Both symptoms and biomarkers were measurably improved after a short period of intermittent restrictive eating practices.
A short-term calorie-restrictive diet could significantly improve physical symptoms and biological indicators of mild-to-moderate Crohn’s disease (CD), a US study has found.
Diet participants achieved significantly higher rates of clinical response and clinical remission after just three months of the diet regiment, which only required calorie restriction for five days out of each month.
The controlled clinical trial randomised 100 participants to a fasting mimicking diet (FMD) or their normal diet for three consecutive months and compared changes in CD Activity Index (CDAI) and inflammatory biomarkers between the groups.
Nearly 70% of the FMD group met the primary outcome of clinical response, defined as a reduction in CDAI of at least 70 points, compared to less than 44% of the control group.
A CDAI of 150 or less after the third diet cycle (clinical remission) was met by around 65% of the FMD group and 38% of the control group.
The diet cycle consisted of eating 700 to 1100 calories a day for five consecutive days per month and then returning to their normal diet for the remainder of the month. Plant-based meals were provided to participants for the calorie deficit periods.
Faecal calprotectin (indicative of inflammation) showed a significant change at the end of the third diet cycle, with a 22% mean reduction in the FMD group and an 8% mean increase in the control group.
Nearly 40% of the FMD group had a faecal calprotectin decline of 50% or more, compared to 6% of the control group.
The mean change in C-reactive protein from baseline was a 1% reduction in the FMD and a 37% increase in the control group, although this narrowly missed statistical significance (P = 0.06). There was no significant difference in erythrocyte sedimentation rate between the groups.
“We were very pleasantly surprised that the majority of patients seemed to benefit from this diet,” Professor Sidhartha Sinha, senior author and assistant professor of gastroenterology and hepatology at Stanford University, told media.
“We noticed that even after just one FMD cycle, there were clinical benefits.”
Authors noted that dietary interventions can be difficult to study due to the reliance on self-reporting and an inability to blind participants. However, this trial was able to demonstrate declines in objective markers of inflammation as well as symptom improvement.
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Less than half of the control group experienced improvements in their symptoms, which researchers said was likely due to natural symptom fluctuations in CD and the efficacy of their standard care and medications.
Clinical response and remission were similar between the groups following a three-month washout period after the third FMD cycle.
This loss of response suggests that the optimal number of FMD cycles required to maintain clinical benefits over extended periods is unclear and that continuing cycles may be necessary for sustained remission, the researchers explained.
Mild CD participants achieved greater clinical response from FMD than control (75% vs 48%), as did those with moderate CD (57% vs 11%).
Participants with colonic disease had a greater rate of clinical response with FMD than control diet (82% vs 33%), as did those with ileocolonic disease (71% vs 30%), but not participants with isolated ileal disease (56% vs 60%).
FMD was also more effective than control in participants who were not on any medical therapy (77% vs 33%).
Mean participant age was 45 years. At baseline, around 40% of both groups had overweight BMI. The control group had a greater proportion of participants with obesity than the FMD group (31% vs 15%) and fewer females than the FMD group (56% vs 80%).
There was no difference in therapy escalation, such as corticosteroid prescription, starting new advanced therapy or dose escalation of advanced therapy, between both groups throughout the study (28% FMD vs 25% control).
While some in the FMD group experienced fatigue and headache throughout the trial, no serious side effects were reported by any participants.
