Simone Mocellin1,2, Marta Briarava1, Pierluigi Pilati3. 1. Department of Surgery Oncology and Gastroenterology, University of Padova, Italy. 2. Istituto Oncologico Veneto, IOV-IRCCS, Padova, Italy. 3. Ospedale Sant'Antonio, Padova, Italy.
Abstract
Background: Vitamin B6 is involved in many biochemical reactions and might play a role in carcinogenesis. We summarized the evidence linking vitamin B6 to cancer risk. Methods: We conducted a systematic review of both observational and intervention studies investigating the relationship between vitamin B6 intake or blood levels of its bioactive form pyridoxal-5'-phosphate (PLP) and the risk of any type of cancer. Random-effects meta-analysis was used to calculate pooled relative risks (RRs) and their 95% confidence intervals (CIs) across studies for high vs low categories of vitamin intake or PLP levels. We also performed a random-effects dose-response meta-analysis. Results: We identified 121 observational studies (participants, n = 1 924 506; cases, n = 96 , 436) and nine randomized controlled trials (RCTs; participants, n = 34 911; cases, n = 2539) considering 19 tumor sites. High intake of dietary (food only) vitamin B6 was statistically significantly associated with lower risk of all cancers (relative risk [RR] = 0.78, 95% CI = 0.73 to 0.84) and specific tumors, with special regard to gastrointestinal carcinomas (RR = 0.68, 95% CI = 0.61 to 0.75). An inverse association was also observed between high PLP levels and the risk of all cancers (RR = 0.66, 95% CI = 0.58 to 0.76) and single tumor sites, the most consistent results being those for gastrointestinal tumors (RR = 0.56, 95% CI = 0.48 to 0.65). There was a statistically significant inverse linear relationship between cancer risk and both vitamin B6 dietary intake and PLP levels. When total (food and supplements) intake was considered, the associations were weaker or null. Findings from RCTs did not support a protective effect of vitamin B6 against cancer, although this evidence was graded as low level. Conclusions: Epidemiological evidence supports the potential of vitamin B6 as a cancer risk reduction agent and the role of PLP as a cancer screening biomarker, especially for gastrointestinal tumors. However, inconsistent findings from total intake and intervention studies suggest that vitamin B6 might also be an indicator of other dietary protective micronutrients.
Background: Vitamin B6 is involved in many biochemical reactions and might play a role in carcinogenesis. We summarized the evidence linking vitamin B6 to cancer risk. Methods: We conducted a systematic review of both observational and intervention studies investigating the relationship between vitamin B6 intake or blood levels of its bioactive form pyridoxal-5'-phosphate (PLP) and the risk of any type of cancer. Random-effects meta-analysis was used to calculate pooled relative risks (RRs) and their 95% confidence intervals (CIs) across studies for high vs low categories of vitamin intake or PLP levels. We also performed a random-effects dose-response meta-analysis. Results: We identified 121 observational studies (participants, n = 1 924 506; cases, n = 96 , 436) and nine randomized controlled trials (RCTs; participants, n = 34 911; cases, n = 2539) considering 19 tumor sites. High intake of dietary (food only) vitamin B6 was statistically significantly associated with lower risk of all cancers (relative risk [RR] = 0.78, 95% CI = 0.73 to 0.84) and specific tumors, with special regard to gastrointestinal carcinomas (RR = 0.68, 95% CI = 0.61 to 0.75). An inverse association was also observed between high PLP levels and the risk of all cancers (RR = 0.66, 95% CI = 0.58 to 0.76) and single tumor sites, the most consistent results being those for gastrointestinal tumors (RR = 0.56, 95% CI = 0.48 to 0.65). There was a statistically significant inverse linear relationship between cancer risk and both vitamin B6 dietary intake and PLP levels. When total (food and supplements) intake was considered, the associations were weaker or null. Findings from RCTs did not support a protective effect of vitamin B6 against cancer, although this evidence was graded as low level. Conclusions: Epidemiological evidence supports the potential of vitamin B6 as a cancer risk reduction agent and the role of PLP as a cancer screening biomarker, especially for gastrointestinal tumors. However, inconsistent findings from total intake and intervention studies suggest that vitamin B6 might also be an indicator of other dietary protective micronutrients.
Authors: Despoina Theofylaktopoulou; Øivind Midttun; Per M Ueland; Klaus Meyer; Anouar Fanidi; Wei Zheng; Xiao-Ou Shu; Yong-Bing Xiang; Ross Prentice; Mary Pettinger; Cynthia A Thomson; Graham G Giles; Allison Hodge; Qiuyin Cai; William J Blot; Jie Wu; Mikael Johansson; Johan Hultdin; Kjell Grankvist; Victoria L Stevens; Marjorie M McCullough; Stephanie J Weinstein; Demetrius Albanes; Regina Ziegler; Neal D Freedman; Arnulf Langhammer; Kristian Hveem; Marit Naess; Howard D Sesso; J Michael Gaziano; Julie E Buring; I-Min Lee; Gianluca Severi; Xuehong Zhang; Meir J Stampfer; Jiali Han; Stephanie A Smith-Warner; Anne Zeleniuch-Jacquotte; Loic Le Marchand; Jian-Min Yuan; Renwei Wang; Lesley M Butler; Woon-Puay Koh; Yu-Tang Gao; Nathaniel Rothman; Ulrika Ericson; Emily Sonestedt; Kala Visvanathan; Miranda R Jones; Caroline Relton; Paul Brennan; Mattias Johansson; Arve Ulvik Journal: Int J Cancer Date: 2018-01-04 Impact factor: 7.396
Authors: Joanna L Clasen; Alicia K Heath; Heleen Van Puyvelde; Inge Huybrechts; Jin Young Park; Pietro Ferrari; Mattias Johansson; Ghislaine Scelo; Arve Ulvik; Øivind Midttun; Per Magne Ueland; Christina C Dahm; Jytte Halkjær; Anja Olsen; Theron Johnson; Verena Katzke; Matthias B Schulze; Giovanna Masala; Francesco Segrado; Maria Santucci de Magistris; Carlotta Sacerdote; Marga C Ocké; Leila Luján-Barroso; Ana Ching-López; José María Huerta; Eva Ardanaz; Pilar Amiano; Ulrika Ericson; Jonas Manjer; Björn Gylling; Ingegerd Johansson; Julie Schmidt; Elisabete Weiderpass; Elio Riboli; Amanda J Cross; David C Muller Journal: Am J Clin Nutr Date: 2021-07-01 Impact factor: 7.045