Grass-finished beef (GFB) can provide beneficial bioactive compounds to healthy diets, including omega-3 polyunsaturated fatty acids (n-3 PUFAs), conjugated linoleic acid (CLA), and secondary bioactive compounds, such as phytochemicals. The objective of this study was to compare fatty acids (FAs), micronutrients, and phytochemicals of beef fed a biodiverse pasture (GRASS), a total mixed ration (GRAIN), or a total mixed ration with 5% grapeseed extract (GRAPE). This was a two-year study involving fifty-four Red Angus steers (n = 54). GFB contained higher levels of n-3 PUFAs, vitamin E, iron, zinc, stachydrine, hippuric acid, citric acid, and succinic acid than beef from GRAIN and GRAPE (p < 0.001 for all). No differences were observed in quantified phytochemicals between beef from GRAIN and GRAPE (p > 0.05). Random forest analysis indicated that phytochemical and FA composition of meat can predict cattle diets with a degree of certainty, especially for GFB (5.6% class error). In conclusion, these results indicate that GFB contains higher levels of potentially beneficial bioactive compounds, such as n-3 PUFAs, micronutrients, and phytochemicals, compared to grain-finished beef. Additionally, the n-6:n-3 ratio was the most crucial factor capable of separating beef based on finishing diets.

As the global population increases, so does meat consumption. This trend is accompanied by concerns regarding the meat industry, and consumers are demanding transparency on the environmental and health effects of the products they are purchasing. Many leading health organizations recommend reducing red meat consumption. Nevertheless, no differentiation is made among red meats and beef. The beef production system is generally ignored despite nutritional differences between grain- and grass-fed beef. Compared to grain-fed beef, grass-fed beef contains a healthier fatty acid profile, including more omega-3 polyunsaturated fatty acids and conjugated linoleic acid, and increased concentrations of phytochemicals desired by health-conscious customers. However, there is a lack of consistency among grass-fed beef in the United States regarding clear product labeling and cattle dietary components. Grass-fed beef labeling confusion has emerged, including misunderstandings between grass-fed and grass-finished beef. Along with this, previous studies observed significant nutritional variation among grass-finished beef from different producers across the country. Cattle diet has the strongest influence on the nutritional composition of beef. Therefore, understanding differences in feeding practices is key to understanding differing nutritional quality of grass-fed beef. Feeding cattle diverse pastures composed of multiple plant species including grasses and legumes managed in a rotational grazing fashion results in higher omega-3 polyunsaturated fatty acids and phytochemical levels in beef compared to feedlots and monocultures. Seasonal differences including changes in temperature, rainfall, grazing practices, and plant growth cycles affect the nutritional composition of feeds and ultimately meat. Additional feeds utilized in grass-fed beef production systems such as conserved forages may reduce or increase health-promoting nutrients in grass-fed beef, while supplements such as grape byproducts and flaxseed may improve its nutritional profile. Further research should measure the effects of individual feedstuff and the finishing period on the nutritional profile on grass-fed beef. A better understanding of these details will be a step toward the standardization of pasture-raised ruminant products, strengthening the relationship between grass-fed beef consumption and human health.

Cattle diet and breed modify the nutritional profile of beef. The objective of this study was to compare the fatty acid (FA) and micronutrient profiles of Red Angus (RA) and RA x Akaushi (AK) crossbreed steers fed either a grass or grain diet. This two-year study randomly assigned steers to the diets using a 2 × 2 factorial experiment. FAs and micronutrients were analyzed. Diet effect was the strongest with grass-finished beef being higher in n-3 polyunsaturated FAs (p < 0.001), conjugated linoleic acid (p < 0.05), vaccenic acid (p < 0.05), iron (p < 0.001), and vitamin E (p < 0.001) compared to grain-finished beef. Breed effects were observed for lauric and myristic acids (p < 0.05), selenium (p < 0.05), and zinc (p < 0.01) with AK containing more of these compounds than RA. Diet × breed effects were non-existent. These results indicate that diet has a stronger influence than breed on modifying the nutritional profile of beef. Because of a more favorable FA and antioxidant profile, consumption of grass-finished beef could benefit human health.

Beef raised using rotational grazing practices on biodiverse pastures offers potential benefits to animal and environmental health and can improve the nutrient density of meat to favor human health. However, many cattle producers contend with the seasonal unavailability of fresh forage, necessitating the utilization of supplementary feeds or indoor feeding. The objective of this study was to profile secondary metabolites and fatty acids in grass-finished beef supplemented with different feeds (4.5 kg/head/day) and to explore the potential for grass-finished beef authentication. In this two-year study, steers (n = 115) were randomly allocated to one of four diets: 1) pastured/supplemented with hay (control group), 2) pastured/supplemented with baleage, 3) pastured/supplemented with soybean hulls, or 4) baleage/soybean hulls in confinement. Secondary metabolites and fatty acids were measured using UHPLC-MS/MS and GC-MS, respectively. Of the 94 measured metabolites, pyridoxine, alpha-tocopherol, hippuric acid, and gallic acid differed between diets (p < 0.05 for all). Based on random forest classification, beef from the pasture/hay, pasture/baleage, pasture/soybean hulls, and confinement baleage/soybean hulls groups could be identified with a predictive accuracy of 100%, 50%, 41%, and 97%, respectively. Although minimal significant differences were observed, our data indicate that certain supplemental feeds maintain favorable nutritional profiles of grass-finished beef. In addition, metabolomics can predict cattle on exclusively forage-based or feed-based diets with a high degree of certainty.

Background: Skin carotenoids measured by reflection spectroscopy (RS) score as a biomarker of fruit and vegetable (F/V) intake has not been used extensively in USA minority populations, and there are concerns about the impact of skin tone on the validity of skin carotenoid scores as a biomarker of F/V intake. Methods: The aim of this study was to examine the relationship between skin carotenoids measured by RS score, plasma carotenoids, dietary carotenoids, and F/V intake in African American/Black college students and explore the effect of skin tone on RS score readings. One hundred African American/Black students at a Historically Black Colleges and Universities institution participated in this study. RS score was assessed by Veggie Meter, plasma carotenoids measured by high performance liquid chromatography, and dietary carotenoids and F/V intake were estimated by a weekly food frequency questionnaire (FFQ). Skin tone was matched visually and read using a skin swatch on a scale of 1-15, 1 being the lightest and 15 being the darkest. Correlations between RS scores with total plasma carotenoid concentrations, dietary carotenoids, and F/V intake were examined. Multiple linear regression analysis was conducted to assess the relationship of skin tone at the fingertip and inner arm, BMI, and %body fat on the correlation between RS and total plasma carotenoid levels. Results: Skin carotenoid levels indicated by RS scores were correlated with total plasma carotenoid concentrations (R= 0.595, p