1. by Island RDN: Ayla Shaw MS, Registered Dietitian Nutritionist
Dissecting the Relationship between Dietary Fiber Intake and Cancer Risk
by Island RDN: Ayla Shaw MS, Registered Dietitian Nutritionist

2. Dissecting the Relationship between Dietary Fiber Intake and Cancer Risk
The Gut Microbiome
Fiber & Cancer Prevention

3. What is Dietary Fiber?

4. Dietary Fiber Indigestible Carbohydrate Plant-foods
Beans and Legumes
Fruits
Vegetables
Whole grains
RDA: grams per day

5. Dietary Fiber Soluble Insoluble Draws water into GI tract
Loosens stools
Fruits, Vegetables, Grains
Products with added fiber
Inulin
Chicory Root
Absorbs water
Adds bulk to stool
Binds Cholesterol
Beta-Glucans

6. Average Dietary Fiber Intake between Countries
1. Mertens, Elly, et al. “Geographic and Socioeconomic Diversity of Food and Nutrient Intakes: A Comparison of Four European Countries.” European Journal of Nutrition, Mar. 2018, pp. 1–19. link.springer.com, doi: /s
2. McGill, Carla R., et al. “Ten-Year Trends in Fiber and Whole Grain Intakes and Food Sources for the United States Population: National Health and Nutrition Examination Survey 2001–2010.” Nutrients, vol. 7, no. 2, Feb. 2015, pp. 1119–30. PubMed Central, doi: /nu

7. The Gut Microbiome

8. The Gut Microbiome Microbes 30 trillion bacterial cells
Funji
Viruses
30 trillion bacterial cells
Every person’s microbiome is slightly different
Fingerprint
Sender R, Fuchs S, Milo R. Revised Estimates for the Number of Human and Bacteria Cells in the Body. PLoS Biol Aug 19;14(8):e

9. What’s the difference? Prebiotic Probiotic Indigestible fiber
Provides energy and nutrients to probiotics
Beneficial Microbes
Living organism that use prebiotics for fuel

10. Altered gut bacteria have been linked to several diseases
Inflammatory bowel disease
Irritable bowel syndrome
Obesity
Type 2 diabetes
Cancer

11. Fiber and Cancer Risk

12. Fruit, Vegetable, and Fiber Intake in Relation to Cancer Risk: Findings from the European Prospective Investigation into Cancer and Nutrition (EPIC)
EPIC STUDY
Over 500,000 participants in 10 Countries
Colorectal, Liver, and Breast Cancer Risk inversely associated with fiber intake
Bradbury, Kathryn E., et al. “Fruit, Vegetable, and Fiber Intake in Relation to Cancer Risk: Findings from the European Prospective Investigation into Cancer and Nutrition (EPIC).” The American Journal of Clinical Nutrition, vol. 100 Suppl 1, July 2014, pp. 394S-8S. PubMed, doi: /ajcn

13. Dietary and Lifestyle Factors Associated with Colorectal Cancer Risk and Interactions with Microbiota: Fiber, Red or Processed Meat and Alcoholic Drinks
Mini-review assesses dietary pattern versus individual nutrients
Positive relationships between fiber and health gut microbiome
Supports recommendations of high fiber diet along with limited consumption of red meat and alcohol
Tuan, Juan, and Ying-Xuan Chen. “Dietary and Lifestyle Factors Associated with Colorectal Cancer Risk and Interactions with Microbiota: Fiber, Red or Processed Meat and Alcoholic Drinks.” Gastrointestinal Tumors, vol. 3, no. 1, Sept. 2016, pp. 17–24. PubMed, doi: /

14. Dietary Fiber for the Prevention of Recurrent Colorectal Adenomas and Carcinomas
Meta-analysis of seven studies with 4798 participants
Purpose: Assess the effect of dietary fiber on the recurrence of colorectal cancer
Results found lack of evidence to suggest that increased dietary fiber intake will reduce the risk of recurrence
Yao, Yibo, et al. “Dietary Fibre for the Prevention of Recurrent Colorectal Adenomas and Carcinomas.” The Cochrane Database of Systematic Reviews, vol. 1, , p. CD PubMed, doi: / CD pub2.

15. Dietary Fiber Intake in Young Adults and Breast Cancer Risk
90,534 participants for 20 years
44,263 participants for 10+ years
Early adulthood total dietary fiber intake was associated with significantly lower breast cancer risk
Farvid, Maryam S., et al. “Dietary Fiber Intake in Young Adults and Breast Cancer Risk.” Pediatrics, vol. 137, no. 3, Mar. 2016, p. e PubMed, doi: /peds

16. Dietary Fiber Intake and Risk of Breast Cancer: A Systematic Review and Meta-analysis of Epidemiological Studies
Review of twenty-four epidemiologic studies
Population-based studies across multiple countries
Higher dietary fiber reduced risk of breast cancer
Particularly in postmenopausal women
Chen, Sumei, et al. “Dietary Fibre Intake and Risk of Breast Cancer: A Systematic Review and Meta-Analysis of Epidemiological Studies.” Oncotarget, vol. 7, no. 49, Dec. 2016, pp –89. PubMed, doi: /oncotarget

17. Intake of Bean Fiber, Beans, and Grains and Reduced Risk of Hormone Receptor-Negative Breast Cancer: The San Francisco Bay Area Breast Cancer Study.
ER‐PR breast cancer
An aggressive subtype
Few risk factors have been identified
Analyzed food frequency data from 2135 breast cancer cases
High intake of bean fiber & fiber‐rich foods may lower the risk of ER-PR
Sangaramoorthy, Meera, et al. “Intake of Bean Fiber, Beans, and Grains and Reduced Risk of Hormone Receptor-Negative Breast Cancer: The San Francisco Bay Area Breast Cancer Study.” Cancer Medicine, vol. 7, no. 5, May 2018, pp. 2131–44. PubMed, doi: /cam

18. Dietary Fiber and Other Cancers
Pancreatic Cancer
Better diet quality is associated with reduced risk
Endometrial Cancer
Inconlusive
Head and Neck Cancer
Greater intake of fiber may lower risk.
Zheng, Jiali, et al. “Dietary Patterns and Risk of Pancreatic Cancer: A Systematic Review.” Nutrition Reviews, vol. 75, no. 11, Nov. 2017, pp. 883–908. PubMed, doi: /nutrit/nux038.
Chen, Kangning, et al. “Dietary Fiber Intake and Endometrial Cancer Risk: A Systematic Review and Meta-Analysis.” Nutrients, vol. 10, no. 7, July PubMed, doi: /nu
Kawakita, Daisuke, et al. “Dietary Fiber Intake and Head and Neck Cancer Risk: A Pooled Analysis in the International Head and Neck Cancer Epidemiology Consortium.” International Journal of Cancer, vol. 141, no. 9, , pp. 1811–21. PubMed, doi: /ijc

19. Conclusion Single nutrient vs diet pattern
Disease Risk vs Cause-and-effect
Objective methods for measuring intake
More RCT needed into “Mediterranean-style” diet

20. QUESTIONS?