Health-promoting compounds are higher in grass-fed meat and milk

Authors: VAN VLIET, STEPHAN - Duke University; PROVENZA, FREDERICK - Utah State University; Kronberg, Scott

Submitted to: Frontiers in Sustainable Food Systems
Publication Type: Review Article
Publication Acceptance Date: 12/14/2020
Publication Date: 2/1/2021
Citation: Van Vliet, S., Provenza, F.D., Kronberg, S.L. 2021. Health-promoting compounds are higher in grass-fed meat and milk. Frontiers in Sustainable Food Systems. 4. https://doi.org/10.3389/fsufs.2020.555426.
DOI: https://doi.org/10.3389/fsufs.2020.555426

Interpretive Summary:

Technical Abstract: While commission reports and nutrition guidelines raise concerns about the effects of consumption of red meat on human health, the impacts of how livestock are raised and finished on consumer health are generally ignored. Emerging data indicate that when livestock are eating a diverse array of plants on pasture, a wide variety of phytochemicals – terpenoids, phenols, carotenoids, and anti-oxidants – with known anti-inflammatory, anti-carcinogenic, and cardioprotective effects are concentrated in their meat and milk. Some of the phytochemicals found in pasture-raised meat and milk are in quantities comparable to those found in plant foods. As meat and milk are often not considered as sources of phytochemicals, their presence has remained largely underappreciated in discussions of nutritional differences between conventional (grain-fed) and pasture-raised (grass-fed) meat and dairy, which have predominantly been centered around omega-3 fatty acids and CLA. Grazing livestock on plant-species- diverse pastures concentrates both higher amounts and a wider variety of phytochemicals in their meat and milk when compared to animals grazing non-diverse pastures, while phytochemicals often remain absent in meat and milk from animals fed grain-based concentrates in feedlots. The co-evolution of plants and herbivores has led to plants/crops being more productive when properly grazed. The increased phytochemical richness of productive vegetation consumed by livestock has the potential to improve the health of livestock and upscale these nutrients in their products to benefit human health. Several studies have found an increased anti-oxidant activity in the meat and milk of grass-fed animals when compared to meat and milk from grain-fed animals. Only a handful of studies have investigated the effects of grass-fed meat and dairy consumption on human health. Though research is sparse, some studies show a potential for anti-inflammatory effects and improved lipoprotein profiles in consumers. Future research should systematically assess the linkages between phytochemical richness of livestock diets, the nutrient quality of animal products, and the subsequent effects of human metabolic health. This will be important given current societal concerns about red meat consumption and its impacts on human health. Addressing this research gap will require greater collaborative efforts from the fields of agriculture and human nutrition.