Incorporation of Plant-Based Diet Surpasses Current Standards in Therapeutic Outcomes in Inflammatory Bowel Disease

Abstract

There has been no study of the therapeutic effect of a plant-based diet (PBD) in inflammatory bowel disease (IBD) except for our studies in Japan. In this review, we describe the rationale for the requirement of PBD in IBD and the outcomes of our modality incorporating PBD together with a literature review. The biggest problem in current therapy for IBD is the lack of a widely appreciated ubiquitous environmental factor in IBD. Therefore, a radical strategy against IBD has not been established. Japanese data showed an increased incidence of IBD in association with dietary westernization. Current global consumption consists of an excess of unhealthy foods and a shortage of healthy foods recognized as pro-inflammatory. Patients with IBD are no exception. One of the recommended healthy reference diets is PBD recognized as anti-inflammatory. We assert that IBD occurs in susceptible individuals mainly as a result of our omnivorous (westernized) diet. Therefore, we developed and began to provide a PBD, a lacto-ovo-vegetarian diet, for IBD patients in 2003. Infliximab and PBD as first-line (IPF) therapy was administered for all patients with newly developed Crohn's disease (CD) and for severe ulcerative colitis (UC). Our modality broke the barrier of primary nonresponders to biologics, with a remission rate of 96% in CD, and created a new relapse-free course in slightly over half of the patients (52%) with CD. Based on the rationale derived from available evidence and the clinical outcomes, PBD is highly recommended for IBD.

Keywords: Crohn’s disease; diet; inflammatory bowel disease; natural course; plant-based diet; relapse; semi-vegetarian diet; therapy; ulcerative colitis.

Figure 1

Clinical course of a 14-year-old girl with an initial attack of Crohn’s disease. KM, kanamycin; CP, chloramphenicol; TPN, total parenteral nutrition; ED, elemental diet; Fe, ferrum; BT, body temperature; TP, total protein; Alb, albumin; Hb, hemoglobin; ESR, erythrocyte sedimentation rate; CRP, C-reactive protein (reference ≤0.3 mg/dL); BW, body weight; IOIBD score, International Organization for Inflammatory Bowel Disease score.

Figure 2

An attempt to gradually replace Ensure Liquid (polymeric enteral nutrition) with ordinary food in a male student with Crohn’s disease. BE, barium enema; SF, sigmoido (fiber)scopy; CF, colono (fiber)scopy; ED, elemental diet; CRP, C-reactive protein (reference ≤0.3 mg/dL).

Figure 3

Case-control study in Crohn’s disease in Japan (CD n = 104).

Figure 4

Chronological change in dietary intake and incidence of inflammatory bowel disease in Japan. The daily intake per capita of rice, animal protein, and animal fat is shown in the upper panel based on data for 35 years from 1965 to 2000 collected in the National Nutritional Survey. The incidence of ulcerative colitis and Crohn’s disease every 5 years is shown in the lower panel.

Figure 5

Correlation between Crohn’s disease and ulcerative colitis in the annual numbers of new cases in Japan. In Japan, the national registration of ulcerative colitis cases and Crohn’s disease cases started in 1975 and 1976, respectively. A scattergram was generated based on data for 24 years from 1977 to 2000. The linear regression formula and correlation coefficient are shown.

Figure 6

Calories derived from fats, carbohydrates, and proteins as a percent of total calories according to the income of the countries, data from [25].

Figure 7

Schematic pathogenesis of inflammatory bowel disease (IBD). IBD occurs in genetically susceptible persons when triggered by environmental factors. The breadth of the arrow reflects the degree of the contributing role in the pathogenesis. The greatest environmental factor is gut dysbiosis (imbalance of gut microbiota), which is formed by a westernized diet, namely, westernized diet-associated gut dysbiosis [4] (with permission from the Permanente Federation).

Figure 8

The semi-vegetarian-diet food guide pyramid.

Figure 9

Semi-vegetarian diet (1400 kcal/day). From left to right: breakfast, lunch, and supper.

Figure 10

Protocol of infliximab and a plant-based diet as first-line (IPF) therapy.

Figure 11

Induction rate of remission with biologics in patients with Crohn’s disease (CD) who were naïve to biologics. A: Infliximab and plant-based diet (n = 44) [62] B: Infliximab and azathioprine (n = 65) [70] C: Infliximab and azathioprine (n = 169) [71] D: Infliximab (n = 41) [72] E: Adalimumab (n = 45) [73] F: Ustekinumab (n = 191) [74].

Figure 12

Roentgenograms of barium enema study during the induction phase in a 34-year-old man with severe ulcerative colitis (initial episode case) treated with infliximab and a plant-based diet as first-line (IPF) therapy. Numerous collar button ulcerations (arrows) are observed in the whole transverse colon 1 day before IPF therapy (A). They are resolved on the 13th day, 1 day before the second infliximab infusion (B). Further recovery with good distensibility is observed 1 day before the third infliximab infusion (C). HF, hepatic flexure; SF, splenic flexure.

Figure 13

Enrollment of inpatients with active Crohn’s disease (CD) for IPF therapy. IPF therapy, infliximab, and a plant-based diet as first-line therapy.

Figure 14

The relapse-free rate at 10 years after the first induction in Crohn’s disease. A: Report from Japan. Induction by infliximab and a plant-based diet as first-line therapy followed by the recommendation of adherence to a plant-based diet (n = 26) [84] B: Report from Denmark on induction by conventional therapy (n = 373) [58]. C: Report from seven European countries and Israel on induction by conventional therapy (n = 358) [59]. D: Report from Norway on induction by conventional therapy (n = 237) [60].

Figure 15

Graphic of clinical course in Crohn’s disease. Solberg et al. [60] presented four graphic clinical courses of CD: curve 1 (decrease in the severity of bowel symptoms), curve 2 (increase in the severity of bowel symptoms), curve 3 (chronic continuous bowel symptoms), and curve 4 (chronic relapsing bowel symptoms) (with permission from Elsevier). A relapse-free course was achieved in nearly half of the CD patients with infliximab and a plant-based diet as first-line (IPF) therapy (with permission from the Permanente Federation).