The gut–brain axis is the biochemical signaling that takes place between the gastrointestinal tract and the central nervous system. A new study suggests that supplementation with a variety of probiotic strains may have an effect on functional connectivity in the brain. The results indicate an influence of probiotic administration not only on emotional processes, but other cognitive processes as well.

Participants included 45 healthy, right-handed adults. One-third took a multi-strain probiotic, one-third took a placebo, and one-third took nothing daily for four weeks. The multi-strain probiotic contained nine bacterial strains; Lactobacillus casei W56, Lactobacillus acidophilus W22, Lactobacillus paracasei W20, Bifidobacterium lactis W51, Lactobacillus salivarius W24, Lactococcus lactis W19, Bifidobacterium lactis W52, Lactobacillus plantarum W62 and Bifidobacterium bifidum W23.

Participants underwent two brain MRI scans, one at baseline and one at the end of the study. They also filled out daily diaries regarding their gastrointestinal symptoms and details about their probiotic or placebo intake.

At the end of the study period, participants in the probiotic group showed changes in functional connectivity in several networks in the brain, including the default mode network, the salience network, the visual network, and the middle and superior frontal gyrus network. No changes in functional connectivity were seen in the placebo or control group. No structural changes were seen in any of the groups.

The study was conducted by researchers from the University of Graz. It was published online ahead of print on May 30, 2019 in the European Journal of Nutrition.

The human body has up to 4.5 pounds of microbes in the gut, known as the gut microbiome. Two-thirds of the gut microbiome is unique to each individual, and composition is dependent on the food we eat, the air we breathe, and other environmental factors. A new study suggests that the bacteria in each persons gut respond differently to foods, even when they have similar nutritional content.

Participants in the study included 34 healthy adults. The researchers took daily stool samples over the course of 17 days. They also documented participants’ nutritent intake. Two participants were assigned to only consume meal replacement beverages in order to assess the effect of a stable diet.

The researchers found that gut microbiome composition was more strongly associated with food choices rather than conventional nutrient profiles. They also found that daily microbial responses to diet were highly personalized, even when participants consumed the same foods. 

In addition, they found that consuming a stable diet (meal replacement beverages), did not produce microbiome stability. Instead, overall dietary diversity was more strongly associated with microbiome stability.

The study was conducted by researchers from the University of Minnesota. It was published on June 12, 2019 in the journal Cell Host and Microbe.

Most of the microbes in your intestines are found in a “pocket” of your large intestine called the cecum, and they are referred to as the gut microbiome. These microbes help control weight, fight infection, regulate sleep, and keep skin healthy. A new study has found that consumption of fruits, vegetables, and whole grains results in a higher prevalence of beneficial bacteria in the gut microbiome.

Researchers from Baylor College of Medicine analyzed the composition and structure bacteria in the gut microbiome via gene sequencing of colonic mucosal biopsies taken from 34 participants. A food frequency questionnaire was used to determine dietary consumption of the participants. 

The researchers also used the Healthy Eating Index (HEI) to assess the correlation between foods consumed and the presence of beneficial bacteria. The scores used were total HEI, total and whole fruits (HEI 1 and HEI 2), whole grains (HEI 6), milk products and soy beverages (HEI 7), and solid fat, alcohol, and added sugar (HEI 12).

A lower score for total HEI and HEIs 2, 7, and 12 was associated with significantly lower abundance of potentially beneficial bacteria and increased abundance of potentially harmful bacteria.  A higher total score was associated with significantly higher abundance of potentially beneficial bacteria, such as those with anti-inflammatory properties.

The study was published on July 10, 2019 in The American Journal of Clinical Nutrition.

Antibiotics work by killing bacteria. Since they can’t differentiate between good and bad bacteria, antibiotic use often results in a reduction of good bacteria in the gut. According to a new study, prebiotic chicory root fiber may help maintain healthy levels of gut bacteria in children, even during antibiotic treatment.

Participants included 258 healthy children between the ages of 3 and 6. Half of them took 6 grams per day of chicory root fiber for 24 weeks. The other half took a placebo. Fecal samples were taken throughout the study period in order to measure gut microbiota.

At the end of the study, levels of Bifidobacterium were higher in the chicory root group than in the placebo group. While both groups showed a reduction in microbiota during antibiotic treatment, participants in the chicory root group had a significantly higher presence of Bifidobacterium, compared to the control group.

The study was conducted by researchers from the Clinical Center of the University of Pécs. It was published online ahead of print on February 19, 2019 in the journal Beneficial Microbes.