Background and methodology
In recent years, awareness of the importance of diet in human health has led many authorities to recommend that the contributions of fat and especially saturated fatty acid (SFA) to dietary energy intake should be reduced. Within these guidelines, more particular advice is to reduce the intake of short-and medium-chain SFA and the intake of n-6 polyunsaturates relative to n-3. This paper considers the options for meat, a food which has been criticized on the grounds of its fat and fatty acid content.
Meat is often wrongly identified as food having a high fat content and an undesirable balance of fatty acids. Lean meat is very low in fat. Pork and poultry have a favorable balance between PUFA and SFA (P:S). Grazing ruminants produce muscle with desirable n-6:n-3 PUFA ratio. The saturating effect of rumen can be overcome by feeding PUFA, which are protected chemically by processing, or naturally. Some protection occurs when grain-based or grass based diets are fed normally leading to a relatively more n-6 or n-3 fatty acids respectively. These produce different flavors in cooked meat due to the different oxidative changes occurring during storage and cooking. In pigs and poultry, high n-3 fatty acid concentrations in meat are associated with fishy flavors. In ruminants, supranutritional vitamin E delays the oxidative change of oxymyoglobin to brown metmyoglobin and may also influence the characteristic flavors of beef and lamb.
Wood, J. D & Esner, M. (1997). Factors affecting fatty acids in meat and the role of antioxidants in improving meat quality. British Journal of Nutrition 78: 49-60.