Dale Lee

Diet in the Pathogenesis and Treatment of Inflammatory Bowel Diseases

Some of the most common symptoms of the inflammatory bowel diseases (IBD, which include ulcerative colitis and Crohns disease) are abdominal pain, diarrhea, and weight loss. It is therefore not surprising that clinicians and patients have wondered whether dietary patterns influence the onset or course of IBD. The question of what to eat is among the most commonly asked by patients, and among the most difficult to answer for clinicians. There are substantial variations in dietary behaviors of patients and recommendations for them, although clinicians do not routinely endorse specific diets for patients with IBD. Dietary clinical trials have been limited by their inability to include a placebo control, contamination of study groups, and inclusion of patients receiving medical therapies. Additional challenges include accuracy of information on dietary intake, complex interactions between foods consumed, and differences in food metabolism among individuals. We review the roles of diet in the etiology and management of IBD based on plausible mechanisms and clinical evidence. Researchers have learned much about the effects of diet on the mucosal immune system, epithelial function, and the intestinal microbiome; these findings could have significant practical implications. Controlled studies of patients receiving enteral nutrition and observations made from patients on exclusion diets have shown that components of whole foods can have deleterious effects for patients with IBD. Additionally, studies in animal models suggested that certain nutrients can reduce intestinal inflammation. In the future, engineered diets that restrict deleterious components but supplement beneficial nutrients could be used to modify the luminal intestinal environment of patients with IBD; these might be used alone or in combination with immunosuppressive agents, or as salvage therapy for patients who do not respond or lose responsiveness to medical therapies. Stricter diets might be required to induce remission, and more sustainable exclusion diets could be used to maintain long-term remission.

Diet and Inflammatory Bowel Disease: Review of Patient-Targeted Recommendations

Patients have strong beliefs about the role of diet in the cause of inflammatory bowel disease (IBD) and in exacerbating or alleviating ongoing symptoms from IBD. The rapid increase in the incidence and prevalence of IBD in recent decades strongly suggests an environmental trigger for IBD, one of which may be dietary patterns. There are several pathways where diet may influence intestinal inflammation, such as direct dietary antigens, altering the gut microbiome, and affecting gastrointestinal permeability. However, data that altering diet can change the natural history of IBD are scarce, and evidence-based dietary guidelines for patients with IBD are lacking. Patients, therefore, seek nonmedical resources for dietary guidance, such as patient support groups and unverified sources on the Internet. The aim of this review is to identify patient-targeted dietary recommendations for IBD and to critically appraise the nutritional value of these recommendations. We review patient-targeted dietary information for IBD from structured Internet searches and popular defined diets. Patient-targeted dietary recommendations focus on food restrictions and are highly conflicting. High-quality dietary intervention studies are needed to facilitate creation of evidence-based dietary guidelines for patients with IBD.

Lean mass deficits, vitamin D status and exercise capacity in children and young adults after Fontan palliation

Objective We sought to evaluate body composition in children and young adults with Fontan physiology. Leg lean mass (LM) deficits correlate with diminished exercise capacity in other populations and may contribute to exercise limitations in this cohort. Methods This cross-sectional study included whole body dual energy X-ray absorptiometry scans in 50 Fontan participants ≥5 years, and measures of peak oxygen consumption (VO2) in 28. Whole body and leg LM (a measure of skeletal muscle) were converted to sex- and race-specific Z-scores, relative to age and stature, based on 992 healthy reference participants. Results Median age was 11.5 (range 5.1–33.5) years at 9.3 (1.1–26.7) years from Fontan. Height Z-scores were lower in Fontan compared with reference participants (−0.47±1.08 vs 0.25±0.93, p<0.0001). Body mass index Z-scores were similar (0.15±0.98 vs 0.35±1.02, p=0.18). LM Z-scores were lower in Fontan compared with reference participants (whole body LM −0.33±0.77 vs 0.00±0.74, p=0.003; leg LM −0.89±0.91 vs 0.00±0.89, p<0.0001). LM Z-scores were not associated with age or Fontan characteristics. Leg LM Z-scores were lower in vitamin D deficient versus sufficient Fontan participants (−1.47±0.63 vs −0.71±0.92, p=0.01). Median per cent predicted peak VO2 was 81% (range 13%–113%) and was associated with leg LM Z-scores (r=0.54, p=0.003). Conclusions Following Fontan, children and young adults are shorter than their peers and have significant LM deficits. Skeletal muscle deficits were associated with vitamin D deficiency and reduced exercise capacity. Future studies should examine the progression of these deficits to further understand the contribution of peripheral musculature to Fontan exercise capacity.

The Benefit to Risk Balance of Combining Infliximab with Azathioprine Varies With Age: A Markov Model

BACKGROUND & AIMS Combination therapy with infliximab and azathioprine has demonstrated benefit over monotherapy for moderate-to-severe Crohns disease. Clinical trials and models have not accounted for age-specific risks associated with these therapies, including the risk of immunosuppression-related cancer and infection. After accounting for these risks, the strategy yielding the greatest benefit may vary with age. METHODS We assessed age-specific risks and benefits of combination therapy compared with infliximab monotherapy by using Markov modeling. The base case was a 35-year-old male patient with a 1-year time horizon. We assumed the incidence of lymphoma to be 5.28-fold higher with combination therapy. Secondary analyses accounted for life expectancy, therapy beyond 1 year, and age-specific surgical and infection risks. Quality-adjusted life years (QALYs) were calculated for 25- to 75-year old individuals. RESULTS Combination therapy was found to be of greater benefit in the base case (0.7522 QALYs for combination therapy vs 0.7426 QALYs for monotherapy). Accounting for life years lost, monotherapy was the best approach if the hazard ratio for lymphoma with combination therapy was >8.1 patients who were 75 years old. Monotherapy provided greater net benefit to patients 55, 65, or 75 years old if therapy was extended for 9, 7, or 5 years, respectively. For 25-year-old men, monotherapy resulted in fewer deaths but only yielded greater QALYs if the annual incidence of hepatosplenic T-cell lymphoma exceeded 36/100,000 persons. CONCLUSIONS After accounting for age-specific risks of lymphoma, infection, and surgical complications, benefits of combination therapy outweighed the risks as a short-term and intermediate-term strategy for most patients with moderate-to-severe Crohns disease who were younger than 65 years. For young male patients, combination therapy yields greater QALYs but at cost of an increased risk of death from lymphoma.

Effect of Low‐Magnitude Mechanical Stimuli on Bone Density and Structure in Pediatric Crohn's Disease: A Randomized Placebo‐Controlled Trial

Pediatric Crohns Disease (CD) is associated with low trabecular bone mineral density (BMD), cortical area, and muscle mass. Low‐magnitude mechanical stimulation (LMMS) may be anabolic. We conducted a 12‐month randomized double‐blind placebo‐controlled trial of 10 minutes daily exposure to LMMS (30 Hz frequency, 0.3 g peak‐to‐peak acceleration). The primary outcomes were tibia trabecular BMD and cortical area by peripheral quantitative CT (pQCT) and vertebral trabecular BMD by QCT; additional outcomes included dual‐energy X‐ray absorptiometry (DXA) whole body, hip and spine BMD, and leg lean mass. Results were expressed as sex‐specific Z‐scores relative to age. CD participants, ages 8 to 21 years with tibia trabecular BMD <25th percentile for age, were eligible and received daily cholecalciferol (800 IU) and calcium (1000 mg). In total, 138 enrolled (48% male), and 121 (61 active, 60 placebo) completed the 12‐month trial. Median adherence measured with an electronic monitor was 79% and did not differ between arms. By intention‐to‐treat analysis, LMMS had no significant effect on pQCT or DXA outcomes. The mean change in spine QCT trabecular BMD Z‐score was +0.22 in the active arm and –0.02 in the placebo arm (difference in change 0.24 [95% CI 0.04, 0.44]; p = 0.02). Among those with >50% adherence, the effect was 0.38 (95% CI 0.17, 0.58, p < 0.0005). Within the active arm, each 10% greater adherence was associated with a 0.06 (95% CI 0.01, 1.17, p = 0.03) greater increase in spine QCT BMD Z‐score. Treatment response did not vary according to baseline body mass index (BMI) Z‐score, pubertal status, CD severity, or concurrent glucocorticoid or biologic medications. In all participants combined, height, pQCT trabecular BMD, and cortical area and DXA outcomes improved significantly. In conclusion, LMMS was associated with increases in vertebral trabecular BMD by QCT; however, no effects were observed at DXA or pQCT sites.

Serum Infliximab, Antidrug Antibodies, and Tumor Necrosis Factor Predict Sustained Response in Pediatric Crohn's Disease.

Background:Serum infliximab (s-IFX) levels, antibodies to IFX (ATI), and inflammatory markers are important in predicting clinical outcomes in adults, but their roles in pediatric Crohns disease (CD) require further study. The primary aim of this study was to determine the association between serologic parameters during induction and ongoing IFX therapy at 12 months in pediatric CD. Methods:S-IFX, ATI, serum tumor necrosis factor alpha (s-TNF-&agr;), and C-reactive protein were measured at IFX initiation, 10 weeks, 6 months, and 12 months in a prospective cohort study of children with CD at a single tertiary care center. Results:At 12 months, 60 of 77 participants (78%) remained on IFX. Participants who completed 12 months of IFX had higher 10-week median s-IFX levels (20.40 &mgr;g/mL; interquartile range [IQR], 11.20–35.00] versus 8.70 &mgr;g/mL; IQR 0.90–16.90; P = 0.01), a greater proportion with undetectable 10-week ATI (P = 0.008), and a greater median change in s-TNF-&agr; between baseline and week 10 (−5.96 pg/mL; IQR, −8.73 to −4.17 versus −1.76 pg/mL; IQR, −5.60 to 0.30; P = 0.006). Receiver operating characteristic analysis to predict ongoing IFX at 12 months showed area under the curve (95% confidence interval) for 10-week s-IFX and change in s-TNF-&agr; from baseline to 10 weeks to be 0.71 (0.54–0.88) and 0.74 (0.58–0.91), respectively. C-reactive protein was not associated with ongoing therapy. Conclusions:ATI, s-IFX, and s-TNF-&agr; during IFX induction are associated with 12-month clinical outcomes in pediatric CD. Future studies are needed to further define the clinical role of s-TNF-&agr; measurement and to compare the clinical utility of 10 and 14-week ATI and s-IFX levels.

Ustekinumab in Pediatric Crohn Disease Patients.

Objectives: We describe the use of ustekinumab for 4 patients with pediatric Crohn disease treated at the Seattle Childrens Hospital Inflammatory Bowel Disease Center. Methods: A retrospective chart review was done to identify patients’ clinical data, disease phenotype, treatment history, and laboratory and growth parameters before treatment with ustekinumab and at last follow-up. Adverse events while on ustekinumab were also recorded. Results: Four adolescent patients with Crohn disease at our center received ustekinumab. All had previously received corticosteroids, methotrexate, azathioprine/6-mercaptopurine, and both infliximab and adalimumab. Patients had varying disease phenotypes. Ages at ustekinumab initiation were 12, 13, 16, and 17 years. Weight ranged from 40.5 to 57.8 kg, mean 49.5 kg. Two patients showed clinical response and remain on ustekinumab. Two patients discontinued therapy because of continued symptoms and disease complications and required multiple hospitalizations. Conclusions: Ustekinumab was used in 4 children with pediatric Crohn disease with 2 of 4 patients showing clinical response (1 with persistently elevated C-reactive protein). A prospective study is needed to define its efficacy, safety, and placement in managing pediatric Crohn disease in the future.

Clinical and Fecal Microbial Changes With Diet Therapy in Active Inflammatory Bowel Disease.

Goal: To determine the effect of the specific carbohydrate diet (SCD) on active inflammatory bowel disease (IBD). Background: IBD is a chronic idiopathic inflammatory intestinal disorder associated with fecal dysbiosis. Diet is a potential therapeutic option for IBD based on the hypothesis that changing the fecal dysbiosis could decrease intestinal inflammation. Study: Pediatric patients with mild to moderate IBD defined by pediatric Crohn’s disease activity index (PCDAI 10-45) or pediatric ulcerative colitis activity index (PUCAI 10-65) were enrolled into a prospective study of the SCD. Patients started SCD with follow-up evaluations at 2, 4, 8, and 12 weeks. PCDAI/PUCAI, laboratory studies were assessed. Results: Twelve patients, ages 10 to 17 years, were enrolled. Mean PCDAI decreased from 28.1±8.8 to 4.6±10.3 at 12 weeks. Mean PUCAI decreased from 28.3±23.1 to 6.7±11.6 at 12 weeks. Dietary therapy was ineffective for 2 patients while 2 individuals were unable to maintain the diet. Mean C-reactive protein decreased from 24.1±22.3 to 7.1±0.4 mg/L at 12 weeks in Seattle Cohort (nL<8.0 mg/L) and decreased from 20.7±10.9 to 4.8±4.5 mg/L at 12 weeks in Atlanta Cohort (nL<4.9 mg/L). Stool microbiome analysis showed a distinctive dysbiosis for each individual in most prediet microbiomes with significant changes in microbial composition after dietary change. Conclusions: SCD therapy in IBD is associated with clinical and laboratory improvements as well as concomitant changes in the fecal microbiome. Further prospective studies are required to fully assess the safety and efficacy of dietary therapy in patients with IBD.

The Importance and Challenges of Dietary Intervention Trials for Inflammatory Bowel Disease.

Abstract: Inflammatory bowel disease is believed to be caused by a combination of genetic and environmental stimuli such as our diet. Diets high in meat and fats and low in fruits and vegetables have been associated with new-onset inflammatory bowel disease. This has triggered interest in using dietary modification as a treatment. The 3 principle models of dietary intervention are supplementation with selected dietary components, exclusion of selected dietary components, or use of dietary formulas in place of a normal diet. Despite the high level of interest in dietary interventions as a treatment for inflammatory bowel disease, few well-designed clinical trials have been conducted to firmly establish the optimal diet to induce or maintain remission. This may be in part related to the challenges of conducting dietary intervention trials. This review examines these challenges and potential approaches to be used in dietary intervention trials.

Nutritional Adequacy of the Specific Carbohydrate Diet in Pediatric Inflammatory Bowel Disease

Introduction: The specific carbohydrate diet (SCD) is an exclusion diet used as a therapy in inflammatory bowel disease. The aim of this study was to evaluate the nutritional adequacy of the SCD. Methods: Prospective dietary data for 12 weeks were analyzed for pediatric patients on the SCD. Intake of 20 key nutrients was compared to dietary recommended intake levels and nutrient intake data from similarly aged children from The National Health and Nutrition Examination Survey National Youth Fitness Survey in 2012. Results: Nine patients enrolled, with 8 patients completing the study. Six of 8 individuals completing the study had gained weight, 1 individual had weight loss, and 1 had no change in weight. Energy intake was significantly greater than 100% of the recommended daily allowance (RDA)/adequate intake for 64% of daily intakes completed for this study. The majority of participants’ daily intakes met or exceeded the RDA for vitamins B2, B3, B5, B6, B7, B12, C, A, and E. One hundred percent of participants’ intakes were below the RDA for vitamin D. Seventy-five percent of daily intakes were less than the RDA for calcium. The upper limit was met or exceeded for magnesium in 42% of daily intakes. Average vitamin A intake was significantly greater than the upper limit (P = 0.01). Conclusions: Nutrient intake of pediatric inflammatory bowel disease patients on the SCD was adequate when compared with a healthy peer reference population, but adequacy was variable when compared with the dietary recommended intakes. Close monitoring with a multidisciplinary team for patients using the SCD as an alternative or adjunct therapy is recommend to ensure positive outcomes for overall patient health.