Trans Fatty Acids and Bioactive Lipids in Ruminant Milk

Abstract

There is increasing evidence that nutrition plays an important role in the development of chronic diseases in the human population, including cancer, cardiovascular disease, insulin resistance, and obesity. Developing foods that enhance human health is central to dietary approaches for preventing and reducing the economic and social impacts of chronic disease. Numerous studies in human subjects have implicated a high consumption of saturated fatty acids (SFA) and trans fats as risk factors for cardiovascular disease risk, with evidence that high-SFA intakes may also be related to lowered insulin sensitivity, which is a key factor in the development of themetabolic syndrome.While it is generally accepted that SFA raise plasma total and low-density lipoprotein cholesterol concentrations, atherogenic effects are confined to 12:0, 14:0, and 16:0. Consistent with the effects of individual SFA, there is some evidence to suggest that physiological responses to trans fatty acids (TFA) may also be isomer-dependent. National nutritional guidelines with the target of reducing the incidence of cardiovascular disease have advocated a population-wide reduction in the intake of total fat, SFA, and TFA. Milk and dairy products are the major source of 12:0 and 14:0 in the human diet and also make a significant contribution to 16:0 and TFA intake. However, developing public health policies promoting a decrease in milk, cheese, and butter consumption ignores the value of these foods as a versatile source of nutrients. Furthermore, consumption of milk and dairy products may confer beneficial effects with respect to the prevention of osteoporosis, cancer, atherosclerosis, and other degenerative disorders (Heaney, 2000; Ness et al., 2001; Kalkwarf et al., 2003; Valeille et al., 2006). A number of minerals, proteins, peptides, and lipids in milk and fermented dairy products exhibit bioactive properties with the potential to