Whole-Milk Dairy Foods: Biological Mechanisms Underlying Beneficial Effects on Risk Markers for Cardiometabolic Health

Abstract

Lifestyle modifications that include adherence to healthy dietary patterns that are low in saturated fat have been associated with reduced risk for cardiovascular disease, the leading cause of death globally. Whole-milk dairy foods, including milk, cheese, and yogurt, are leading sources of saturated fat in the diet. Dietary guidelines around the world recommend the consumption of low-fat and fat-free dairy foods to obtain overall healthy dietary patterns that help meet nutrient recommendations while keeping within recommended calorie and saturated fat limitations. A body of observational and clinical evidence indicates, however, that whole-milk dairy food consumption, despite saturated fat content, does not increase the risk for cardiovascular disease. This review describes the proposed biological mechanisms underlying inverse associations between whole-milk dairy food consumption and risk markers for cardiometabolic health, such as altered lipid digestion, absorption, and metabolism; influence on the gut microflora; and regulation of oxidative stress and inflammatory responses. The dairy food matrix, a term used to describe how the macronutrients and micronutrients and other bioactive components of dairy foods are differentially packaged and compartmentalized among fluid milk, cheese, and yogurt, may dictate how each affects cardiovascular risk. Current evidence indicates consideration of dairy foods as complex food matrices, rather than delivery systems for isolated nutrients, such as saturated fatty acids, is warranted.

Keywords: cardiovascular disease; cheese; dairy; fermented dairy; food matrix; metabolic health; milk; milk fat globular membrane; milk polar lipids; yogurt.

FIGURE 1

The milk fat globular membrane (MFGM) is unique in that it is a trilayer membrane that surrounds the lipids (triacylglycerols) of the milk fat globule core. The MFGM is composed of phospholipids and sphingolipids, referred to as milk polar lipids. Figure created with BioRender.com.

FIGURE 2

1) The milk polar lipids present in the milk fat globular membrane may improve cardiometabolic health by alleviating plasma and hepatic hyperlipidemia through reduced intestinal cholesterol absorption attributable to intraluminal emulsification [11] and the ability of milk sphingomyelin to bind pancreatic colipase, inhibiting the action of pancreatic lipase activity [12]; 2) Milk polar lipids may beneficially affect cardiometabolic health by mitigating inflammatory responses in the gastrointestinal tract [11]; 3) Results from observational studies in humans and preclinical trials in cell culture and animals indicate C15:0 and C17:0, odd-chain fatty acids present in milk fat, have beneficial effects on cardiometabolic health by improving dyslipidemia, stimulating mitochondrial repair, and reducing inflammation [13]; 4) Total serum iso–branched-chain saturated fatty acids were inversely correlated with serum insulin, triglycerides, and C-reactive protein (CRP) concentration, indicating potential beneficial effects of iso–branched-chain saturated fatty acids on cardiometabolic health [14]; 5) Preclinical research indicates short- and medium-chain saturated fatty acids may attenuate metabolic stress and inflammation via effects on the gut–brain axis [15]; 6) A body of preclinical research demonstrated that milk-derived bioactive peptides may attenuate atherosclerotic plaque formation by inhibiting the NF-κB pathway in a peroxisome proliferator–activated receptor (PPAR) γ dependent manner, and by modifying the expression of C-C motif chemokine receptor 2 and toll-like receptor 4 receptors in monocytes [16]. Figure created with BioRender.com. ∗Mechanism applies to low-fat and fat-free dairy foods as well. NF-κB, nuclear transcription factor κB.