Obesity is on its way to becoming the leading cause of preventable cancer, second only to tobacco usage. According to research from the American Cancer Society, excess body weight is responsible for about 8% of all cancers in the United States, as well as about 7% of all cancer deaths.
Being overweight or obese is clearly linked to an overall increased risk of cancer. What’s less clear is exactly how obesity increases that risk. Experts believe it’s largely due to the inflammation caused by visceral fat – the fat that surrounds the vital organs. The problem with excessive visceral fat is that it affects certain processes in the body. This includes how the body manages hormones, like insulin and estrogen. All of this can lead to an increased cancer risk by affecting how and when cells divide and die.
Visceral fat cells are large, and there are a lot of them. This excess fat doesn’t have much room for oxygen. And that low-oxygen environment triggers inflammation. Inflammation is the body’s natural response to injury and disease. For example, when you get a deep cut, the area around the cut becomes red and painful to touch. This minor inflammation around the wounded area helps repair the damaged tissue and aids with the healing process. But long-term inflammation caused by excess visceral fat can damage your body and increase your risk for cancer. Cancer happens when cells reproduce uncontrollably, damaging the cells around them and causing illness. The more cells divide and reproduce, the higher the risk that something will go wrong and a tumor will form.
Fat tissue (or adipose tissue) also produces excess amounts of estrogen, high levels of which have been associated with increased risks of breast, endometrial, ovarian, and some other cancers. Obese people often have increased blood levels of insulin and insulin-like growth factor-1 (IGF-1). This condition, known as hyperinsulinemia or insulin resistance, precedes the development of type 2 diabetes. High levels of insulin and IGF-1 may promote the development of colon, kidney, prostate, and endometrial cancers.
Fat cells produce adipokines, hormones that may stimulate or inhibit cell growth. For example, the level of an adipokine called leptin, which seems to promote cell proliferation in the blood increases with increasing body fat. And another type of adipokine, called adiponectin, which is less abundant in obese people than in those of normal weight, may have antiproliferative effects.
In addition, having too much belly fat (a larger waistline), regardless of the rest of your body weight, increases the risk of colon and rectal cancer, and is linked to a higher risk of cancers of the pancreas, endometrium, and breast cancer (in women past menopause.)
Being obese or overweight hurts your body’s ability to work well. One of the most important things you can do to decrease your cancer risk is to maintain a healthy weight. In the meantime, make sure you get regular check ups and follow all recommended preventative evaluations like mammograms, colonoscopy, and prostate exams. Talk to your healthcare provider- you’re not alone in this battle.