Title-plus-abstract versus title-only first-level screening approach: a case study using a systematic review of dietary patterns and sarcopenia risk to compare screening performance.

BACKGROUND: Conducting a systematic review is a time- and resource-intensive multi-step process. Enhancing efficiency without sacrificing accuracy and rigor during the screening phase of a systematic review is of interest among the scientific community. METHODS: This case study compares the screening performance of a title-only (Ti/O) screening approach to the more conventional title-plus-abstract (Ti + Ab) screening approach. Both Ti/O and Ti + Ab screening approaches were performed simultaneously during first-level screening of a systematic review investigating the relationship between dietary patterns and risk factors and incidence of sarcopenia. The qualitative and quantitative performance of each screening approach was compared against the final results of studies included in the systematic review, published elsewhere, which used the standard Ti + Ab approach. A statistical analysis was conducted, and contingency tables were used to compare each screening approach in terms of false inclusions and false exclusions and subsequent sensitivity, specificity, accuracy, and positive predictive power. RESULTS: Thirty-eight citations were included in the final analysis, published elsewhere. The current case study found that the Ti/O first-level screening approach correctly identified 22 citations and falsely excluded 16 citations, most often due to titles lacking a clear indicator of study design or outcomes relevant to the systematic review eligibility criteria. The Ti + Ab approach correctly identified 36 citations and falsely excluded 2 citations due to limited population and intervention descriptions in the abstract. Our analysis revealed that the performance of the Ti + Ab first-level screening was statistically different compared to the average performance of both approaches (Chi-squared: 5.21, p value 0.0225) while the Ti/O approach was not (chi-squared: 2.92, p value 0.0874). The predictive power of the first-level screening was 14.3% and 25.5% for the Ti/O and Ti + Ab approaches, respectively. In terms of sensitivity, 57.9% of studies were correctly identified at the first-level screening stage using the Ti/O approach versus 94.7% by the Ti + Ab approach. CONCLUSIONS: In the current case study comparing two screening approaches, the Ti + Ab screening approach captured more relevant studies compared to the Ti/O approach by including a higher number of accurately eligible citations. Ti/O screening may increase the likelihood of missing evidence leading to evidence selection bias. SYSTEMATIC REVIEW REGISTRATION: PROSPERO Protocol Number: CRD42020172655.

Reply to Consavage Stanley, K.; Kraak, V.I. Comment on "Lau et al. Trends in Beef Intake in the United States: Analysis of the National Health and Nutrition Examination Survey, 2001-2018. Nutrients 2023, 15, 2475".

We thank the authors [...].

Trends in Beef Intake in the United States: Analysis of the National Health and Nutrition Examination Survey, 2001-2018.

Evidence-based dietary advice regarding meats (including beef), requires accurate assessment of beef and other red meat intakes across life stages. Beef intake is subject to misclassification due to the use of broad categories such as "red and processed meat". In the current study, intake trends for total beef (i.e., any beef type) and specific beef types (fresh lean, ground, processed) among Americans participating in the National Health and Nutrition Examination Survey (NHANES) 2001-2018 (n = 74,461) were characterized and usual intake was assessed using NHANES 2011-2018 (n = 30,679). The usual intake amounts of beef were compared to those of relevant protein food subgroups modeled in the Healthy U.S.-Style Dietary Pattern (HDP) reported in the 2020-2025 Dietary Guidelines for Americans (DGA). Total per capita beef consumption declined an average of 12 g (p < 0.0001) for ages 2-18 years and 5.7 g (p = 0.0004) for ages 19-59 years per 2-yr NHANES cycle, over the 18-year timeframe, while remaining unchanged for Americans aged 60+ years. On a per capita basis, Americans aged 2 years and older consumed 42.2 g (1.5 ounces) of total beef per day. Fresh lean beef per capita consumption was 33.4 g (1.2 ounces) per day. Per capita intake was similar across all age groups and below the daily HDP modeled amount of 3.7 ounce equivalents for the "Meats, Poultry, Eggs" (MPE) subgroup, while approximately 75% of beef consumers' intakes of total beef was within HDP modeling. Evidence from intake trends suggests beef is not overconsumed by the majority of Americans but rather within the amounts for MPE and red meat modeled in the HDP of the DGA at the 2000-calorie level.

Dietary Patterns and the Risk of Sarcopenia: A Systematic Review and Meta-Analysis.

The purpose of this systematic review is to examine the relationship between dietary patterns and sarcopenia using a protocol developed for use by the 2020 Dietary Guidelines Advisory Committee, and to conduct a meta-analysis to summarize the evidence. Multiple electronic databases were searched for studies investigating sarcopenia risk factors or risk of sarcopenia and dietary patterns. Eligible studies were 1) peer-reviewed controlled trials or observational trials, 2) involving adult or older-adult human subjects who were healthy and/or at risk for chronic disease, 3) comparing the effect of consumption or adherence to dietary patterns (measured as an index/score, factor or cluster analysis; reduced rank regression; or a macronutrient distribution), and 4) reported on measures of skeletal muscle mass, muscle strength, muscle performance, and/or risk of sarcopenia. Thirty-eight publications met all inclusion criteria for qualitative synthesis. Thirteen observational studies met inclusion criteria for meta-analysis. Higher adherence to a healthy dietary pattern was associated with a decreased risk of gait speed reduction (OR = 0.58; 95% CI: 0.18, 0.97). The association between healthy dietary pattern adherence and other intermediate markers or risk of sarcopenia was not statistically significant. The majority of individual studies were judged as "serious" risk of bias and analysis of the collective evidence base was suggestive of publication bias. Studies suggest a significant association between healthy dietary patterns and maintenance of gait speed with age, an intermediate marker of sarcopenia risk, but the evidence base is limited by serious risk of bias, within and between studies. Further research is needed to understand the association between healthy dietary patterns and risk of sarcopenia.

Iron-Rich Complementary Foods: Imperative for All Infants.

Nearly 1 in 5 (18%) infants in the United States is not consuming sufficient iron. A deficiency of iron during early life may be associated with long-term neurodevelopmental consequence(s). The 2020-2025 Dietary Guidelines for Americans (DGA) are the first DGA to address recommendations for children under 2 y of age. The 2020 Dietary Guidelines Advisory Committee scientific report includes food-group combinations emphasizing iron-rich foods for 6-12-mo-old infants, but these examples did not meet criteria to establish DGA recommended dietary patterns; consequently, iron-rich dietary patterns for ages 6-12 mo are not provided in the 2020-2025 DGA. The 2020-2025 DGA encourage iron-rich foods by 6 mo of age while emphasizing the importance "particularly for infants fed human milk." Early feeding transitions are dynamic and milk feeding groups are rarely static or exclusive such that emphasizing milk feeding groups may become confusing. Risk-to-benefit favors iron-rich complementary feeding for all infants.

A Systematic Review of Renal Health in Healthy Individuals Associated with Protein Intake above the US Recommended Daily Allowance in Randomized Controlled Trials and Observational Studies.

A systematic review was used to identify randomized controlled trials (RCTs) and observational epidemiologic studies (OBSs) that examined protein intake consistent with either the US RDA (0.8 g/kg or 10-15% of energy) or a higher protein intake (≥20% but <35% of energy or ≥10% higher than a comparison intake) and reported measures of kidney function. Studies (n = 26) of healthy, free-living adults (>18 y old) with or without metabolic disease risk factors were included. Studies of subjects with overt disease, such as chronic kidney, end-stage renal disease, cancer, or organ transplant, were excluded. The most commonly reported variable was glomerular filtration rate (GFR), with 13 RCTs comparing GFRs obtained with normal and higher protein intakes. Most (n = 8), but not all (n = 5), RCTs reported significantly higher GFRs in response to increased protein intake, and all rates were consistent with normal kidney function in healthy adults. The evidence from the current review is limited and inconsistent with regard to the role of protein intake and the risk of kidney stones. Increased protein intake had little or no effect on blood markers of kidney function. Evidence reported here suggests that protein intake above the US RDA has no adverse effect on blood pressure. All included studies were of moderate to high risk of bias and, with the exception of 2 included cohorts, were limited in duration (i.e. <6 mo). Data in the current review are insufficient to determine if increased protein intake from a particular source, i.e., plant or animal, influences kidney health outcomes. These data further indicate that, at least in the short term, higher protein intake within the range of recommended intakes for protein is consistent with normal kidney function in healthy individuals.

A Meta-Analysis of Randomized Controlled Trials and Prospective Cohort Studies of Eicosapentaenoic and Docosahexaenoic Long-Chain Omega-3 Fatty Acids and Coronary Heart Disease Risk.

OBJECTIVE: To conduct meta-analyses of randomized controlled trials (RCTs) to estimate the effect of eicosapentaenoic and docosahexaenoic acid (EPA+DHA) on coronary heart disease (CHD), and to conduct meta-analyses of prospective cohort studies to estimate the association between EPA+DHA intake and CHD risk. METHODS: A systematic literature search of Ovid/Medline, PubMed, Embase, and the Cochrane Library from January 1, 1947, to November 2, 2015, was conducted; 18 RCTs and 16 prospective cohort studies examining EPA+DHA from foods or supplements and CHD, including myocardial infarction, sudden cardiac death, coronary death, and angina, were identified. Random-effects meta-analysis models were used to generate summary relative risk estimates (SRREs) and 95% CIs. Heterogeneity was examined in subgroup and sensitivity analyses and by meta-regression. Dose-response was evaluated in stratified dose or intake analyses. Publication bias assessments were performed. RESULTS: Among RCTs, there was a nonstatistically significant reduction in CHD risk with EPA+DHA provision (SRRE=0.94; 95% CI, 0.85-1.05). Subgroup analyses of data from RCTs indicated a statistically significant CHD risk reduction with EPA+DHA provision among higher-risk populations, including participants with elevated triglyceride levels (SRRE=0.84; 95% CI, 0.72-0.98) and elevated low-density lipoprotein cholesterol (SRRE=0.86; 95% CI, 0.76-0.98). Meta-analysis of data from prospective cohort studies resulted in a statistically significant SRRE of 0.82 (95% CI, 0.74-0.92) for higher intakes of EPA+DHA and risk of any CHD event. CONCLUSION: Results indicate that EPA+DHA may be associated with reducing CHD risk, with a greater benefit observed among higher-risk populations in RCTs.

Global survey of the omega-3 fatty acids, docosahexaenoic acid and eicosapentaenoic acid in the blood stream of healthy adults.

Studies reporting blood levels of the omega-3 polyunsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), were systematically identified in order to create a global map identifying countries and regions with different blood levels. Included studies were those of healthy adults, published in 1980 or later. A total of 298 studies met all inclusion criteria. Studies reported fatty acids in various blood fractions including plasma total lipids (33%), plasma phospholipid (32%), erythrocytes (32%) and whole blood (3.0%). Fatty acid data from each blood fraction were converted to relative weight percentages (wt.%) and then assigned to one of four discrete ranges (high, moderate, low, very low) corresponding to wt.% EPA+DHA in erythrocyte equivalents. Regions with high EPA+DHA blood levels (>8%) included the Sea of Japan, Scandinavia, and areas with indigenous populations or populations not fully adapted to Westernized food habits. Very low blood levels (≤4%) were observed in North America, Central and South America, Europe, the Middle East, Southeast Asia, and Africa. The present review reveals considerable variability in blood levels of EPA+DHA and the very low to low range of blood EPA+DHA for most of the world may increase global risk for chronic disease.

Docosahexaenoic acid and adult memory: a systematic review and meta-analysis.

INTRODUCTION: Subjective memory complaints are common with aging. Docosahexaenoic acid (DHA; 22:6 n-3) is a long-chain polyunsaturated fatty acid (LCPUFA) and an integral part of neural membrane phospholipids that impacts brain structure and function. Past research demonstrates a positive association between DHA plasma status/dietary intake and cognitive function. OBJECTIVES: The current meta-analysis was designed to determine the effect of DHA intake, alone or combined with eicosapentaenoic acid (EPA; 20:5 n-3), on specific memory domains: episodic, working, and semantic in healthy adults aged 18 years and older. A secondary objective was to systematically review/summarize the related observational epidemiologic literature. METHODS: A systematic literature search of clinical trials and observational studies that examined the relationship between n-3 LCPUFA on memory outcomes in healthy adults was conducted in Ovid MEDLINE and EMBASE databases. Studies of subjects free of neurologic disease at baseline, with or without mild memory complaints (MMC), were included. Random effects meta-analyses were conducted to generate weighted group mean differences, standardized weighted group mean differences (Hedge's g), z-scores, and p-values for heterogeneity comparing DHA/EPA to a placebo. A priori sub-group analyses were conducted to evaluate the effect of age at enrollment, dose level, and memory type tested. RESULTS: Episodic memory outcomes of adults with MMC were significantly (P<.004) improved with DHA/EPA supplementation. Regardless of cognitive status at baseline, > 1 g/day DHA/EPA improved episodic memory (P<.04). Semantic and working memory changes from baseline were significant with DHA but no between group differences were detected. Observational studies support a beneficial association between intake/blood levels of DHA/EPA and memory function in older adults. CONCLUSION: DHA, alone or combined with EPA, contributes to improved memory function in older adults with mild memory complaints.

Impact of grass/forage feeding versus grain finishing on beef nutrients and sensory quality: the U.S. experience.

Studies of forage and/or grass feeding of cattle versus grain finishing have been conducted in varying regions throughout the world but generalization of these results to beef from U.S. cattle may not be appropriate. In particular, available grass/forage variety and form as well as cattle breed have a significant impact on the nutritional profile of beef. The current review summarizes the nutritional characteristics of beef as reported from the limited number of studies comparing U.S. grass/forage-fed versus grain-finished cattle and estimates the intake of key nutrients that might be expected from consumption of U.S. beef from either feeding system. In addition, many studies report changes in fatty acids solely as a percentage of total fatty acids. Since grass/forage feeding typically results in a leaner product; the current review compares the fatty acid profile of beef from grass/forage feeding to that of grain-finished cattle on a mg/100 g of meat basis.

A meta-analysis of randomized controlled trials that compare the lipid effects of beef versus poultry and/or fish consumption.

BACKGROUND: Limited consumption of red meat, including beef, is one of many often-suggested strategies to reduce the risk of coronary heart disease (CHD). However, the role that beef consumption specifically plays in promoting adverse changes in the cardiovascular risk factor profile is unclear. OBJECTIVE: A meta-analysis of randomized, controlled, clinical trials (RCTs) was conducted to evaluate the effects of beef, independent of other red and processed meats, compared with poultry and/or fish consumption, on lipoprotein lipids. METHODS: RCTs published from 1950 to 2010 were considered for inclusion. Studies were included if they reported fasting lipoprotein lipid changes after beef and poultry/fish consumption by subjects free of chronic disease. A total of 124 RCTs were identified, and 8 studies involving 406 subjects met the prespecified entry criteria and were included in the analysis. RESULTS: Relative to the baseline diet, mean ± standard error changes (in mg/dL) after beef versus poultry/fish consumption, respectively, were -8.1 ± 2.8 vs. -6.2 ± 3.1 for total cholesterol (P = .630), -8.2 ± 4.2 vs. -8.9 ± 4.4 for low-density lipoprotein cholesterol (P = .905), -2.3 ± 1.0 vs. -1.9 ± 0.8 for high-density lipoprotein cholesterol (P = .762), and -8.1 ± 3.6 vs. -12.9 ± 4.0 mg/dL for triacylglycerols (P = .367). CONCLUSION: Changes in the fasting lipid profile were not significantly different with beef consumption compared with those with poultry and/or fish consumption. Inclusion of lean beef in the diet increases the variety of available food choices, which may improve long-term adherence with dietary recommendations for lipid management.

Red meat in global nutrition.

The influence of data and recommendations from developed countries on nutrition guidance has overshadowed recognition of the key micronutrients and protein contributed by red meat to the global food supply. Relative to the energy it contributes, the impact of red meat on the nutritional quality of the human diet via its contribution of protein and key micronutrients is under-appreciated. The current discussion will review red meat nutrient composition and global consumption rates and discuss the evidence underpinning current dietary recommendations. The beneficial role of red meat in reducing risk factors associated with noncommunicable disease in developed countries and improving the nutritional status of developing nations will also be reviewed.

The evolution of lean beef: identifying lean beef in today's U.S. marketplace.

Changes in cattle breeding and management coupled with extensive trimming of visible fat from retail cuts have resulted in the wide-spread availability of lean beef to U.S. consumers. Despite these changes, there is limited awareness regarding the reduced total fat content and the favorable fatty acid profile of beef. Relative to the calories it contributes, the impact of beef on the nutritional quality of the American diet via its contribution of protein and certain key micronutrients is often under appreciated. The following discussion documents the progressive reduction in fat content of U.S. beef during the past 30 years, highlights ongoing efforts to update United States Department of Agriculture nutrient data for beef, and summarizes findings from randomized controlled trials of beef and plasma lipid outcomes. Beef is a popular, nutrient-dense food and the availability of at least 29 lean cuts of beef in the U.S. marketplace can help consumers meet their cardiovascular health goals.

Lipid responses to a dietary docosahexaenoic acid supplement in men and women with below average levels of high density lipoprotein cholesterol.

OBJECTIVE: To assess fasting lipid responses to a docosahexaenoic acid (DHA) supplement in men and women with below-average levels of high-density lipoprotein (HDL) cholesterol. METHODS: This randomized, double-blind, controlled clinical trial included 57 subjects, 21-80 years of age, with fasting HDL cholesterol concentrations < or =44 mg/dL (men) and < or =54 mg/dL (women), but > or =35 mg/dL. Subjects were randomly assigned to receive either 1.52 g/day DHA from capsules containing DHA-rich algal triglycerides or olive oil (control) for six weeks. RESULTS: There were no significant differences between groups in baseline lipid values. The DHA supplemented group showed significant changes [-43 (DHA) vs. -14 (controls) mg/dL, p = 0.015] and percent changes [-21% (DHA) vs. -7% (controls), p = 0.009] in triglycerides, total (12 vs. 3 mg/dL; p = 0.021 and 6% vs. 2%; p = 0.018) and low-density lipoprotein (17 vs. 3 mg/dL; p = 0.001 and 12% vs. 3%; p = 0.001) cholesterol concentrations, and in the triglyceride to HDL cholesterol ratio (-1.33 vs. -0.50, p = 0.010), compared with controls. In addition, there was a significant reduction in the percentage of LDL cholesterol carried by small, dense particles in the DHA supplemented group (changes = -10% vs. -3%, p = 0.025). CONCLUSIONS: Supplementation with 1.52 g/d of DHA in men and women with below-average HDL cholesterol concentrations raised the LDL cholesterol level, but had favorable effects on triglycerides, the triglyceride/HDL cholesterol ratio and the fraction of LDL cholesterol carried by small, dense particles. Further research is warranted to evaluate the net impact of these alterations on cardiovascular risk.

Lipid responses in mildly hypertriglyceridemic men and women to consumption of docosahexaenoic acid-enriched eggs.

This randomized, double-blind, controlled clinical trial assessed lipid responses in mildly hyper-triglyceridemic men and women to consumption of docosahexaenoic acid (DHA)-enriched eggs or ordinary chicken eggs. The study included 153 subjects aged 21-80 years, with serum triglyceride concentrations between 140 and 450 mg/dL, inclusive, and serum total cholesterol concentrations < 300 mg/dL. Subjects were randomly assigned to receive either DHA-enriched (147 mg DHA/egg) or ordinary eggs (20 mg DHA/egg), added to their usual diets for six weeks (10 eggs/week). Both treatments significantly lowered triglycerides and increased high-density lipoprotein (HDL) cholesterol levels from baseline; however, these changes were not significantly different between treatments. Low-density lipoprotein (LDL) cholesterol concentrations increased significantly in subjects who consumed DHA-enriched eggs (p = 0.047 vs. control). This increase was significantly higher than that observed with ordinary eggs. However, there was no significant increase in cholesterol carried by small, dense LDL particles, as determined by nuclear magnetic resonance analysis. Results of exploratory analyses suggest favorable effects of the DHA-enriched eggs over ordinary eggs on triglyceride and HDL cholesterol levels in subjects with body mass index > or = 30 kg/m2; the DHA treatment produced a larger reduction in serum triglyceride concentration vs. ordinary eggs (-12.3 vs. 2.1%; p = 0.027), and there was a greater increase for HDL cholesterol in the DHA-enriched vs. ordinary egg group (5.0 vs. 1.1%; p = 0.040).