Towards healthy diets for parents: effectiveness of a counselling intervention

Abstract

Towards Healthy Diets for parents: efectiveness of a counselling intervention Eveline J.C. Hooft van Huysduynen Abstract Introduction and Objective: As parents’ modelling of dietary behaviour is one of the factors influencing children’s diets, improving parents’ diets is expected to result in improved dietary intake of their children. This thesis describes research that was conducted to develop and evaluate a counselling intervention to improve parental adherence to the Dutch dietary guidelines. Methods: A counselling intervention was developed, which was underpinned with the theory of planned behaviour and the transtheoretical model. In 20 weeks, five face-to-face counselling sessions were provided by a registered dietician who used motivational interviewing to improve parental adherence to the Dutch dietary guidelines. In addition, parents received three individually tailored email messages. During the counselling, the dietary guidelines and additional eating behaviours, that were hypothesized to affect diet quality, were addressed. The intervention was evaluated in a randomised controlled trial with 92 parents receiving the counselling and 94 parents as controls. Effects on dietary intake, biomarkers, intermediate markers of health and children’s dietary intake were evaluated. With mediation analyses, it was investigated if changes in dietary intake were established via changes in behavioural determinants. Thereby, it was also examined if spot urine samples could be used to replace 24 h urine samples for evaluating changes in sodium and potassium intake. Results: The intervention group increased their adherence to the dietary guidelines, as assessed with the Dutch Healthy Diet-index (ranging from 0 to 100 points), by 6.7 points more than the control group did. This improvement was achieved by small increases in the scores of seven out of ten index components. The most substantial changes were shown in fruit and fish intakes of which increases in fish intake were reflected in changes in fatty acid profiles derived from blood plasma. Also a small decrease in waist circumference was observed. Based on parental reports, the children in the intervention group increased their intakes of fruit, vegetables and fish more than the children in the control group. Improvements in parental fruit intake were mediated by changes in the behavioural determinants attitude and habit strength. Decreases in snack intake were mediated by changes in self-identity as a healthy eater. Although the results of a study in young Caucasian women showed that spot urine can be used to rank individuals for their ratios of sodium to potassium, no intervention effects on these ratios were observed. Conclusion: This thesis provides empirical knowledge on potential effective elements for counselling interventions aiming at improving the dietary pattern as a whole of parents and provides knowledge on methods to evaluate changes in dietary intake