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.

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 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 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.

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.

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.

This scoping review examines the interaction of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) and genetic variants of various types of cancers. A comprehensive search was performed to identify controlled and observational studies conducted through August 2017. Eighteen unique studies were included: breast cancer (n = 2), gastric cancer (n = 1), exocrine pancreatic cancer (n = 1), chronic lymphocytic leukemia (n = 1), prostate cancer (n = 7) and colorectal cancer (n = 6). An additional 13 studies that focused on fish intake or at-risk populations were summarized to increase readers’ understanding of the topic based on this review, DHA and EPA interact with certain genetic variants to decrease breast, colorectal and prostate cancer risk, although data was limited and identified polymorphisms were heterogeneous. The evidence to date demonstrates that omega-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) may decrease cancer risk by affecting genetic variants of inflammatory pathways, oxidative stress and tumor apoptosis. Collectively, data supports the notion that once a genetic variant is identified, the benefits of a targeted, personalized therapeutic regimen that includes DHA and/or EPA should be considered.