Research is emerging that shows there could be a link between type 2 diabetes and the gut microbiome.
Many studies have begun exploring the relationship between the microbes that live in the human gut and the development of diabetes.
Now, a 2021 study has found that imbalance in the gut microbiome may be the root cause of as many as 90 percent of type 2 diabetes cases.
According to Oluf Borbye Pedersen, a professor of human molecular metabolism at the University of Copenhagen, there is evidence for links between the gut microbiome and approximately 30 different conditions ranging from Alzheimer’s disease to asthma to diabetes.
However, we still can’t say for certain whether changes to the gut microbiome cause diabetes.
At this point, it’s like a chicken and egg situation for researchers, Pedersen explains.
What we do know is that in the gut of individuals with type 2 diabetes, there are certain changes that can be observed, including decreased bacterial diversity.
“To have a healthy gut microbiome, you need as high diversity as possible. The more diverse your gut microbiome is, the more health benefits,” says Pedersen.
“In the Western world, we have the problem that we are missing many of the gut bacteria, fungi, and viruses,” he says.
This issue is exaggerated in the gut microbiome of people with type 2 diabetes.
“A classic example is in type 2 diabetes, where you have a reduced diversity and a reduced number of bacterial genes,” says Pedersen.
What this reduced diversity means is that the gut microbiome can’t carry out the same functions as you would expect in someone without diabetes.
At the same time, researchers have also found groups of bacteria that are more prevalent in people with type 2 diabetes.
According to Pedersen, these clusters of bacteria are known for causing inflammation in the body, which is also linked to many common disorders, including type 2 diabetes and prediabetes.
So far, there have been no human studies looking into how modifying the microbiome can influence type 2 diabetes.
However, researchers have found that certain lifestyle measures can increase the diversity of bacteria in the gut microbiome in a general population.
As Pedersen explains, it is likely that these lifestyle interventions can also help to improve the gut microbiomes of people with diabetes.
Here are five tips for building a healthier gut microbiome with type 2 diabetes.
Diet is a major factor when it comes to building a healthier gut microbiome, says Mark O. Goodarzi, MD, PhD, a diabetologist and endocrinologist at Cedars-Sinai in Los Angeles.
“If you eat a healthy diet, we believe that promotes the growth of beneficial bacterial species,” he says.
When it comes to building a healthier microbiome, a healthy diet is a high fiber diet, says Goodarzi.
“With a high fiber diet, you’re basically feeding the good bacteria,” he explains.
That means eating vegetables, fruit, and whole grains every day.
A 2018 study found that those who followed a high fiber diet experienced changes in their entire gut microbe community, which helped to alleviate the symptoms of type 2 diabetes.
A 2020 international review of both animal and human studies also found that fiber-rich diets can work to control weight loss and reduce the symptoms of type 2 diabetes.
As well as increasing the amount of fiber in your diet, you may also benefit from managing your intake of saturated fat.
“A high-fat diet seems to promote the growth of harmful bacteria,” says Goodarzi. “Generally, we worry about diets that are high in saturated fat,” he adds.
A 2019 animal study found high-fat diets led to clear shifts in the gut microbiome of mice.
According to Pedersen, we also know from studies that cutting down on animal fats and animal meat while increasing vegetable intake can increase the diversity of bacteria in the gut.
At the same time, it can reduce the number of pro-inflammatory bacteria in the gut, which may be beneficial for those with type 2 diabetes.
Research also suggests that a plant-based diet can help promote a healthier microbiome.
A 2019 review found that a vegetarian or vegan diet is effective at promoting a diverse ecosystem of beneficial bacteria in the gut.
Another U.S.-based study of individuals following plant-based diets over a span of more than 20 years revealed that participants who adhered more closely to a healthful, plant-based diet had a lower risk of type 2 diabetes.
On the other hand, participants who followed the healthful plant-based diet less closely had a higher risk of diabetes.
A healthful plant-based diet is characterized by higher amounts of fruits, vegetables, whole grains, nuts, legumes, and tea and coffee, and lower amounts of other plant foods such as refined grains and foods high in sugars.
Though you may be tempted to opt for artificial sweeteners instead of refined sugar, that’s not necessarily the best choice for building a healthier gut microbiome.
“There’ve been a few studies looking at the effects of artificial sweeteners, like saccharin, showing that they can have adverse effects on the gut microbiome,” says Goodarzi.
In another 2018 study, researchers observed that Neotame, a low-calorie, high-intensity artificial sweetener, reduced the diversity of the gut microbiome in mice over a period of 4 weeks.
There is also evidence that physical activity can influence the health of the gut microbiome.
“You can increase your bacterial diversity with daily physical activity,” says Pedersen.
Another study of college students found that differences in physical activity levels also led to differences in the gut microbial diversity of the participants.
Pedersen warns that smoking and excessive alcohol intake can further harm your gut bacterial diversity, so it’s important to look at your lifestyle holistically if you’re trying to build a healthier gut microbiome.
There’s currently not enough evidence to say for certain if the gut microbiome contributes to type 2 diabetes.
However, research shows that following a high fiber diet rich in vegetables, fruit, and whole grains, and leading an active lifestyle can have a positive influence on your gut microbiome and is likely to be beneficial for people with diabetes.
Elizabeth Harris is a writer and editor with a focus on plants, people, and our interactions with the natural world. She’s been happy to call many places home and has traveled across the world, collecting recipes and regional remedies. She now splits her time between the United Kingdom and Budapest, Hungary, writing, cooking, and eating. Learn more on her website.