Changing the Mediterranean diet: effects on blood pressure.

An increase in the polyunsaturated to saturated fatty acid ratio (P:S) in the diet has been reported to reduce blood pressure in man. We have investigated whether an increase in the percentage of saturated fatty acids in the typical Mediterranean diet would affect blood pressure in a sample of healthy rural population of southern Italy. Fifty-seven non-hospitalized normotensive volunteers (29 male, 28 female, aged 30-50 years) were studied. After a 2-week baseline period on their customary diet (P:S=0.44), they underwent a 6-week isocaloric dietary intervention with a 70% increase in energy from saturated fatty acids and a corresponding decrease in carbohydrate and mono-unsaturated fat (P:S=0.23). Thereafter they returned to their usual diet and were followed-up for 6 more weeks (switch-back period). By the end of the intervention period, systolic pressure was increased by 2.6 mmHg in men (P These findings suggest that changes in the saturated fatty acid content of the diet with moderate change in the dietary P:S ratio can influence blood pressure to a significant extent.