Strengthening Research that Answers Nutrition Questions of Public Health Importance: Leveraging the Experience of the USDA Nutrition Evidence Systematic Review Team.

The Nutrition Evidence Systematic Review (NESR) team conducts nutrition- and public health-related systematic reviews and is within the USDA's Center for Nutrition Policy and Promotion. NESR has collaborated with scientific experts to conduct systematic reviews on nutrition and public health topics for more than a decade and is uniquely positioned to share recommendations with the research community to strengthen research quality and impact, especially the evidence base that supports public health nutrition guidance, including future editions of the Dietary Guidelines for Americans. Leveraging the expertise of NESR and its systematic review process resulted in the following recommendations for the research community: a) use the strongest study design feasible with sufficient sample size(s); b) enroll study participants who reflect the diversity of the population of interest and report participant characteristics; c) use valid and reliable dietary assessment methods; d) describe the interventions or exposures of interest and use standard definitions to promote consistency; e) use valid and reliable health outcome measures; f) account for variables that may impact the relationship between nutrition-related interventions or exposures and health outcomes; g) carry out studies for a sufficient duration and include repeated measures, as appropriate; and h) report all relevant information to inform accurate interpretation and evaluation of study results. Implementing these recommendations can strengthen nutrition and public health evidence and increase its utility in future public health nutrition systematic reviews. However, implementation will require additional support from the entire research community, including scientific journals and funding agencies.

Temporal Trends in Dietary Sodium Intake Among Adults Aged ≥19 Years - United States, 2003-2016.

Hypertension, which can be brought on by excess sodium intake, affects nearly one half of U.S. adults and is a major risk factor for heart disease, the leading cause of death in the United States (1). In 2019, the National Academies of Sciences, Engineering, and Medicine (NASEM) established the Chronic Disease Risk Reduction (CDRR) intake, a chronic-disease-specific recommendation for dietary sodium of 2,300 mg/day. Reducing daily sodium to CDRR intake is expected to reduce chronic disease risk among healthy persons, primarily by lowering blood pressure (2). Although the 2019 sodium CDRR intake is equivalent in number to the 2005 Tolerable Upper Limit (UL) released by NASEM (then known as the Institute of Medicine), the UL was intended to provide guidance on safe intake levels, not to serve as an intake goal (2). To describe excess sodium intake in the context of the CDRR intake goal, this report analyzed National Health and Nutrition Examination Survey (NHANES) data from 2003 to 2016 to yield temporal trends in usual sodium intake >2,300 mg/day and in mean sodium intake, unadjusted and adjusted for total energy intake, among U.S. adults aged ≥19 years. The percentage of U.S. adults with sodium intake above CDRR intake was 87.0% during 2003-2004 and 86.7% during 2015-2016. Among U.S. adults overall, no significant linear trend was noted from 2003 to 2016 in unadjusted or energy intake-adjusted mean sodium intake. Small, significant declines were observed in mean usual sodium intake among some groups (adults aged 19-50 years, non-Hispanic White adults, adults experiencing obesity, and adults without hypertension). However, after energy adjustment, only adults aged ≥71 years and Mexican American adults demonstrated significant change in usual sodium intake. Many U.S. adults might be at risk for chronic disease associated with sodium intake above CDRR intake, and efforts to lower sodium intake could improve population cardiovascular health. The results of this report support enhanced efforts to reduce population sodium intake and cardiovascular disease risk, including the Food and Drug Administration's (FDA's) recently released guidance for the reduction of sodium in the commercially processed, packaged, and prepared food supply.

Mapping and Analysis of US State and Urban Local Sodium Reduction Laws.

CONTEXT: Excessive sodium consumption contributes to high blood pressure, which is a risk factor for cardiovascular disease. OBJECTIVES: To (1) identify state and urban local laws addressing adult or general population sodium consumption in foods and beverages and (2) align findings to a previously published evidence classification review, the Centers for Disease Control and Prevention Sodium Quality and Impact of Component (QuIC) evidence assessment. DESIGN: Systematic collection of sodium reduction laws from all 50 states, the 20 most populous counties in the United States, and the 20 most populous cities in the United States, including Washington, District of Columbia, effective on January 1, 2019. Relevant laws were assigned to 1 or more of 6 interventions: (1) provision of sodium information in restaurants or at point of purchase; (2) consumer incentives to purchase lower sodium foods; and provision of lower sodium offerings in (3) workplaces, (4) vending machines, (5) institutional meal services, and (6) grocery, corner, and convenience stores. The researchers used Westlaw, local policy databases or city Web sites, and general nutrition policy databases to identify relevant laws. RESULTS: Thirty-nine sodium reduction laws and 10 state laws preempting localities from enacting sodium reduction laws were identified. Sodium reduction laws were more common in local jurisdictions and in the Western United States. Sodium reduction laws addressing meal services (n = 17), workplaces (n = 12), labeling (n = 13), and vending machines (n = 11) were more common, while those addressing grocery stores (n = 2) or consumer incentives (n = 6) were less common. Laws with high QuIC evidence classifications were generally more common than laws with low QuIC evidence classifications. CONCLUSIONS: The distribution of sodium laws in the US differed by region, QuIC classification, and jurisdiction type, indicating influence from public health and nonpublic health factors. Ongoing research is warranted to determine how the strength of public health evidence evolves over time and how those changes correlate with uptake of sodium reduction law.

Evaluation of Dietary Patterns and All-Cause Mortality: A Systematic Review.

Importance: The 2020 Dietary Guidelines Advisory Committee conducted a systematic review of existing research on diet and health to inform the current Dietary Guidelines for Americans. The committee answered this public health question: what is the association between dietary patterns consumed and all-cause mortality (ACM)? Objective: To ascertain the association between dietary patterns consumed and ACM. Evidence Review: Guided by an analytical framework and predefined inclusion and exclusion criteria developed by the committee, the US Department of Agriculture's Nutrition Evidence Systematic Review (NESR) team searched PubMed, the Cochrane Central Register of Controlled Trials, and Embase and dual-screened the results to identify articles that were published between January 1, 2000, and October 4, 2019. These studies evaluated dietary patterns and ACM in participants aged 2 years and older. The NESR team extracted data from and assessed risk of bias in included studies. Committee members synthesized the evidence, developed conclusion statements, and graded the strength of the evidence supporting the conclusion statements. Findings: A total of 1 randomized clinical trial and 152 observational studies were included in the review. Studies enrolled adults and older adults (aged 17-84 years at baseline) from 28 countries with high or very high Human Development Index; 53 studies originated from the US. Most studies were well designed, used rigorous methods, and had low or moderate risks of bias. Precision, directness, and generalizability were demonstrated across the body of evidence. Results across studies were highly consistent. Evidence suggested that dietary patterns in adults and older adults that involved higher consumption of vegetables, fruits, legumes, nuts, whole grains, unsaturated vegetable oils, fish, and lean meat or poultry (when meat was included) were associated with a decreased risk of ACM. These healthy patterns were also relatively low in red and processed meat, high-fat dairy, and refined carbohydrates or sweets. Some of these dietary patterns also included intake of alcoholic beverages in moderation. Results based on additional analyses with confounding factors generally confirmed the robustness of main findings. Conclusions and Relevance: In this systematic review, consuming a nutrient-dense dietary pattern was associated with reduced risk of death from all causes.

The Macronutrient Content of Sodium-Modified Foods Is Unchanged Compared with Regular Counterparts: An Evaluation of Select Categories of Packaged Foods in the United States, 2018.

BACKGROUND: Lowering excess sodium in packaged foods is part of a public health strategy to reduce cardiovascular disease risk. Sales of foods with labeled sodium claims increased during the past decade. Yet, it is unclear whether sugars or fats were added during the reformulation of foods that might counter the benefits of sodium reduction. OBJECTIVE: It was hypothesized that the nutrient content of packaged foods with lower sodium label claims (ie, sodium-modified) would differ from their regular (ie, unmodified) counterparts. DESIGN: This cross-sectional study compared label data of 153 sodium-modified foods and 141 regular, matched counterparts within four food categories: soups, processed meats, vegetables, and savory snacks. Foods were identified by searching manufacturer websites of the top-10 brands in each category. Sodium, calories, total carbohydrate, sugar, protein, total fat, saturated fat, and potassium (when reported) were compared by labeled serving and per 100 g food. RESULTS: The average amount in milligrams of sodium per serving in regular foods ranged from 162 mg for savory snacks to 782 mg for soups. Compared with regular foods, the matched lower sodium foods had significantly less sodium per serving (-95 to -387 mg) and per 100 g (-184 to -462 mg) (P<0.01 for all comparisons), except for soups per 100 g (P = 0.166), and were similar to their regular counterparts in calories, total carbohydrate, sugar, protein, total fat, and saturated fat (P>0.05 for all comparisons). Of the soups that reported potassium on the label, potassium was 244 mg/serving (P=0.004) and 139 mg/100 g (P=0.002) higher among matched lower sodium soups. CONCLUSIONS: The similarity in macronutrient contents on the labels for sodium-modified foods and their regular counterparts suggests that reformulation did not include the addition of significant amounts of sugars, fats, or other macronutrients among major food brands in the selected categories. Potassium content and additional food categories deserve further investigation.

Iron Content of Commercially Available Infant and Toddler Foods in the United States, 2015.

OBJECTIVES: To describe the iron content of commercially available infant and toddler foods. METHODS: Nutrition Facts label data were used from a 2015 database of 1037 commercial infant and toddler food and drink products. Products were grouped into food categories on the basis of name, ingredients, target age, and reference amounts customarily consumed (RACC). Mean and median iron content per 100 g and per RACC were calculated. The proportion of products considered good and excellent sources of iron were determined on the basis of percent daily value (% DV) thresholds. RESULTS: Among products marketed for infants (aged 4-12 months), infant cereals had the highest mean (6.19 mg iron per RACC; 41.25 iron mg per 100 g) iron content. Among products marketed for toddlers (aged 12-36 months), vegetable-based mixtures or meals contained the highest mean iron in mg per RACC (mean: 2.97 mg) and dry, grain-based desserts had the highest mean iron in mg per 100 g (mean: 6.45 mg). Juice and drink products had the lowest mean iron contents in both infant and toddler products. CONCLUSIONS: Most commercially available infant cereals are considered to be an excellent source of iron, likely from fortification, but wide variability was observed in iron content by food category. Products that are considered good or excellent sources of iron (≥10% DV) can help consumers identify products with higher iron content, such as infant cereals or toddler vegetable-based mixtures/meals.

Dietary Sodium Intake and Health Indicators: A Systematic Review of Published Literature between January 2015 and December 2019.

As the science surrounding population sodium reduction evolves, monitoring and evaluating new studies on intake and health can help increase our understanding of the associated benefits and risks. Here we describe a systematic review of recent studies on sodium intake and health, examine the risk of bias (ROB) of selected studies, and provide direction for future research. Seven online databases were searched monthly from January 2015 to December 2019. We selected human studies that met specified population, intervention, comparison, outcome, time, setting/study design (PICOTS) criteria and abstracted attributes related to the study population, design, intervention, exposure, and outcomes, and evaluated ROB for the subset of studies on sodium intake and cardiovascular disease risks or indicators. Of 41,601 abstracts reviewed, 231 studies were identified that met the PICOTS criteria and ROB was assessed for 54 studies. One hundred and fifty-seven (68%) studies were observational and 161 (70%) focused on the general population. Five types of sodium interventions and a variety of urinary and dietary measurement methods were used to establish and quantify sodium intake. Five observational studies used multiple 24-h urine collections to assess sodium intake. Evidence mainly focused on cardiovascular-related indicators (48%) but encompassed an assortment of outcomes. Studies varied in ROB domains and 87% of studies evaluated were missing information on ≥1 domains. Two or more studies on each of 12 outcomes (e.g., cognition) not previously included in systematic reviews and 9 new studies at low ROB suggest the need for ongoing or updated systematic reviews of evidence on sodium intake and health. Summarizing evidence from assessments on sodium and health outcomes was limited by the various methods used to measure sodium intake and outcomes, as well as lack of details related to study design and conduct. In line with research recommendations identified by the National Academies of Science, future research is needed to identify and standardize methods for measuring sodium intake.

Nutrient Content of Squeeze Pouch Foods for Infants and Toddlers Sold in the United States in 2015.

BACKGROUND: To describe the availability and nutrient composition of U.S. commercially available squeeze pouch infant and toddler foods in 2015. MATERIALS AND METHODS: Data were from information presented on nutrition labels for 703 ready-to-serve, pureed food products from 24 major U.S. infant and toddler food brands. We described nutritional components (e.g., calories, fat) and compared them between packaging types (squeeze pouch versus other packaging types) within food categories. RESULTS: 397 (56%) of the analyzed food products were packaged as squeeze pouches. Differences in 13 nutritional components between squeeze pouch versus other packaging types were generally small and varied by food category. Squeeze pouches in the fruits and vegetables, fruit-based, and vegetable-based categories were more likely to contain added sugars than other package types. CONCLUSION: In 2015, squeeze pouches were prevalent in the U.S. commercial infant and toddler food market. Nutrient composition differed between squeeze pouches and other packaging types for some macro- and micronutrients. Although it is recommended that infants and toddlers under two years old not consume any added sugars, a specific area of concern may be the inclusion of sources of added sugar in squeeze pouches. Linking this information with children's dietary intake would facilitate understanding how these differences affect overall diet quality.

Sodium, sugar, and fat content of complementary infant and toddler foods sold in the United States, 2015.

Background: As part of a healthy diet, limiting intakes of excess sodium, added sugars, saturated fat, and trans fat has been recommended. The American Heart Association recommends that children aged <2 y should avoid added sugars.Objective: We sought to determine commercial complementary infant-toddler food categories that were of potential concern because of the sodium, added sugar, saturated fat, or trans fat content.Design: Nutrition label information (e.g., serving size, sodium, saturated fat, trans fat) for 1032 infant and toddler foods was collected from manufacturers' websites and stores from May to July 2015 for 24 brands, which accounted for >95% of infant-toddler food sales. The presence of added sugars was determined from the ingredient list. Reference amount customarily consumed (RACC) categories were used to group foods and standardize serving sizes. A high sodium content was evaluated on the basis of the Upper Intake Level for children aged 1-3 y and the number of potential servings per day ([i.e., 1500 mg/7 servings (>210 mg/RACC)], a sodium amount >200 mg/100 g, or a mean sodium density >1000 mg/1000 kcal.Results: In 2015, most commercial infant-only vegetables, fruit, dinners, and cereals were low in sodium, contained no saturated fat, and did not contain added sugars. On average, toddler meals contained 2233 mg Na/1000 kcal, and 84% of the meals had >210 mg Na/RACC (170 g), whereas 69% of infant-toddler savory snacks had >200 mg Na/100 g. More than 70% of toddler meals, cereal bars and breakfast pastries, and infant-toddler grain- or dairy-based desserts contained ≥1 sources of added sugar. Approximately 70% of toddler meals contained saturated fat (mean: 1.9 g/RACC), and no commercial infant-toddler foods contained trans fats.Conclusion: Most commercial toddler meals, cereal bars and breakfast pastries, and infant-toddler snacks and desserts have high sodium contents or contain added sugars, suggesting a need for continued public health efforts to support parents in choosing complementary foods for their infants and toddlers.