Eating to Prevent Bends

Food supplements laced with bacteria may someday protect divers from the ravages of decompression sickness, reports New Scientist magazine. Experiments with pigs have shown that methane-producing microorganisms that live in the gut can help ward off the bends.

Susan Kayar and her colleagues at the Naval Medical Research Center in Bethesda, Maryland, reasoned that deep dives would be made safer if more dissolved hydrogen could be removed from the divers’ blood. They turned to a bacterium called Methanobrevibacter smithii, which lives in the gut and metabolizes hydrogen to form methane. They injected cultures of the bacteria into the intestines of pigs, then put the animals in a hyperbaric chamber for an ascent from a three-hour dive at 240 meters.

The researchers found that pigs that were not given the bacterial cultures were nearly twice as likely to show DCS symptoms. The treated pigs were more flatulent, releasing large quantities of methane. The more bacteria that were added to their guts, the more methane they produced: indeed, a new form of offgassing.

Kayar says the bacterial supplements appear as harmless as live yogurt. “These are microbes that you have in your intestine right now,” she says. The treated pigs seemed to suffer no ill effects and their altered gut microflora later returned to normal.