What is the relationship between obesity and cancer?
Obesity is a condition in which a person has an unhealthy and abnormally high proportion of fat accumulated in different parts of the body. Doctors measure obesity using a scale known as the body mass index (BMI). “BMI is calculated by dividing a person’s weight (in kilograms) by their height (in meters) squared,” explains Dr. Vikas Goswami. Excess fat in the body can have adverse effects, like generation of hormones and growth factors that affect the functioning of our cells. It raises the risk of several diseases, including cancer. So there is a close linking between obesity and cancer risk factor.
Obesity is linked with increased risk of the following types of cancer, and perhaps others as well:
- Colon and rectum
- Endometrium (lining of the uterus)
- Bowel cancer
- Breast (after menopause)
- Gastric cardia cancer (a type of stomach cancer)
This list includes two most common types of cancers – bowel and breast cancer - and three of the toughest to treat – esophageal, pancreatic and gallbladder cancers.
Why being obese is associated with different types of cancer?
When the fat cells in our body become active, they produce proteins and hormones that are released into the bloodstream and circulated across the body. Due to this circulation, these ‘chemical messengers’ affect several parts of the body, and increase the risk of different types of cancer. Fat cells also attack immune cells which release chemicals that cause enduring inflammation which can increase the risk of cancer.
Does losing weight reduce cancer risk?
Researches indicating the direct impact of losing weight on lowering the risk of cancer are limited. However, there’s emerging evidence that weight loss might reduce the risk of breast cancer, more intrusive forms of prostate cancer, and probably other cancers, as well.
While we still have a lot to learn about the connection between weight loss and cancer risk, people who are obese should be encouraged to lose weight.