Systematic Review on the Impact of Salt-Reduction Initiatives by Socioeconomic Position to Address Health Inequalities in Adult Populations.

CONTEXT: International evidence shows that individuals from low socioeconomic positions (SEPs) consume a greater amount of salt than those from higher SEPs. This health inequality reflects a disproportionate effect of salt-reduction initiatives, and explains a higher prevalence of cardiovascular disease among the most vulnerable populations. Assessing this impact can help tailor implementation strategies in the future for the benefit of the whole population. OBJECTIVE: The aim was to systematically review the literature and assess the impact of salt-reduction initiatives on health and behavioral outcomes of adults by SEP. DATA SOURCES: The search strategy was conducted in 6 databases (CINAHL, Scopus, Embase, MEDLINE, PubMed, and Web of Science) using the terms sodium or salt, social class, policy, intervention or campaign. Peer-reviewed articles assessing salt-reduction interventions in adults reporting dietary or behavioral changes on salt consumption measurements by SEP were considered for inclusion. Articles in which salt intake data were not reported by SEP were excluded. DATA EXTRACTION: Two reviewers collected data independently using a predesigned electronic form. The AXIS and RoB 2 tools were used for critical appraisal. DATA ANALYSIS: Eight studies containing data from 111 548 adults were interpreted according to study design following a narrative synthesis approach. RESULTS: Salt-reduction initiatives are effective at reducing the intake of salt and sodium in adults. When reporting the impact of these initiatives, research outcomes are generally not evaluated by SEP, representing a question yet to be explored. CONCLUSION: A small number of articles that focused on the impact of salt-reduction interventions reported salt consumption measurements by SEP, indicating a critical gap in research. The limited evidence suggests potentially greater health benefits to be gained from the implementation of population-wide initiatives in adults of low SEP. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. CRD42021238055.

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).

Aligning Environmental Sustainability, Health Outcomes, and Affordability in Diet Quality: A Systematic Review.

Improving diet quality while simultaneously maintaining planetary health is of critical interest globally. Despite the shared motivation, advancement remains slow, and the research community continues to operate in silos, focusing on certain pairings (diet-climate), or with a discipline-specific lens of a sustainable diet, rather than examining their totality. This review aimed to summarize the literature on adherence to a priori defined dietary patterns in consideration of diet quality, metabolic risk factors for noncommunicable diseases (NCDs), environmental impacts, and affordability. A methodology using PRISMA guidelines was followed, and searches were performed in 7 databases as of October 2022. The Appraisal tool for Cross-Sectional Studies (AXIS) and the National Institutes of Health (NIH) quality assessment tool for observational cohort studies were employed for quality appraisal. The evidence was narratively synthesized according to the characteristics of the diet quality metrics. The review includes 24 studies published between 2017-2023. Thirteen distinct diet quality scores were identified, with those measuring adherence to national dietary guidelines the most reported. Thirteen distinct environmental impact indicators were identified, with greenhouse gas emissions (n=23) reported most. All studies reported on body mass index, and 7 studies assessed the cost of adherence. Our results are consistent with previous findings that healthier diets can reduce environmental impacts; however, incongruities between population and planetary health can occur. Hence, the "sustainability" of dietary patterns is dependent on the choice of indicators selected. Further, healthy, lower impact diets can increase financial cost, but may also provide a protective role against the risk of obesity. Given the Global Syndemic, strategies to reduce obesity prevalence should emphasize the win-win opportunities for population and planetary health through dietary change. Research should identify diets that address multiple environmental concerns to curtail burdens potentially transferring, and harmonize this with sociocultural and equity dimensions. This review was registered at PROSPERO as CRD42021238055.