Abstract

Background: The efficacy of dietary supplements in chronic fatigue syndrome (CFS) is uncertain, with conflicting evidence.Aim: To assess the effect of a polynutrient supplement on fatigue and physical activity of patients with CFS.Design: Prospective randomized placebo‐controlled, double‐blind trial.Methods: Fifty‐three patients (16 males, 37 females) fulfilling the CDC criteria of CFS. The entry criteria were a score on the Checklist Individual Strength subscale fatigue severity (CIS fatigue) ≥40 and a weighted sum score of ≥750 for the eight subscales of the Sickness Impact Profile (SIP8) and no use of nutritional supplements in the 4 weeks prior to entry. The exclusion criteria were pregnancy and lactose intolerance. The intervention—a polynutrient supplement containing several vitamins, minerals and (co)enzymes, or placebo, twice daily for 10 weeks—was preceded by 2 weeks of baseline measurements. Outcome measurements took place in week 9 and 10 of the intervention. Five participants dropped out (4 supplement, 1 placebo). The main outcome measures were CIS fatigue score, number of CDC symptoms and SIP8 score. Efficacy analyses were performed on an intention‐to‐treat basis.Results: No significant differences were found between the placebo and the treated group on any of the outcome measures: CIS fatigue +2.16 (95%CI −4.3 to +4.39, p=0.984); CDC symptoms +0.42 (95%CI −0.61 to +1.46, p=0.417); SIP8 +182 (95%CI −165 to +529, p=0.297). No patient reported full recovery.Discussion: The findings do not support the use of a broad‐spectrum nutritional supplement in treating CFS‐related symptoms.