Risk factors for Increased Risk of Rectal Cancer
Elevated insulin production, as reflected by elevated concentrations of plasma C-peptide, may predict the risk of developing colorectal cancer, independently of BMI, factors related to insulin resistance, or levels of IGF-I and IGFBP-3. [J Natl Cancer Inst. 2004 Apr 7;96(7): pp.546-53]
Increased Risk of Rectal Cancer can lead to
Recommendations for Increased Risk of Rectal Cancer
Study subjects who ate two or more servings of fish weekly had a much lower risk for esophageal, stomach, colon, rectum, and pancreatic cancers than those who avoided fish. In fact, the rates of these types of cancer were 30 to 50 percent lower among fish eaters. High fish consumption was also associated with lower risks for cancers of the larynx (30 percent lower risk), endometrial cancer (20 percent lower risk), and ovarian cancer (30 percent lower risk).
A higher dietary calcium intake (914mg/d compared to 486mg/d) was associated with a reduced risk of colorectal cancer in a study of 61,463 women followed for an average of 11 years. [Nutr Cancer 2002;43(1): pp.39-46]
The rate of colorectal cancer is much higher in the United States, where a high-fat diet is common, than in Japan, where people don’t eat a lot of fat and colorectal cancer is almost nonexistent. But no one has understood why that is. At least part of the answer lies in lithocholic acid, a bile acid produced to help digest fat.
Lithocholic acid is probably the most toxic compound that your body naturally makes, so you have to have a way to get rid of it. Normally, bile acids are made in the liver and stored in the gallbladder. Bile acids solubilize foods. When you eat a high-fat diet, your body makes more bile acids. Usually they are efficiently recycled, with the exception of lithocholic acid. Lithocholic induces changes in DNA.
If you give animals high concentrations, just directly put it into the intestine, they get colon cancer. But laboratory animals given doses of vitamin D and then given lithocholic acid do not get colon cancer. Colon cancer patients also have high concentrations of lithocholic acid. Vitamin D has a role in detoxifying lithocholic acid.
A colorectal cancer study, published online February 6, 2006 in the American Journal of Preventive Medicine, is a meta-analysis of five studies that explored the association of blood levels of 25(OH)D with risk of colon cancer. All of the studies involved blood collected and tested for 25 (OH)D levels from healthy volunteer donors who were then followed for up to 25 years for development of colorectal cancer.
“Through this meta-analysis we found that raising the serum level of 25-hydroxyvitamin D to 34 ng/ml would reduce the incidence rates of colorectal cancer by half,” said co-author Edward D. Gorham, Ph.D. “We project a two-thirds reduction in incidence with serum levels of 46ng/ml, which corresponds to a daily intake of 2,000 IU of vitamin D3. This would be best achieved with a combination of diet, supplements and 10 to 15 minutes per day in the sun.”
And in another study, if vitamin D3 levels among populations worldwide were increased, 600,000 cases of breast and colorectal cancers could be prevented each year, according to researchers from the Moores Cancer Center at the University of California, San Diego (UCSD). This includes nearly 150,000 cases of cancer that could be prevented in the United States alone.
The researchers estimate that 250,000 cases of colorectal cancer and 350,000 cases of breast cancer could be prevented worldwide by increasing intake of vitamin D3, particularly in countries north of the equator.
The study examines the dose-response relationship between vitamin D and cancer, and is the first to use satellite measurements of sun and cloud cover in countries where blood serum levels of vitamin D3 were also taken.
Serum vitamin D levels during the winter from 15 countries were combined, then applied to 177 countries to estimate the average serum level of a vitamin D metabolite among the population.
An inverse association between serum vitamin D and the risk of colorectal and breast cancers was found.
Protective effects began when 25-hydroxyvitamin D levels (the main indicator of vitamin D status) ranged from 24 to 32 nanograms per milliliter (ng/ml). In the United States, late winter 25-hydroxyvitamin D levels ranged from 15 to 18 ng/ml.
Previous research has suggested that raising levels to 55 ng/ml was actually optimal to prevent cancer, the researchers said.
To increase your vitamin D3 levels, the researchers recommended a combination of dietary methods, supplements and sunlight exposure of about 10 to 15 minutes a day, with at least 40 percent of your skin exposed. [The Journal of Steroid Biochemistry and Molecular Biology March 2007; 103(3-5):708-11]
|Strong or generally accepted link|
|Very strongly or absolutely counter-indicative|
|May do some good|
|Likely to help|
A hormone secreted by the pancreas in response to elevated blood glucose levels. Insulin stimulates the liver, muscles, and fat cells to remove glucose from the blood for use or storage.
A cancerous tumor of the large intestine. It is marked by dark, sticky stools containing blood and a change in bowel habits.
Refers to the various types of malignant neoplasms that contain cells growing out of control and invading adjacent tissues, which may metastasize to distant tissues.