Page 26 - EJMO-9-2

Eurasian Journal of
Medicine and Oncology Gut microbiome effects on obesity

manifest as hypertrophy, where adipocytes increase in size, of them were adults. By 2035, it is projected that 51% of
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or as formation of new fat cells, a mechanism known as the global population will be classified as either overweight
hyperplasia. This pathogenesis can trigger inflammation, or obese, prompting WHO member states to agree on a
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1,2
dyslipidemia, insulin resistance, hypertension, and global plan to accelerate the response to obesity by 2030.
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vascular endothelium dysfunction and is associated with Further data from the WHO European Region reclaim
serious health conditions such as cardiovascular diseases, that obesity is prevalent in nearly 60% of adults, affecting
non-alcoholic fatty liver disease, type 2 diabetes mellitus one in three children, with prevalence rates of 27% among
(T2DM), and cancers. 3 girls and 29% among boys. Furthermore, the current
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The gut microbiota (GM) is made up of over evidence indicates that obesity now exceeds underweight
1500 species from fifty distinct phyla. Among them, in prevalence across all regions except sub-Saharan
Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria, Africa and Asia. Previously correlated with high-income
and Verrucomicrobia are the dominant types. Firmicutes countries, obesity has become increasingly prevalent in
and Bacteroidetes are the most abundant, making up at middle- and low-income countries, where its incidence has
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least 90% of the human gut microbial population. This been dramatically increasing.
4
complex ecosystem plays an essential role in monitoring Obesity is linked to a multitude of serious health
the progression of various human diseases. Moreover, conditions and non-communicable diseases, including
the role of GM in numerous health conditions has been type 2 diabetes (T2D), cardiovascular diseases, chronic
increasingly elucidated through the extensive application kidney disease, as well as certain types of cancer.
3,24
of deep sequencing technologies. 5 In addition, it is linked to other health risks such as
In recent years, increased investigations have suggested inflammation, dyslipidemia, insulin resistance, and
3
that an imbalance in the GM could be a contributing factor hypertension. A systematic review and meta-analysis
to obesity. 6-11 Low-grade inflammation present in obesity of almost 1 million participants identified a significant
is a consequence of GM alterations, which are, in turn, association between obesity and T2D, as well as coronary
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linked to disorders in numerous metabolic pathways and artery disease (CAD). CAD is a type of heart disease
molecules. 12,13 Together, obesity and gut dysbiosis can lead characterized by the narrowing or blockage of the coronary
to the alteration of metabolic pathways. 14 arteries, primarily due to the accumulation of cholesterol
and fatty deposits within the arterial walls, leading to
2. Obesity plaque formation. Other study has demonstrated high
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levels of liver fat fractions in patient affected by T2DM and
Obesity has been presented as an abnormal fat morbid obesity. The findings showed that hepatic steatosis
accumulation according to the World Health Organization was associated with different measures of insulin sensitivity
(WHO). The pathogenesis of obesity involves various in patients suffering from T2DM and severe obesity. 27
intricate mechanisms. The buildup of fat, a process
called adipogenesis, can manifest as hypertrophy, where 2.1. Common risk factors of obesity
adipocytes increase in size, or through the formation of Obesity and overweight can be attributed to a multitude of
new fat cells, a mechanism known as hyperplasia. Body factors, including unhealthy lifestyle habits such as poor
1,2
mass index (BMI) is a commonly used metric to estimate
total body fat, calculated as weight in kilograms divided dietary patterns, physical inactivity, or insufficient sleep, in
by the square of height in meters. It serves as an effective addition to certain medications, genetic predispositions,
indicator of the risk of diseases associated with overweight or family history. The pathophysiological mechanisms of
obesity are complex, encompassing numerous overlapping
and obesity. Recently, waist circumference (WC) has 28
emerged as a potentially more accurate measure of obesity. genetic and environmental factors. The main cause of
15
The Global Burden of Disease study affirmed that, since overweight and obesity is an energy imbalance between
the 1980s, the occurrence of obesity has expanded rapidly caloric intake and energy expenditure, affected by some
in over seventy countries, with a continuous upward trend genetic predisposition, feeding behavior, and lifestyle
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factors.
observed in the majority of other nations. 16(p25) In 2013,
the American Medical Association officially recognized A familial history of obesity is a significant risk factor
obesity as a disease requiring medical treatment and for both obesity and its early onset in childhood. In
follow-up. Health risks linked to this disease have addition, it is associated with the severity of obesity. 30,31
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escalated to alarming levels, making obesity a major global Previous research has shown a significant relationship
concern. In 2022, data showed that more than 1 billion between maternal pre-pregnancy obesity and childhood
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individuals worldwide were living with obesity and 43% obesity, including overweight and obesity combined, as

Volume 9 Issue 2 (2025) 18 doi: 10.36922/ejmo.8318