Differences in dietary habits of people with vs without irritable bowel syndrome and their association with symptom and psychological status: A pilot study

Table 1 Sociodemographic characteristics, n (%)

	IBS patients (n = 25)	Non-IBS participants (n = 178)	P value
Age, yr	36.0 (29.5, 43.0)	32.0 (28.0, 38.0)	0.215
Gender, male:female	10 : 15	71 : 107	0.991
Body mass index, kg/m2a	22.31 (21.22, 23.40)a	23.50 (21.3, 26.2)	0.033
Level of educationa			0.007
Junior middle school	2 (8.0)	5 (2.8)
Senior middle school	5 (20.0)	46 (25.8)
Undergraduate	10 (40.0)	110 (61.8)
Master degree or above	8 (32)	17 (9.6)
Drinking			0.699
Yes	8 (32.0)	64 (36.0)
No	17 (68.0)	114 (64.0)
Smoking			0.753
Yes	6 (24.0)	48 (27.0)
No	19 (76.0)	130 (73.0)
Predominant bowel pattern			N/A
Diarrhea	7 (28)	N/A
Constipation	5 (20)	N/A
Mixed	9 (36)	N/A
Unclassified	4 (16)	N/A

The data are presented as the median (Q1, Q3) or numbers (percentages).

^aP < 0.05 vs controls.

IBS: Irritable bowel syndrome; N/A: Not applicable.

Table 2 Dietary habits, clinical characteristics, and psychological states of irritable bowel syndrome patients and non-irritable bowel syndrome participants, n (%)

	IBS patients	Non-IBS participants	P value
Dietary habits	n = 25	n = 110
Quantity per time (g for solid food and mL for liquid food)
Seafood	150 (100, 200)	100 (75, 150)	0.004
Soybean and its products	250 (150, 350)	200 (100, 250)	< 0.001
Spicy food	250 (150, 300)	200 (150, 250)	0.036
Dry-fried nuts	75 (50, 100)	62.5 (50, 75)	0.021
Soft drinks			< 0.001
0 mL	5 (20.0)	45 (40.9)
250 mL	9 (36.0)	54 (49.1)
500 mL	11 (44.0)	11 (10.0)
Vegetables	350 (300, 400)	250 (200, 300)	< 0.001
Fruits	250 (200, 300)	200 (150, 250)	< 0.001
Intake frequency [times per week (t/wk)]
Egg			0.019
≤ 1 t/wk	2 (8.0)	41 (37.3)
2–6 t/wk	13 (52.0)	38 (34.5)
≥ 7 t/wk	10 (40.0)	31 (28.2)
Soybean and its products			< 0.001
≤ 1 t/wk	10 (40.0)	95 (86.4)
2–6 t/wk	7 (28.0)	12 (10.9)
≥ 7 t/wk	8 (32.0)	3 (2.7)
Spicy food			0.001
≤ 1 t/wk	7 (28.0)	63 (57.3)
2–6 t/wk	7 (28.0)	33 (30.0)
≥ 7 t/wk	11 (44.0)	14 (12.7)
Barbecue			< 0.001
≤ 1 t/wk	12 (48.0)	93 (84.5)
2–6 t/wk	9 (36.0)	14 (12.7)
≥ 7 t/wk	4 (16.0)	3 (2.7)
Dry-fried nuts			< 0.001
≤ 1 t/wk	15 (60.0)	102 (92.7)
2–6 t/wk	4 (16.0)	7 (6.4)
≥ 7 t/wk	6 (24.0)	1 (0.9)
Coarse grain			0.019
≤ 1 t/wk	9 (36.0)	54 (49.1)
2–6 t/wk	3 (12.0)	36 (32.7)
≥ 7 t/wk	13 (52.0)	20 (18.2)
Clinical and psychological score	n = 25	n = 178
IBS-SSS	150.0 (37.5, 187.5)	N/A	N/A
IBS-QOL	46.0 (35.5, 74.5)	N/A	N/A
GSRS	4.0 (3.0, 6.5)	3.0 (1.0, 5.0)	0.007
VSI	64.0 (53.0, 68.5)	29.0 (17.5, 38.25)	< 0.001
HADS anxiety score	7.0 (3.5, 10.0)	3.0 (1.0, 6.0)	< 0.001
HADS depression score	5.0 (2.5, 8.0)	3.0 (1.0, 6.0)	0.026

The data are presented as the median (Q1, Q3) or numbers (percentages). All P < 0.05 vs controls. IBS: Irritable bowel syndrome; IBS-SSS: IBS symptom severity scale; IBS-QOL: IBS-specific quality of life; VSI: Visceral sensitivity index; HADS: Hospital anxiety and depression scale; GSRS: Gastrointestinal symptom rating scale; N/A: Not applicable.

Table 3 Association between dietary factors and symptom scores/ psychological factors

	IBS-SSS		HADS (a)		HADS (d)
	r	P value	r	P value	r	P value
Quantity per time
Soybean and its products	0.415	0.039	0.635	0.001	0.604	0.001
Spicy food	0.590	0.002	0.454	0.022	0.483	0.014
Dry-fried nuts	0.738	< 0.001	0.608	0.001	0.616	0.001
Intake frequency
Soybean and its products	0.702	< 0.001	0.422	0.036	0.566	0.003
Spicy food	0.691	< 0.001	0.451	0.024	0.424	0.034
Dry-fried nuts	0.512	0.009	0.605	0.001	0.622	0.001

All P < 0.05. IBS-SSS: Irritable bowel syndrome-symptom severity scale; HADS: Hospital anxiety and depression scale; a: Anxiety; d: Depression.

Table 4 Evaluation of dietary factors for IBS by logistic regression analysis

	Univariable				Multivariable
	OR	95%CI		P value	OR	95%CI		P value
		Lower	Upper			Lower	Upper
Quantity per time
Soybean and its products	1.009	1.004	1.014	0.001
Spicy food	1.006	1	1.013	0.04
Dry-fried nuts	1.032	1.01	1.054	0.004
Intake frequency [times per week (t/wk)]
Soybean and its products				< 0.001				0.015
≤ 1 t/wk	Ref			/
2–6 t/wk	4.318	1.351	13.801	0.014	2.433	0.625	9.473	0.200
≥ 7 t/wk	23.03	5.314	99.804	< 0.001	11.613	2.145	62.855	0.004
Spicy food				0.002				0.184
≤ 1 t/wk	Ref			/
2–6 t/wk	1.909	0.617	5.905	0.262
≥ 7 t/wk	7.071	2.329	21.47	0.001
Dry-fried nuts				0.001				0.078
≤ 1 t/wk	Ref			/
2–6 t/wk	3.886	1.015	14.88	0.048
≥ 7 t/wk	40.8	4.588	362.841	0.001

CI: Confidence interval; OR: Odds ratio; Ref: Reference.