Alleviation of metabolic syndrome with dietary egg white protein

Abdominal fat accumulation causes metabolic syndrome, which is a cluster of metabolic abnormalities such as dyslipidemia, glucose intolerance, insulin resistance or hyperinsulinemia, and hypertension, leading to the development of diabetes and cardiovascular disease. Diets are known to contribute to the development or prevention of metabolic syndrome. Several studies have reported that the quality of dietary proteins may be an important modulator of the risk of this syndrome. We investigated the effects of consuming egg white protein (EWP) or lactic-fermented egg white (LE), an easy-to-consume form of egg white, on the development of metabolic syndrome in animal models and humans. In comparison with casein, dietary EWP decreased lymphatic lipid transport in thoracic lymph duct-cannulated rats. In an in vitro experiment, EWP pepsin hydrolysate decreased the cholesterol micellar solubility and cholesterol transfer rate from micelles to oil phase, and increased water-holding capacity, settling volume in water, and relative viscosity compared with casein pepsin hydrolysate. The daily consumption of LE for 8 weeks reduced serum total cholesterol and LDL cholesterol levels in men with mild hypercholesterolemia. Furthermore, dietary EWP reduced the body fat mass of rats by increasing the body protein mass and accelerating hepatic β-oxidation. The daily consumption of LE for 12 weeks reduced the visceral fat area and improved the ratio of the visceral to subcutaneous fat area. Taken together, these results indicated that dietary EWP and LE would be useful for preventing or alleviating metabolic syndrome.