Beyond Saturated Fat: A Four-Dimensional Framework for Understanding Milk Fat in Human Health.

For a long time, milk fat has been recognized as a potential risk factor in the diet for cardiovascular disease because of its high saturated fatty acid content. However, mounting evidence may call into question this narrow-minded view, as it does not account for the complex and at times paradoxical relationship between dairy consumption and health. This review suggests that an integrative approach should be adopted to re-evaluate the health benefits of milk fat. We suggest that milk fat should not be viewed from a solely "saturated fat" perspective and should be considered a four-dimensional system: functional lipid diversity, food matrix structure, dose-response relationship, and individual metabolic characteristics. We first call attention to the fact that milk fat is not simplified in its fatty acid classifications and thus is molecularly heterogeneous. Second, we will discuss the modulation of lipid digestion kinetics and metabolic fate by the food matrix. Third, we combine epidemiological evidence, which shows the different kinds of nonlinear dose-response relationships between dairy consumption and health outcomes. Fourth, we discuss the contribution of genetic background, gut microbiota, and metabolic status to interindividual variability in response to milk fat. Finally, we discuss the implications of this framework for dietary guidelines, clinical practice, and innovation of dairy products. The change in paradigm from a single "saturated fat" to a multidimensional approach resolves inconsistencies that plagued the single "saturated fat" paradigm and offers a scientific playing field for personalized nutrition and precision dietary recommendations.