Are vitamins relevant to cancer risks? A Mendelian randomization investigation

•A genetics-based Mendelian randomization analysis revealed the lack of relevance between the intake of three vitamins and the risk for five cancers.•Some results were supported by epidemiological observations.•Some results were supported by survival analysis using The Cancer Genome Atlas data. The relationship between vitamin intake and the occurrence of cancer is controversial. The aim of this study was to examine the genetic associations between vitamins D, E, and B12 and five cancers (i.e., colorectal cancer, breast cancer, prostate cancer, malignant melanoma, and squamous cell carcinoma). This study started from genome-wide association data for three vitamins (N = 11 238) and five cancers (N = 373 316). The study analyzed their associations using Mendelian randomization (MR) methods. Additionally, survival analysis was performed using data from The Cancer Genome Atlas (TCGA) to further evaluate some MR results. MR analysis indicated that intake of vitamins D, E, and B12 is not relevant to the risk for the five cancers (PMR > Bonferroni-corrected P = 0.02). Some of the results were supported by epidemiological observations; some were further supported by survival analysis using TCGA data. There is no genetic evidence to support the association between intake of vitamins D, E, and B12 and the risk for colorectal, breast, and prostate cancers, malignant melanoma, and squamous cell carcinoma. [Display omitted]