Shhh…you’re not alone. One hundred trillion bacteria are feasting, reproducing and releasing their waste in your digestive system right now.1 Many provide health benefits in exchange for room and board, but a growing stack of research suggests that disturbances of your microbiome may play a role in the development of type 2 diabetes. Now, Belgian experts say future treatments to prevent or control diabetes will harness this roiling, microscopic world.2
It’s a hot topic. Plenty of research is underway looking at the effects of foods, supplements, drugs and even “fecal transfers” on the 1,000-plus types of bacteria in the human gut, according to a recent review in the journal Diabetologia. The authors, long-time microbiome investigators from the Université catholique de Louvain in Brussels, say gut bugs are “promising targets” for the future management of blood sugar.
But, they add, we’ll have to wait. It’s too soon to recommend specific pills, special diet plans or treatments. There’s lots more to learn. Australian dietitian Nicole Kellow, who is researching gut bacteria in people with prediabetes at Monash University and Baker IDI Heart & Diabetes Institute, agrees.
“It is very early days in gut bacteria research, because we still don't know what the optimal numbers and proportions of different bacterial species in the gut should be,” she says. “I think there will eventually be a time in the future when people will have their gut bacterial composition analyzed (from a stool sample) and are provided with a cocktail of prebiotics and probiotics to improve their gut and total body health. But we are certainly not at that point yet.”
Prebiotics plus diabetes medications. In mouse studies, a combination of the oral diabetes medication sitagliptin (Januvia), plus a ‘fermentable fiber’ that gut bugs love to eat reduced blood sugar levels further than sitagliptin alone, the researchers say. Other studies have gotten similar results with metformin plus fiber.
A “microbiota transfer.” In a human study from the Academic Medical Center in Amsterdam, bacteria from the intestines of slim people were infused into the gut of people with metabolic syndrome (a prediabetes condition). 3 After six weeks, their sensitivity to insulin (the hormone in charge of blood sugar absorption) increased significantly. It’s not ready for prime time, the Belgian researchers note in their review.
“This type of experiment assessing the role of the gut microbiota in the control of diabetes in humans is currently a proof-of-concept rather than a potential therapy. Additional studies are needed to confirm the lack of harmful effects linked to the transfer of fecal microorganisms, most of which are unidentified and uncharacterized at present.”
More good guys. Some bacteria may be especially helpful. One, called Akkermansia muciniphila, seems to help protect against obesity and insulin resistance by maintaining the mucus layer on the inner wall of the intestines. Others bacteria tamp down inflammation, a diabetes risk, or churn out short-chain fatty acids that help with insulin sensitivity. But, the researchers note, most of the science is still in animals. It’s not clear which bacteria will help humans, but review co-author Patrice D. Cani, PhD, says simple eating strategies can affect the balance of bacteria, at least in animal studies. “We have previously demonstrated that high saturated-fat feeding is associated with a lower abundance of Akkermansia in rodents,” he notes.
“We have also associated the ingestion of non-digestible and fermentable carbohydrate with the abundance of Akkermansia (i.e., higher fermentatble dietary fibres).” He expects to start a human study, testing an Akkermansia supplement in obese people with insulin resistance, in late 2015.
A “good bug” eating plan. The reviewers say more research is needed before a bacteria-pampering diet plan to prevent diabetes can be developed. But, they have clues. Foods rich in fermentable fibers called inulin-type fructans can help nurture beneficial gut bacteria, study show. These are found in foods such as leek, asparagus, chicory, Jerusalem artichoke, garlic, artichoke, onion, wheat, bananas, oats and soybeans, according to nutrition researchers from the UK’s University of Reading.4 Plant compounds called polyphenols, found fruit, vegetables, tea, coffee, wine, soymilk, nuts and chocolate may also contribute to healthy blood sugar via beneficial effects on gut bacteria, the researchers note. Meanwhile, artificial sweeteners have been shown recently to change gut bacteria colonies in ways that may contribute to blood-sugar problems, they report.
“The best advice for people who want to improve their health and keep their beneficial gut bacteria happy at present is still what we have recommended for many years,” Kellow adds. “Base your diet on plenty of vegetables and fruits and wholegrain breads and cereals. Include nuts, lean meats, and fish, chicken and dairy products. Minimize your intake of highly processed foods that are high in saturated fat, sugar and salt. Try to get at least 30 minutes of exercise each day, and don't smoke.”