Dietary fats, marbling and human health

Abstract

This paper provides a description of dietary fats, including saturated, monounsaturated and polyunsaturated fats, as well as trans fatty acids and dietary cholesterol. The main concerns about dietary fats for human health are discussed, with particular reference to obesity, coronary heart disease and cancer. In relation to obesity, concern is with total fat intake in relation to excess energy intake; for heart disease this is also an issue but perhaps more important is the issue of the type of fats consumed, notably the role of saturated v. polyunsaturated and monounsaturated fats. For cancer, evidence suggests few links with either total or type of fat in the diet. The paper then reviews red meat as a source of dietary fat, concentrating on Australian beef and the types of fat found in the beef. In the USA, current data tables indicate fat levels from 3.7% for the leanest cuts with most cuts being at least 6–7% fat. In Australia, analyses show lower fat levels with between 1.6 and 6.5% fat for pasture-fed beef and 1.6 and 6.5% for grain-fed beef. Generally, the fatty acid composition of marbling fat is similar to subcutaneous fat from the same animal. Contrary to some commonly held beliefs it does not, therefore, confer any health benefit but merely contributes to the overall fat level.