Trehalose is a sugar consisting of two molecules of glucose. However unlike the sugar on top of a jelly doughnut, it does not display the qualities of glucose when introduced into the body as it resists breakdown back into the simple sugars. Trehalose has high water retention capabilities, and is used in food, cosmetics, and as a drug. Because of its physical properties, trehalose possesses unique capabilities when it comes to maintaining the structure of proteins. It acts like a chaperone ‘splinting’ proteins in place when conditions become inhospitable (such as becoming dried out or frozen). Some bacteria, fungi, plants and invertebrate animals synthesize it as a source of energy, and to survive freezing and lack of water.
Trehalose also possesses the ability to induce a chemical activity called autophagy. Autophagy, from the Ancient Greek αὐτόφαγος autóphagos, meaning “I eat myself”, is the cellular equivalent of a town’s department of sanitation, garbagemen who day in and day out remove the debris of metabolism. Not surprisingly, because of these two special properties, trehalose has been looked at as a possible nutraceutical treatment for Alzheimers Disease.
But all news is not good in trehalose land.
There has been a recent flurry of news reports regarding a study linking trehalose to an increased severity of Clostridium difficile (‘C-diff’) infections, a gastrointestinal infection seen in immune-compromised hospital patients.
This was a small study that was done in-vitro (cell culture). It did not show that trehalose caused C-diff infections, but rather, culturing C-diff organisms with trehalose seemed to increase the pathological behavior of the organism by increasing the preponderance of two particular strains, known as RT027 and RT078.
However the evidence is far from conclusive. Trehalose has been added to food since 1995 in Japan, but neither of the pathogenic strains studied have been linked to outbreaks there. In the U.S., data suggests that these pathogenic variants had emerged well before 2000 and were already prevalent in hospitals. The data from Canada is even weaker. Outbreaks of RT027-associated C-diff predated the approval of trehalose as a food ingredient there in late 2005.
One university microbiologist reviewing the paper was quoted as saying: “It would be a shame if as a society we took this off the table before we’re really sure that it’s a problem. Let’s reevaluate the epidemiology and make sure that it makes sense, and then let’s do clinical research to make sure that this indeed is relevant to sick patients.” (JAMA. Published online March 21, 2018)
Finally, we should really keep things in perspective: C-diff infection is typically seen in immune-compromised patients who have been overprescribed antibiotics. Although the incidence is rising, this is a rather small percentage of the overall population, even in hospitals. It is far from conclusive that these results would duplicate in actual people, as the amount of trehalose that was used in the cell culture was far greater than what one would expect to be exposed to, even if taking it as a supplement.
- 1. https://www.nature.com/articles/cddis2017501
- 3. https://www.nature.com/articles/nature25178