A Mediterranean diet quality index (MDQI) was devised to give an overall assessment of dietary habits and to identify groups at risk.

The MDQI was based on scores given for selected levels of consumption of selected nutrients and foods.

Mediterranean southern France.

The sample included 473 men and 491 women in three age classes recruited at random.

Only 9.5% of men, 9.0% of women, 4.7% of 20–34 year old subjects, 6.6% of 35–54 year old subjects and 14.0% of 55–76 year old subjects were shown to have a healthy diet. However, 10.1% of men, 8.6% of women, 19.4% of 20–34 year old subjects, 10.2% of 35–54 year old subjects and 4.6% of 55–76 year old subjects were shown to have a poor diet. There were significantly fewer smokers among subjects with a good diet but the distribution of moderate wine drinkers was comparable between those with a good diet and those with a poor diet. Correspondence analysis associated a healthy diet with 55–76 year old men and women living in rural areas, who had received primary schooling only and who were manual workers. Both men and women with a poor MDQI score tended to be young and smokers. In addition, women with a poor MDQI tended to be heavy drinkers and obese.

This study showed that the Mediterranean model, which is generally recognized as a healthy diet, appears restricted to older people and to rural areas, whereas urbanized young people depart from it. A nutritional prevention policy targeted at young adults is required to encourage them to adhere to the Mediterranean model. Smoking and drinking showed different distribution patterns in the sample under study.

To fulfil a comprehensive approach to consumption, which is necessary to characterise food habits and their relationship to diseases, using a diet quality index (DQI) developed for a Mediterranean region (Med-DQI).

A cross-sectional nutritional survey provided the data for the construction of the DQI.

A representative sample made up of 964 subjects from a French Mediterranean area, Hérault département.

Foods such as olive oil, fish and cereals were used instead of nutrients to build up scores which constructed the Med-DQI. Biochemical analysis identified biomarkers used to validate the Med-DQI. Correspondence factorial analysis illustrated the characteristics of subjects with different scores given by the Med-DQI.

The subjects could be satisfactorily classified by the Med-DQI. The oldest age, less educated, overweight, manual workers, living in a rural area and male classes showed a better Med-DQI. For women, they were also from the oldest age class, but some of them were from the upper social class, with an ideal BMI and lived by the Mediterranean shore. A composite biomarker index, based on plasma carotene and vitamin E levels and the percentage of EPA and DHA in erythrocytes membranes, can identify subjects with good and poor Med-DQI.

Med-DQI G is a good instrument to identify groups at risk with regard to nutritional quality. Subjects with α+β-carotene levels > 1 mg/l, vitamin E > 30 mg/l, EPA > 0.65% and DHA > 4% of fatty acids in erythrocytes are likely to have a good diet.