Fact: A large body of evidence says a diet high in saturated fat increases blood cholesterol and heart disease risk.
However, an old idea has recently found new legs: the idea that saturated fats aren’t that bad. The latest rumblings were published in Lipids based on a session at the 2009 Annual Convention of the American Oil Chemists Society (AOCS). The AOCS is an industry organisation ‘for those interested in the science and technology of fats, oils, surfactants and related materials’.
One article reviewed the biochemical roles of saturated fatty acids. Yes, saturated fatty acids have a role in the diet. No-one is saying remove saturated fats completely from the diet – it is impossible because all dietary fats are composed of a mixture of fatty acids anyway. Incidentally, the body can synthesise its own saturated fatty acids, but we must consume essential omega-6 and omega-3 ALA polyunsaturates from our diet to do so.
Another article was in defence of dairy. Prospective cohort studies fail to show increased heart disease, diabetes and death rates from consuming dairy foods. In fact people who consume the most dairy tend to live longer lives and have an 8% lower risk of heart disease. This makes sense as dairy contains a bundle of important nutrients. These studies are problematic because of their imperfect measurement of dairy intake, for example there are inconsistencies between whether the dairy foods were reduced fat or not. This review does not constitute a green light for eating saturated fat. Dietary guidelines suggest we take the good and leave the bad by choosing reduced fat milk and yoghurt, and limiting butter.
Another article suggests that because human breast milk contains 50% saturated fatty acids there may be benefits we don’t yet understand. This is placed best into context by one of the authors Professor J. Bruce German from the Department of Food Science and Technology at the University of California, ‘The relationship between dietary intake of fats and health is intricate, and variations in factors such as human genetics, life stage and lifestyles can lead to different responses to saturated fat intake’. So perhaps what’s best for infants is not best for adults.
So what is muddying the water on the saturated fat issue? In part, it’s because many studies have only examined saturated fat intake and failed to consider that unsaturated fat intake is protective and that too much of the wrong type of carbohydrate can be detrimental. There are several studies that have now investigated the role of GI and the risk of cardiovascular disease, and the majority have found a positive association between the GI of the diet and increased risk. The Harvard Nurses Health study, for example, showed that women consuming high GI carbs had twice the risk of having a heart attack over a 10 year period.
The bottom line? Replace saturated fats with unsaturated fats or low GI carbs in a balanced diet.
Nicole Senior MSc (Nut&Diet) BSc (Nut) is an Accredited Practising Dietitian and Nutritionist. For more information on heart-friendly eating and fabulous recipes low in saturated fat and high on flavour check out Nicole’s books Eat to beat Cholesterol and Heart Food HERE.