By age 60, two-thirds of all Americans will have developed diverticulosis.[i] Twenty-five percent of patients with diverticulosis will go on to develop acute diverticulitis. This imposes a significant burden on healthcare systems, resulting in greater than 300,000 admissions per year with an estimated annual cost of $3 billion.[ii]
Back in 1979, a research article in the British journal, the Lancet, reported that the prevalence of diverticular disease in vegetarians was almost one third that of meat eaters. It was noted in this study that vegetarians had a mean intake of fiber of 42gm/day vs. 21 gm/day for meat eaters.[iii]
More recently, in a more detailed British study, the relative risk of diverticular disease of diverticular disease was 27% (0.58 to 0.920) less for vegetarians and 72% less for vegans (0.10 to 0.74) compared to meat eaters.[iv] Dietary fiber was also determined to be an independent factor, reducing the relative risk of diverticular disease by 41% for those consuming the most. Other important variables were obesity, hypertension, cigarette smoking, hormone replacement therapy and oral contraceptives.
The reasons vegetarians, and especially vegans, have lower rates of diverticular disease may be their higher fiber intake, and a lower incidence of other risk factors such as obesity and hypertension. It also may be reasonably hypothesized that the properties of plant foods (the phytonutrients they contain), and the healthier and less inflammatory intestinal flora that vegetarians and especially vegans have, contribute significantly to their reduced incidence of diverticulosis and diverticulitis and its complications.[v]
We think it’s important for clinicians and researchers alike to be aware of the full spectrum of diseases that a plant-based diet can help prevent and treat. The etiology for diverticular disease may be more complicated than once thought. However, the clinical implications of the research so far indicates that a plant-based, or vegan diet, that emphasizes high fiber, especially insoluble fiber, would be indicated.[vi]
[i] M.H. Floch and I Bina. 2004. The natural history of diverticulitis: fact and theory. Journal of Clinical Gastroenterology 38(5 Suppl):S2-7
[ii] Amit K Agarwal, Burzeen E Karanjawala, Justin A Maykel, Eric K Johnson, Scott R Steele Routine colonic endoscopic evaluation following resolution of acute diverticulitis: Is it necessary? World J Gastroenterol 2014 September 21; 20(35): 12509-12516
[iii] Gear JS, Ware A, Fursdon P, Mann JI, Nolan DJ, Brodribb AJ, Vessey MP. Symptomless diverticular disease and intake of dietary fibre. Lancet. 1979 Mar 10;1(8115):511-4.
[iv] Crowe FL, Appleby PN, Allen NE, Key TJ. Diet and risk of diverticular disease in Oxford cohort of European Prospective Investigation into Cancer and Nutrition (EPIC): prospective study of British vegetarians and non-vegetarians. BMJ. 2011 Jul 19;343:d4131.
[v] Kim MS, Hwang SS, Park EJ, Bae JW. Strict vegetarian diet improves the risk factors associated with metabolic diseases by modulating gut microbiota and reducing intestinal inflammation. Environ Microbiol Rep. 2013 Oct;5(5):765-75.
[vi] Aldoori W, Ryan-Harshman M Preventing diverticular disease. Review of recent evidence on high-fibre diets. Can Fam Physician. 2002 Oct;48:1632-7.