A double blind placebo controlled trial examining the relationship between Health-Related Quality of Life and dietary supplements

Objectives. This study was conducted to examine the relationship between Health-Related Quality of Life (QOL) and dietary supplements. It was hypothesized that taking dietary supplements would lead to improvements in QOL. Design. A double blind placebo controlled trial was carried out, over an 8-week period. Method. In a group of 313 healthy adults, QOL was examined at the beginning and end of the trial, through the Multi-Modal Strain Questionnaire (MMSQ), Profile of Mood States (POMS) and the SF-36 health survey questionnaire. The Dietary Instrument for Nutrition Education (DINE) questionnaire was used to examine quality of dietary intake, and the Dutch Eating Behaviour Questionnaire (DEBQ) to examine levels of restrained eating. Results. While those taking dietary supplements showed greater improvements in QOL than those in the placebo group, these improvements were not statistically significant at the .05 level, with the exception of the confusion bewilderment scale on the POMS, and the behavioural strain scale on the MMSQ. There were no significant interactions between condition (supplements or placebo) and quality of dietary intake. However, significant interactions were found between restraint and condition for the tension anxiety, depression dejection, fatigue inertia and confusion bewilderment scales of the POMS; the behavioural strain, cognitive strain, physical strain and overall strain scales on the MMSQ; and the bodily pain, vitality and mental health scales of the SF-36. Conclusion. It is concluded that for high restrained eaters, otherwise healthy individuals who restrict their food intake to lose weight, dietary supplements may improve QOL.