(CNN) -- The bacteria got its name -- Akkermansia muciniphila -- just 15 years ago. But the species, which breaks down gel-like proteins in the intestines, may soon offer hope to those with obesity-related disorders.
According to a study published Monday in the journal Nature Medicine, overweight people who drank supplements of the gut bacterium -- which occurs naturally in the digestive system -- showed improved sensitivity to insulin, a hormone that lets the body use sugar in the blood and is implicated in diabetes.
Compared to those who received a placebo, patients who consumed the bacteria also had lower cholesterol levels and lost 5 pounds on average over three months, although the weight loss was not statistically significant.
Thirty-two overweight or obese people participated in the study, and all of them had some symptoms of metabolic syndrome, a group of risk factors -- such as high waist circumference or high blood pressure -- that increases the likelihood of heart disease, stroke and diabetes.
The small sample size may explain why researchers couldn't definitively report that the bacteria, and not other factors, led to the weight loss. The researchers wrote that their study "was not powered to deliver definitive conclusions" on metrics like BMI or body fat but was a "promising start" nonetheless for obese people who are insulin-resistant.
"We were not really expecting effects on the body weight [and waist and hip measurements], but we still observed interesting trends," said Patrice Cani, the study's senior author and a professor at Belgium's Catholic University of Louvain.
He emphasized that "this approach will never replace appropriate dietary habits and physical activity," but he said the bacteria could complement diet and exercise to "boost the metabolism and help to improve metabolic factors."
The study was the first known example of scientists administering the bacteria to humans, and the research was designed in part to assess its safety. "There were no side effects," said Cani.
Dead bacteria were more effective
Insulin resistance occurs when muscle, fat or liver cells don't respond well to insulin, which typically signals cells to absorb sugar from the blood. The pancreas then produces more insulin to compensate for the resistance, which can lead to prediabetes, or higher than normal blood sugar levels.
Those who are obese tend to have lower levels of Akkermansia muciniphila in their gut, and dieting to improve insulin resistance tends to work better in people who have more of the bacteria, according to a 2016 study.
In the new study, the bacteria "prevented the deterioration of the health status of the subjects by targeting several cardiovascular risk factors," said Cani. Living microorganisms with health benefits are known as probiotics, but Cani found that Akkermansia muciniphila was most effective when pasteurized, or killed through heat.
In a 2007 study, his research team hypothesized that pasteurization may offer the body easier access to beneficial parts of the bacteria -- such as proteins on the membrane of the organism -- or may prevent live cells from producing substances that limit their health benefits.
"Although the bacteria is dead," Cani said, "its activity is very strong. This may also increase the safety profile for future approaches."
It may be a couple years until that dead bacteria is available to consumers.
"The main thing that needs to happen before this becomes a real clinical intervention is a big clinical trial with more people, and for a longer period of time," said Ken Cadwell, an associate professor at NYU Langone Health's Skirball Institute of Biomolecular Medicine. "Given the exciting results of this study, I'm sure this will happen soon."
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