Table 1.

Effect of diets or dietary components on the change of faecal pH or organic acids (mM) based on the literature data. pH and organic acid values are shown as difference compared to control diet or baseline period.

Diet type or food	Control diet	n*	nc*	pH	Acetate	Butyrate	Propionate	Reference
Low FODMAP	sham	21	20	0.4	−24.5	−10.2	−8.7	[23]
Low FODMAP	habitual	33		0.2	−2	−2.7	−1	[24]
Yacon (FOS, inulin)	habitual	24		−0.4	−2.9	0.5	−1.6	[27]
Inulin	habitual	32		−1	11	3	−1	[28]
Oat beta-glucan	habitual	25			12.8	2.1	2.8	[29]
High-amylose barley	Refined grain	17		−0.3	10.1	8.8	2.2	[30]
Almond	habitual	35		−0.3	−4.6	0.8	1.1	[31]
Vegan	omnivore	36	36	−0.3	0	3.3	−3.9	[32]
Wholegrain-rich	Refined grain	50		−0.1	no	0.7	no	[4]
Wheat bran (28 g/day)	habitual	13		−0	8.1	10	−2.1	[33]
Wheat bran + RS (12 + 22 g/day	habitual	20		−0.1	8.6	12	−2.4	[34]
Wheat bran fibre (30 g/day)	Low fibre	24			3.5	2.1	0.1	[35]
RS (30 g/day)	Low fibre	24			2.9	3.5	−1.2	[35]
RS rich foods (38 g/day)	Low RS (5 g/day)	11		−0.6	21	7.2	−2.5	[36]
Wheat bran extract (AXOS, 10 g/day)	placebo	57		−0.2	0.3	−0.1	0.1	[37]
AX (15 g/day)	placebo	17		0.2	6.2	2.5	0.5	[38]
Mediterranean	Western	40	31	0.3	3.7	−1.0	−1.9	[39]
Normal protein weight loss	maintenance	18		−0.2	−9	−2.9	−2	[21]
HP, low fat	habitual	11	15	0.7				[25]
HP weight loss	maintenance	18		0.1	−15.9	−9.4	−2.8	[21]
HP MC	maintenance	17		0.1	−6.2	−2.2	−3.7	[22]
HP MC	maintenance	16			−21.6	−8.8	−6.5	[26]
HP LC	maintenance	17		0.5	−22.4	−8.5	−6.4	[22]
HP LC	maintenance	18			−29.6	−13.3	−9.5	[26]
Colorectal cancer	Healthya	21	14	1				[40]
Colorectal cancer	Healthya	93	49	0.5	−10.3	−4.1	−7.1	[3]

n* and n_c* - indicates the number of participants in the study intervention group or control group, respectively. If n_c is missing it indicates to the cross-over study.

^aCompared with no CRC subjects, RS – resistant starch, AX – arabinoxylan, AXOS – arabinooligosaccharides, HP - high protein, LC - low carbs, MC - medium carbs.