Body Fat and Your Colorectal Cancer Risk

WebMD

6 hours ago

Experts say that being overweight or having obesity increases the chances of several types of cancer, including colorectal cancer (CRC). A new study has found that where you carry extra body fat may be more of a risk than your overall weight.
Body Fat Location Matters
People with excess body fat can have chronic inflammation that promotes tumor growth. In addition, fat cells produce hormones and other compounds that contribute to cell growth, including tumor cells. Though being overweight or having obesity has been associated with a greater chance of CRC in several studies, the new research found that those who carried more of their extra fat in the abdominal area, also called central obesity, were at an even greater risk.
The researchers studied nearly 461,000 men and women ages 40 to 69, 67% of whom either were overweight or had obesity as determined by body mass index (BMI). The study also measured participants' waist circumference.
During a 12-and-a-half-year period, nearly 6,000 people developed CRC. Having central obesity was related to a greater risk of CRC in men and women, even when BMI was taken out of the equation. However, in this study, the association of BMI alone with CRC risk was considered weak.
Different Fat, Different Effects
Every study has its limitations. In this case, the authors note that measuring waist circumference is not the most accurate determination of central obesity because it doesn't separate subcutaneous fat from visceral fat.
Most of the fat on your body is subcutaneous and lies just beneath the skin. The remaining type of fat is visceral fat, which surrounds your internal organs and is below the muscles of the abdomen.
As you age, the body favors storing fat in the belly area, and some people with central obesity, including women, may have more visceral fat than others. That's because men tend to hold more subcutaneous fat in the abdominal area earlier in their adult lives, while women start to accumulate more visceral fat during midlife, and after menopause occurs.
Though the study didn't determine if visceral fat was riskier for CRC, it likely presents a greater threat because it produces more compounds that can trigger inflammation. Past research
shows that visceral fat is related to a greater likelihood of colorectal adenomas, which are precancerous polyps that can turn into tumors if not removed.
Tips to Decrease CRC Risk
Follow a balanced diet. A 2023 British Journal of Sports Medicine review pooled the results of 36 studies and found that fewer calories and regular exercise helped people lose visceral fat. Exercise appeared to have a stronger effect on visceral fat reduction than cutting calories. However, you can't spot-reduce visceral fat by doing exercises that target your belly.
Include soluble fiber. Soluble fiber, found in foods such as oatmeal, beans (including canned), lentils, apples, blueberries, and sweet potatoes, can help with belly fat. Studies show that people who ate more soluble fiber and increased their moderate physical activity (30 minutes of exercise two to four times weekly) gained less abdominal fat over five years. Aim for at least 30 grams of fiber daily.
Measure your weight and your waist. It's a good idea to know your BMI as well as your waist measurement to reduce CRC risk. Though imaging techniques are much more reliable, measuring your waist at home or in the doctor's office with a tape measure is quick and inexpensive, and provides a good enough idea of where you stand. In women, a waist circumference of 35 inches or less is considered desirable, and in men, 40 inches or less is ideal.