A new study has revealed that dietary fiber can cause a shift in the gut toward beneficial bacteria, reducing the risk of colon cancer, type 2 diabetes, and other diseases, while the two specific functional fibers may also have the potential to assist in weight loss when made part of a long-term, daily diet.

Kelly Swanson, a U of I professor of nutrition, said that in the gut, bacteria have the capacity to do a lot of different things, such as fermenting proteins, carbohydrates, or other substrates and they have already been able to identify what bacteria are there and the changes that occur with diet.

The researchers said that now they are asking if they can change the machinery or the capacity of what functions the bacteria have. Knowing what bacteria are there may matter, but it may not matter as much as identifying their function.

It was found that what was most surprising and novel in the recent study was a shift in the Bacteroidetes:Firmicutes ratio toward more Bacteroidetes, something the researchers had not seen previously.

The new information is helping the researchers to understand more about the functional capabilities of the bacteria in the gut when these fibers are consumed as part of a regular diet.

The researchers said that the study was of particular interest to us because other research has shown that having more Bacteroidetes may be beneficial because the higher that proportion is, the individual tends to be leaner. With higher Firmicutes, that individual tends to be more obese.

They added that they don't know if there is any causality for weight loss, but studies have shown that having a higher fiber diet is protective against obesity. It's an exciting shift and helps to drive researchers to study these fibers as part of a weight loss diet.

Holscher added that the whole-genome sequencing data also revealed shifts in the functional capacity of the microbiome including modifications in nutrient metabolism and they saw that there was a decrease in genes associated with protein metabolism, which correlated with the reduced protein fermentation that occurred in the study participants' guts when they consumed the fibers.

The study was published in the American Journal of Clinical Nutrition.