Gas-sensing pills sniff out fiber’s effect on the gut

Intestinal gases are more than just an embarrassing problem. Changes in the type of gases are linked to digestive diseases like irritable bowel syndrome, which affects at least 15.8 million people in the United States alone. But doctors and scientists didn’t have an easy, reliable tool for figuring out how gases change in sick people—until now.

Australian scientists have reported the first-ever animal trials of “smart pills”—tiny electronic capsules that measure gases in real-time as they travel safely through the gut. These smart pills could help scientist figure out what diets and drugs affect the gut. And they might help doctors better diagnose people with IBS, inflammatory bowel disease, and even colon cancer.

Doctors have traditionally used breath tests to measure the intestinal gases wafting out of a patient’s mouth, writes Ariel Bogle for Mashable. But when gases waft out, they’re all jumbled together. “The smart pills allow us to identify precisely where the gases are produced and help understand the microbial activity in these areas,” says study author Kourosh Kalantar-zadeh in a press release.

That microbial activity comes from the trillions of bacteria in people’s guts which help digest food, writes John Boyd for IEEE Spectrum. In heathy people, this microbial fermentation produces the usual mix of hydrogen, methane, and carbon dioxide gases. However, a disease like IBS stresses the microbes and changes the relative concentration of gases.

But before doctors could start measuring sick people’s gases, the scientists had to test the pills in pigs. The scientists gave the pills to one group of pigs eating a high-fiber diet and to a second group eating a low-fiber diet. They were expecting that the pigs eating more fiber would have more microbial fermentation, and therefore produce more hydrogen and methane gases.

What they found instead was a “complete surprise,” says Kalantar-zadeh. Instead of the high-fiber diets producing more hydrogen and methane, the low-fiber diet produced four times more hydrogen in the pigs’ small intestines. This suggests that people who have IBS and microbial overgrowth in their small intestine could eat a high-fiber diet to reduce their hydrogen gas. However, the high-fiber diet produced more methane in the pigs’ large intestine as expected—suggesting that a low-fiber diet might better prevent painful bloating.

Starting in the next two months, the scientists will find out if that’s the case in humans. An upgraded version of the capsule with a temperature sensor and more gas sensors will be tested in healthy human volunteers, writes Boyd. Hopefully, the pills will prove both smart and safe, and doctors will soon use them to help millions of people suffering from more than just an embarrassing problem.

Kalantar-Zadeh K, Yao CK, Berean KJ, Ha N, Ou JZ, Ward SA, Pillai N, Hill J, Cottrell JJ, Dunshea FR, McSweeney C, Muir JG, & Gibson PR (2016). Intestinal Gas Capsules: A Proof-of-Concept Demonstration. Gastroenterology, 150 (1), 37-9 PMID: 26518389

Unintended consequences: Arsenic, iron, and your gut bacteria


Francesco de Medici, a possible victim of arsenic poisoning, may have something in common with the human gut microbiome.  Image via Wikipedia.

Arsenic—the infamous “king of poisons” used by the murderous Borgias—can poison humans and bacteria alike.  But it doesn’t just poison bad bacteria–arsenic hurts the helpful bacteria that make up our gut microbiome, which protects us from E. coli and helps digest our food.  Even worse, the microbiome may be harmed by a common method of mixing iron into water to remove the arsenic.  Chinese researchers reported recently that mice which consumed arsenic-contaminated water with iron had healthier intestines than mice which drank only the water without iron.  However, the healthier mice still had unhealthy microbiomes.  Their gut bacteria had evolved methods for protecting themselves against the toxic metals—methods, unfortunately, which also protected them against antibiotics.  The researchers cautioned that people drinking iron-treated water to avoid arsenic poisoning may develop antibiotic-resistant bacteria, making them vulnerable to dangerous infections.