How obesity increases the risk of several types of cancer

 There's nothing to discuss about this relationship: obesity has been proven to increase the risk of at least thirteen types of malignant tumors. The World Health Organization itself has assumed this for some time.

Excess fat maintains a poor relationship with the body's most diverse tissues, spreading substances that inflame them and triggering chaos, with trouble everywhere. For many overweight people, cancer is one of them... - See more at The risk appears to be greater for women: among those who received news of cancer, 55% had a tumor associated with obesity, while this only happened with 24% of men diagnosed with malignant disease. That's what I learned in the class of doctor Ada Cuevas, director of the Centro Avanzado de Medicina Metabólica y Nutrición, in Santiago, Chile. She outlined the differences between biological sexes in the incidence of cancers related to excess weight, during the ICO (International Congress on Obesity), which took place in the middle of this year in São Paulo... - See more at According to the doctor, for women Women the danger increases after menopause, when estrogen levels drop. "While this hormone remains high, they accumulate more subcutaneous fat", he commented. "Then, the distribution of adipose tissue changes and it becomes more concentrated between the viscera." Yes, it is in the increased abdominal circumference — or, in clear English, in the voluminous belly — that the problem lies.

Therefore, because they have always accumulated more fat around the waist, in the end, men have the highest number of cases of tumors linked to obesity, despite representing only a quarter of cancer diagnoses among them.

How much would obesity increase the relative risk? For you to understand the concept of "relative" in Medicine, it would be the probability of someone who has or has been exposed to something — in this case, who has obesity — developing a health problem compared to those individuals who do not have the same factor. of risk. In this matter, therefore, the comparison is with people with normal weight and abdominal circumference of up to 102 centimeters for men and up to 88 centimeters for women. The 13 tumors associated with obesity

Below, you will find out how many times, on average, obesity multiplies the risk of each of these diseases appearing, considering global data.

Endometrial cancer: 7.1 times, being by far the type most influenced by excess adiposity. In fact, half of the cases have to do with this…Esophageal cancer: 4.8 times.

Stomach cancer: 1.8 times, that is, the risk almost doubles.

Liver cancer: 1.8 times, but some suspect it would be much more than that.

Kidney cancer: 1.8 times, too.

Pancreatic cancer: 1.5 times, that is, 50% more.

Meningioma, the tumor in the meninges of the brain: 1.5 times…Why does the risk increase?

I took the question to endocrinologist Fernando Gerchman, who is a professor at UFRGS (Federal University of Rio Grande do Sul). Firstly, because he also participated in the class on cancer and obesity at ICO 2024. But, above all, because he is one of the greatest scholars on the subject in the country. His research goes well beyond the story of how people lose weight and how they maintain their new weight. The doctor, who in his training passed through the oncology department of American institutions, is interested in the intricate relationship between the prevention and treatment of excess weight and various health conditions and has several articles along these lines published in internal magazines... "Why Does the risk of cancer increase? Is insulin resistance one of the reasons", Professor Gerchman begins to answer me. "And it makes perfect sense: insulin is an anabolic hormone. This means that it stimulates tissue growth, triggering several reactions that, in the end, promote cell division."

We are tired of hearing the following story: insulin is the key that makes the glucose present in the blood enter the most diverse cells in the body to provide energy. Well: in those who are obese, it's as if this key doesn't work properly. This resistance leaves nutrients in the blood, something that the pancreas tries to compensate for by producing more and more insulin. It results. "Although, in people with obesity, this hormone does not adequately capture glucose, its elevation in the blood hyperactivates the pathways that cause cell division", adds the doctor. “Now, anything that accelerates cell division in an organ increases its risk of cancer,” he concludes.

That's right: the more a cell divides, plundered by insulin to accelerate the pace of this work, the greater the probability that it will, without hesitation, do somethingMechanical questions

Sometimes, they also count. "Those who are obese can accumulate a lot of fat in the abdomen and this causes mechanical pressure that can interfere with the motility of the digestive organs, increasing the risk of esophageal reflux", says Professor Gerchman. It's a well-known fact. : when stomach juices go against the grain, defy gravity and rise to the esophagus, the walls of this organ suffer, as they are not used to so much acidity. The irritation caused by this back and forth of acids forces the esophageal mucosa to renew itself more than usual. Soon... We return to the conversation about cell division: the threat of esophageal cancer increases.

Fat in the pancreas and other wrong places. Adipose tissue is made to store fat. "But, especially the one we find in the abdomen, it has its limits there, which are determined by a series of factors, including genetics", explains Professor Gerchman. "In other words, each of us has a maximum capacity, greater or lesser, in abdominal adipose tissue."

When this maximum capacity is about to be reached, the cells of this tissue, which is tremendously active, try to defend themselves. They release substances that culminate in insulin resistance — "it's a strategy so that nutrients have difficulty entering the adipocytes themselves, so that they don't have to store even more", explains the end... However, this tactic often doesn't work and the limit is exceeded. Then, the fat, without finding shelter in the tissue where it should be stored, ends up in the cells of other organs. In the pancreas, for example. "It is very likely that this is related to pancreatic cancer", observes the professor.

In the liver, this story is already very well told by science. When fat infiltrates liver cells, it first causes inflammation, steadohepatitis. Inflammation, in turn, damages the liver, which forms scars or fibrosis as a reaction. And fibrosis would be like the precursor to cirrhosis or even liver cancer. The interference of sexual hormones

To top it off, people with obesity tend to exhibit altered levels of sex hormones. "This imbalance can also increase the cell division process", highlights Professor Gerchman.

The hypothesis is that this is yet another explanation for the higher incidence in overweight women of some malignant tumors that have hormonal involvement — breast, ovarian and endometrial tumors. About tumor prevention

Logic would say that, if a person with obesity lost weight, their risk of developing malignant tumors would drop—"just like what happens with an individual who stops smoking: the probability of him having lung cancer decreases over time, remaining almost the same to that of non-smokers after about fifteen years of smoking cessation", compares the professor. "But perhaps this is not the case with obesity", he regrets to inform. Studies lasting four or five years still do not demonstrate a significant reduction in the risk of cancer in people with obesity who have lost excess weight. But the doctor from Rio Grande do Sul is not discouraged. "It was like that with cardiovascular diseases, that is, we had no proof that losing weight would help prevent them", he recalls. What he's getting at: the scientific community believes it is very likely that the protective effects of weight loss will only appear after a long time of maintaining a new weight. This only reinforces the idea that the treatment is for the rest of your life — including, Studies prove that, contrary to what some feared, new anti-obesity drugs do not increase the risk of breast cancer or any other tumor. But, of course, not even reaching that point on the scale, avoiding obesity. And cancer, by the way.