Nutrition and Pancreatic Cancer Risk

When diagnosed with pancreatic cancer, one may wonder if something (or lack of something) in the diet caused the cancer.  People want to know what they should eat now and how to advise their families and friends to maintain health.  It is important to acknowledge that no clear associations exist between nutrition and the development of pancreatic cancer, but some associations are being examined.

The information below provides a brief update of the recent research on the possible links between nutrition and pancreatic cancer.  Some research studies have provided conflicting results.  Additional investigation is needed.

Type 2 Diabetes (Diabetes Mellitus) There is a recognized link in the medical literature between type 2 diabetes and pancreatic cancer; however, the exact relationship is not clear.  Does type 2 diabetes put people at increased risk of pancreatic cancer or is diabetes an indicator of pancreatic cancer?  According to the American Diabetes Association, most people who get type 2 diabetes are overweight.  Therefore, it can also be asked whether it is the diabetes or obesity contributing to cancer.

Most literature indicates that having type 2 diabetes for five years increases the risk of pancreatic cancer.  The mechanisms are still unknown, but the role of high blood glucose levels and resulting increase in insulin is under scrutiny.

In a large study, diets of women diagnosed with pancreatic cancer during 18 years of monitoring were examined.  Investigators evaluated dietary records for carbohydrate intake and glycemic index.  Glycemic index is the blood sugar response for each gram of carbohydrate.  The association between a diet high in carbohydrates and pancreatic cancer was most apparent in overweight women (Body Mass Index (BMI) greater than 25).  Impaired glucose metabolism may play a role, and dietary carbohydrates may only be a risk factor in those who are sedentary and overweight or who already have insulin resistance.

High sugar intake, such as from soft drinks, contributes to a high glycemic load.  Glycemic load is calculated using the total amount of carbohydrates consumed and the glycemic index of the diet.  Since there has been a link of glycemic load to the risk of diabetes, it is logical to question whether it is associated with pancreatic cancer risk.  Findings of recent studies have not confirmed that high glycemic index, glycemic load and intake of carbohydrates increase risk of pancreatic cancer.

A recent study concluded that higher fasting blood glucose levels were associated with an increase in the number of cancer cases and deaths. (Journal of the American Medical Association, January 2005)  High blood sugar and diabetes almost doubled the risk of developing pancreatic cancer for men and more than doubled the risk of developing pancreatic cancer for women.

A study by the Mayo Clinic has shown that patients with newly diagnosed diabetes at age 50 and older have a higher risk of developing pancreatic cancer. (Gastroenterology, August 2005)  Finally, a National Cancer Institute study concluded that men had 2.5 times the risk of getting pancreatic cancer if they reported having diabetes and taking medication for their diabetes.  When men reported having diabetes and not taking medication, they had 2 times the risk of developing pancreatic cancer. (NCI Bulletin, October 2004)
Simply put, evidence is building and indicates that having diabetes or being at risk for diabetes is a risk factor for developing pancreatic cancer.  This risk may be seen more in men.  The question remains: is diabetes a true risk factor or does pancreatic cancer cause diabetes?

Obesity and Physical Activity Studies over recent years support that obesity increases the risk for pancreatic cancer. Similar to the link with diabetes, the mechanisms of this association needs further investigation.

As discussed above, obesity and physical inactivity may increase the risk of pancreatic cancer due to their influence on the body’s ability to use insulin.  “Clinically overweight” is defined as BMI greater than 25, “obese” as BMI 30 or greater, and “morbidly obese” as BMI greater than 40.

Foods Some studies have examined the relationship between the intake of dietary fat, (total fat, polyunsaturated and monounsaturated fatty acids, saturated fat and cholesterol) and risk of developing pancreatic cancer.  Currently, no solid conclusions can be made. 

Some studies have shown that an increased consumption of red meat cooked at high temperatures (grilled, barbecued, broiled) was associated with increased risk of pancreatic cancer. It is important to note that other studies have reported no association. More studies specific to cooking method of the meat are needed. No association was found with chicken or poultry.

Most studies show increased intake of fruits and vegetables can be protective against cancer, but the results are not conclusive.  Strong evidence exists for the protective benefits of folate, lycopene and vitamin C.  Common dietary sources of folate include fortified breakfast cereal, whole wheat products, liver, asparagus, leafy green vegetables, oranges, strawberries and melons.  Sources of dietary lycopene include fruits and vegetables, primarily tomatoes and tomato-based products.  Dietary sources of Vitamin C include fruits and vegetables such as guava, papaya, citrus fruits, broccoli, green bell pepper, tomatoes, and spinach.  Interestingly, one study also showed a possible protective effect from one or more servings of cabbage per week. 

Frequent consumption of nitrate from animal sources is associated with increased risk of pancreatic cancer.  Dietary sources of nitrate include cured, smoked or pickled meats and fish, dried meats, cooked bacon, non-fat dry milk and other protein foods cooked at high temperatures or those preserved with nitrite. 
One study has examined the relationship of pancreatic cancer risk and the intake of methionine and vitamin B6.  Findings suggested that higher intakes of methionine, an essential amino acid found in fish, meats, legumes, poultry, sesame seeds and Brazil nuts, may decrease the risk of pancreatic cancer.  No association was found with vitamin B6.

More research is needed before definitive statements about nutrition and the prevention of pancreatic cancer can be made.  While the research is still pending, exercise and a balanced diet overall lead to a healthier weight and body.

Additional References: Pancreatic Cancer and Nutrition Risk factors Hart A, Kennedy H, Harvey I.  Pancreatic Cancer: a review of the evidence of causation.  Clinical Gastroenterology and Hepatology: the Official Clinical Practice Journal of the American Gastroenterological Association. 2008;6:275-282.
Gumbs A, Bessler M, Milone L, et al.  Contribution of Obesity to pancreatic carcinogenesis.  Surgery for Obesity and Related Diseases: Official Journal of the American Society for Bariatric Surgery 2008;4:186-193.
Heinen M, Verhage B, Lumey L et al. Glycemic load, glycemic index and pancreatic cancer risk in the Netherlands Cohort Study.  The American Journal of Clinical Nutrition 2008;87:970-977.
Giovannucci E, Michaud D.  The role of obesity and related metabolic disturbances in cancers of the colon, prostate, and pancreas.  Gastroenterology 2007;132:2208-2225.
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Jee S, Ohrr H, Sull J, et al.  Fasting serum glucose level and cancer risk in Korean men and women.  Journal of the American Medical Association 2005;293:194-202.
Larsson S, Hakansson N, Naslund I, et al.  Fruit and vegetable consumption in relation to pancreatic cancer risk: a prospective study. Cancer Epidemiol Biomarkers Prev 2006;15:301-305.
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Berrington de Gonzalez A, Sweetland, S, Spencer, E. A meta-analysis of obesity and the risk of pancreatic cancer. British Journal of Cancer, 2003;89:519-523.
Michaud D, Giovannucci E, Willett W et al. Physical activity, obesity, height, and the risk of pancreatic cancer. Journal of the American Medical Association, 2001;8:921-929.
Michaud D, Giovannucci E, Willett W et al. Dietary meat, dairy products, fat, and cholesterol and pancreatic cancer risk in a prospective study. American Journal of Epidemiology, 2003;157:1115-1125.
Coss A, Cantor K, Reif T et al. Pancreatic cancer and drinking water and dietary sources of nitrate and nitrite. Am J Epidemiol 2004;159:693-701.
Fisher W.  Diabetes:  Risk factor for the development of pancreatic cancer or manifestation of the disease?  World Journal of Surgery, 2001;25:503-508.

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