Medical science considered it a victory when it found a way to banish freeloading parasites from our bodies, but new research suggests that some parasitic worms may have been paying rent all along. The review published in the journal eLife reports on growing evidence that, without helminth parasites, our bodies experience more aging-associated inflammation compared to bodies with worm. Could it be that kicking rates of heart disease and dementia was as simple as walking with rhythm?
"A decline in exposure to commensal microbes and gut helminths in developed countries has been linked to increased prevalence of allergic and autoimmune inflammatory disorders - the so-called 'old friends hypothesis'," explained author Bruce Zhang, Undergraduate Assistant at the UCL Institute of Healthy Ageing (UCL IHA), London, in a statement. "A further possibility is that this loss of 'old friend' microbes and helminths increases the sterile, ageing-associated inflammation known as inflammageing."
Inflammaging – beyond being fun to say – is an increasingly relevant area of medicine as a contributor to some of the diseases attributed to the highest rates of annual deaths. Some of the big names include heart disease, dementia, cancer, and – since the fever dream that was 2020 – symptom severity during SARS-CoV-2 infections.
So, how can a case of the worms help us in the face of such serious conditions? In the last year alone, swathes of research have been released regarding the role of the gut microbiome on our wider health. Our gut microbiome is the population of microscopic organisms that naturally occur in our digestive tract, many of which aid our digestion among other things. This new research, however, suggests that the pivotal community could be bigger than we realize. Enter, the macrobiome.
This community is the ecosystem inside our bodies which is made up of macro (big) organisms, including helminth parasites such as hookworms, flukes, and tapeworms. Helminths have long wriggled in tandem with human evolution with ring-side seats in our very organs, and as a result, could well be the master manipulators of many of our physiological responses.
Could it be, then, that because we evolved with worms inside us, their removal has left us at somewhat of a disadvantage? Quite possibly, says the review titled "Gross Ways to Live Long: Parasitic worms as an anti-inflammaging therapy." When reviewing the medical literature, the researchers found ties between the loss of helminths and rising rates of asthma, atopic eczema, inflammatory bowel disease, multiple sclerosis, rheumatoid arthritis, and diabetes. Worms have even shown their worth in studies that found that infection with helminths alleviated disease symptoms in multiple sclerosis and eczema, say the authors.
If you’re not coming round to the idea of a worm a day to keep the inflammatory diseases away, it’s possible we could instead glean the benefits of parasites through helminth-derived proteins instead of the living worms themselves. The next step, the researchers say, is to look at populations where helminth infection rates are very high and see how the rates of disease vary from areas where the worms are banished.
"It goes without saying that improvements in hygiene and elimination of helminth parasites have been of incalculable benefit to humanity, but a cost coupled to this benefit is abnormalities of immune function," said co-author David Gems, Professor of Biogerontology and Research Director at the UCL IHA. "In the wake of successes during the last century in eliminating the evil of helminths, the time now seems right to further explore their possible benefits, particularly for our ageing population - strange as this may sound."