student profile: Mr Kenneth Daniel


Thesis work

Thesis title: Effects of Extra Virgin Olive Oil on Ulcerative Colitis

Supervisors: Luis VITETTA , Helen O'CONNOR , Maria FIATARONE SINGH

Thesis abstract:

Ulcerative Colitis (UC) is an inflammatory bowel disease (IBD) mainly affecting the superficial mucosa of the large intestine (colon) and rectum. It is a chronic, progressive condition characterised by periods of acute inflammation and remission (1, 2). Disease expression during the active phase may include a variety of symptoms including but not limited to chronic diarrhoea, rectal bleeding, urgency, abdominal pain (3), with intermittent episodes of fevers, nausea, vomiting, weight loss, and fatigue (3-5). Onset of the condition primarily occurs in youths and those in early adult ages, however presentation of the disease may occur at any age throughout the lifespan, with 5% of cases occurring in those above the age of 60. Although the disease has a low mortality rate with current interventions, it has significant influence on quality of life (6). Patients often describe a negative impact on work and leisure activities despite active therapy (5).

Medical therapy to cure the disease is not currently available due to complexities in identifying exact disease aetiology. Treatment strategies therefore focuses on the resolution of symptoms and healing of the colonic mucosa through individualized therapies which may include the use of anti-inflammatory drugs, steroids, and biologics (6, 7). Although the benefits of such therapies outweigh the risks, it should be noted that significant side effects such as impaired kidney function, osteoporosis and pancreatitis have been documented (7, 8). These effects, in addition to disease severity, tolerance, response and impact on quality of life are therefore frequent considerations in selecting individual treatment strategies, which may continuously evolve throughout the life of the disease.

Epidemiological data suggests UC is mostly prevalent in developed nations such as North America, Europe, Australia and New Zealand while being relatively uncommon in developing countries (9). The incidence of UC along with other forms of IBD in newly industrialized nations such as Asia, South America and the Middle East however has increased considerably in the past decade (10-12). Interestingly, several studies reported comparable rates of developing UC between native Europeans and second-generation migrants residing in those countries (13-15). This suggests the potential significance of environmental and lifestyle factors in UC aetiology, and may hold clues for future approaches in disease prevention and management strategies (16).

One of the strategies of interest for both UC patients and clinicians is diet, which has been identified as a risk factor for the development (2, 17) and progression (18, 19) of UC. Food intolerances and dietary restriction due to negative gastrointestinal outcomes are often reported in this cohort in (20, 21). Dietary components associated with such symptoms are highly variable between cases, however commonly implicated foods include red meat, dairy, bread, sugar, food additives, and alcohol (19, 20, 22). Certain forms of fermentable carbohydrates are another potential source of gastrointestinal symptoms, with preliminary studies of exclusion diets suggesting short term improvements (23-25). The long-term impact of such diets has not been fully investigated, and the challenges associated with adherence to dietary restrictions, variability of food reactions, and the continuous adjustment of medical therapy may pose a challenge in translating such strategies at a community level. Furthermore, the impact of such diets on intestinal inflammation and colonic mucosa has not been fully investigated beyond the improvement of transient symptoms (26).

Another potential option for dietary intervention focuses on the use of traditional diet patterns, most notably the Mediterranean Diet. In comparison to a “Western Diet”, the Mediterranean Diet is characterized by higher consumption of whole plant-based food items and lower consumption of red meat, processed foods, sugar, and refined oils (27). Prospective studies on such eating patterns have suggested its role in protecting against inflammatory processes (28) with potential applications in Ulcerative Colitis (29). Some of the protective effects observed have been attributed to the balance of fatty acids which contain a significant proportion of Oleic Acid (OA) in the diet due to the use of olive oil (30, 31). Incorporating such fats into the diet may also influence disease risk by reducing the proportion of dietary omega-6 polyunsaturated fatty acids (n-6 PUFA) which has been associated with UC incidence and active symptoms (32, 33).

Beyond observational data and prospective cohort studies of populations without IBD, the role of dietary olive oil in active UC is unclear. Acute feeding studies on experimental colitis have suggested improvements of disease outcomes (34, 35) and notable impact on gastrointestinal microflora (36, 37), however no rigorously designed human trials have been identified to date. As such, this project examines the effects of dietary fat manipulation using olive oil on the disease expression of UC. We hypothesise that olive oil consumption would influence UC disease expression, with distinct features between active disease and apparently healthy controls without IBD. The investigation of a single dietary component would allow for application across multiple dietary strategies while fulfilling a gap in evidence on the diet-disease relationship in active UC. Furthermore, outcomes from this study would inform distinctions between those with chronic gastrointestinal conditions and apparently healthy subjects and their individual response to diet therapy, which may explain the role of such approaches in managing and mitigating disease.


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2. da Silva BC, Lyra AC, Rocha R, Santana GO. Epidemiology, demographic characteristics and prognostic predictors of ulcerative colitis. World Journal of Gastroenterology : WJG. 2014;20(28):9458-67.

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11. Molodecky NA, Soon IS, Rabi DM, Ghali WA, Ferris M, Chernoff G, et al. Increasing Incidence and Prevalence of the Inflammatory Bowel Diseases With Time, Based on Systematic Review. Gastroenterology. 2012;142(1):46-54.e42.

12. Ng SC, Tang W, Ching JY, Wong M, Chow CM, Hui AJ, et al. Incidence and Phenotype of Inflammatory Bowel Disease Based on Results From the Asia-Pacific Crohn's and Colitis Epidemiology Study. Gastroenterology. 2013;145(1):158-65.e2.

13. Carr I, Mayberry JF. The effects of migration on ulcerative colitis: a three-year prospective study among Europeans and first- and second-generation South Asians in Leicester (1991–1994). American Journal Of Gastroenterology. 1999;94:2918.

14. Li X, Sundquist J, Hemminki K, Sundquist K. Risk of inflammatory bowel disease in first- and second-generation immigrants in Sweden: A nationwide follow-up study. Inflammatory Bowel Diseases. 2011;17(8):1784-91.

15. Hammer T, Lophaven SN, Nielsen KR, von Euler-Chelpin M, Weihe P, Munkholm P, et al. Inflammatory bowel diseases in Faroese-born Danish residents and their offspring: further evidence of the dominant role of environmental factors in IBD development. Alimentary Pharmacology & Therapeutics. 2017;45(8):1107-14.

16. Loftus EV. Clinical epidemiology of inflammatory bowel disease: incidence, prevalence, and environmental influences. Gastroenterology. 2004;126(6):1504-17.

17. Geerling BJ, Dagnelie PC, Badart-Smook A, Russel MG, Stockbrügger RW, Brummer RJM. Diet as a risk factor for the development of ulcerative colitis. American Journal Of Gastroenterology. 2000;95:1008.

18. Lee D, Albenberg L, Compher C, Baldassano R, Piccoli D, Lewis JD, et al. Diet in the pathogenesis and treatment of inflammatory bowel diseases. Gastroenterology. 2015;148(6):1087-106.

19. Jowett SL, Seal CJ, Pearce MS, Phillips E, Gregory W, Barton JR, et al. Influence of dietary factors on the clinical course of ulcerative colitis: a prospective cohort study. Gut. 2004;53(10):1479-84.

20. Bach U, Jensen HN, Rasmussen HH, Fallingborg J, Holst M. Dietary Habits in Patients with Ulcerative Colitis¡ªCause of Nutrient Deficiency? Food and Nutrition Sciences. 2014;Vol.05No.20:6.

21. Casanova MJ, Chaparro M, Molina B, Merino O, Nuevo-Siguairo OK, Dueñas-Sadornil C, et al. Prevalence of Malnutrition and Nutritional Characteristics of Patients With Inflammatory Bowel Disease (IBD). Gastroenterology. 2017;150(4):S89.

22. Jowett SL, Seal CJ, Phillips E, Gregory W, Barton JR, Welfare MR. Dietary beliefs of people with ulcerative colitis and their effect on relapse and nutrient intake. Clinical Nutrition. 2004;23(2):161-70.

23. Hou JK, Lee D, Lewis J. Diet and inflammatory bowel disease: review of patient-targeted recommendations. Clin Gastroenterol Hepatol. 2014;12(10):1592-600.

24. Cox SR, Prince AC, Myers CE, Irving PM, Lindsay JO, Lomer MC, et al. Fermentable carbohydrates (FODMAPs) exacerbate functional gastrointestinal symptoms in patients with inflammatory bowel disease: a randomised, double-blind, placebo-controlled, cross-over, re-challenge trial. J Crohns Colitis. 2017.

25. Gearry RB, Irving PM, Barrett JS, Nathan DM, Shepherd SJ, Gibson PR. Reduction of dietary poorly absorbed short-chain carbohydrates (FODMAPs) improves abdominal symptoms in patients with inflammatory bowel disease-a pilot study. J Crohns Colitis. 2009;3(1):8-14.

26. Gibson PR. Use of the low-FODMAP diet in inflammatory bowel disease. Journal of gastroenterology and hepatology. 2017;32(S1):40-2.

27. Sue R-V, Antigone K-B, Maria Fiatarone S, Victoria MF. Evolution of Mediterranean diets and cuisine: concepts and definitions. Asia Pacific Journal of Clinical Nutrition. 2017;26(5):749-63.

28. Estruch R. Anti-inflammatory effects of the Mediterranean diet: the experience of the PREDIMED study. Proceedings of the Nutrition Society. 2010;69(3):333-40.

29. Haskey N, Gibson DL. An Examination of Diet for the Maintenance of Remission in Inflammatory Bowel Disease. Nutrients. 2017;9(3).

30. de Silva PSA, Luben R, Shrestha SS, Welch A, Khaw K, Hart AR. OC-014?Dietary oleic acid protects against the development of ulcerative colitis: a UK prospective cohort study using data from food diaries. Gut. 2010;59(Suppl 1):A6-A.

31. Shores DR, Binion DG, Freeman BA, Baker PRS. New Insights into the Role of Fatty Acids in the Pathogenesis and Resolution of Inflammatory Bowel Disease. Inflammatory bowel diseases. 2011;17(10):2192-204.

32. Tjonneland A, Overvad K, Bergmann MM, Nagel G, Linseisen J, Hallmans G, et al. Linoleic acid, a dietary n-6 polyunsaturated fatty acid, and the aetiology of ulcerative colitis: a nested case-control study within a European prospective cohort study. Gut. 2009;58(12):1606-11.

33. Richman E, Rhodes JM. Review article: evidence-based dietary advice for patients with inflammatory bowel disease. Alimentary Pharmacology & Therapeutics. 2013;38(10):1156-71.

34. Sánchez-Fidalgo S, Cárdeno A, Sánchez-Hidalgo M, Aparicio-Soto M, Villegas I, Rosillo MA, et al. Dietary unsaponifiable fraction from extra virgin olive oil supplementation attenuates acute ulcerative colitis in mice. European Journal of Pharmaceutical Sciences. 2013;48(3):572-81.

35. Takashima T, Sakata Y, Iwakiri R, Shiraishi R, Oda Y, Inoue N, et al. Feeding with olive oil attenuates inflammation in dextran sulfate sodium-induced colitis in rat. The Journal of Nutritional Biochemistry. 2014;25(2):186-92.

36. Patterson E, O' Doherty RM, Murphy EF, Wall R, O' Sullivan O, Nilaweera K, et al. Impact of dietary fatty acids on metabolic activity and host intestinal microbiota composition in C57BL/6J mice. British Journal of Nutrition. 2014;111(11):1905-17.

37. Hidalgo M, Prieto I, Abriouel H, Cobo A, Benomar N, Gálvez A, et al. Effect of virgin and refined olive oil consumption on gut microbiota. Comparison to butter. Food Research International. 2014;64:553-9.

Note: This profile is for a student at the University of Sydney. Views presented here are not necessarily those of the University.