Linking Cancer to Obesity
It's estimated that 25-30% of cancer is related to being overweight or obese.
Let’s look at the impact this might have on the number of cancers in this country.
Obesity and overweight: How bad is the problem?
-There are currently 93.3 million obese adults, that equals 39.8% of the adult population in the United States. There are another 34% who are overweight. Thus, 75% of the adult population has an increased risk of developing cancer due to body fatness.
In Iowa, we have the 4th highest obesity rate in the country. It has been estimated that obesity related cancers accounted for 40% of all cancer diagnoses in Iowa in the year 2015. In women, the percentage of obesity related cancers was 55% and in men 24% in 2015.
Obesity, overweight and cancer: what is the association?
-Obesity is associated with inflammatory mediators and metabolic and endocrine abnormalities that promote cell growth and exert anti-apoptotic effects, meaning cancer cells do not self -destruct even following severe DNA damage.
-Greater body fatness is a cause of many cancers and this association has grown stronger over the last decade.
- Accumulating evidence points to the importance of the systemic metabolic milieu of the body, as reflected in anthropometric measurements such as body fatness- as being a key determinant of cancer susceptibility.
- Maintaining a healthy weight throughout life is one of the most important ways to protect against cancer.
- In the obese state many of the metabolic and endocrine abnormalities associated with obesity, such as elevated levels of insulin and estrogen, as well as inflammatory mediators associated with obesity exert proliferative effects (cause cells to grow). Thus in the obese state there is a general up-regulation of cell growth.
-Obesity is recognized as a chronic inflammatory state that predisposes to cancer and chronic inflammation has been implicated in the link between nutrition and cancer.
- Cancers associated with increased body fatness: mouth, pharynx and larynx, esophageal, stomach, liver, pancreas, gallbladder, post-menopausal breast, kidney, colorectal, endometrial, ovarian, prostate, thyroid and multiple myeloma.
- It is well established that body fatness has a causal role in the development of several other diseases including: type 2 diabetes, dyslipidemia, high blood pressure, stroke, coronary heart disease, as well as digestive and musculoskeletal disorders.
- Ensure that your body weight during childhood and adolescence projects toward the lower end of the healthy adult BMI range.
- Keep your weight as low as you can within the healthy range throughout life (BMI 19-24.9).
- Avoid weight gain throughout adulthood.
- Be moderately physically active incorporating at least 30 minutes of walking into your daily life (minimum 5 days per week).
-Limit sedentary habits (for every hour of sitting get up and move for 10 of those minutes).
- Greater screen time is a cause of overweight and obesity.
There is strong evidence that physical activity protects against cancers of the colon, breast and endometrium and is probably important in the prevention of many other cancers as well.
-Physical activity has been shown to promote healthy immune and hormonal systems.
-Physical activity has a beneficial effect on cancer risk, likely through multiple mechanisms such as reductions in circulating estrogen levels, insulin resistance and inflammation – all of which have been linked to cancer development.
-Physical activity improves insulin sensitivity and reduces fasting insulin levels.
-Physical activity has been shown to enhance immunity and promote tumor surveillance.
-Physical activity can also decrease oxidative stress and enhance DNA repair mechanisms decreasing the potential development of cancer cells.
The bottom line is that being overweight or obese is a major risk factor for the development of cancer. We should do everything in our power to achieve a normal body weight and stay there.
Note: this subject is part of the John Stoddard Cancer Center: Trending Topics series.