Table 1 Main characteristics of included studies.

Tayyem, 2015¹⁶

Jordan

Nutrients

417

193/224

CRC Cancer Yes/No

69/90

(OR 1.21; 95% CI 0.81–1.81)

8

Shivappa,2017¹⁷

Iran

Asian Pacific Journal of Cancer Prevention

213

105/108

CRC First and Second Degree

13/3

(OR 10.38; 95% CI 2.85–37.81)

8

Alsheridah, 2018¹⁸

Kuwait

BMC Cancer

309

168/141

CRC Cancer Yes/No

18/22

(OR 1.77; 95% CI 0.90–3.47)

8

Alqahtani, 2020¹⁹

Saudi Arabia

Journal of Family Medicine and Primary Care

242

138/104

CRC Cancer Yes/No

19/9

(OR 2.31; 95% CI 1.00–5.35)

8

Deoula, 2020²⁰

Morocco

JMIR research protocols

2966

1474/1492

CRC Cancer Yes/No

83/12

(OR 7.26; 95% CI 3.95–13.37)

7

Khatatbeh, 2018²¹

Jordan

Asian Pacific Journal of Cancer Prevention

300

147/153

CRC Cancer Yes/No

19/13

(OR 3.25; 95% CI 1.53–6.90)

8

Lo, 2010²²

Egypt

Diseases of the Colon & Rectum

860

457/403

CRC Cancer Yes/No

Any Cancer Yes/No

43/46

CRC: (OR 5.86; 95% CI 1.29–26.60)/ANY: (OR 0.97; 95% CI 0.62–1.50)

6

Ghrouz, 2021²³

Palestine

Nutrition and Cancer

210

115/95

CRC Cancer Yes/No,

Any Cancer Yes/No

22/5

CRC: (OR 4.82; 95% CI 1.01–22.91)/ANY: (OR 5.30; 95% CI 1.92–14.60)

7

Soliman, 1998²⁴

Egypt

International journal of cancer

222

120/102

CRC Cancer Yes/No

Any Cancer Yes/No

18/1

CRC: (OR 8.54; 95% CI 1.05–69.50)/ANY: (OR 21.29; 95% CI 2.78–162.51)

5

Azzeh 2017²⁵

Saudi Arabia

BMC Public Health

301

NA

CRC Cancer Yes/No

22/27

(OR 0.97; 95% CI 0.52–1.79)

6

Farahani 2020²⁶

Iran

Journal of Gastrointestinal Cancer

170

90/80

CRC Cancer Yes/No

21/8

(OR 3.44; 95% CI 1.42–8.29)

6

El kinany, 2020²⁷

Morocco

European Journal of Nutrition

2906

1432/1474

CRC Cancer Yes/No

80/12

(OR 6.99; 95% CI 3.79–12.89)

9

Mafiana, 2018²⁸

Oman

Asian Pacific Journal of Cancer Prevention

279

141/138

CRC Cancer Yes/No

97/161

(OR 0.45; 95% CI 0.18–1.11)

8

Abu Mweis, 2015²⁹

Jordan

European Journal of Cancer Prevention

407

187/220

CRC Cancer Yes/No

68/89

(OR 1.16; 95% CI 0.77–1.74)

6

Gharbi, 2020³⁰

Tunisia

La Tunisie Médicale

102

52/50

CRC Cancer Yes/No

13/7

(OR 2.15; 95% CI 0.77–5.94)

7

Teimoorian, 2018³¹

Iran

Iranian Journal of Pathology

117

NA

CRC Cancer Yes/No,

Any Cancer Yes/No

1/4

CRC: (OR 0.49; 95% CI 0.02–9.38)/ANY: (OR 1.50; 95% CI 0.15–14.29)

6

Tayyem, 2016³²

Jordan

Integrative cancer Therapies

501

248/253

CRC Cancer Yes/No

84/101

(OR 1.10; 95% CI 0.76–1.58)

6

Arafa, 2011³³

Jordan

Asian Pacific Journal of Cancer Prevention

440

236/204

CRC First Degree

20/9

(OR 2.34; 95% CI 1.04–5.27)

6

Azizi, 2015³⁴

Iran

Asian Pacific Journal of Cancer Prevention

414

220/194

CRC First Degree

58/28

(OR 2.48; 95% CI 1.50–4.10)

7

Rafiee, 2020³⁵

Iran

European Journal of Cancer Prevention

370

199/171

CRC First Degree,

Any Cancer Yes/No

66/89

CRC: (OR 0.73; 95% CI 0.22–2.37)/ANY: (OR 1.75; 95% CI 1.13–2.69)

6

Bener, 2010³⁶

Qatar

Asian Pacific Journal of Cancer Prevention

428

149/179

Any Cancer Yes/No

61/52

(OR 3.17; 95% CI 2.03–4.95)

6

Safaee, 2010³⁷

Iran

Indian Journal of Cancer

786

424/362

Any Cancer Yes/No

143/96

(OR 1.77; 95% CI 1.30–2.40)

7

Golshiri, 2016³⁸

Iran

International Journal of Preventive Medicine

200

122/78

Any Cancer Yes/No

34/36

(OR 0.91; 95% CI 0.51–1.63)

8

Moazzen, 2020³⁹

Iran

Annals of Global Health

405

0/405

Any Cancer Yes/No

33/49

(OR 1.45; 95% CI 0.88–2.40)

9

Khan, 2015⁴⁰

Pakistan

Asian Pacific Journal of Cancer Prevention

222

105/117

Any Cancer Yes/No

14/14

(OR 2.23; 95% CI 1.00–4.97)

9

Abolhassani, 2019⁴¹

Iran

Ecotoxicology and Environmental Safety

72

43/29

Any Cancer Yes/No

12/9

(OR 0.93; 95% CI 0.33–2.61)

7

Khodaverdi, 2021⁴²

Iran

BMC Cancer

80

40/40

Any Cancer Yes/No

4/3

(OR 1.37; 95% CI 0.28–6.55)

6