A remedy against obesity? The role of lactoferrin in the metabolism of glucose and lipids

摘要

Obesity, dyslipidemia, hyperglycemia/type II diabetes and hypertension together constitute the so-called metabolic syndrome. Frequency of occurrence of these serious metabolic disturbances is associated with life style and is on the rise in prosperous industrialized countries. These diseases represent not only a serious health problem but also social and economic ones, and involve in prophylaxis and treatment various specialists (physicians, dieticians and psychologists). For about two decades research has been conducted on the possibility to apply milk-derived proteins in prevention and treatment of the above mentioned metabolic diseases. Lactoferrin (LF), a protein present in milk and excretory fluids of mammals, is one of the most intensively studied milk proteins for therapeutic application. Initial trials revealing an advantageous effect of LF on lipid metabolism and obesity enrolled only a few volunteers and were performed in Japan in 2003. Subsequent trials were conducted on animals as well as in clinics, and the positive results were supported by in vitro tests. After oral administration of LF, decreases of body weight, waist measurement, visceral fat tissue, plasma and liver fatty acid concentrations, triglycerides and cholesterol were registered. The mechanism of LF action may involve several processes, such as inhibition of adipogenesis, decrease of dietary triglyceride absorption, elevation of HDL cholesterol possessing anti-atherogenic properties, inhibition of accumulation of oxidized LDL cholesterol forms in macrophages and protection against formation of foam cells. LF also increases the susceptibility of cells to insulin action, including in conditions when the response to insulin is lowered (during inflammation). In addition, LF regulates activity of insulin-like growth factor (IGF). The data collected to date indicate that LF is a promising, completely nontoxic, natural remedy which (as for example a food supplement) may be applied in long-term prophylaxis and therapy of metabolic disturbances, such as dyslipidemia, obesity and insulin resistance/type II diabetes.