Strategies for altering population intakes of fats and fatty acids.

Quantitative dietary guidelines for fats were first issued in 1977 in the USA and these guidelines have changed little since then. In the UK only 14% of the population achieve the dietary goal for fat (33% energy) and only 3% achieve the target (10% energy) from saturated fatty acids. Analysis of the Dietary and Nutritional Survey of British Adults reveals that across quartiles of decreasing total fat intake, the actual fatty acid composition of this fat does not alter; i.e. when total fat is lowered, all fatty acid categories are equally lowered. This arises because 85% of total fat and of each of the categories of fatty acids are provided by just five foods (milk, meat, cereals, spreads and vegetables). When total fat in the UK is lowered, the intake of polyunsaturated fatty acids is lowered. The problem is that if the intake of polyunsaturated fatty acids falls below a threshold of about 5% energy, the cholesterol-raising properties of certain saturated fatty acids, e.g. myristic acid, are greatly augmented. In order to alter the balance of dietary fatty acids, more data are needed on food choices of those in the population achieving particular targets. These targets cannot be based on existing dietary goals, since so few people attain them. A new set of 'interim attainable dietary guidelines', based on prevailing dietary intakes, must be the basis for establishing sensible food-based dietary guidelines.