg/day) (p = 0.012, r = 0.374), spring/summer outdoor hours (p = 0.006, r = 0.402) and dominant grip strength (kg) (p = 0.044, r = 0.317). Vitamin D sufficient participants had higher dietary vitamin D intake (µg/day) (p = 0.021), supplement intake (µg/day) (p = 0.028) and spring/summer outdoor hours (p = 0.015). (4) Conclusion: Over half of the children were vitamin D deficient or insufficient. Wintertime supplementation, the consumption of vitamin D rich foods and spring/summer outdoor activities should be encouraged to minimise the risk of vitamin D inadequacy.

Vitamin D biomarkers for Dietary Reference Intake development in children: a systematic review and meta-analysis

BACKGROUND

Circulating 25-hydroxyvitamin D [25(OH)D] has been the accepted vitamin D exposure/intake biomarker of choice within recent DRI exercises, but use of other vitamin D-related biomarkers as well as functional markers has been suggested. These may be of value in future vitamin D DRI exercises, such as the FAO/WHO's one for young children.

OBJECTIVES

To systematically review the usefulness of circulating 25(OH)D, parathyroid hormone (PTH), free and bioavailable 25(OH)D, C3-epimer of 25(OH)D, vitamin D3, 24,25-dihydroxyvitamin D [24,25(OH)2D], and bone turnover markers and calcium absorption as vitamin D biomarkers for DRI development in children.

METHODS

Methods included structured searches of published articles, full-text reviews, data extraction, quality assessment, meta-analysis, and random-effects meta-regression.

RESULTS

Fifty-nine vitamin D supplementation randomized controlled trials (RCTs) were included (39 in infants/children as the priority group and the remainder in adults since pediatric studies were absent/limited). Vitamin D supplementation significantly raised circulating 25(OH)D in infants and children, but the response was highly heterogeneous [weighted mean difference (WMD): 27.7 nmol/L; 95% CI: 22.9, 32.5; 27 RCTs; I2 = 93%]. Meta-regression suggested an increase by 1.7 nmol/L (95% CI: 0.7, 2.6) in serum 25(OH)D per each 100-IU increment in vitamin D intake (P = 0.0005). Vitamin D supplementation had a significant effect on circulating 24,25(OH)2D (WMD: 3.4 nmol/L; 95% CI: 2.4, 4.5; 13 RCTs; I2 = 95%), with a dose-response relation (+0.15 nmol/L per 100 IU; 95% CI: -0.01, 0.29). With circulating PTH, although there was a significant effect of vitamin D on WMD (P = 0.05), there was no significant dose-response relation (P = 0.32). Pediatric data were too limited in relation to the usefulness of the other biomarkers.

CONCLUSIONS

Circulating 25(OH)D may be a useful biomarker of vitamin D exposure/intake for DRI development in infants and children. Circulating 24,25(OH)2D also showed some promise, but further data are needed, especially in infants and children.

25-Hydroxyvitamin D reference percentiles and the role of their determinants among European children and adolescents

BACKGROUND/OBJECTIVES

To provide age- and sex-specific percentile curves of serum 25-hydroxyvitamin D (25(OH)D) by determinants from 3-<15 year-old European children, and to analyse how modifiable determinants influence 25(OH)D.

SUBJECTS/METHODS

Serum samples were collected from children of eight European countries participating in the multicenter IDEFICS/I.Family cohort studies. Serum 25(OH)D concentrations were analysed in a central lab by a chemiluminescence assay and the values from 2171 children (N = 3606 measurements) were used to estimate percentile curves using the generalized additive model for location, scale and shape. The association of 25(OH)D with time spent outdoors was investigated considering sex, age, country, parental education, BMI z score, UV radiation, and dietary vitamin D in regressions models.

RESULTS

The age- and sex-specific 5th and 95th percentiles of 25(OH)D ranged from 16.5 to 73.3 and 20.8 to 79.3 nmol/l in girls and boys, respectively. A total of 63% had deficient (<50 nmol/l), 33% insufficient (50-<75 nmol/l) and 3% sufficient (≥75 nmol/l) levels. 25(OH)D increased with increasing UV radiation, time spent outdoors, and vitamin D intake and slightly decreased with increasing BMI z score and age. The odds ratio (OR) for a non-deficient 25(OH)D status (reference category: deficient status) by one additional hour spent outdoors was 1.21, 95% CI [1.12-1.31], i.e., children who spent one more hour per day outdoors than other children had a 21% higher chance of a non-deficient than a deficient status.

CONCLUSION

A majority of children suffer from deficient 25(OH)D. UV radiation, outdoor time, and dietary vitamin D are important determinants of 25(OH)D.

Vitamin D: Dosing, levels, form, and route of administration: Does one approach fit all?

The 4^th International Conference on Controversies in Vitamin D was held as a virtual meeting in September, 2020, gathering together leading international scientific and medical experts in vitamin D. Since vitamin D has a crucial role in skeletal and extra-skeletal systems, the aim of the Conference was to discuss improved management of vitamin D dosing, therapeutic levels and form or route of administration in the general population and in different clinical conditions. A tailored approach, based on the specific mechanisms underlying vitamin D deficiency in different diseases that were discussed, was recommended. Specifically, in comparison to healthy populations, higher levels of vitamin D and greater amounts of vitamin D were deemed necessary in osteoporosis, diabetes mellitus, obesity (particularly after bariatric surgery), and in those treated with glucocorticoids. Emerging and still open issues were related to target vitamin D levels and the role of vitamin D supplementation in COVID-19 since low vitamin D may predispose to SARS-CoV-2 infection and to worse COVID-19 outcomes. Finally, whereas oral daily cholecalciferol appears to be the preferred choice for vitamin D supplementation in the general population, and in most clinical conditions, active vitamin D analogs may be indicated in patients with hypoparathyroidism and severe kidney and liver insufficiency. Parenteral vitamin D administration could be helpful in malabsorption syndromes or in states of vitamin D resistance.Specific guidelines for desired levels of vitamin D should be tailored to the different conditions affecting vitamin D metabolism with the goal to define disease-specific normative values.

Lifestyle Modification Program on a Metabolically Healthy Elderly Population with Overweight/Obesity, Young-Old vs. Old-Old. CONSEQUENCES of COVID-19 Lockdown in This Program

The SARS-CoV-2 pandemic led to lockdowns, which affected the elderly, a high-risk group. Lockdown may lead to weight gain due to increased food intake and reduced physical activity (PA). Our study aimed to analyze the impact of a 12-month lifestyle intervention on a metabolically healthy overweight/obese elderly (MHOe) population and how the lockdown by COVID-19 affected this program. Methods: MHOe participants (65–87 years) were recruited to participate in a lifestyle modification intervention based on the Mediterranean diet (MedDiet) and regular PA. Participants were classified into two groups: young-old (<75 years) or old-old (≥75 years). Anthropometric and clinical characteristics, energy intake, and energy expenditure were analyzed at baseline and after 12 months of intervention. Results: The final sample included 158 MHOe participants of both sexes (age: 72.21 ± 5.04 years, BMI: 31.56 ± 3.82 kg/m²): 109 young-old (age: 69.26 ± 2.83 years, BMI: 32.0 ± 3.85 kg/m²) and 49 old-old (age: 78.06 ± 2.88 years, BMI: 30.67 ± 3.64 kg/m²). After 12 months of intervention and despite lockdown, the young-old group increased MedDiet adherence (+1 point), but both groups drastically decreased daily PA, especially old-old participants. Fat mass significantly declined in the total population and the young-old. Depression significantly increased (26.9% vs. 21.0%, p < 0.0001), especially in the old-old (36.7% vs. 22.0%, p < 0.0001). No significant changes were found in the glycemic or lipid profile. Conclusions: This study indicates that ongoing MedDiet intake and regular PA can be considered preventative treatment for metabolic diseases in MHOe subjects. However, mental health worsened during the study and should be addressed in elderly individuals.

Vitamin D Food Fortification and Biofortification Increases Serum 25-Hydroxyvitamin D Concentrations in Adults and Children: An Updated and Extended Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Low vitamin D status is a global public health issue that vitamin D food fortification and biofortification may help to alleviate.

OBJECTIVES

We investigated the effect of vitamin D food fortification and biofortification on circulating 25-hydroxyvitamin D (25(OH)D) concentrations. We expanded the scope of earlier reviews to include adults and children, to evaluate effects by vitamin D vitamer, and investigate linear and nonlinear dose-response relations.

METHODS

We conducted a systematic review and meta-analysis. We searched CINAHL, MEDLINE, PubMed, Embase, the Cochrane Library, and gray and unpublished literature sites for randomized controlled trials, including people of all ages, with the criteria: absence of illness affecting vitamin D absorption, duration ≥4 wk, equivalent placebo food control, dose quantification, dose ≥5 μg/d, baseline and endpoint or absolute change in 25(OH)D concentrations reported, random allocation, and participant blinding. Quality was assessed using the Jadad Scale.

RESULTS

Data from 34 publications (2398 adults: 1345 intervention, 1053 controls; 1532 children: 970 intervention, 562 controls) were included. Random-effects meta-analysis of all studies combined (mean dose 16.2 μg/d) indicated a pooled treatment effect of 21.2 nmol/L (95% CI: 16.2, 26.2), with a greater effect for studies using cholecalciferol than ergocalciferol. Heterogeneity was high (I2  > 75%). Metaregression analyses for all studies combined suggested positive effect differences for baseline circulating 25(OH)D concentrations <50 nmol/L, dose ≥10 μg/d and a negative effect difference when the intervention arm included a calcium dose ≥500 mg/d greater than the control arm. Dose-response rates were found to be nonlinear (Wald test for nonlinearity P < 0.001). For all studies combined, a threshold occurred at ∼26 nmol/L for a dose of ∼21 μg/d.

CONCLUSIONS

These results support use of vitamin D food fortification to improve circulating 25(OH)D circulations in populations. This work was registered with PROSPERO as CRD42020145497.

Vitamin D Incorporation in Foods: Formulation Strategies, Stability, and Bioaccessibility as Affected by the Food Matrix

Inadequate intake of vitamin D is a global health issue related to severe diseases, mainly involving subjects with dark skin pigmentation, patients affected by malnutrition, malabsorption syndromes, or obesity, and elderly people. Some foods fortified with vitamin D have been tested in vivo, but fortification strategies with a global outreach are still lacking. This review is focused on food fortification with vitamin D, with the aim to collect information on (a) formulation strategies; (b) stability during processing and storage; and (c) in vitro bioaccessibility. Approaches to add vitamin D to various foods were analyzed, including the use of free vitamin D, vitamin D loaded in simple and double nanoemulsions, liposomes, casein micelles, and protein nanocapsules. Numerous studies were reviewed to elucidate the impact of food technologies on vitamin D’s stability, and mechanisms that lead to degradation were identified—namely, acid-catalyzed isomerization, radical-induced oxidation, and photo-oxidation. There is, however, a lack of kinetic data that allow for the prediction of vitamin D’s stability under industrial processing conditions. The roles that lipids, proteins, fibers, and antioxidants play in vitamin bioaccessibility have been clarified in various studies, while future needs include the design of specific food matrices that simultaneously achieve a balance between the long-term stability, bioaccessibility and, ultimately, in vivo functionality of vitamin D.

Foods for Plant-Based Diets: Challenges and Innovations

Plant-based diets have become popular as a means of reducing the environmental footprint of the diet and promoting human health and animal welfare. Although the percentages of vegetarians and vegans are low compared to omnivores, their numbers have increased significantly in the last years. The use of non-animal food products other than meat alternatives is also increasing and this tendency constitutes an opportunity for the food industry. In this review, we present that plant-based meat and milk alternatives are consolidated but that there is a niche for egg, seafood alternatives, and new products which may not resemble any traditional animal food. However, not all animal food substitutes are sustainable and some of them are even ultra-processed. In addition, there are concerns on safety and labeling, and consumers demand clear information and regulation. The challenges in this field are connected with food design and technology, sensory science, nutrition, and dietetics. Moreover, adequate selection and combination of foods is important in order to achieve consumer acceptance while preventing nutritional deficiencies in those who choose this type of diet.

Meteorological Condition and Air Pollution Exposure Associated with Vitamin D Deficiency: A Cross-Sectional Population-Based Study in China

Objective

The aim of this study was to investigate the status of Vitamin D deficiency and the effect of environmental factors on Vitamin D levels so as to provide theoretical support for public health promotion in this region.

Methods

A total of 22,387 subjects who underwent a physical examination at the center in the West China Hospital, Sichuan University, between April, 2018 and May, 2020 were enrolled in this study. Their data on gender, age, inspection date, serum 25 hydroxyvitamin D (25-(OH) D), parathyroid hormone (PTH), and total calcium were retrospectively reviewed. Next, the percentage of Vitamin D status was compared in different sex and age groups, and the fluctuation of Vitamin D level was described in relation to the change of environment. Finally, the univariable and multivariable linear regression analyses were performed to explore the risk and protective factors of Vitamin D deficiency.

Results

The proportion of Vitamin D deficiency in this area was 42.17%, and it was significantly higher among women and young people. The fluctuation trend of 25-(OH) D levels are consistent with temperature and solar radiation, and opposite to air quality, in the whole year. There was a positive relationship between 25-(OH) D levels with temperature and solar radiation; however, parathyroid hormone, female and AQI were negatively correlated with Vitamin D levels.

Conclusion

Vitamin D deficiency is common in subtropic areas, such as Sichuan Basin, which is related to solar radiation and air pollution.

Contribution of Vitamin D2 and D3 and Their Respective 25-Hydroxy Metabolites to the Total Vitamin D Content of Beef and Lamb

BACKGROUND

Red meat and meat products can contribute meaningfully to the mean daily intake of vitamin D. Beef and lamb can contain vitamin D3 and 25-hydroxyvitamin D3 [25(OH)D3] but also potentially vitamin D2 and 25-hydroxyvitamin D2 [25(OH)D2], all of which contribute to meat's vitamin D activity.

OBJECTIVES

We aimed to measure the vitamin D3, vitamin D2, 25(OH)D3, and 25(OH)D2 content of Irish beef and lamb.

METHODS

Full striploin steaks (longissimus dorsi) (n = 39) from beef cattle slaughtered in winter, spring, summer, and autumn as well as lamb steaks (hind leg) from sheep slaughtered in autumn (n = 8) were sourced and homogenized. The contents of all 4 vitamin D-related compounds were analyzed using an LC-tandem MS method in conjunction with the National Institute of Standards and Technology's standard reference material no. 1546a-Meat Homogenate. The total vitamin D activity of meat was defined as: {vitamin D3 + [25(OH)D3 × 5] + vitamin D2 + [25(OH)D2 × 5]}.

RESULTS

The median (IQR) total vitamin D activity of striploin beef steak (n = 39, irrespective of season) was 0.56 (0.37-0.91) μg/100 g. The content of all 4 vitamin D compounds in beef steak varied significantly (P < 0.0001) with season (n = 8-11/season group). Median total vitamin D activity of beef steak increased in a stepwise manner (P < 0.0001) from winter to the following autumn (increasing from 0.31 to 1.07 μg/100 g). The mean total vitamin D activity of lamb samples (n = 8) from autumn was 0.47 μg/100 g.

CONCLUSIONS

About one-third of the total vitamin D activity of Irish beef was attributable to its combined vitamin D2 and 25(OH)D2 content, estimates of which are largely or completely missed in food composition tables. There was significant seasonal variation in all 4 vitamin D compounds as well as in total vitamin D activity, which has implications for vitamin D nutrient claims for beef.