The multiple relationships between obesity and health

Mondo Health Updated on 2024-02-12

"Hot and Hot" directed and starring a star was released for 2 days during the Spring Festival, and the total box office has exceeded 600 million yuan, and a star's **100 pounds has also become a hot spot, and it has become an inspirational role model. However, there are also concerns that such a ** may lead to discrimination against obesity. In fact, the discrimination against obesity in society has existed for a long time and will not disappear because of some events and people. However, what really needs to be noted is that the scientific understanding of obesity, if possible, is best to control weight, which is good for health and longevity.

To recognize this, we still need to look at it from the latest obesity research results.

Although there are differing views on obesity, such as whether the body mass index (BMI) is used as a criterion for diagnosing obesity and whether obesity is a normal and diverse body shape, the impact of obesity on health and quality of life cannot be ignored. Some new research suggests that obesity is indeed associated with many cancers, and is also associated with lower survival after cancer.

A research team at the University of Gothenburg in Sweden found that obesity at a young age increases the risk of many types of cancer in middle and old age, and the fatter you are, the higher the mortality rate after cancer. Statistics show that obesity at a young age may be at high risk of 17 different cancers later in life, including lung cancer, head and neck cancer, brain cancer, thyroid cancer, esophageal cancer, stomach cancer, pancreatic cancer, liver cancer, colon cancer, rectal cancer, kidney cancer, bladder cancer, melanoma, leukemia, myeloma, Hodgkin lymphoma, and non-Hodgkin lymphoma.

The study still uses BMI as a standard to measure obesity, and although this standard has been repeatedly questioned, it is still a commonly used international standard to measure the degree of fat and thinness of the human body and whether it is healthy. BMI = weight height squared, BMI at 18Between 5 and 25 is the standard, BMI index greater than 25 is overweight, and more than 30 is obese. China's BMI standards are different from those of the United States and Europe, with the Chinese standard BMI value of 185-23.9. More than 24 is overweight, and more than 28 is obese.

Obesity is measured by BMI, and the obesity standard in the United States and the West is more lenient than in China. Even so, obesity has been linked to several types of cancer. The researchers came to their conclusions based on a historical study of the physical condition of 1489115 men in the Swedish Selective Service Registry. The average age of these people at baseline was 18 years and they were divided into 3 groups based on their BMI index, with a BMI of less than 185 is underweight, 25-299 is overweight, and 30 or more is obese.

The relationship between BMI and site-specific cancers in these men was then observed and analyzed over a 31-year time frame. During this time period, 78,217 people were found to have cancer. If you are overweight or obese at the age of 18, you have a higher risk of developing 17 different cancers in the next 31 years.

What stands out is that obesity is more closely related to esophageal, gastric and kidney cancers, and the risk of developing these cancers is higher and higher, respectively. 6 times. For head and neck cancer, esophageal cancer, stomach cancer, pancreatic cancer, liver cancer, kidney cancer, and melanoma, even if the BMI is in the normal range (20-22.)4) The risk of cancer is already increasing.

Not only that, but another study by the same research team from the University of Gothenburg in Sweden revealed that the survival rate after cancer in different BMI people was significantly reduced in obese people. The study was also based on data on cancer in men from the Swedish Selective Service Register. The higher the BMI, the higher the mortality rate after cancer, and men who are overweight or obese are 2-3 times more likely to die within 5 years after being diagnosed with **cancer, Hodgkin lymphoma, thyroid cancer, bladder cancer, and cancer, and 1-3 times more likely to die from head and neck, rectal cancer, and kidney cancer4-2 times.

However, these two studies only revealed the association between obesity and the high risk of multiple cancers, and the association between obesity and high mortality from cancer, but did not explain the mechanism. Another study adds to this, although it is not a study of humans, but of mice, but with a certain degree of science.

Obese people have more fat in all parts of the body, and the liver is an important organ for fat accumulation, that is, the formation of fatty liver, even people who do not drink alcohol, will also form non-alcoholic fatty liver disease (NAFLD) due to obesity, which will be transformed into hepatocellular carcinoma (HCC) due to various conditions, of which lifestyle is one of the important reasons, such as staying up late or circadian rhythm disorder.

Previous studies have found that circadian rhythms are an important precipitator of nonalcoholic fatty liver disease-associated hepatocellular carcinoma, and now trials in humanized mice have confirmed this conclusion. Humanized mice are transplanted human hematopoietic cells or tissues into immunodeficient mice to establish human-mouse chimeras. Research using humanized mouse models can lead to a similar understanding of human diseases and life mechanisms.

A team of researchers from Baylor University School of Medicine in the United States has just published the latest research results showing that circadian rhythm disruption can accelerate the development of non-alcoholic fatty liver disease-related hepatocellular carcinoma. This is the result of experiments conducted on a mouse humanized liver model, which not only directly induces the occurrence of non-alcoholic fatty liver disease-associated hepatocellular carcinoma by circadian rhythm disruption, but also accelerates distant metastasis of hepatocellular carcinoma through gene transcriptome reprogramming.

The researchers forcibly let human-derived mice with non-alcoholic fatty liver disease "work 8 hours of night shift" by adjusting light, and the experiment showed that compared with mice in a stable light dark cycle, the life span of "night shift mice" was significantly shortened, and there were obvious symptoms of liver cirrhosis, jaundice and significant development and distant metastasis of hepatocellular carcinoma.

The reason is that circadian rhythm disorders have a significant effect on the gene expression of liver parenchymal and nonparenchymal cells, which is manifested by abnormal metabolism and inflammatory response of hepatocytes to glucose, bile acids, cholesterol and other substances, especially in the case of non-alcoholic fatty liver disease due to obesity, various metabolism and functions of the liver are defective, and defects occur in the processes of epithelial-mesenchymal transition (EMT), metabolic reprogramming, immune checkpoints and p53 signaling disorders. These factors directly lead to the cancerous transformation of liver cells.

Moreover, this study showed that as long as there is obesity and non-alcoholic fatty liver disease, circadian rhythm disruption can promote the conversion of non-alcoholic fatty liver disease to hepatocellular carcinoma, regardless of how normal the mice's food is. Moreover, the molecular pathways and pathological characteristics of mouse hepatocytes induced by circadian rhythm disorder are highly similar to those of human hepatocellular carcinoma patients, but the gradual normalization of circadian rhythm can reduce the incidence and distant metastasis of hepatocellular carcinoma.

Even if they are not obese, people who stay up late often will develop non-alcoholic fatty liver disease, and then, if they stay up late, even if they eat normally and exercise, they will also develop hepatocellular carcinoma. Therefore, this study provides a reasonable explanation for the conclusion that obesity is highly associated with 17 types of cancer.

Non-alcoholic fatty liver disease (NAFLD) is actually the bane of childhood obesity. According to the Report on the Status of Nutrition and Chronic Diseases in China (2020), the overweight and obesity rates of children aged 6 to 17 in China have reached 111% and 79%。With the increase in overweight and obesity, the incidence of non-alcoholic fatty liver disease has increased significantly. The prevalence of NAFLD in obese children in China is between 30% and 70%, and the prevalence of NAFLD in obese children in some developed countries is between 20% and 80%, indicating that the prevalence of NAFLD in obese children in China is higher than that in developed countries. If non-alcoholic fatty liver disease in children is not detected, diagnosed and diagnosed in time, it may develop into cirrhosis and induce hepatocellular carcinoma. Once cirrhosis develops, 30% to 40% of children will die within 10 years.

Obesity at a young age, especially if children are overweight and obese, not only will they develop non-alcoholic fatty liver disease, but they will also face a high risk of developing 17 types of cancer in their later lives. Adopting a healthy lifestyle and managing obesity is an important way to reduce the risk of cancer in the future.

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