Hypertension is a key feature of the metabolic syndrome. Lifestyle and dietary changes may affect blood pressure (BP), but the knowledge of the effects of dietary fat modification in subjects with the metabolic syndrome is limited. The objective of the present study was to investigate the effect of an isoenergetic change in the quantity and quality of dietary fat on BP in subjects with the metabolic syndrome. In a 12-week European multi-centre, parallel, randomised controlled dietary intervention trial (LIPGENE), 486 subjects were assigned to one of the four diets distinct in fat quantity and quality: two high-fat diets rich in saturated fat or monounsaturated fat and two low-fat, high-complex carbohydrate diets with or without 1·2 g/d of very long-chain n-3 PUFA supplementation. There were no overall differences in systolic BP (SBP), diastolic BP or pulse pressure (PP) between the dietary groups after the intervention. The high-fat diet rich in saturated fat had minor unfavourable effects on SBP and PP in males.

Controlled human intervention trials are required to confirm the hypothesis that dietary fat quality may influence insulin action. The aim was to develop a food-exchange model, suitable for use in free-living volunteers, to investigate the effects of four experimental diets distinct in fat quantity and quality: high SFA (HSFA); high MUFA (HMUFA) and two low-fat (LF) diets, one supplemented with 1·24 g EPA and DHA/d (LFn-3). A theoretical food-exchange model was developed. The average quantity of exchangeable fat was calculated as the sum of fat provided by added fats (spreads and oils), milk, cheese, biscuits, cakes, buns and pastries using data from the National Diet and Nutrition Survey of UK adults. Most of the exchangeable fat was replaced by specifically designed study foods. Also critical to the model was the use of carbohydrate exchanges to ensure the diets were isoenergetic. Volunteers from eight centres across Europe completed the dietary intervention. Results indicated that compositional targets were largely achieved with significant differences in fat quantity between the high-fat diets (39·9 (sem 0·6) and 38·9 (sem 0·51) percentage energy (%E) from fat for the HSFA and HMUFA diets respectively) and the low-fat diets (29·6 (sem 0·6) and 29·1 (sem 0·5) %E from fat for the LF and LFn-3 diets respectively) and fat quality (17·5 (sem 0·3) and 10·4 (sem 0·2) %E from SFA and 12·7 (sem 0·3) and 18·7 (sem 0·4) %E MUFA for the HSFA and HMUFA diets respectively). In conclusion, a robust, flexible food-exchange model was developed and implemented successfully in the LIPGENE dietary intervention trial.

The prevalence of obesity, overweight and type 2 diabetes are increasing in all regions of Europe. Obesity is already commonplace, affecting 10–20% of men and 10–25% of women, and by 2010 approximately 31 million of the population will require treatment for diabetes and its related complications, including the ‘metabolic syndrome’ (a cluster of cardiovascular risk factors). Associated health and social welfare costs are expected to rise to economically unsustainable levels in Europe as a direct result of these trends. Effective strategies are needed to tackle this major public health problem and to decrease dependence on medical management. These issues are the focus of LIPGENE (FOOD-CT-2003-505944), funded by the European Commission, which will investigate the interactions between dietary constituents and the genome in the development of chronic diseases, such as the metabolic syndrome, and will utilise new technologies to identify novel solutions. The LIPGENE consortium comprises twenty-five research centres across Europe. Features of the 5-year work programme include a major human nutrition intervention study in eight European cities, development of a sustainable vegetable oil product naturally rich in long-chain n-3 fatty acids, and identification of a protocol for feeding dairy cows that will result in milk with a more favourable fatty acid composition. Other work packages will provide a detailed economic analysis of the current and future healthcare costs associated with the metabolic syndrome, and an analysis of consumer attitudes. There is also a dissemination programme associated with the project that features conferences, workshops and associated publications.