Episode 130: Epigenetics in childhood obesity

Saakshi and Dr. Arreaza discuss some principles of epigenetics implicated in the development of obesity in children. 

Written by Saakshi Dulani, MS3, Western University College of Osteopathic Medicine of the Pacific. Edited by Hector Arreaza, MD.

You are listening to Rio Bravo qWeek Podcast, your weekly dose of knowledge brought to you by the Rio Bravo Family Medicine Residency Program from Bakersfield, California, a UCLA-affiliated program sponsored by Clinica Sierra Vista, Let Us Be Your Healthcare Home. This podcast was created for educational purposes only. Visit your primary care provider for additional medical advice.

This topic is constantly expanding, and I’m excited to talk about it. It is a fact that epigenetic changes play a role in the development of certain diseases such as Prader-Willi syndrome, Fragile X syndrome, and various cancers. It has been demonstrated that certain foods can alter gene expression in animals, for example. 

What is epigenetics?

Epigenetics is the regulation of gene expression without a change in the base sequence of DNA. Epigenetics means “on top of” the genes. Genes can be turned “on” or “off” as a response to external influences. 

Obesity and Epigenetics.

The link between genetics and obesity is complex, but it is known that epigenetics plays a significant role in childhood obesity. Surprisingly, exposure to environmental factors starts in the uterus. 

Fetuses are exposed to intrauterine signals that increase their potential to develop obesity. Factors such as in-utero hyperglycemia, gestational diabetes mellitus, and early childhood diet and lifestyle practices can affect the development of the gut microbiome, modify gene expression through DNA methylation, and increase the risk of childhood obesity. 

These gene expression changes can be passed on to future generations. DNA methylation is the addition of a methyl group to part of the DNA molecule. That methyl group acts as a “chemical cap,” which prevents gene expression. Another example of epigenetics is histone modification. Histones are proteins that are used by DNA as spools to wrap around pieces of information that are “not needed”. The reason why a scalp cell and a neuron are different is that the expression of certain genes is suppressed while other genes are expressed.

Factors that influence obesity.

Some factors that increase the risk of childhood obesity through epigenetic changes include neonatal intestinal microbiome, C-section delivery, maternal insulin resistance, exposure to antibiotics and other environmental toxins, early introduction of complementary foods, parental diets high in carbohydrates and low in fruits and vegetables, and poor sleep. There are many other factors, but we will discuss only a few of them.

Microbiome:

The microbiome is a whole new world that is being explored by many investigators. The gut microbiome refers to the diverse community of organisms, including bacteria, fungi, and viruses, that reside in the human intestine. The neonatal intestinal microbiome is established during the first two years of life and may be influenced by factors such as the method of delivery, maternal obesity, and the maternal gut microbiome. 

Some bacteria worth mentioning are Bacteroides, Clostridium, and Staphylococcus. These gut bacteria are higher in pregnant women who have obesity, and they also have a low count of Bifidobacterium. Infants born to obese mothers have higher levels of bacteria associated with increased energy harvest compared to infants born to normal-weight mothers. The gut microbiome of infants delivered by C-section is different than infants delivered vaginally.

Link to antibiotics:

Early exposure to antibiotics is associated with the development of res