50 Research Facts About the Obesity-Cancer Nexus

Obesity was confirmed as a tumor promoter by researchers at the University of California, San Diego in January 2010. The results of their findings were published in the January 22nd issue of the journal Cell, a Cell Press publication.

Though heart ailments and type 2 diabetes top the list of obesity complications, as many as 90,000 lives per year in the United States can be saved if researchers can focus more on the elevated cancer risk owing to obesity.

50 Research Facts About the Obesity-Cancer Nexus:

1. It is estimated that obese people are prone to 33 types of cancer, with breast, uterus, kidneys, colon and esophagus being the most affected organs.

2. Obese people are 1.5 times more at risk of developing cancer overall according to epidemiological studies.

3. The risk of obese people developing liver cancer is 4.5 times greater.

4. In the United States, 20 percent of deaths in women caused by cancer and 14 percent of deaths from this ailment in men are due to overweight and obesity.

5. Two inflammatory factors IL-6 and TNF are found to be the source of obesity’s tumor-promoting effect.

6. Carbohydrates is a common contributor of obesity and a diet high in this nutrient was found to increase esophageal cancer rates in February 2008.

7. According to a research study done at The University of Texas M. D. Anderson Cancer Center in Match 2010, obesity was linked to poor prognosis of colon cancer.

8. Obesity increases the insulin levels in the body, which in turn raises the risk of developing breast cancer in women by nearly a 1.5-folds when compared to women with the lowest insulin levels, according to researchers at the Albert Einstein College of Medicine in New York (December 2008).

9. If women above the age of 50 years can maintain a BMI under 25 during their adult lives, an estimated 11,000 to 18,000 deaths per year from breast cancer in U.S. can then be avoided.

10. Obese men are more at risk of developing colon cancer when compared to their female counterparts.

11. Overweight people are at 36 percent increased risk of developing kidney cancer.

12. Overweight and obese people are two times more likely of developing esophagus cancer according to the National Cancer Institute.

13. There was no association found between prostate cancer and obesity in more than 35 studies carried out on the nexus.

14. Obese women are two to four times at greater risk of developing the disease when compared to women maintaining healthy weight, regardless of menopausal status.

15. A meta-analysis on pancreatic cancer and obesity nexus found that obese people are at 19 percent higher risk of getting this cancer than those with a healthy BMI. However, there is a lack of conclusive evidence on this subject.

16. Abdominal fat in men and waist-hip ratio in women are two major risk factors for colon cancer.

17. Postmenopausal obese women who do not use menopausal hormones are at increased risk of breast cancer.

18. Though gallbladder stones especially in obese women are considered to be a major risk factor for cancer, there are very few evidences to support to claim.

19. Obesity status raises the risk of kidney cancer to 84 percent when compared to healthy people.

20. Though the underlying mechanism between obesity and kidney cancer nexus is not understood yet, people with excess weight are at two-four times higher risk of developing this cancer.

21. An estimated 3.2 percent of all new cancers diagnosed in the United States every year are linked to obesity.

22. According to a research study presented at the 2010 Institute of Food Technologists (IFT) Annual Meeting & Food Expo, reducing the intake of Omega-6 fatty acids and calories can prevent 1 out of every 3 cancer related deaths in humans and dogs.

23. Leptin is an important signaling molecule associated with the intake and expenditure of energy in the body. It is found to promote the growth of cancer cells.

24. A research study at the Sbarro Institute for Cancer Research and Molecular Medicine, Temple University, Philadelphia, found this hormone to be a new target for breast cancer.

25. According to researchers at the Saban Research Institute of Children’s Hospital, Los Angeles, obesity speeds up the progress of Acute Lymphoblastic Leukemia (ALL) in children. This research fact was published in Cancer Prevention Research journal, on October 5, 2010.

26. CNN health published an article on November 5, 2009 which stated that more than 100,000 cases of cancer each year are caused by obesity.

27. In the same report, it was mentioned that the American Institute for Cancer Research experts found 9 percent of colorectal cancer cases and 17 percent of breast cancer cases related to obesity.

28. 21 percent of gallbladder cancer cases, 24 percent of kidney cancer cases and 28 percent of pancreatic cancer cases were linked to obesity.

29. 49 percent of endometrial cancers followed by 35 percent of esophageal cancer cases are caused by obesity.

30. Obesity is not only associated with the cause of the disease but also makes prognosis and treatment difficult.

31. When fat levels rise in the body, it is followed by increased levels of oxidative stress and swelling components in the blood. They cause changes in the DNA structures probably leading to cancer.

32. Researchers at the University of Sheffield in the United Kingdom in February 2010 found that deficiency of testosterone affects the quality of life of the male cancer survivors and the relation between obesity and low testosterone levels is well known.

33. Excess production of oestrogen hormone is responsible for causing breast and ovarian cancers, the two most deadly forms of this ailment affecting obese women.

34. Obese breast cancer women have poor survival rate when compared to their leaner counterparts.

35. Women diagnosed with breast cancer should exercise in order to the reduce the pain and fatigue associated with the condition. It was found by researchers at the Ohio State University in May 2007 and the result was published in Springer’s Journal of Cancer Survivorship.

36. Side effects of Stereotactic body radiation therapy in Lung cancer patients is increased significantly by obesity. This fact was presented at the 51st Annual Meeting of the American Society for Radiation Oncology (ASTRO) in November 2009.

37. In pancreatic cancer patients, the inflammatory markers of obesity were found at higher levels in a research study carried out by researchers at the Jefferson Pancreatic, Biliary and Related Cancers Center in February 2010.

38. Surprisingly a research study carried out at the Department of Preventive Medicine, School of Medicine, Palacky University, Olomouc, Czech Republic, found that increased BMI reduced the risk of lung cancer.

39. A study carried out by researchers at the University of Alabama at Birmingham (UAB) Comprehensive Cancer Center in January 2009, found that thr isk of developing ovarian cancer was same in obese and non-obese women.

40. Even a weight loss of only 5 to 10 percent of total weight can be beneficial against cancer risk.

41. Weight loss is found to reduce the cancer risks of colon, breast (postmenopausal), endometrium, kidney, and esophagus, with no substantial evidence for all other cancers.

42. The exact mechanism explaining the nexus between cancer and obesity physical disorder depends on the type of the cancer ailment.

43. The Four Corners Breast and Endometrial Cancer Study funded by the National Cancer Institute is trying to understand how obesity and weight changes are related to the rise in breast and endometrial cancer among Hispanic, non-Hispanic white and Native American women.

44. Postmenopausal women by walking about 30 minutes per day can reduce the risk of breast cancer by 20 percent.

45. The protective effect of physical activity against breast cancer is not found in obese and overweight women.

46. Insulin and sex hormones are believed to be major risk factors for causing cancer in obese people.

47. Intentional weight loss of 20 pounds or more can reduce the risk of cancer, but when weight is reduced by unintentional means the risk remains unchanged.

48. Obesity is responsible for causing 40 percent of endometrial or uterus cancer though there is no explanation for the possible nexus.

49. Regular physical exercise can reduce the risk of colon cancer by 20 percent according to a major research study carried out in 2002.

50. There is limited evidence for whether risk of thyroid cancers can be reduced by weight loss.

How Obesity Raises the Risk of Cancer?

An estimated figure of 61% Americans are either overweight or obese as per the Center for Disease Control. According to a survey conducted by the American Institute of Cancer, only 1 in 4 people were aware of the fact that obesity can lead to cancer. Hence, most of the obese Americans may be unaware of the fact they could minimize the risk of having cancer by weight loss.

Most of the American people, who are either overweight or obese due to abdominal fat or body fat, will now be successful in lowering their susceptibility to cancer by simply changing their dietary plans. Cancer is the second most leading disease which causes death in the U.S. the prime reason behind obesity or overweight is when food intake exceeds the number of calories burned.

If high amount of body fat is present, it increases the estrogen levels in the blood. This makes the female reproductive system prone to cancer. Gastro esophageal reflux disease is caused to excessive weight of the body is considered as a risk factor for esophageal cancer. This raises the insulin which causes the body to secrete a hormone that leads to abnormal cell multiplication.

A Recent Report

According to a recent report, there is a link between 19 different cancers and obesity. Out of the 19 cancers which were evaluated, 8 were directly linked to body fat. A factor called Persons Years of Lost Life (PYLL) because of each cancer type was evaluated using actual death rates due to the cancers and life expectancy tables.

The table below shows the results of the study:

Table 1, Cancers with increased risk due to Overweight and Obese people. The source of this information is the National Cancer Institute (2).
PYLL for 2004Type of CancerCauseMitigated by
783,000BreastBody Fatness
Abdominal Fat
Total Fat
Greater birth weight
Adult attained height
Adult weight gain
Physical activity
752,000ColorectumBody fatness
Abdominal fat
Sugary drinks
Animal fat
Foods with iron
Red meat
Processed meat
Adult attained height
Foods containing dietary fiber
Fruits, Fish, Milk, Garlic
Non-starchy vegetables
Foods containing Folate
Foods containing selenium
Foods containing vitamin D
Calcium supplements
Physical activity
463,000PancreasBody fatness
Abdominal fat
Red meat
Adult attained height
Foods containing folate
Physical activity
258,000LiverBody fatness
Aflatoxins (mold)
257,000EndometriumBody Fatness
Abdominal fat
Processed meats
Non-starchy vegetables
Physical activity
205,000OestophagusBody fatness
Red meat
Processed meat
Non-starchy vegetables
Foods containing B-Carotene
Foods containing vitamin C
Foods containing dietary fiber
Foods containing folate
Foods containing Pyridoxine
Foods containing vitamin E
193,000KidneyBody Fatness
Arsenic in water
Physical activity (3)
Fruits and vegetables (3)
N/AGall BladderBody fatnessPhysical activity (4)
Watch less TV (4)

Steps To Prevent Cancer From Obesity

A comprehensive report on the link between nutrition and cancer says obesity heightens the risk of cancer. The solution lies in avoiding all processed meats, including bacon and some sausages. It also advises against consuming salt exceeding 6 grams a day. An overweight person’s chances of developing five different types of cancer escalate by 50 percent confirms a new study.
Martin Wiseman, project director of the report, which was published this week by the World Cancer Research Fund and the American Institute for Cancer Research says, “While a number of foods carry a cancer risk, most of them can be eaten in small amounts without noticeably endangering health. However, for salted or cured meats there is no clear safe dose”.

Researchers at the University of Manchester discovered that those who put on weight equal to a five-point increase in the body mass index (BMI) were at considerable risk of contracting cancer of the colon, breast, skin, thyroid. The researchers said that there was a 50 percent increase in the chances of developing the cancers if a person’s weight goes up by more than two stones. An overweight person’s chances of developing five different types of cancer escalate by 50 percent confirms a new study.

So, it is high time for the overweight to buck up and start eating healthy and move about to lose a few pounds. Some oft-followed and highly recommended ways to reduce weight are:

  • Say no to red meat and avoid fatty food.
  • Exercise for at least 30 minutes a day. This not only increases the blood circulation but also keeps diseases at bay.
  • Drink lots of water. For, there is nothing that water cannot cure. This flushes out toxins from the body and keeps the digestive system clean.
  • Increase your servings of fresh fruits and vegetables. This not only replenishes your body with the essential vitamins but also wards off those dangerous cravings for munchies.

How Weight Loss Surgical Options Can Bring Down Cancer Risks?

According to a research study carried out at the McGill University Health Centre (MUHC), Canada, in June 2008, weight loss surgery options were found to reduce obesity by 70 percent and the risk of cancer by 80 percent.

The study was the first of its kind to reveal that this surgery reduced the cancer risk. Results of the study were presented at the 25th Annual Meeting of the American Society for Metabolic & Bariatric Surgery in June 2008.

How Weight Loss Surgical Options Can Bring Down Cancer Risks?

  • The results of the study were known after analysing 1,035 patients who underwent the surgery and 5,746 patients who did not undergo the operation between 1986 and 2002 at the research center.
  • Diagnosis of cancer in the morbidly obese group one was 70 percent lower for colon and pancreatic cancers and 85 percent lower for breast cancer when compared to the morbidly obese group two patients along with the reduced risks of other cancer types.
  • Though the effect of obesity on the body is complex to understand, the researchers believe that this physical disorder disturbs the hormone producing mechanism of the body.
  • Hormones are the signalling molecules which either initiate or end various chemical processes.
  • Excess fat in the body causes the disruption by increasing the production of these signalling molecules and raises the risk of developing breast and colon cancers.
  • Weight loss caused by surgery is believed to change the hormone production in the body of patients to cause the beneficial effects.


In the United States, the National Institutes of Health recommends weight loss surgical options to obese people with BMI factor 40. The media is helping in the development of awareness about the benefits of this surgery by covering news of celebrities who have opted for it in recent times. The general public (especially those whose loved ones suffer from obesity) as a result is increasingly trying out these surgical options.

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