Randomized controlled trial: effect of nutritional counselling in general practice

Objectives To investigate the effectiveness of a non-structured 15-min educational intervention by general practitioners (GPs) on modifications of daily diet among healthy adults. Design Two arms randomized trial lasting 12 months. Setting Italian general practitioner wards. Subjects A total of 3186 men and women aged 18-65 years recruited in the medical ward by their GPs. Interventions An educational intervention and a brochure on the basics of a healthy diet based on the Italian Guidelines for a Correct Nutrition, 1998. The main study goal was to attain an intake of fruits and vegetables > 5 servings per day. Follow-up visit every 6 months. Main outcome measures Weight, blood pressure, and a 40-items Food Frequency Questionnaire. Results The intervention group showed a slightly reduced net intake of meat and a slightly increased net intake of fruits and vegetables, fish products, and olive oil. Body mass index (BMI) changed only in the treatment arm [-0.41 95% confidence interval (95% CI) -0.11 to -0.53]. The net change at 1 year in the intervention arm was +1.31 (CI 0.90-4.39) for fruits and vegetables, and -0.22 (-0.11 to -0.69) for meat (portions per week). We also computed a 'healthy diet score' reflecting compliance with recommended dietary habits. In the intervention group, the mean score at recruitment was significantly lower than the mean score at the end of follow-up (Crude score change = 0.29; CI 0.19-0.48). No differences were observed in the control group (Crude score change = -0.04; CI -0.22-0.02). The difference in score from baseline to the final visit, comparing the intervention vs the control group, was statistically significant (P < 0.001) (MANOVA adjusted by sex, BMI, education, and time). Conclusions A brief educational intervention by GPs can induce multiple diet changes that may lower BMI and potentially reduce chronic disease risk in generally healthy adults.