South African lamb and cardiovascular disease risk

Recent analyses of the composition of South African lamb have yielded more positive findings than those reported previously. Evidently the fat content is much less than previously reported, and more appropriate according to recommendations set for the prevention of cardiovascular disease. The protein content and the vitamin constituents are proposed to be conducive to the metabolism of methionine, thereby preventing accumulation of homocysteine in the circulation with lamb intake. This editorial evaluates the relevance of these results in terms of the possible implications for cardiovascular disease. New data on South African lamb shows that it contains on average 42% less fat and 59% less energy (kJ) 1 than previously reported by the Medical Research Council. 2 Previous data were compiled from international reports. Table 1 depicts the new findings. The study of van Heerden et al. 1 reports that South African lamb and mutton contains on average less than 10% fat, with the shoulder cut containing 9.86 g, the loin containing 7.80 g and the leg containing 7.67 g fat. According to recommendations of both the Heart Foundation (www.heartfoundation.com) and the Cancer Foundation (www.cancer.org), meat should contain less than 10% fat, and intake of South African lamb and mutton are therefore acceptable. Furthermore, it is important to note that the nutrient content of leaner meat is higher, as fat dilutes the nutrients in a protein matrix. Ruminant meat is a natural source of conjugated linoleic acid (CLA) 3,4 and of the different ruminants, lamb is the richest meat source of CLA. 5 Lamb is also reported to have a higher proportion of unsaturated fatty acids compared with saturated fatty acids (SFAs), 5 which is favourable as increased risk of cardiovascular disease is related to the intake of diets high in saturated fatty acids. 6 The proportion of fatty acids will be affected by trimming as lean meat is higher in polyunsaturated fatty acids (PUFA) and lower in SFAs than untrimmed meat. 4 Lean red meat is a source of polyunsaturated fats, including omega-3 fatty acid, and pasture feeding contributes significantly to long-chain omega-3 fatty acid intake in the diet. 4 In contrast, meat from grain-fed animals has no omega-3 fatty acids as grain does not contain omega-3 fatty acids, but is high in omega-6 fatty acids (linoleic acid). 6 Cooked loin of South African lamb appears to be an excellent source of protein as reported in the study of van …