Obesity has long been associated with increased risks of developing cancer. Diets high in sugar and fat have also been thought to be cancer-promoting. But there haven’t been any firm links - until now.
New research has uncovered why there’s a link between high fat diets and colon cancer. It has to do with how the body metabolizes both fat and sugar.
Researchers at Temple University, under the guidance of Carmen Sapienza, Ph.D., professor of pathology in Temple’s Fels Institute for Cancer Research and Molecular Biology, have found that a person’s diet can actually turn on and off the genes involved with cancer.
Comparing the colon tissue of people with cancer to healthy tissue, the team found alterations in the chemistry of genes involved in breaking down carbohydrates, lipids (fats) and amino acids.
In simplest terms, Sapienza explains that the insulin genes are “pumping out more insulin than the body requires.” He adds that cancer cells gobble up insulin and tumor cells feed on it to get fatter.
“Insulin is only supposed to be expressed in your pancreas, so having this extra insulin is bad,” Sapienza said.
Fat And Cancer: “Fat and Fact”
To clear the “confusion” between fat and fiction is to show the fact about why fat is not responsible for the development of breast, colorectal, and prostate cancers.
In a prospective study (WINS) during the period between 1994 and 2001, Chlebowski RT et al used 2,437 postmenopausal women who were 62 years of age (48-72 years) in average, and had breast cancer and appropriate cancer treatment based on the type of cancer during the previous year. The reason for using the postmenopausal group, but not the premenopausal group, is to avoid a wide variety of breast cancers, which are observed in the latter group.
The study divided the participants into the Standard Diet Group (SDG) and the Interventional Diet Group (IDG). The averaged daily fat intake for the SDG was 51 grams (40% of daily calories) and the IDG was 33 grams (20% of daily calories). The median of follow-up was 5 years. The incidence of breast cancer relapse was 12.4% for the SDG and 9.8% for the IDG.
In contrast, a large randomized controlled dietary modification trial in the US, “The Women’s Health Initiative (WHI)”, had been conducted during the period between 1993 and 2005, involved 48,835 postmenopausal women, aged between 50 and 79 years, with an averaged follow-up of 8.1 years.  The Intervention Group (IG) reduced the fat consumption to 20% of daily calories and increased the daily amount of vegetables and fruits to at least 5 servings and grains to at least 6 servings. In the meantime, the Comparison Group (CG) had no dietary requirement. The study results are illustrated below.
Robert Su, Pharm.B., M.D.
It’s unclear when this all happens. Sapienza supposes there’s a change in the body’s metabolism at some point, and after a DNA change occurs, then cancer has the right menu to grow.
“There have always been questions about why things like diet and obesity are independent risk factors for colon cancer. This study suggests how and why high fat diets are linked to colon cancer.”
He and his team say that if these changes are found in other tissues, this might lead to the development of a saliva or blood test to diagnose colon cancer along with colonoscopy.