Developing and testing personalised nutrition feedback for more sustainable healthy diets: the MyPlanetDiet randomised controlled trial protocol.

PURPOSE: Agriculture and food production contribute to climate change. There is mounting pressure to transition to diets with less environmental impact while maintaining nutritional adequacy. MyPlanetDiet aimed to reduce diet-related greenhouse gas emissions (GHGE) in a safe, nutritionally adequate, and acceptable manner. This paper describes the trial protocol, development, and testing of personalised nutrition feedback in the MyPlanetDiet randomised controlled trial (RCT). METHODS: MyPlanetDiet was a 12-week RCT that provided standardised personalised nutrition feedback to participants based on new sustainable healthy eating guidelines (intervention) or existing healthy eating guidelines (control) using decision trees and corresponding feedback messages. To test the personalised nutrition feedback, we modelled a sample of 20 of the MyPlanetDiet participants baseline diets. Diets were modelled to adhere to control and intervention decision trees and feedback messages. Modelled nutrient intakes and environmental metrics were compared using repeated measure one-way analysis of covariance. RESULTS: Intervention diets had significantly lower (p < 0.001) diet-related GHGE per 2500 kilocalories (kcal) (4.7 kg CO2-eq) relative to control (6.6 kg CO2-eq) and baseline (7.1 kg CO2-eq). Modelled control and intervention diets had higher mean daily intakes of macronutrients (carbohydrates, fibre, and protein) and micronutrients (calcium, iron, zinc, and iodine). Modelled control and intervention diets had lower percent energy from fat and saturated fat relative to baseline. CONCLUSIONS: Adherence to the MyPlanetDiet personalised nutrition feedback would be expected to lead to better nutrient intakes and reduced diet-related GHGE. The MyPlanetDiet RCT will test the effectiveness and safety of personalised feedback for a more sustainable diet. TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION: Clinical trials registration number: NCT05253547, 23 February 2022.

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.

Access to nutrition advice and knowledge, attitudes and practices of pregnant women in Ireland: A cross-sectional study.

BACKGROUND: Healthy nutritional status, appropriate gestational weight gain and a balanced diet are important predictors of perinatal health outcomes. However, gaps exist in the translation of nutrition recommendations into dietary practices of women before and during pregnancy. The present study explored the relationship between access to nutrition advice, nutrition knowledge, attitudes and practices among pregnant women. METHODS: Pregnant women aged > 18 years in Ireland were eligible to complete a self-administered survey consisting of four subsections (demographics, nutrition knowledge, attitudes and practices) delivered online through Qualtrics. RESULTS: In this convenience sample (n = 334, median [interquartile range] gestation, 25.0 [16.0, 34.0] weeks), 85% had at least an honours bachelor degree and 88.9% planned their pregnancy. Two out of five women received nutrition advice during their pregnancy, mostly from a midwife. Based on the percentage of correct answers (of 15 questions), women with previous nutrition education (e.g., school home economics) had better median [interquartile range] nutrition knowledge than those with none (80.0% [66.7, 86.7%] vs. 73.3% [60.0, 80.0%], p < 0.001). Those who received nutrition advice during pregnancy did not score higher than those who did not (73.3% [66.7, 80.0%] vs. 73.3% [66.7, 80.0%], p = 0.6). Over three-quarters of participants considered nutritional supplement use to be very or extremely important. Although 73.6% and 92.4% took supplements prior to and during pregnancy, only 25.7% reported compliance with periconceptional folic acid supplementation guidelines. Half of respondents considered healthy eating during pregnancy as very or extremely important. CONCLUSIONS: Access to nutrition advice during pregnancy was inadequate with poor nutrition knowledge, attitudes and practices observed. Accessible, evidence-based nutrition education for women prior to and during pregnancy is required.

Can micronutrient requirements be met by diets from sustainable sources: outcomes of dietary modelling studies using diet optimization.

BACKGROUND: Consumption of diets from sustainable sources is required for planetary health, however, large sections of the population, including females of reproductive age and children, will be at risk of not meeting their micronutrient (MN) requirements in a complete transition to plant-based foods. Constrained diet optimization methods use mathematical programming to construct diets that meet predefined parameters and may contribute towards modelling dietary solutions that meet nutritional and planetary targets. OBJECTIVE: Review the evidence from diet optimization studies proposing solutions to ensure MN availability in the context of a transition to diets from sustainable sources. APPROACH: Narrative review focusing on literature published over the last five years. RESULTS: Dietary modelling using diet optimization can design a range of omnivorous and plant-based diets that meet individual MN requirements, have reduced environmental impacts, and minimize deviation from culturally acceptable dietary practices. Using data from large-scale dietary surveys, diet optimization can support development of food-based dietary guidelines; identify limiting MNs in a particular context or a conflict between constraints e.g. nutrition and environment; explore food-based strategies to increase nutrient supply, such as fortification; and support trial design. Methods used and outcomes reported are sources of variability. Individual-level dietary data and MN requirements for population sub-groups such as females of reproductive age and children are important requirements. Although maintaining iron and zinc intakes are regularly reported to present challenges in diets from sustainable sources, few studies have considered bioavailability, which reduces with increased dietary phytate. These and other data gaps including acceptability and affordability must be addressed to improve the applicability of modelling outcomes in population recommendations. CONCLUSIONS: Dietary modelling using diet optimization can be useful in the design of more sustainable diets that meet MN requirements, however, translation of outcomes into dietary intervention studies is required to test real-world application and adoption into dietary guidelines.

A widespread shift towards plant-based diets could increase the risk of inadequate intakes of micronutrients typically sourced in foods of animal origin, particularly among females of reproductive age and children.Modelling of dietary intake data collected among individuals using techniques such as diet optimization could be helpful in guiding recommendations and intervention strategies; translation into intervention studies is required.Representative data in different population groups and settings, with methods incorporated to address data gaps on bioavailability of micronutrients, food fortification, and affordability, will improve the applicability of modelling outcomes.

Impact of consuming an environmentally protective diet on micronutrients: a systematic literature review.

BACKGROUND: 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. OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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).

A Systematic Review Supporting the Endocrine Society Clinical Practice Guidelines on Vitamin D.

CONTEXT: Low vitamin D status is common and is associated with various common medical conditions. OBJECTIVE: To support the development of the Endocrine Society's Clinical Practice Guideline on Vitamin D for the Prevention of Disease. METHODS: We searched multiple databases for studies that addressed 14 clinical questions prioritized by the guideline panel. Of the 14 questions, 10 clinical questions assessed the effect of vitamin D vs no vitamin D in the general population throughout the lifespan, during pregnancy, and in adults with prediabetes; 1 question assessed dosing; and 3 questions addressed screening with serum 25-hydroxyvitamin D (25[OH]D). The Grading of Recommendations Assessment, Development and Evaluation approach was used to assess certainty of evidence. RESULTS: Electronic searches yielded 37 007 citations, from which we included 151 studies. In children and adolescents, low-certainty evidence suggested reduction in respiratory tract infections with empiric vitamin D. There was no significant effect on select outcomes in healthy adults aged 19 to 74 years with variable certainty of evidence. There was a very small reduction in mortality among adults older than 75 years with high certainty of evidence. In pregnant women, low-certainty evidence suggested possible benefit on various maternal, fetal, and neonatal outcomes. In adults with prediabetes, moderate certainty of evidence suggested reduction in the rate of progression to diabetes. Administration of high-dose intermittent vitamin D may increase falls, compared to lower-dose daily dosing. We did not identify trials on the benefits and harms of screening with serum 25(OH)D. CONCLUSION: The evidence summarized in this systematic review addresses the benefits and harms of vitamin D for the prevention of disease. The guideline panel considered additional information about individuals' and providers' values and preferences and other important decisional and contextual factors to develop clinical recommendations.

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.