Garlic consumption and colorectal cancer risk in US adults: a large prospective cohort study

Zongze Jiang; Huilin Chen; Ming Li; Wei Wang; Feiwu Long; Chuanwen Fan

doi:10.3389/fnut.2023.1300330

Garlic consumption and colorectal cancer risk in US adults: a large prospective cohort study

Front Nutr. 2023 Dec 6:10:1300330. doi: 10.3389/fnut.2023.1300330. eCollection 2023.

Authors

Zongze Jiang^#¹, Huilin Chen^#², Ming Li^{1

3}, Wei Wang¹, Feiwu Long¹, Chuanwen Fan^{1

4}

Affiliations

¹ Department of Gastrointestinal, Bariatric and Metabolic Surgery, Research Center for Nutrition, Metabolism and Food Safety, West China-PUMC C.C. Chen Institute of Health, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China.
² Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing, China.
³ Department of Nutrition, Food Hygiene, and Toxicology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China.
⁴ Department of Oncology and Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden.

^# Contributed equally.

Abstract

Objective: To clarify the inconsistent findings of epidemiological studies on the association between dietary garlic consumption and colorectal cancer (CRC) incidence, by prospectively assessing the association in a large US population.

Methods: Data of 58,508 participants (aged 55-74) from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial were analyzed. Dietary data were collected using a validated questionnaire. Multivariable Cox regression analysis determined hazard ratio (HR) and 95% confidence interval (CI). Restricted cubic spline regression was used to investigate the non-linear relationship, and subgroup analysis was conducted to examine potential effect modifiers.

Results: During a median follow-up of 12.05 years, 782 CRC cases were documented, including 456 proximal colon cancer cases, 322 distal CRC cases, and 4 CRC cases with an unknown site. Moderate dietary garlic consumption was significantly associated with a reduced risk of overall CRC (HR_{quintile 3vs. 1}: 0.70, 95% CI: 0.54 to 0.91, p = 0.007, P for trend: 0.434), exhibiting a U-shaped dose-response pattern, and also with overall CRC in males in the stratified Cox regression model (Model 2: HR_{quintile 3vs. 1}: 0.57, 95% CI: 0.40 to 0.81, p = 0.002), but not in females. The protective association was more pronounced in men, Caucasian, and those with lower alcohol consumption. Notably, these protective effects were observed for overall distal CRC (HR_{quintile 3vs. 1}: 0.62, 95% CI: 0.42 to 0.93, p = 0.021; and HR_{quintile 4vs. 1}: 0.63, 95% CI: 0.43 to 0.92, p = 0.018, P for trend: 0.208); and for distal CRC in males (HR_{quintile 3vs. 1}: 0.40, 95% CI: 0.22 to 0.71, p = 0.002, P for trend: 0.696), but not for proximal CRC.

Conclusion: Moderate consumption of dietary garlic is associated with a decreased CRC risk in the US population, with variations based on CRC anatomic subsites. Further in-depth prospective studies are needed to validate these findings in different populations and to explore subsites-specific associations.

Keywords: adults; cohort study; colorectal cancer; epidemiology; garlic.

Grants and funding

The authors declare financial support was received for the research, authorship, and/or publication of this article. This research was funded by the Natural Science Foundation of Sichuan Province, China (Grant No. 2022NSFSC0764) and the Fundamental Research Funds for the Central Universities (Grant Nos. 2022SCU12025 and 2022SCU12020).