Table 3.

Clinical trials with FODMAP diet and BCFA levels.

References	Subjects	Intervention	Samples	Outcomes
Halmos et al., 2014 [53]	IBS patients (all subtypes, n = 27), healthy controls (n = 6)	Habitual diet	Feces	↑ Isobutyrate and isovalerate in healthy controls.
		2 groups LFD (3.05 g FODMAP). Australian diet (23.7 g).	Feces	No statistically significant difference in BCFAs among the groups.
Wilson et al., 2020 [54]	IBS patients (n = 69)	3 groups Sham diet with placebo supplement (control) (n = 23). LFD supplemented with placebo (n = 22). LFD supplemented with 1.4 g/d B-GOS (n = 24).	Feces	No statistically significant difference in isobutyrate and isovalerate in LFD with or without supplements of B-GOS.
Zhang et al., 2021 [55]	IBS-D patients (n = 100)	2 groups LFD (n = 51). TDA (n = 49).	Feces	In LFD group: ↑ Isobutyrate and isovalerate.
Nordin et al., 2023 [56]	IBS patients (n = 103)	3 groups 1. Placebo–gluten–FODMAPs (n = 35). 2. FODMAPs–placebo–gluten (n = 33). 3. Gluten–FODMAPs–placebo (n = 35).	Feces and plasma	No statistically significant difference in isobutyrate among groups (feces). ↓ Isovalerate after gluten vs. placebo. ↓ Isobutyrate after FODMAPs compared to the placebo (plasma).

LFD: low-FODMAP diet; TDA: traditional dietary advice; IBS-D: irritable bowel syndrome with diarrhea; BCFAs: branched-chain fatty acids.