High Glycemic Index Food and Endometrial Cancer

This article review discusses the findings of a recent study on high glycemic index foods and risk of endometrial cancer (Review of Int J Cancer 2003;105(3):404-407).

A study published in the International Journal of Cancer looked at several dietary factors and endometrial cancer risk. This article review discusses the findings of this study. This study indicates that eating more of the 'high glycemic index' foods increases risk of endometrial cancer. We provide PRACTICAL information on what these findings mean. We explain what glycemic index is. We explain why and how high glycemic index foods appear to increase risk of endometrial cancer. Most importantly, we provide ideas for using this information in a dietary plan to reduce endometrial cancer risk. Factors such as reproductive history, age, and genetics cannot be changed, but diet and nutrition can! This type of information will allow women to take concrete and practical steps to decrease their risk of endometrial cancer.

Note: Numbers appearing at the end of sentences indicate research references. References are listed at the end of each article.

Background

As early as the 1970s, researchers concluded that diet might be linked with hormone related cancers such as breast, prostate, endometrial and ovarian cancers (1-3). In the 1980s researchers found that obesity increased risk of this cancer (4-10). Over the past decade, researchers have continued to study the connection between diet and endometrial cancer more actively (11-28). However, the role of high glycemic foods in endometrial cancer risk was not studied until very recently. High glycemic foods are those foods that appear to raise blood sugar in the body most quickly after they are eaten. In general, this includes items such as soda pop, sugary desserts and snacks, and certain starchy foods. A recent study published in the International Journal of Cancer looked at amounts of high glycemic index foods consumed by women with and without a history of endometrial cancer (29). It is hoped that this type of research will help identify what type of diet increases or decreases risk of endometrial cancer. Factors such as reproductive history, age, and genetics cannot be changed, but diet and nutrition can! This type of information will allow women to take concrete and practical steps to decrease their risk of endometrial cancer.

About Glycemic Index

Glycemic index is a number value that gives us an idea of how quickly the carbohydrate found in a specific food will raise blood sugar in the body. The higher the number, the more quickly the carbohydrate from a given food will raise your blood sugar. Specifically, glycemic index is a standardized number that refers to how quickly 50 grams of carbohydrate from specific food will turn into blood sugar in the body. This is compared to a 'reference' food. Most commonly, white bread or white table sugar is used as the reference food. In summary, glycemic index tells us how quickly 50 grams of carbohydrate from a specific food will turn into sugar in the body, compared to 50 grams of carbohydrate from bread or table sugar. This allows us to rank foods, regarding how quickly they increase blood sugar in the body. The reference food, which is most often white bread, is given a value of 100. So, carbohydrate from foods that have a glycemic index below 100 is absorbed more slowly than carbohydrate from bread. Carbohydrate from foods that have a glycemic index above 100 is absorbed more quickly than carbohydrate from white bread.

What The Study Found

For this study (29), researchers combined women from two smaller studies together to allow them to better study the connection between diet and endometrial cancer risk. A total of 410 women with endometrial cancer and 753 women without endometrial cancer were asked about their diet. This information was used to classify the women regarding the amounts and types of different foods they had eaten in the past. In particular, the researchers looked at how many high glycemic index foods the women ate. High glycemic foods are those foods that appear to raise blood sugar in the body most quickly after they are eaten. This is important to study because eating more high glycemic index foods may increase risk of diabetes, heart disease, and some cancers (30). Information on other lifestyle factors was collected and accounted for in the study. Researchers used this information to examine whether or not eating more high glycemic index foods was related to having a history of endometrial cancer. Two important results came out of this study.

First, the researchers found that women who ate a diet with the highest glycemic index had more than TWICE the risk of endometrial cancer when compared to women eating a diet with the lowest glycemic index. In other words, the study suggested that eating more high glycemic index foods increases the risk of endometrial cancer.

Second, the study tells us that having a diet with a higher overall glycemic load increases risk of endometrial cancer. Women eating a diet with the highest glycemic load had nearly THREE times the risk of endometrial cancer when compared to women eating a diet with the lowest glycemic load. This is not surprising, because glycemic index and glycemic load are related to one another. They are similar ways to measure how a specific food will affect blood sugar. However, glycemic load is a more useful way to understand how foods affect our blood sugar, when eaten in typical serving sizes.

Why is glycemic load important? 

Glycemic index does NOT tell us how many carbohydrates are in a SERVING of a specific food. This is why glycemic load can be more useful. Glycemic load takes into account the glycemic index of a food AND how many carbohydrates are in a normal SERVING of that food. To see why this is helpful, we can compare carrots to white pasta.

Fifty grams of carrot carbohydrate has a glycemic index of 131, using white bread as the reference food. Fifty grams of pasta carbohydrate has a glycemic index of 71. This might make us think carrots are an unhealthy food and that they will raise our blood sugar faster than white pasta. However, one whole carrot (a serving) only contains 4 grams of carbohydrate. One cup of pasta has 40 grams of carbohydrate. This means that the glycemic load, which adjusts glycemic index for serving size, is much lower for carrots. A SERVING of carrots has a glycemic load of 5.2. The glycemic load for a serving of pasta (1 cup) is very high at 28 (20). In order to have the same glycemic load from carrots, you would have to eat nearly TWO pounds of them! This shows how glycemic index can be misleading. Just because a food has a high glycemic index, does NOT mean it will raise blood sugar quickly, when eaten in a normal serving size!

What do these results mean?

If we assume that the women studied are similar to most women, then this study suggests that eating more of the higher glycemic foods increases risk of endometrial cancer. More importantly, having a diet with an overall high glycemic load increases risk of endometrial cancer. This is one of the first studies to look at how these particular types of food affect endometrial cancer risk. However, other research tells us that eating higher glycemic index foods and more sugar may increase risk of other cancers including ovarian, breast, colorectal, pancreatic and lung cancers (32-38). Therefore, it makes sense that this may be the case for endometrial cancer too.

However, don't get bogged down in the specifics of each food's glycemic index. You will drive yourself crazy trying to check the glycemic index of all of the foods you eat. Just remember, that your total pattern of diet is what matters. Eating one or two foods with a higher glycemic index is NOT important. If you general diet is healthy, and the overall glycemic load of your diet is low, having a sweet treat now and then is not a problem. Also remember, glycemic index can be misleading. Carrots have a high glycemic index, but a LOW glycemic load. And, if you eat one food with a high glycemic index, but combine it with some low glycemic index foods, then the total glycemic load of your meal or snack will be low. In summary, don't get concerned with each specific number. Rather, focus your whole pattern of eating on a healthy, low-glycemic load pattern.

In general, WHOLE plant foods, such as vegetables, fruits, whole grains, and especially legumes (beans) have a LOW glycemic load. If you base your choices around these foods, you will do well to keep your glycemic load low. In addition to this, there is plenty of research that tells us that plant foods, especially fruits and vegetables, can reduce risk of endometrial cancer (17,19,22,23,27,28). Therefore, if you focus your diet around WHOLE plant foods, you will both eat a diet of low glycemic load AND you will be including the cancer fighting phytochemicals found in plant foods.

How can I change my diet to reduce my risk of endometrial cancer?

What should you do to help reduce your risk of endometrial cancer? According to this study (29), focusing your diet on foods that have a low glycemic index and eating a diet that has a low glycemic load overall, may be helpful for protecting against endometrial cancer. Use the tips below to accomplish this goal.

Quick Tips On How to Eat a Diet with a Low Glycemic Load

• Do not drink soda pop anymore.
• Let me say that again. Do not drink soda pop anymore. Regular soda pop is nothing but PURE sugar. Worse yet, it is liquid sugar, which means it affects your body quicker than sugar in foods. It raises insulin and other hormones faster than sugar in foood.
• When you switch from regular soda pop to water, decrease the amount of soda pop you drink slowly. This will help prevent symptoms of caffeine withdrawal, such as headaches.
• If you do not like plain water, try carbonated water that does not contain sugar. Look at the label. If the water contains calories, put it back on the shelf. Instead pick a brand that does not contain calories. Plain, flavored or carbonated water will not contain calories. If the water contains calories, then it contains sugar. Water with sugar is no better than soda pop. There are several brands of carbonated, NON-sugar, flavored waters from which to chose.
• Chose WHOLE fruit over fruit juice. There are three nutrients that slow down the absorption of sugar in food. These are fiber, fat, and protein. WHOLE fruit contains fiber while fruit juice does not contain fiber. A piece of whole fruit is almost always a better choice than juice.
• Sprinkle ground flax seeds into your cereal, yogurt, fruit smoothies, and salads. This will add protein & fat to the meal or snack. This slows sugar absorption for a healthier effect on the body.
• Sprinkle nuts (walnuts, almonds, etc.) into salads and stir fry dishes. Again, this adds healthy fat to the meal to help balance your diet.
• Replace store bought salad dressings with your own mixture of balsamic or apple cider vinegar and olive oil for your salads. Store bought dressings can contain a lot of sugar.
• If you are too busy to prepare you own salad dressing, try a 'healthy' brand such as Annie's Naturals or Chelton House. These can be found in the health food section of your grocery store. Look for a dressing that contains no sugar, no corn syrup, and no hydrogenated fats. If you read the ingredient list and see the words 'hydrogenated' or 'partially hydrogenated', this dressing is less healthy. Try a different brand.
• Start basing your diet around UNPROCESSED whole plant foods including vegetables, fruit, whole grains, and legumes. Do this instead of basing your food choices around fast food, microwave meals, or 'instant dinner' trays. These often contain sugar. They also contain unhealthy fats and too many calories. Plus, they do not contain the healthy cancer-fighting phytochemicals of whole plant foods.
• Instead of pretzels or chips, have a small handful of nuts as a snack. Watch portion size, because nuts are high in calories. But, remember, those calories come from HEALTHY fats. Most snack foods such as pretzels contain no healthy nutrients and may contain simple sugar.
• Replace snack foods with WHOLE vegetables & fruits. Try baby carrots and hummus as a quick, easy and tasty snack.
• For a great snack, try one piece of fruit with a small handful of nuts or a spoonful of nut butter. The nuts add protein and healthy fat to your diet.
• When you buy bread products, read the label. If you see the word 'enriched', then the product is NOT a whole grain. Instead look for words such as 'whole grain', 'stone ground', 'whole ground', 'whole wheat flour', 'whole oat flour', or 'whole barley flour'. These are tips that tell you that this food IS a whole grain! Remember, these contain more protein and fiber and are healthier for you. Usually, they contain less simple sugar as well!
• Try to eat foods that are as close to their 'natural form' as possible. For example, a corn chip is made of corn, but it's NOT a whole food. To make a corn chip, first the corn is picked, then ground and crushed. Next the fiber portion of the corn is thrown out. Then the corn is fried in processed fat (hydrogenated fat). Next it is treated with artificial flavors, dyes, and preservatives. This hardly looks like corn anymore!
• Now think of corn on the cob. It is picked, shipped, and ends up on your dinner table! It is not processed. It is a WHOLE food. The less processing that a food undergoes before you eat it, the better it is for you!!
• Make dessert an OCCASSIONAL treat. There is nothing wrong with having a sweet treat now and then. Just make sure 'now and then' only means a few times per week.
• Cut out desserts and sugary foods that you do not care about. For example, if you absolutely cannot live without chocolate, make sure that when you do enjoy a sweet treat, you save it for those chocolate treats that you really love. Don't waste your treats on foods that you can live without.
• Say the statement, "I absolutely cannot live without _______." Insert the name of your favorite sweet treat. Then, when you eat a sweet treat, MAKE SURE it is your special treat, not something you only enjoy a little bit.

Recipes to Help You Eat a Low Glycemic Load Diet

Baked Alaskan Salmon

Lentil Sweet Potato Soup

Wheat Berry Salad

NOTE: If you are in cancer treatment, these diet changes may not be right for you.

References

1. Berg JW. Can nutrition explain the pattern of international epidemiology of hormone-dependent cancers? Cancer Res. 1975;35(11 pt 2):3345-50.

2. Armstrong B, Doll R. Environmental factors and cancer incidence and mortality in different countries, with special reference to dietary practices. Int J Cancer. 1975;15(4):617-31.

3. Stadel BV. Dietary iodine and risk of breast, endometrial, and ovarian cancer. Lancet. 1976;1(7965):890-91.

4. La Vecchia C. Nutritional factors and cancers of the breast, endometrium, and ovary. Eur J Cancer Clin Oncol. 1989;25(12):1945-51.

5. Hershcopf RJ, Bradlow HL. Obesity, diet, endogenous estrogens, and the risk of hormone-sensitive cancer. Am J Clin Nutr. 1987.

6. Osler M. Obesity and cancer. A review of epidemiological studies on the relationship of obesity to cancer of the colon, rectum, prostate, breast, ovaries, and endometrium. Dan Med Bull. 1987;34(5):267-74.

7. La Vecchia C, Decarli A, Fasoli M, Gentile A. Nutrition and diet in the etiology of endometrial cancer. Cancer. 1986;57(6):1248-53.

8. Jensen H. Relationship of premorbid state of nutrition to endometrial carcinoma. Acta Obstet Gynecol Scand. 1986;65(4):301-06.

9. Villani C, Pucci G, Pietrangeli D, Pace S, Tomao S. Role of diet in endometrial cancer patients. Eur J Gynaecol Oncol. 1986;7(2):139-43.

10. Jensen H. Endometrial carcinoma. A retrospective, epidemiological study. Dan Med Bull. 1985;32(4):219-28.

11. Hu FB. Overweight and obesity in women: health risks and consequences. J Womens Health (Larchmt). 2003;12(2):163-72.

12. Petridou E, Kedikoglou S, Koukoulomatis P, Dessypris N, Trichopoulos D. Diet in relation to endometrial cancer risk: a case-control study in Greece. Nutr Cancer. 2002;44(1):16-22.

13. Furberg AS, Thune I. Metabolic abnormalities (hypertension, hyperglycemia and overweight), lifestyle (high energy intake and physical inactivity) and endometrial cancer risk in a Norwegian cohort. Int J Cancer. 2003;104(6):669-76.

14. Terry P, Vainio H, Wolk A, Weiderpass E. Dietary factors in relation to endometrial cancer: a nationwide case-control study in Sweden. Nutr Cancer. 2002;42(1):25-32.

15. Terry P, Wolk A, Vainio H, Weiderpass E. Fatty fish consumption lowers the risk of endometrial cancer: a nationwide case-control study in Sweden. Cancer Epidemiol Biomarkers Prev. 2002;11(1):143-45.

16. Kasum CM, Nicodemus K, Harnack LJ, Jacobs DR Jr, Folsom AR. Whole grain intake and incident endometrial cancer: the Iowa Women's Health Study. Nutr Cancer. 2001;39(2):180-86.

17. Littman AJ, Beresford SA, White E. The association of dietary fat and plant foods with endometrial cancer (United States). Cancer Causes Control. 2001;12(8):691-702.

18. Jain MG, Rohan TE, Howe GR, Miller AB. A cohort study of nutritional factors and endometrial cancer. Eur J Epidemiol. 2000;16(10):899-905.

19. McCann SE, Freudenheim JL, Marshall JR, Brasure JR, Swanson MK, Graham S. Diet in the epidemiology of endometrial cancer in western New York (United States). Cancer Causes Control. 2000;11(10):965-74.

20. Tavani A, La Vecchia C, Gallus S, Lagiou P, Trichopoulos D, Levi F, Negri E. Red meat intake and cancer risk: a study in Italy. Int J Cancer. 2000;86(3):425-28.

21. Fernandez E, Chatenoud L, La Vecchia C, Negri E, Franceschi S. Fish consumption and cancer risk. Am J Clin Nutr. 1999;70(1):85-90.

22. Goodman MT, Hankin JH, Wilkens LR, Lyu LC, McDuffie K, Liu LQ, Kolonel LN. Diet, body size, physical activity, and the risk of endometrial cancer. Cancer Res. 1997;57(22):5077-85.

23. Goodman MT, Wilkens LR, Hankin JH, Lyu LC, Wu AH, Kolonel LN. Association of soy and fiber consumption with the risk of endometrial cancer. Am J Epidemiol. 1997;146(4):294-306.

24. Tzonou A, Lipworth L, Kalandidi A, Trichopoulou A, Gamatsi I, Hsieh CC, Notara V, Trichopoulos D. Dietary factors and the risk of endometrial cancer: a case-control study in Greece. Br J Cancer. 1996;73(10):1284-90.

25. Negri E, La Vecchia C, Franceschi S, Levi F, Parazzini F. Intake of selected micronutrients and the risk of endometrial carcinoma. Cancer. 1996;77(5):917-23.

26. Zheng W, Kushi LH, Potter JD, Sellers TA, Doyle TJ, Bostick RM. Dietary intake of energy and animal foods and endometrial cancer incidence. The Iowa women's health study. Am J Epidemiol. 1995;142(4):388-94.

27. Levi F, Franceschi S, Negri E, La Vecchia C. Dietary factors and the risk of endometrial cancer. Cancer. 1993;71(11):3575-81.

28. Potischman N, Swanson CA, Brinton LA, McAdams M, Barrett RJ, Berman ML, Mortel R, Twiggs LB, Wilbanks GD, Hoover RN. Dietary associations in a case-control study of endometrial cancer. Cancer Causes Control. 1993;4(3):239-50.

29. Augustin LS, Gallus S, Bosetti C, Levi F, Negri E, Franceschi S, Dal Maso L, Jenkins DJ, Kendall CW, La Vecchia C. Glycemic index and glycemic load in endometrial cancer. Int J Cancer. 2003;105(3):404-07.

30. Augustin LS, Franceschi S, Jenkins DJ, Kendall CW, La Vecchia C. Glycmic index in chronic disease: a review. Eur J Clin Nutr. 2002;56(11):1049-71.

31. Willett, W. Eat, Drink, and Be Healthy: The Harvard Medical School Guide to Healthy Eating. Simon & Schuster. 2001.

32. McCann SE, Freudenheim JL, Marshall JR, Graham S. Dietary glycemic index, glycemic load and ovarian cancer risk: a case-control study in Italy. Ann Oncol. 2003;14(1):78-84.

33. Augustin LS, Dal Maso L, La Vecchia C, Parpinel M, Negri E, Vaccarella S, Kendall CW, Jenkins DJ, Francesch S. Dietary glycemic index and glycemic load, and breast cancer risk: A case-control study. Ann Oncol. 2001;12 (11):1533-1538.

34. Franceschi S, Dal Maso L, Augustin L, Negri E, Parpinel M, Boyle P, Jenkins DJ, La Vecchia C. Dietary glycemic load and colorectal cancer risk. Ann Oncol. 2001;12(2):173-78.

35. Singh PN, Fraser GE. Dietary risk factors for colon cancer in a low-risk population. Am J Epidemiol. 1998;148(8):761-74.

36. Slattery ML, Benson J, Berry TD, Duncan D, Edwards SL, Caan BJ, Potter JD. Dietary sugar and colon cancer. Cancer Epidemiol Biomarkers Prev. 1997;6(9):677-85.

37. Michaud DS, Liu S, Giovannucci E, Willett WC, Colditz GA, Fuchs CS. Dietary sugar, glycemic load, and pancreatic cancer risk in a prospective study. J Natl Cancer Inst. 2002;94(17):1293-300.

38. De Stefani E, Deneo-Pellegrini H, Mendilaharsu M, Ronco A, Carzoglio JC. Dietary sugar and lung cancer: a case-control study in Uruguay. Nutr Cancer. 1998;31(2):132-37.

39. Barbone F, Austin H, Patridge EE. Diet and endometrial cancer: a case-control study. Am J Epidemiol. 1993;137(4):393-403.

Publish Date: 10/2003