When we’re told to get more good bacteria in our diet, yogurt gets all of the glory.  But as researchers learn more about what constitutes a healthy gut microbiome, the case for making more of your grains whole gets stronger and stronger. 

All humans have trillions of microbes living inside of them, but the exact population varies from person to person. The microbes that inhabit our digestive tract offer clues as to how susceptible we are to disease, weight gain, and other health factors.

To see how making all of your grains whole affects gut health, researchers randomly assigned 81 healthy adults in Boston to diets with either whole grains or refined grains for 6 weeks, keeping all other foods and nutrients consistent between the groups. After the unenviable job of analyzing stool samples from participants, researchers found that making all of your grains whole is linked with “modest, positive effects on gut micriobiota,” due to higher concentrations of “good” gut microbes.

Additionally, although the diets were designed to be isocaloric (meaning that people were supposed to maintain their same body weight), the resting metabolic rate (how many calories your body burns at rest) became significantly higher (by 43 calories) in the whole grain group. In fact, the whole grain group significantly improved their metabolism over the 6-week study compared with the refined grains group, burning 92 more calories per day – without changing their exercise habits. 

The results of this study are not unique. After comparing a whole grain based diet to a red meat based meat diet, European researchers found that those on the whole grain diet had healthier gut microbes, and also lost a significant amount of weight and body fat, even though both diets had the same amount of calories. Similarly, after comparing how people digest a whole grain sandwich with real cheese to how they digest a sandwich on white bread with a processed cheese product, scientists in California found that people burned 50% more calories breaking down the whole grain version, even though both sandwiches had the same amount of calories and the same ratio of bread to cheese.
 
Whether you’re concerned about a protruding waistline, or the microbial community living inside of you, it seems that whole grains are the key to a healthy gut, both inside and out. To stay up-to-date on more whole grain research, be sure to browse our health studies database. (Kelly)