Gulf War illness is characterized by a range of symptoms, including chronic fatigue, cognitive issues, pain and gastrointestinal complaints -- which persist even 30 years after deployment -- impacting quality of life. This study, which builds on previous pilot research conducted by the same team, further validates the link between an imbalance in the gut microbiome and Gulf War illness.
Saurabh Chatterjee, MSc, Ph.D., corresponding author and professor at the UC Irvine Joe C. Wen School of Population & Public Health, and team discovered distinct differences in the gut bacterial composition between those affected by Gulf War illness and those who are not.
The study used stool samples and Multidimensional Fatigue Inventory data from 89 Gulf War veteran participants, 63 of whom have Gulf War illness as the study group and 26 who do not have the illness as the control group.
The study is published in the International Journal of Environmental Research and Public Health.
Notably, veterans with Gulf War illness had a noticeably different mix of gut bacteria, often expressed as Bray-Curtis beta diversity, compared to those without the illness. This mix is important because it has implications for gut, immune and brain health.
Specifically, veterans with Gulf War illness had more of a certain bacteria that are usually less beneficial, like Blautia, Streptococcus, Klebsiella, and Clostridium, and fewer of the helpful ones, such as Akkermansia and Bacteroides.
The team used advanced machine learning algorithms to identify two bacteria called Coprococcus and Eisenbergiella as critical predictors of Gulf War illness. The results were impressively accurate -- nearly 75% of the time the algorithm was able to correctly distinguish between veterans with Gulf War illness and those without it using those two bacteria.
Additionally, higher fatigue scores in affected veterans were associated with altered gut bacterial diversity, particularly in species like Lachnospiraceae and Blautia.
These findings not only deepen the understanding of Gulf War illness but also suggest potential therapeutic targets focusing on the gut microbiome of veterans to alleviate specific symptoms of the illness.
"This study offers hope for the development of new treatments for Gulf War illness that specifically target gut health, potentially improving the quality of life for veterans who have suffered for decades," said Chatterjee who has parallel appointments at the UC Irvine School of Medicine and the Long Beach VA Medical Center.
"We've only scratched the surface in our understanding of the association between the microbiome imbalance and chronic fatigue but see this as a breakthrough leading to more in-depth studies on Gulf War veterans."