Fasting May Improve Gut Microbiome Balance in People with Obesity

Recently, research has found increasing evidence of the potential effects of the human microbiome on our health.

The microbiome consists of bacteria, archaea, viruses and eukaryotic microbes that live in and on our bodies. A healthy adult will house around 1000 different species of bacteria, the majority of which are in the gut.

In most people, the core microbiota remain stable throughout adulthood, but the gut microbiota differs between different people. It is affected by body mass index (BMI) level, exercise frequency, lifestyle, cultural and dietary habits, and antibiotic use.

Studies in people with obesity have found that they tend to have a less diverse gut microbiome, and the balance of species is different from that of leaner people. 

Other studies have suggested that the ease with which people lose weight on diets is linked to the composition of their gut microbiome. However, research has not yet revealed a consistent association between gut microbiota and obesity.

A meta-analysis of studies found that weight loss was associated with an increase in microbiome diversity and a reduction in intestinal permeability.

Now, a small study from China has suggested that intermittent energy restriction (IER), as well as helping people with obesity to lose weight, may alter their gut microbiota.

The study is published in Frontiers in Cellular and Infection Microbiology.

As part of the study, the researchers recruited 25 people with a body mass index (BMI) of between 28kg/m2 (classed as overweight) and 45kg/m2 (classed as severely obese). None of the participants had any other uncontrolled health conditions.

To start, they ate a regular diet for four days, and the researchers recorded the energy content of this as their baseline daily intake. For the rest of the study, the researchers interspersed the days of regular baseline energy intake with days where the participants had severely restricted energy intake formulated by a clinical dietitian.

The researchers collected the participants’ blood and fecal samples at the beginning, midpoint, and end of phases II (highly-controlled fasting) and phase III (less-controlled fasting) during the two months the study was conducted. They also recorded their body weight, waist circumference, body fat, systolic blood pressure, and diastolic blood pressure at each time point.

During the study, participants lost, on average, 7.8% of their body weight. And at the end of phase II, their gut microbial diversity had increased from the baseline. However, at the end of phase III, there was no significant difference from the start of the study.

There were also some changes in the species making up the gut microbiota, with a decrease in Escherichia coli and an increase in Faecalibacterium prausnitzii, Parabacteroides distasonis, and Bacteroides uniforms.

The researchers noted that these changes were associated with significant reductions in the activity of brain regions implicated in the regulation of appetite and addiction. However, they do not explain what effect these changes are likely to have on appetite.

Sources:

Jing Zhou, Xiaoling Wu, Tianyuan Xiang, Fei Liu, Hui Gao, Li Tong, Bin Yan, Zhonglin Li, Chi Zhang, Linyuan Wang, Lei Ou, Zhongxia Li, Wen Wang, Tingting Yang, Fengyun Li, Huimin Ma, Xiaojuan Zhao, Na Mi, Ziya Yu, Canhui Lan, Qi Wang, Hao Li, Liming Wang, Xiaoning Wang, Yongli Li, Qiang Zeng. Dynamical alterations of brain function and gut microbiome in weight loss. ORIGINAL RESEARCH article Front. Cell. Infect. Microbiol., 20 December 2023. Sec. Intestinal Microbiome. Volume 13 – 2023 | DOI: https://doi.org/10.3389/fcimb.2023.1269548

Frontiers (December, 2023). Fasting may improve gut microbiome balance in people with obesity. MedicalNewsToday. Retrieved December 27, from: https://www.medicalnewstoday.com/articles/fasting-may-improve-gut-microbiome-balance-in-people-with-obesity 

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