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The Lyon Diet Heart Study was the first trial based on a Mediterranean-type dietary intervention and showed a beneficial effect on the survival rate after myocardial infarction. We undertook an intervention study with a Mediterranean diet-based nutritional approach.
The first goal of the study was primary prevention of cardiovascular diseases by evaluating the effects of 2 diets (Mediterranean type diet and low fat, low cholesterol diet) on arteriosclerosis risk factors in subjects presenting at least one risk factor.
A second objective of the study was to implement extensive biological investigation in relation to the dietary intervention, with a special interest on fasting and postprandial examinations of lipid parameters and lipoproteins as well as some genetic polymorphisms influencing lipoprotein metabolism and homeostasis. Volunteers visiting the Centre for Detection and Prevention of Arteriosclerosis at La Timone Univeristy Hospital in Marseille were identified as potential participants if they presented at least one risk factor (e.g. obesity, untreated cholesterolemia, etc.). Subjects treated by hypolipemic and hypoglycaemic drugs were excluded. The final sample was made of 212 subjects, 69 men and 100 women (n=169) were back after 3 months intervention.
At 3 months in the Mediterranean diet group (vs the prudent low fat, low cholesterol group), the proportion of energy related to macronutrients was improved with a significant increase in carbohydrates intake up to 45.9% (vs 44.8%) and decrease in lipid down to 34.6% (vs 33.9%) especially SFA down to 10.0% (vs 10.3%), MUFA increasing from 14.3 to 15.6% in Mediterranean-diet group (vs decreasing from 14.4% to 13.4%). Fibre also significantly increased up to 22.3 g/d (vs 20.6 g/d). Plasma fatty acid measurements showed a significant decrease in palmitic acid and increase in oleic acid, alpha-linolenic acid, EPA and DHA.
After 3 months, the following relative changes in fasting biochemical parameters have been observed for the fasting biochemical parameters. Body mass index: -5.2% (vs -4.2%); plasma total cholesterol: -7.4% (vs -4.4%); LDL-cholesterol: -9.9% (vs -5.4%); HDL-cholesterol: +1.5% (vs +0.03%); plasma triglycerides: -13.0% (vs -7.9%); plasma glucose: -3.0% (vs -3.5%); plasma insulin: -21.3% (vs -17.5%). Except for HDL cholesterol, all these changes were statistically significant (p<0.05).
The data obtained show that, in subjects at risk, changing from the nowadays habitual (westernized) diet to a Mediterranean type diet improves blood biochemical parameters. The amplitude of the beneficial changes is less marked when changing for a prudent low-fat, low-cholesterol diet.
Analysis of data after 12 months follow up is on-going and confirms the trends observed after 3 months. |
