Does sugar cause cancer? Specifically, what role does glycosylation - PowerPoint PPT Presentation

Does sugar cause cancer? Specifically, what role does glycosylation play in oncogenesis? Allison Hayward and Sarah Lopes

First of all... These two questions are actually different topics, and there are no available studies that address both. Glycosylation is the addition of a glycan (carbohydrate) to a protein, for structural or functional purposes. Aberrant (abnormal) glycosylation is a “hallmark” of cancer. Studies on this topic are very technical, examining changes to DNA that occur during cancer development. Glycosylation is not a direct response to dietary sugar intake, and abnormal glycosylation is a feature of cancer cells, not a cause of cancer development.

1. Sugars in diet and risk of cancer in the NIH-AARP Diet and Health Study Tasevska N, Jiao L, Cross AJ, et al. (2012) Overview and Methods: AARP members were recruited from 8 U.S. states with the use of a questionnaire send by mail. At baseline, subjects completed a FFQ measuring intake of 124 food items over the previous 12 months. Multiple exclusion criteria reduced a potential population of 617,119 respondents to n = 435,674. Associations between sugar intake and 24 malignancies were investigated in this population of adults, aged 50-71 years. Over the course of 7.2 years, cancer was diagnosed in 29,099 men and 13,355 women.

1. Sugars in diet and risk of cancer in the NIH-AARP Diet and Health Study Tasevska N, Jiao L, Cross AJ, et al. (2012) Overview and Methods: Sugar consumption was measured in several subcategories: total sugars, sucrose, fructose, added sugars, added sucrose, and added fructose. Consumption of each subcategory of sugars was broken into quintiles for comparative analysis. Both separate and combined gender analyses were performed. The authors discuss hypotheses suggesting that high-sugar diets may play a role in cancer development due to their stimulation of insulin and insulin-like growth factor-I (IGF-I) synthesis and well as promoting oxidative stress and that added sugars affect the body differently than integral sugars due to the fact that they are “free in solution” and thus rapidly metabolized.

1. Sugars in diet and risk of cancer in the NIH-AARP Diet and Health Study Tasevska N, Jiao L, Cross AJ, et al. (2012) Results: Positive Correlations: -A strong positive association was found between intake of added sugars and risk for esophageal adenocarcinoma in gender-combined analysis. -All investigated sugars were related to increased risk of pleural (between the lung and chest cavity) cancer. -In women, total sugars, added sugars and added fructose intakes were positively associated with risk of leukemia, and high fructose intake was associated with increased risk of bladder cancer. -High intake of fructose, and added fructose in particular, was correlated with a greater than two-fold increase in risk for small intestine cancer. -Positive correlations found for rarer cancers, and inconsistency in results between genders suggest a possibility for some chance results.

1. Sugars in diet and risk of cancer in the NIH-AARP Diet and Health Study Tasevska N, Jiao L, Cross AJ, et al. (2012) Results: Inverse Correlations or No Association: None of the investigated sugars were associated with increased risk of potentially IGF-I-related cancers such as colorectal, breast, prostate, pancreatic or endometrial cancer. Total sugars, fructose, and added fructose intake were associated with decreased risk of all cancers in men. In women, all investigated sugars were inversely associated with risk of ovarian cancer and added sucrose and added fructose were inversely associated with pancreatic cancer. High added fructose intake was inversely associated with liver cancer.

1. Sugars in diet and risk of cancer in the NIH-AARP Diet and Health Study

1. Sugars in diet and risk of cancer in the NIH-AARP Diet and Health Study Tasevska N, Jiao L, Cross AJ, et al. (2012) Conclusions: Positive associations were established between intakes of certain sugar categories and specific types of cancer, but there were many inconsistencies between genders and a lot of statistically insignificant data. No association or inverse association was found more often than positive association. Strengths: This study was the first to investigate the association of various forms and dietary classifications of sugars with multiple malignancies. Large sample size allowed examination of rarer cancers. Limitations: The authors admit in their conclusions that there is high probability that some of the findings may have occurred due to chance, which is a common problem in analyses of this type, examining multiple comparisons. In some instances where inverse association was demonstrated, such as decreased risk of liver cancer with high intake of added fructose, there may have been an unidentified confounder.

2. Sugar-sweetened beverage intake and cancer recurrence and survival in CALGB 89803 Fuchs MA, Sato K, Niedzwiecki D, et al. (2014) Overview and Methods: Assessed association between sugar-sweetened beverage consumption on cancer recurrence and mortality by using food frequency questionnaires. Subjects: 1,011 stage III colon cancer patients

2. Sugar-sweetened beverage intake and cancer recurrence and survival in CALGB 89803 Fuchs MA, Sato K, Niedzwiecki D, et al. (2014) Overview and Methods : All subjects participated in CALGB: National Cancer Institute-sponsored Cancer and Leukemia Group B (CALGB) Food Frequency Questionnaires addressed 113 foods and had space to write in additional foods that weren’t listed. It addressed sugar sweetened beverage consumption by asking about frequency: from less than twice per month to greater than 2 times per day.

2. Sugar-sweetened beverage intake and cancer recurrence and survival in CALGB 89803 Fuchs MA, Sato K, Niedzwiecki D, et al. (2014) Results: Patients consuming more than 2 servings of sugar sweetened beverages per day had a greater risk or recurrence or mortality (1.67) than those who consumed sugar sweetened beverages less than 2 times per month. Rates of cancer recurrence or mortality were greater in patients that had a body mass index above 25 kg/m2 combined with decreased physical activity. There was no significant difference in whether it was soda or kool-aid as long as it was a sugar- sweetened beverage.

2. Sugar-sweetened beverage intake and cancer recurrence and survival in CALGB 89803 Fuchs MA, Sato K, Niedzwiecki D, et al. (2014) Conclusions: Strengths: Participants were from a multicenter (community and academic centers) study that represented the general population well. When the researchers accounted for confounding variables such as BMI, physical activity levels, energy factors and consuming a Westernized diet the results stayed just about the same. Limitations: There could be confounding variables that weren’t accounted for. Conclusion: Patients that have stage 3 colon cancer and consume 2 or more sugar-sweetened beverages per day are at a higher risk for developing colon cancer again or dying as a result of colon cancer than patients that consume a diet much lower in sugar-sweetened beverages.

3. Sucrose, High-Sugar Foods, and Risk of Endometrial Cancer—a Population-Based Cohort Study Friberg E, Wallin A, Wolk A. (2011) Overview and Methods: This study used data from the Swedish Mammography Cohort, which included 61,226 women aged 40-74 years. Consumption of high-sugar foods (such as cookies and “sweet buns”) and total sucrose was examined in relation to endometrial cancer risk using incidence rate ratios (RR). A questionnaire inquiring about consumption frequency of 67 common food items as well lifestyle variables (exercise, smoking, use of supplements, etc.) was sent along with mammography screening invitations to all women residing in two counties of Sweden who were born between 1914 and 1948. Completed questionnaires were received from 66,651 women. A second questionnaire, inquiring about 96 food items, was mailed out to 56,030 members of the same group still living in the area in 1997. A total of 39,227 women completed both questionnaires. The study cohort was linked to the Swedish Cancer Register, Swedish In-patient Register, Swedish Death Register and Swedish Population Register in order to obtain complete and accurate records pertaining to cancer diagnoses, hysterectomy, death, or migration out of the study area, respectively.

3. Sucrose, High-Sugar Foods, and Risk of Endometrial Cancer—a Population-Based Cohort Study Friberg E, Wallin A, Wolk A. (2011) Overview and Methods: “Person-years”were calculated as a unit of time measurement between events. Person-time was calculated from January 1, 1998, through December 31, 2008. Statistical analyses included 36,773 subjects, 379,760 person-years, and 304 cases of endometrial cancer. Researchers hypothesized that a link between consumption of high-sugar foods and endometrial cancer risk may exist, based on the association of endometrial cancer with insulin resistance, hyperinsulinemia, and obesity which has been previously established.

Why “sweet buns,” specifically? The Swedish Kanelbulle is the “cousin” of the American cinnamon bun. Kanelbullar (plural form) are commonly enjoyed during fika (“fee-ka”), the daily coffee break of the Swedish. In other words, this is a food that most adults in Sweden consume on a daily basis. We have no equivalent to this in the U.S.