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) >or=40 and a weighted sum score of >or=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.