Food and Behaviour Research

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Effect of supplement with lactic-acid producing bacteria on fatigue and physical activity in patients with chronic fatigue syndrome.

Sullivan A, Nord CE, Evengård B. (2009) Nutr J.  8:4 1475-2891 

Web URL: View this and related abstracts via PubMed here. Free full text of this article is available online


Disturbances in intestinal microbial ecology and in the immune system of the host have been implicated as a part of the pathogenesis in chronic fatigue syndrome. Probiotic lactic acid producing bacteria have been shown to prevent and alleviate gastrointestinal disturbances and to normalize the cytokine profile which might be of an advantage for patients suffering from chronic fatigue syndrome.

The aim of the study was to evaluate the effect of Lactobacillus paracasei ssp. paracasei F19, Lactobacillus acidophilus NCFB 1748 and Bifidobacterium lactis Bb12 on fatigue and physical activity in CFS patients.

Fifteen patients fulfilling the criteria set by international researchers in the field at the US Centre for Disease Control and Prevention in 1994 for chronic fatigue syndrome, were included in the study. The patients had high fatigue severity scores and high disability scores. During the first two weeks baseline observations without treatment were assessed, succeeded by four weeks of 
intake of a probiotic product and a four-week follow-up period. The fatigue, health and physical activity was assessed by the use of the Visual Analogue Scales and the SF-12 Health Survey. Faecal samples were collected and the normal microflora was analysed.

Neurocognitive functions improved during the study period while there were no significant changes in fatigue and physical activity scores. No major changes occurred in the gastrointestinal microflora. At the end of the study 6 of 15 patients reported that they had improved according to the assessment described.

The findings in this study that improvement of health is possible to achieve should encourage further studies with interventions with probiotics in patients with CFS.


This small open study provides preliminary evidence that supplementation with certain probiotics might help to reduce some of the mental symptoms of chronic fatigue syndrome in at least some patients, although no improvements in physical fatigue were found. 

Like most psychiatric diagnoses, CFS is a highly heterogenous condition with no objective markers, and overall benefits were reported by only 6/15 patients. Future studies would therefore do well to collect both clinical and biochemical data in order to try to identify possible subgroups.

The authors also report that no major changes in GI microflora could be detected following supplementation, indicating that both dosages and formulations of the supplements used may merit further investigation.