Page 32 - EJMO-9-2

Eurasian Journal of
Medicine and Oncology Gut microbiome effects on obesity

transplantation appears to be a viable approach for release of GLP-1, which improves insulin sensitivity and
transferring these characteristics. inhibits glucagon production. 168,169 These studies emphasize
the multifaceted role of SCFAs in obesity, energy metabolism,
4. Microbiota-mediated obesity: Molecular and overall health, as well as their regulatory effects on the
insights liver, adipose tissue, and intestinal health.

During the past decades, increasing evidence has Breast milk contains small amounts of SCFAs, with
170
demonstrated that GM plays a significant role in the concentrations varying greatly between individuals. It
171
onset and development of obesity. Several studies have contains microbiota that interacts symbiotically with the
150
analyzed the link between obesity and GM, highlighting infant gut. Certain microbes are beneficial for neonatal
that an imbalance in GM can be a contributing factor to health by producing breast milk butyrate acid (C4),
obesity. 151-153 which plays an important role in enforcing immune and
metabolic development by influencing the abundance of
4.1. SCFAs: Key players in the obesity development the infant GM. 172
GM has diverse functions, including the fermentation of SCFA production can be influenced by both dietary
indigestible carbohydrates into metabolites, such as SCFAs, and genetic factors such as leptin resistance. In a recent
which are the primary byproducts of bacterial fermentation study, they have found that diet-induced obesity in mice
of dietary fiber in the GIT. SCFAs encompass a range of significantly decreased SCFA production in the early stage
154
metabolites, with acetate, propionate, and butyrate being (day 14), with production dynamics differing distinctly
the most prevalent in the human colon. 155,156
from those of control mice on a standard diet. In contrast,
173
Recently studies have confirmed that SCFAs play an genetic obesity caused by leptin resistance initially showed
essential role in host health by acting at multiple levels, such SCFA production like controls, but a significant reduction
as cells, tissues, and organs, through mechanisms related to occurred at the mid-stage (day 60). These results suggest that
glucose homeostasis, gut barrier function, and obesity. diet has a greater effect on the production of SCFAs, while
157
Furthermore, SCFAs are recognized for their role in genetic factors like leptin resistance can also impact SCFA
controlling obesity-associated health conditions across the production, though with a delayed and moderate effect. 173
lifespan by managing energy balance, controlling appetite,
and increasing energy expenditure. 158 4.2. Conjugated linoleic acid (CLA)
Studies suggest that obese individuals show increased Firmicutes and Actinobacteria, of particular interest, have
levels of SCFA than lean individuals, suggesting a possible the ability to generate polyunsaturated omega-6 fatty
role of SCFAs in the energy dynamics associated with acids in addition to CLA. Modification in the synthesis of
obesity, as they serve as energy-rich metabolites. 159,160 Some this fatty acid is particularly related to obesity. CLA has
investigations propose that elevated SCFA levels in obese different features, including anti-obesity effects, such as
individuals contribute to increased adiposity by providing enhanced energy metabolism, increased lipolysis, as well
158
extra energy from dietary fiber fermentation. 161,162 as reduced adipogenesis and lipogenesis. According to
Contradictory findings indicate that SCFA levels are a meta-analysis and systematic review, CLA significantly
notably decreased in obese individuals, 163-165 highlighting increases triglyceride levels and decreases total cholesterol
that the link between SCFAs and obesity remains (TC) compared to placebo and olive oil. They found
incompletely understood. that in obese individuals (BMI ≥ 25) aged over 25 years,
consuming more than 3 mg/day of CLA for at least 8 weeks
Butyrate and acetate serve as energy sources that the resulted in a significant reduction in TC levels. 174
liver relies on to generate energy through the tricarboxylic
acid cycle, a crucial pathway for metabolism that takes place In addition, numerous studies have demonstrated that
in mitochondria. However, they also alter liver function CLA reduces de novo lipid synthesis and triggers adipocyte
166
and influence adipose tissue metabolism by modifying apoptosis. This apoptotic effect on adipose tissue is
175
mitochondrial uncoupling protein 2 (UCP2) expression associated with the activation of TNF-α and UCP2. UCP2
through peroxisome proliferator-activated receptor gamma. disrupts electron transfer across the inner membrane
This mechanism increases the adenosine monophosphate of mitochondria, redirecting energy toward thermal
(AMP)/adenosine triphosphate (ATP) ratio, which dissipation rather than its storage in the form of ATP.
176
promotes aerobic metabolism through AMP-activated Furthermore, it has been revealed that certain strains of
protein kinase (AMPK) signaling. These results suggest that Bifidobacterium spp. and Lactobacillus spp. produce
SCFAs may alleviate MetSyn by increasing energy utilization beneficial CLA, which enhances energy metabolism and
and metabolic efficiency. Moreover, SCFAs stimulate the lipolysis, ultimately affecting BW. 177
167

Volume 9 Issue 2 (2025) 24 doi: 10.36922/ejmo.8318