Is carrot consumption associated with a decreased risk of lung cancer? A meta-analysis of observational studies

Abstract

Findings of epidemiological studies regarding the association between carrot consumption and lung cancer risk remain inconsistent. The present study aimed to summarise the current epidemiological evidence concerning carrot intake and lung cancer risk with a meta-analysis. We conducted a meta-analysis of case–control and prospective cohort studies, and searched PubMed and Embase databases from their inception to April 2018 without restriction by language. We also reviewed reference lists from included articles. Prospective cohort or case–control studies reporting OR or relative risk with the corresponding 95 % CI of the risk lung cancer for the highest compared with the lowest category of carrot intake. A total of eighteen eligible studies (seventeen case–control studies and one prospective cohort study) were included, involving 202 969 individuals and 5517 patients with lung cancer. The pooled OR of eighteen studies for lung cancer was 0·58 (95 % CI 0·45, 0·74) by comparing the highest category with the lowest category of carrot consumption. Based on subgroup analyses for the types of lung cancer, we pooled that squamous cell carcinoma (OR 0·52, 95 % CI 0·19, 1·45), small-cell carcinoma (OR 0·43, 95 % CI 0·12, 1·59), adenocarcinoma (OR 0·34, 95 % CI 0·15, 0·79), large-cell carcinoma (OR 0·40, 95 % CI 0·10, 1·57), squamous and small-cell carcinoma (OR 0·85, 95 % CI 0·45, 1·62), adenocarcinoma and large-cell carcinoma (OR 0·20, 95 % CI 0·02, 1·70) and mixed types (OR 0·61, 95 % CI 0·46, 0·81). Exclusion of any single study did not materially alter the pooled OR. Integrated epidemiological evidence from observational studies supported the hypothesis that carrot consumption may decrease the risk of lung cancer, especially for adenocarcinoma.

Carrot Intake and Risk of Colorectal Cancer: A Prospective Cohort Study of 57,053 Danes

“…Several studies have also found stronger negative correlations of developing cancer and in particular lung cancer with intake of α-carotene rather than β-carotene [13,14]. Thus, it is widely accepted that carrots play a central role as a protecting vegetable against development of cancer, which is supported by recent meta-analysis studies on carrot consumption in relation to the development of breast, gastric, lung and prostate cancer [15][16][17][18]. The cancer-preventive effect of this vegetable has mainly been explained by its high contents of carotenoids; however, intervention studies have shown that supplementation with carotenoids does not protect against development of this disease [10,11,19].…”

Bioactive C17 and C18 Acetylenic Oxylipins from Terrestrial Plants as Potential Lead Compounds for Anticancer Drug Development

“…One of the most important apiaceous vegetables are carrots (Daucus carota L.), for two main reasons. First, they are consumed worldwide, in particular in North America and in European countries, and second, several meta-analysis studies on carrot consumption have indicated that carrots play a central role as a protecting vegetable, against development of different types of cancers [126][127][128][129]. The latter has recently been confirmed in a prospective cohort study, examining the risk of being diagnosed with CRC, as predicted by intake of carrots in a Danish population of 57,053 individuals with a long follow-up [130].…”

Association of Dietary Carrot Intake With Bladder Cancer Risk in a Prospective Cohort of 99,650 Individuals With 12.5 Years of Follow-Up

“…Carrot consumption has been inversely associated with various health outcomes, including colorectal cancer ( 30 ), lung cancer ( 31 ), prostate cancer ( 32 ), breast cancer ( 33 ), and stroke mortality ( 34 ). However, in our study, we failed to find a significant association between carrot intake and bladder cancer risk.…”

“…Participants were followed until cancer diagnosis or death, or end of follow-up (December 31,2009). Study participants were mailed a questionnaire annually to screen cancer cases.…”