- New research shows that having overweight or obesity in early and middle adulthood is linked to an increased risk for gastrointestinal cancer.
- Researchers also note that frequent aspirin use did not impact the increased risk in study participants.
- For healthy weight management, experts recommend portion control, cutting out processed foods, and eating fiber-rich foods to promote gut health.
Growing evidence shows that maintaining a healthy weight is essential to overall health and can help prevent the development of chronic conditions.
Among the most common chronic conditions is obesity. In fact, approximately 1 in 3 adults in the United States are overweight. Colorectal cancer is also prevalent, with more than 150,000 new cases of colon and rectal cancer (CRC) estimated each year.
In addition, colon cancer is increasing among younger adults. In the past 20 years, the number of colorectal cancer cases in people under 55 has nearly doubled.
A new study, published in JAMA Network Open, found a connection between obesity and colorectal cancer.
Researchers discovered that having overweight or obesity during early and middle adulthood is linked to a greater risk for gastrointestinal cancer.
They also found that frequent aspirin use did not affect this increased risk in people who had overweight or obesity.
Holli Loomans-Kropp, PhD, principal investigator of the study and researcher at The Ohio State University Comprehensive Cancer Center-James Cancer Hospital and Solove Research Institute, told Medical News Today:
“The most interesting result of this study is the limited impact of aspirin in reducing colorectal or other gastrointestinal cancer risk among those individuals who were overweight or obese. To me, this highlights the need to better understand how cancer prevention agents work mechanistically, as well as identifying individuals who may not benefit from those agents.”
Excess body fat linked to colorectal cancer
For the study, researchers examined data from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. The analysis included 135,161 participants who ranged in age from 55 to 74 years old with a median age of 62.
The findings present a compelling link between excess body fat — even during young adulthood — and the development of colorectal cancer at later ages.
“Excess body fat, especially visceral fat within the body cavity, can cause chronic inflammation, a known trigger for cancer development and progression,” Dr. William Li, renowned physician, scientist, and author of New York Times bestseller “Eat to Beat Your Diet,” told MNT.
“Excess fat leads to insulin insensitivity that then causes the body to manufacturer more and more insulin,” Dr. Li added.
When the body needs more insulin, a protein is produced that contributes to cancer growth, he explained.
“To support the need for more insulin, high levels of a protein called insulin-like growth factor-1 (IGF-1) are produced. IGF-1 can fuel tumor growth as well as the growth of new blood vessels that feed cancer cells. The combination of chronic inflammation and high levels of IGF-1 set the stage for the development of colorectal and other types of cancer.”
– Dr. William Li, physician, scientist, and bestselling author
Cancer risk and prevention are ‘multifactorial’
The findings of the present study highlight the importance of learning more about precision prevention.
“I think these findings provide compelling epidemiologic evidence that cancer risk, and cancer prevention, is multifactorial,” Dr. Looman-Kropp said.
“These results highlight the need to better understand scenarios where precision is needed in prevention.” The field of precision prevention is still relatively new but a very exciting avenue for cancer prevention research,” Dr. Looman-Kroop added.
Weight management is key to prevention
Maintaining a healthy weight may help reduce cancer risk.
“Controlling body fat at any age is paramount for lowering cancer risk,” Dr. Li noted. “Exercise, getting enough good quality sleep, lowering stress, and eating a healthy diet are important ways to battle excess fat, regardless of your body size.”
Reducing the amount of calories you consume may be an effective method to lose weight.
“Reducing caloric intake is one way to lower body fat,” Dr. Li added. “So is extending the time you do not eat (when you are fasting) because your body burns down fat during this period. When medically indicated, prescription weight loss drugs may also be helpful for reducing body fat.”
Obesity is a serious health concern
The National Institutes of Health (NIH) states that obesity is a global public health issue.
Christopher Esposito, DO, surgeon at Staten Island University Hospital, told MNT:
“This study highlights a glaring need to shift the paradigm of weight management from something that has been conceived as simply a matter of cosmesis to a matter of health. It also underscores that it’s not just extreme obesity that causes problems, being simply overweight is also a risk factor for GI cancer. Obesity should be treated as an active issue during healthcare maintenance visits and consultation with weight loss experts (i.e., bariatric surgeons, medical weight loss physicians, and bariatric dietitians) should be regularly encouraged.”
Weight management lowers colon cancer risk
Maintaining a healthy weight often requires making certain lifestyle changes.
Dr. Li recommends the following:
- Eat moderately and avoid overeating.
- Cut down or cut out ultra-processed foods and red meat from your diet.
- Eat foods rich in polyphenols and dietary fiber, because they promote gut health. A healthy gut microbiome produces substances called short-chain fatty acids lower inflammation and improves immune function. Both can lower cancer risk.
It’s also important to note that these changes should be sustainable. In other words, eat healthy foods you enjoy.
“Diets can be effective but without consistent and reproducible modifications, long-standing results can be difficult to obtain,” Dr. Esposito explained.
“Put simply, if you don’t like the healthy things you’re trying to eat and you can’t make or obtain them easily, you will likely stop eating them and revert to easier and more enjoyable foods. This is the crux of the cycle of dieting.”
Self-reporting may yield inaccurate results
The new research relied on self-reporting, which presents a possible limitation.
“The study relied on self-reporting by subjects of their height and weight which may not be accurate,” Dr. Li noted. “Since weight is central to this study, the possibility of reporting errors is one limitation.”
Additionally, using body mass index (BMI) as a measurement tool for body fat may not be accurate.
“The use of BMI is itself also criticized for not accurately characterizing the amount body fat because total weight used in BMI also includes the mass of bone and muscle in addition to fat,” Dr. Li added.
Dr. Esposito agreed that self-reporting and accurate measurement were potential issues in the new research.
“Though the power (sample size) of this study is significant, there are several limitations to note. This is a retrospective study using a cancer screening trial where much of the data (particularly height and weight) were self-reported and not accurately measured. This may skew the results if patients over or underestimated their height and weight.
– Dr. Christopher Esposito, DO, surgeon
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