Stale bread gets a bad rap—and not for nothing. It’s dry and bland and sticks directly to the roof of your mouth if you decide to try to eat it anyway. For the most part, it only serves to be repurposed: into bread crumbs, food for geese, or toast, if you can stomach it. But we may have been sleeping on stale bread’s health benefits. According to research findings from a recent study at the Royal Melbourne Institute of Technology (RMIT), stale bread may prevent colon cancer. Specifically, the study measured temperature’s effect on a kind of starch, called resistant starch, that bread starts producing almost immediately after it’s baked.
Resistant starch, as Gizmodo explains, “is a set of carbohydrate molecules that are resistant to the body’s own digestive enzymes.” So, intestinal bacteria is able to eat it, which produces beneficial byproducts, keeping your guts as healthy as they can be, from fighting obesity and regulating digestive hormones, to maintaining the growth of healthy cells along the walls of the colon, which could mean halting the cellular reaction that leads to colon cancer.
To research resistant starch’s growth, RMIT scientists baked their own loaves of white bread (kind of love the image of white coats baking bread) and left it out at various temperatures for up to a week. They took samples from each loaf, froze them in liquid nitrogen, pulverized them, and then analyzed the molecular crystallization with x-ray diffraction. (Along with dehydration, crystallization is what causes bread to get stale.) They discovered that the levels of resistant starch were highest in the bread that was stored at 38°F for five days.
While the cancer-fighting possibilities of resistant starch are very exciting, scientists are still figuring out exactly what the impacts could be, and how to harness them. With this study in particular, the researchers acknowledge that white bread—with it’s attendant health concerns and, frankly, still not high levels of resistant starch—maybe wouldn’t be the ideal thing to eat if you’re looking to prevent colon cancer and stay healthy. Whole wheat bread might be a better option.
So next time you’re out eating a diner breakfast, maybe order a side of whole wheat toast and butter it up in the name of intestinal health.