Nutritional bioactivities of milk fat globule membrane and milk polar lipid consumption

Milk fat globule membrane (MFGM) is composed of a variety of polar lipids and membrane proteins. Several dairy co-products are rich in MFGM, such as buttermilk and whey protein phospholipid concentrate (WPPC). Based on its composition, it has been suggested that MFGM could be added to foods for specific benefits in the gut, brain and/or liver. However, despite the fact that up to 32 million tons of WPPC are produced each year, it is still considered a low-value ingredient. Over the last fifteen years, we conducted several studies in rodent and humans to test various hypotheses related to MFGM consumption. In rats, addition of buttermilk to the AIN-76A diet reduced preneoplastic lesions in an aberrant crypt foci model of colon cancer, and had small, but statistically significant effects on systemic lipid metabolism. In mice, buttermilk prevented gut permeability induced by endotoxin injection, but milk polar lipids failed to exert the same effect. Conversely, addition of milk polar lipids to a moderately high fat diet reduced hepatic triglyceride content in obesity-prone (ob/ob) mice, and in mice injected with endotoxin, but not in untreated mice. In humans, addition of buttermilk to a sports nutrition beverage for two weeks did not reduce the gut permeability induced by running 30m at 80% VO₂max, but did reduce post-exercise blood lactate. In moderately obese humans, we tested whether adding 24g/d of buttermilk to yogurt would reduce endotoxin absorption from a high fat breakfast, and found no difference compared to either a dairy-based or soy-based yogurt. In summary, there does appear to be some interesting beneficial nutritional effects of MFGM consumption, but the effects are highly context dependent. It seems likely that future studies may uncover some interesting benefits to adding MFGM and/or polar lipids to foods.