Chronic fatigue syndrome (CFS) is a condition often considered difficult to understand. The main characteristic of CFS is persistent and relapsing fatigue, usually worsened by physical and mental exertion. It also involves neuropsychological symptoms including loss of memory or concentration, headaches, sleep disturbances, depression, and anxiety. Of these symptoms, depression and anxiety are the most common with about half of CFS patients meeting diagnostic criteria for an anxiety or major depressive disorder.

Another common condition found in people with CFS is irritable bowel syndrome (IBS) with over half of people with CFS meeting diagnostic criteria for IBS.1 The link between CFS and the gut could be considered a gut-brain/gut-immune connection. It is known that gut bacteria can actually communicate with the nervous system by way of the vagal nerves (which innervate the digestive tract), thus influencing mood. Brenda has blogged on this topic a few times. Gut bacteria also communicate with the immune system, up to 80 percent of which resides in the gut (in the gut-associated lymphoid tissue).

Lower levels of Bifidobacteria and higher levels of aerobic bacteria have been found in people with CFS.2 This finding prompted the study of probiotic supplementation on emotional symptoms in people with CFS. Twenty four patients consumed 8 billion CFUs of Lactobacillus casei strain Shirota or a placebo after each main meal, or three times daily. The probiotic was found to decrease anxiety symptoms and increase levels of both Lactobacillus and Bifidobacterium when compared to people taking placebo.3

The researchers stated, “It can therefore be concluded that ingestion of the probiotic capsules contributed towards the predominance of bacteria that are associated with a healthy gastrointestinal system,” and, “The rise in Lactobacilli was an expected finding, although the concomitant rise in Bifidobacteria suggests that there may be far reaching effects of oral probiotics on other microbial residents of the gastrointestinal tract.”

The gut-immune connection is important here, since chronic, low-grade inflammation (also called silent inflammation) has been found in people with chronic fatigue syndrome, and the gut is a major source of this inflammation. The researchers recognize this, “Since orally administered probiotics can decrease inflammatory cytokines in humans, it has been postulated that bacteria may be used to positively influence mood in patient populations where both emotional symptoms and inflammatory immune chemicals are elevated. It is becoming increasingly clear that anxiety and stress itself may lower levels of fecal lactic acid bacteria, and this, in turn, may compromise various aspects of health.”

To interrupt the vicious cycle of gut dysbiosis > immune dysfunction > mood disturbances > gut dysbiosis, two important factors must be addressed: The gut must be balanced with proper consumption of probiotics, consumption of a plant-based diet (which strongly supports the growth of beneficial gut bacteria) and stress must be reduced. A balanced gut and proper stress management together can have many positive effects on your health. Consider how you can make changes in both these areas.


  1. W.E. Whitehead, et al., “Systematic review of the comorbidity of irritable bowel syndrome with other disorders: what are the causes and implications?” Gastroenterology. 2002 Apr;122(4):1140-56.
  2. A.C. Logan, et al., “Chronic fatigue syndrome: lactic acid bacteria may be of therapeutic value.” Med Hypotheses. 2003 Jun;60(6):915-23.
  3. A.V. Rao, et al., “A randomized, double-blind, placebo-controlled pilot study of a probiotic in emotional symptoms of chronic fatigue syndrome.” Gut Pathog. 2009 Mar 19;1(1):6.