Obesity is a much more complex issue than a single gene

The obesity has been a growing issue worldwide. With each passing day, people eat more and exercise less. Furthermore, with the proliferation of the famous fast-foods, industrialized food and other types of nonsense are increasingly entering the diet of the average population. Consequently, obesity is becoming one of the most serious and serious problems in the entire world.

Obesity is cited by doctors as a plague of the 21st century. If it is seen with such urgency by specialists, it is because it is one of the things that most lead to death nowadays. In short, the number of people with obesity tripled between 1975 and 2016.

As if that wasn’t worrying enough, children are getting more and more obese. In the UK today, nearly a third of children are overweight or obese.


Obesity is related to several health problems. And more recently it has also been shown to increase the risk of serious illness after infection with COVID-19.

Of course, several factors can contribute to obesity . One of them being genetics. And five experts in genetics, nutrition, obesity and neuroscience were asked if there really is an obesity gene.

To analyze the genetics behind obesity, researchers analyzed the DNA of several people to see if they could identify certain genes or gene variations that correlated with obesity.

“Large-scale genome-wide association studies (GWAS) have identified multiple loci associated with body mass index and not just a single loci/gene. However, in rare cases, obesity is caused by a specific syndrome due to a mutation in a gene,” said Cornelie Nienaber-Rousseau, nutrition expert at North-West University in South Africa.


Those genes that correlate with body mass index or obesity vary quite widely in their function. University of Portsmouth neuroscience specialist Ivor Ebenezer explains that “these genes control hormones, neurotransmitters, neuromodulators and enzymes involved in regulating food intake and energy homeostasis.”

If looked at from an evolutionary perspective, it doesn’t make sense that genes that are passed on from generation to generation help people to have a dangerous condition such as obesity .

“If we look back in history to a time when our hunter-gatherer ancestors roamed the land, we find that primitive man lived primarily on plant roots, which are rich in carbohydrates, and animals hunted for protein and fat. There were periods of many days and sometimes weeks when they were hungry. Those who survived were able to store body fat in times of plenty to provide energy in times of difficulty. So most of us inherited genes from our ancestors that predispose us to accumulate body fat,” explained Ebenezer.

Such genes played an essential role in survival when food was scarce. However, they are currently harmful to people. Since we have easy access to food and we don’t have to physically struggle to get it.


As much as genetics is a factor influencing obesity, it is not the only one. “Obesity is an extremely complex trait controlled by interactions between many genetic and environmental factors. Just look at the changes in obesity levels that we see in modern populations versus our recent ancestors. Our genes have not changed remarkably during this period,” explained Richard Edwards, an expert in bioinformatics and genetics at UNSW Sydney, Australia.

A factor that strongly influences is the environment in which the person lives. “Obesity is due to an excess of energy intake, that is, food, together with a decrease in energy expenditure”, pointed out Ebenezer.

In addition, Ebenezer also explains that “environmental factors, such as maternal hunger or consumption of foods high in sugar, can produce epigenetic changes in the fetus that can result in obesity in the offspring.”

In conclusion, we see that, as much as genetics contribute to obesity, it is not the only factor that is involved. And there is not just one “obesity gene”.

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What if humans didn’t have an appendix?

All organs, which are present in our body, have a specific function. And they are all extremely important. This is a fact. But what if one of these organs, in the midst of an evolutionary process, had ceased to exist? Would we have been harmed? Would our habits be the same? Would our health be in danger? Thinking about this whole scenario, a team of researchers decided to seek answers to such questions. However, for this, it was necessary to choose a specific organ: the appendix.

To understand the researchers’ line of reasoning, it is necessary, above all, to take into account such information, such as, for example, the importance and functionality of the organ. So pay attention to following the flow.

The appendix, Darwin and current scientists

For those who don’t know, the appendix – known in medicine also as the cecal appendix, vermiform appendix and vermicular appendix – is a bag whose shape refers to the idea of ​​a tube. This attached organ, which is located in the lower right region of the belly, obviously plays a role, but until then it was little discussed, after all, in science classes, when we attend high school, few put them in a relevant position. And, throughout life, we only hear about their existence when they talk about appendicitis, an inflammation in the area that causes serious health problems .

The famous Charles Darwin – English naturalist, geologist and biologist – was one of the first scientists to study the organ. At one point in his simple research, Darwin suggested that the appendix helped in the process of digesting food. After studying the evolutionary process of human beings, Darwin began to speculate again on the function that the attached organ played, until, at a certain point, he ended up believing that the appendix was not as functional as imagined.

As it has recently become the focus of new studies, new information about the organ has surfaced, which, interestingly, not only confirmed Darwin’s initial premise but also strengthened it. “Had Darwin known what scientists now know about the appendix, he would never have suggested that the organ was just a useless remnant of evolution. He would have embraced his original idea,” said William Parker, a researcher at Duke University School of Medicine in Durham, North Carolina, United States.


In 2007, Parker and other researchers discovered that the appendix harbors bacteria that help to digest food – which ended up confirming Darwin’s initial theory. These same bacteria, researchers say, can also help restore the healthy state of the intestine. However, scientists have also found that the adnexal organ has a high concentration of lymphoid tissue. This tissue generates white blood cells – known as lymphocytes – which strengthen the immune system. “The appendix, in a nutshell, trains these immune cells,” points out evolutionary biologist Heather F. Smith of Midwestern University in Glendale, Arizona.

As the researchers expose, the appendix has been part of the physiological structure of mammals for at least 80 million years – something that Darwin also had an idea of. During this entire period, the organ has evolved independently at least 32 times. “When we looked at species that have appendixes, we didn’t find anything in common in terms of diet, for example. What we found was that all of the species that had an appendix had a certain concentration of immune tissue, which, given this common theme, assumes a common function,” Smith said.

Face to face with the revelation, the question then arises: what if the appendix had suddenly disappeared?


“If the appendix had disappeared millions of years ago, a large number of lives would have perished. We would have lost millions of people to a range of infectious diseases,” said Parker.

“If the appendix had disappeared when society began to develop agricultural techniques, for example, many would not have been able to live amid poor sanitation conditions , after all, without an immune system, diseases would have spread quickly”, explains Parker.

“Now, if the appendix didn’t integrate our physiology after the Industrial Revolution, a period in which modern society was established, people could survive, but only because of access to antibiotics”, reveals Parker. “However, without an appendix, people would not have the reservoir of useful bacteria to help them recover from certain infections and therefore would need to invest in faecal transplants.”


One potential advantage of a world with human beings without appendages is the end of appendicitis. “There are more than 10 million cases of appendicitis annually. In the midst of this, about 50,000 people die from the problem,” reveals Smith. “Appendectomies, or surgical removal of the appendix, are one of the most commonly performed abdominal surgeries. If we didn’t have the appendix, we wouldn’t have people dying of appendicitis.”

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