This study is not easy to follow, mostly because we are used to focusing on the bug (C. diff.), not the way it evolved. The idea is that this sugar (trehalose) gave the worst C.Diff bug the ability to out-compete all the other less dangerous C. Diff bugs. In addition, this sugar gives this bug the ability to create more dangerous toxins that cause the worst symptoms of C. Diff. While trehalose is a naturally occurring sugar, it isn't something we are normally exposed to, except as a food additive. We ALL have it in our guts, so the question of whether we get the symptoms has to do with the ecology of our gut, and how well different strains of C. Diff. compete with one another in our gut. I assume trehalose is listed as an ingredient on food labels. I know I will be checking food labels for trehalose, and avoiding foods that contain it.
Trehalose is a naturally occurring sugar. It is a disaccharide, meaning that it is made up of two individual sugar molecules — in this case glucose. Trehalose can be found in fungi, algae, and other plants. The food industry uses the sugar to improve the texture and stability of food products.
Prof. Britton explains in his article that the use of trehalose was somewhat limited before the turn of the century; it cost approximately $7,000 to produce just 1 kilogram. However, the discovery of an enzymatic process that allows trehalose to be extracted from corn starch brought this number down to just $3 per kilogram.
"Granted [the] 'generally recognized as safe' status by the U.S. Food and Drug Administration [FDA] in 2000 and approved for use in food in Europe in 2001," Prof. Britton reports, "reported expected usage ranges from concentrations of 2 percent to 11.25 percent for foods including pasta, ground beef, and ice cream."
I asked Prof. Britton whether he thought that the use of trehalose in food will be restricted based on these data. He didn't think so.
"What this work does suggest is that if a hospital or long-term nursing care facility has an outbreak of C. difficile caused by a RT027 or RT078 strain, then patients' diets should be modified to restrict trehalose consumption," he suggested instead.
The biggest group of people at risk of C. difficile infection are over 65s, and particularly those who are taking antibiotics and find themselves in a healthcare setting such as a hospital.
For the rest of the population, C. difficile poses less of a threat. However, the CDC are very clear in their objective that "preventing C. difficile is a national priority."
Prof. Britton and his colleagues are certainly doing their bit. "We are working now to understand how trehalose increases disease severity of C. difficile strains that can metabolize low concentrations of trehalose," he told me.
"We are also screening," he continued, "emerging C. difficile strains from hospitals for their ability to consume trehalose and other dietary sugars to further investigate the link between the diet and C. difficile infection."
While there are many questions still to be answered by the scientists, the link between trehalose and C. difficile is part of an emerging theme showing that our diet seems to play an increasingly crucial role in how our gut microbes behave in sickness and health.