Polar lipids are the phospholids and glycolipids that are functionally associated with the membrane structure and fluidity and are found in dairy products, especially in abundance in cream and buttermilk. They help to naturally stabilize fat droplets.
Researchers from The University of Lyon along from INRA and also other French research entities initially conducted preliminary experiments on animal models that revealed the beneficial effects of milk polar lipids on liver metabolism and the regulation of blood cholesterol levels.
A further human trial, called the ANR VALOBAB project was initiated and spanned over 4 years involving human volunteers with a high cardiovascular risk.
The research team aims were to analyze the impacts of milk polar lipids on the cardiovascular risk profile of overweight postmenopausal women, a group that is vulnerable to cardiovascular risk. 58 volunteers had cream cheese that was enriched in milk polar lipids as part of their daily diet. After a month of consuming a specially-designed buttermilk concentrate enriched in milk polar lipids (a by-product of butter-making process), the team observed a significant reduction in the blood levels of LDL cholesterol, triglycerides and other important markers of cardiometabolic risk in the patients. The results of the trial showed that these milk polar lipids improved the cardiovascular health conditions of these postmenopausal female patients.
The researchers then sought to unravel and understand the mechanism underlying this effect. Their additional studies suggested that certain milk polar lipids and cholesterol (of both dietary and endogenous origin) may form a complex in the small intestine that cannot be digested nor absorbed by the gut and is ultimately excreted in the stools.
These research results could provide foundations for new nutritional strategies to reduce cardiovascular risk factors in certain high risk populations.
The results should contribute to a diversification of the ingredients used by the food-processing industry. The functional properties of milk polar lipids relative to the texture of foods, alongside their potential protective effects on health, could offer a better alternative to the soy lecithin that is presently used in a large number of foods, as well as providing an opportunity for the extolling the benefits of buttermilk.
Reference: Cécile Vors et al. Milk polar lipids reduce lipid cardiovascular risk factors in overweight postmenopausal women: towards a gut sphingomyelin-cholesterol interplay, Gut(2019). DOI: 10.1136/gutjnl-2018-318155