Background & Aims

Dietary restriction of fermentable carbohydrates (a low FODMAP diet) has been reported to reduce symptoms in some patients with irritable bowel syndrome (IBS). We performed a randomized, placebo-controlled study to determine its effects on symptoms and the fecal microbiota in patients with IBS.

Methods

We performed a 2×2 factorial trial of 104 patients with IBS (18–65 years old), based on the Rome III criteria, at 2 hospitals in the United Kingdom. Patients were randomly assigned (blinded) to groups given counselling to follow a sham diet or diet low in FODMAPs for 4 weeks, along with a placebo or multistrain probiotic formulation, resulting in 4 groups (27 receiving sham diet/placebo, 26 receiving sham diet/probiotic, 24 receiving low FODMAP diet /placebo, and 27 receiving low FODMAP diet/probiotic). The sham diet restricted a similar number of staple and non-staple foods as the low FODMAP diet; the diets had similar degrees of difficulty to follow. Dietary counselling was given to patients in all groups and data on foods eaten and compliance were collected. The incidence and severity of 15 gastrointestinal symptoms and overall symptoms were measured daily for 7 days before the study period; along with stool frequency and consistency. At baseline, global and individual symptoms were measured, along with generic and disease-specific health-related quality of life, using standard scoring systems. All data were collected again at 4 weeks, and patients answered questions about adequate symptom relief. Fecal samples were collected at baseline and after 4 weeks and analyzed by quantitative PCR and 16S rRNA sequencing. The co-primary endpoints were adequate relief of symptoms and stool Bifidobacterium species abundance at 4 weeks.

Results

There was no significant interaction between the interventions in adequate relief of symptoms (P = .52) or Bifidobacterium species (P = .68). In the intention-to-treat analysis, a higher proportion of patients in the low FODMAP diet had adequate symptom relief (57%) than in the sham diet group (38%), although the difference was not statistically significant (P = .051). In the per-protocol analysis, a significantly higher proportion of patients on the low FODMAP diet had adequate symptom relief (61%) than in the sham diet group (39%) (P = .042). Total mean IBS-Severity Scoring System score was significantly lower for patients on the low FODMAP diet (173 ± 95) than the sham diet (224 ± 89) (P = .001), but not different between those given probiotic (207 ± 98) or placebo (192 ± 93) (P = .721) Abundance of Bifidobacterium species was lower in fecal samples from patients on the low FODMAP diet (8.8 rRNA genes/g) than patients on the sham diet (9.2 rRNA genes/g) (P = .008), but higher in patients given probiotic (9.1 rRNA genes/g) than patients given placebo (8.8 rRNA genes/g) (P = .019). There was no effect of the low FODMAP diet on microbiota diversity in fecal samples.

Conclusions

In a placebo-controlled study of patients with IBS, a low FODMAP diet associates with adequate symptom relief and significantly reduced symptom scores compared with placebo. It is not clear whether changes resulted from collective FODMAP restriction or removal of a single component, such as lactose. Co-administration of the multistrain probiotic increased numbers of Bifidobacterium species, compared with placebo, and might be given to restore these bacteria to patients on a low FODMAP diet. Trial registration no: ISRCTN02275221.

中文翻译：

---

低 FODMAP 饮食可减轻肠易激综合征患者的症状，益生菌可恢复双歧杆菌：一项随机对照试验

背景与目标

据报道，限制可发酵碳水化合物的饮食（低 FODMAP 饮食）可减轻一些肠易激综合征 (IBS) 患者的症状。我们进行了一项随机、安慰剂对照研究，以确定其对 IBS 患者症状和粪便微生物群的影响。

方法

我们根据罗马 III 标准，在英国的 2 家医院对 104 名 IBS 患者（18-65 岁）进行了 2×2 析因试验。患者被随机分配（盲法）至接受假饮食或低 FODMAP 饮食 4 周的咨询组，同时服用安慰剂或多菌株益生菌制剂，分为 4 组（27 人接受假饮食/安慰剂，26 人接受假饮食/益生菌，24 人接受低 FODMAP 饮食/安慰剂，27 人接受低 FODMAP 饮食/益生菌）。假饮食限制了与低 FODMAP 饮食相似数量的主食和副食；饮食的难度相似。对所有组的患者进行了饮食咨询，并收集了所吃食物和依从性的数据。研究期间前 7 天每天测量 15 种胃肠道症状和总体症状的发生率和严重程度；以及大便频率和稠度。在基线时，使用标准评分系统测量整体和个体症状，以及一般和特定疾病的健康相关生活质量。在 4 周时再次收集所有数据，患者回答有关症状是否充分缓解的问题。在基线和 4 周后收集粪便样本，并通过定量 PCR 和 16S rRNA 测序进行分析。共同主要终点是 4 周时症状和粪便双歧杆菌物种丰度的充分缓解。以及使用标准评分系统的通用和特定疾病的健康相关生活质量。在 4 周时再次收集所有数据，患者回答有关症状是否充分缓解的问题。在基线和 4 周后收集粪便样本，并通过定量 PCR 和 16S rRNA 测序进行分析。共同主要终点是 4 周时症状和粪便双歧杆菌物种丰度的充分缓解。以及使用标准评分系统的通用和特定疾病的健康相关生活质量。在 4 周时再次收集所有数据，患者回答有关症状是否充分缓解的问题。在基线和 4 周后收集粪便样本，并通过定量 PCR 和 16S rRNA 测序进行分析。共同主要终点是 4 周时症状和粪便双歧杆菌物种丰度的充分缓解。

结果

充分缓解症状 ( P = .52) 或双歧杆菌 ( P = .68)的干预措施之间没有显着的相互作用。在意向治疗分析中，低 FODMAP 饮食组患者症状缓解充分的比例（57%）高于假饮食组（38%），尽管差异无统计学意义（P = .051 ） ）。在符合方案分析中，低 FODMAP 饮食的患者有足够的症状缓解 (61%) 明显高于假饮食组 (39%) ( P = .042)。低 FODMAP 饮食 (173 ± 95) 患者的 IBS 严重程度评分系统总平均评分显着低于假饮食 (224 ± 89) ( P= .001)，但在给予益生菌 (207 ± 98) 或安慰剂 (192 ± 93) 之间没有差异 ( P = .721) 低 FODMAP 饮食患者的粪便样本中双歧杆菌的丰度较低（8.8 个 rRNA 基因/g) 高于假饮食患者 (9.2 rRNA 基因/g) ( P = .008)，但益生菌患者 (9.1 rRNA 基因/g) 高于安慰剂患者 (8.8 rRNA 基因/g) ( P = .019)。低 FODMAP 饮食对粪便样本中的微生物群多样性没有影响。

结论

在一项针对 IBS 患者的安慰剂对照研究中，与安慰剂相比，低 FODMAP 饮食与充分的症状缓解和显着降低的症状评分相关。目前尚不清楚变化是由于集体 FODMAP 限制还是去除单一成分（如乳糖）引起的。与安慰剂相比，多菌株益生菌的共同给药增加了双歧杆菌种类的数量，并且可能用于将这些细菌恢复到低 FODMAP 饮食的患者中。试用注册号：ISRCTN02275221。