Research has suggested that the absence of parasite infections may be linked to an increased prevalence of inflammatory conditions. According to a new review of existing studies, parasites may have anti-inflammatory properties that may help prevent aging. Through centuries of evolution, the human body and its surrounding environments have adapted to improve health and promote longevity. For example, the increasing emphasis on hygiene has been effective in combating parasites that cause disease.
These changes have been crucial, as evidenced by the greater life expectancies and lower disease rates in certain regions of the world. However, these benefits come with trade-offs. Parasites and humans share a long history of coexistence. It is likely that the human immune function developed in relation to parasitic mechanisms.
The “old friends” hypothesis states that these parasites were like old friends of the human body that helped improve tolerance and function and that their decline led to a higher prevalence of allergic responses and autoimmune conditions. This decline may also promote inflammaging, which is a chronic form of inflammation that worsens with progressing age. Inflammaging contributes to several age-related conditions, such as dementia, cancer, osteoporosis, and heart disease.
One recent study shows that inflammaging may exacerbate symptoms of COVID-19, as well. Bruce Zhang and Dr. David Gems, from the Institute of Healthy Ageing at University College London in the United Kingdom, conducted a review of the existing literature to explore the use of parasite worms as a therapy to reverse conditions linked to inflammaging. This review article appears in the journal eLife.
The authors focused their research on a specific group of parasitic worms called helminths, which include roundworms, tapeworms, and flukes. These parasites live inside host organisms, such as human bodies, and take advantage of their immune responses in order to survive. These findings also provide a glimpse into the intricacies of the human body’s immune functions.
Scientists associate the decline of helminths with multiple inflammatory conditions that occur earlier in life. These include asthma, eczema, multiple sclerosis (MS), rheumatoid arthritis, inflammatory bowel disease, and type 1 diabetes. Current evidence supports the idea that both natural and deliberate infection with helminths can combat these inflammatory conditions.
Indeed, in 1976, researcher J. A. Turton published a report in which he explained that his hookworm infection reduced the severity of his allergies.