Seventeen weeks of intervention with the C. cochlearium and L. acidophilus pairing led to 17% less body weight gain compared to lab mice fed only the high fat diet, reported scientists from Wayne State University (USA), Georgia State University (USA), and the Guangdong Academy of Medical Sciences (China).
“This investigation showed for the first time that the CC-LA combination had beneficial effects in reducing body weight gain and improving glucose tolerance and insulin sensitivity for [high-fat diet induced obese] mice,” they wrote in the journal Nutrition.
“Furthermore, its beneficial effects were likely to be mediated through the increased microbial diversity, and the modulation of specific gut bacteria such as [the Firmicutes to Bacteroidetes] ratio, Actinobacteria, SMB53, Lactobacillus, and others that remain to be uncovered.”
The link between the gut microbiota and obesity was first reported by Jeffrey Gordon and his group at Washington University in St. Louis, who found that microbial populations in the gut are different between obese and lean people, and that when the obese people lost weight their microflora reverted back to that observed in a lean person. This suggested that obesity has a microbial component (Nature, Vol. 444, pp. 1022-1023, 1027-1031).
A 2013 paper in Science (Vol. 341, Issue 6150), also led by Prof Gordon, found that transplanting gut bacteria from obese humans into germ-free mice leads to greater weight gain and fat accumulation than mice that were given bacteria from the guts of lean humans.
This has led many research groups to explore if probiotics may help manage weight. A probiotic is defined as a “live microorganisms which when administered in adequate amounts confer a health benefit on the host” – FAO/WHO.
The new study divided lad mice into three groups: One group ate a low-fat diet (LF); one group ate a high fat diet (HF); and the third group ate the high-fat diet supplemented with C. cochlearium and L. acidophilus (CC-LA).
After 17 weeks of feeding, the researchers found that, in addition to less body weight gain than the high fat-fed group, the CC-LA group also experienced a decrease in the ratio of Firmicutes to Bacteroidetes from 3.30 in the HF group to 1.94 in the CC-LA group. The Firmicutes/Bacteroidetes ratio is reportedly a good biomarker for obesity and inflammatory bowel disease. Indeed, a 2005 study by Jeffrey Gordon and his group at Washington University in St. Louis indicated that obese mice had lower levels of Bacteroidetes and higher levels of Firmicutes (ie. a higher F/B ratio), compared with lean mice.
In addition, the genera SMB53 had higher relative abundance in high-fat diet only group, compared to the CC-LA group. “… the genus SMB53 has been shown to play important roles in the abnormal metabolism of type 2 diabetes in mice, and it was also increased in obese children and adolescents,” explained the researchers.
Finally, the probiotic-fed mice displayed better responses to the oral glucose tolerance test (OGTT) and had lower HOMA-IR scores (a measure of insulin resistance) as compared to the high-fat diet-only mice.
“Our study was for the first time to determine the effect of L. acidophilus combined with a butyrate producer, C. cochlearium on obesity development,” said the researchers.
Translation to humans?
Translating the potential benefits to humans is clearly the next step. Earlier this year, scientists from APC Microbiome Ireland reported that the anti-obesity effects of Bifidobacterium longum APC1472, which were previously reported in lab animals, only partially translated to overweight/obese adults.
Writing in EBioMedicine, Dr Harriët Schellekens and her co-workers reported that mouse data indicated that supplementing a high-fat diet with B. longum APC1472 led to decreased bodyweight, less build-up of fat, and increased glucose tolerance, compared to control animals. However, when performed in humans, there was no significant impact associated with APC1472 on body mass index (BMI) or waist-to-hip (W/H) ratio. The Cork-based scientists did find that the probiotic improved blood sugar levels, and helped to normalize active ghrelin levels and the cortisol awakening response in overweight/obese adults.
Published online ahead of print, doi: 10.1016/j.nut.2021.111439
“Beneficial effects of a combination of Clostridium cochlearium and Lactobacillus acidophilus on body weight gain, insulin sensitivity and gut microbiota in high-fat diet induced obese mice”
Authors: F. Yang et al.