Robert Thomas

MbChB MRCP MD FRCR

Bedford and Addenbrookes Cambridge University NHS Hospitals

Consultant Oncologist

PLCO (Learn more about this study)

PLCO-335

Jan 11, 2018

Is the regular intake of tea (+/-added sugar) and broccoli (+/- other cruciferous vegetables) linked to the incidence of Prostate and breast Cancer? - An analysis of the PLCO cancer screening trial dataset

Tea has been reported to have anti-cancer activity in laboratory experiments via its anti-oxidant, anti-inflammatory, pro-apoptopic and anti-angiogenic properties [Jankun]. In humans, the double-blind UK Pomi-T, randomised, controlled study demonstrated that a tea extract significantly slowed PSA progression in men with early prostate cancer, when combined with broccoli, pomegranate and turmeric [Thomas]. Some epidemiological studies have reported a reduced risk of breast and prostate cancer [Higdon], but a Cochrane review did not conclude a benefit [Boehm]. Of more concern, an analysis of the PLCO dataset reported total isoflavone intake was linked to an increased risk of prostate cancer and highlighted tea as a significant dietary source [Reger]. One potential reason for the disparity is the practice of adding sugar to tea beverages. Processed sugar has numerous carcinogenic mechanisms via its glycaemic, pro-inflammation and oxidative properties. [Yang]. Epidemiological studies have linked processed sugar intake with weight gain and cancer [Meyerhardt]. We hypothesize that this habit mitigates tea’s health benefits.

It is important not to consider a single food group in isolation, as laboratory and clinical studies have suggested that combinations of foods containing different phytochemicals with different anti-cancer mechanisms have synergistic benefits [ Parada, Niedzwiecki, Wang, Thomas]. Broccoli and other cruciferous vegetables are a good source of polyphenolic phytochemicals, distinct from those found in tea, such as isothiocyanates, which have also demonstrated favorable epigenetic influence on gene expression and other anti-cancer mechanisms [Lampe, Tarka]. Observational studies have linked an inverse correlation between broccoli intake and cancer [Kirsh], and as the PLCO included detailed questions relating to both tea and broccoli in take, it provides an opportunity to test both not only the individual properties separately, but also to test a synergistic effect.

References:

Wang Z et al. (2017). The synergy between natural polyphenol-inspired catechol moieties and plant protein-derived bio-adhesive enhances the wet bonding strength Scientific Reports 7, Article number: 9664.

Niedzwiecki A, et al. (2016). Anticancer Efficacy of Polyphenols and Their Combinations. Nutients 8(9):552.

Parada J (2007). Food combinations and microstructure affects the bioavailability of several nutrients. J Food Sci 72: 21–23.

Meyerhardt JA, Sato K, Niedzwiecki D. Dietary glycemic load and cancer recurrence and survival in patients with stage III colon cancer: findings from CALGB 89803. J Natl Cancer Inst 2012 21;104 (22):1702-11.

Higdon JV (2003). Tea catechins and polyphenols: health effects, metabolism, and antioxidant functions. Crit Rev Food Sci Nutr, 43(1): 89-143.

Jankun J et al (1997). Why drinking green tea could prevent cancer. Nature, 387 (6633): 561.

Reger M et al. (2017). Dietary intake of isoflavones and coumestrol and the risk of prostate cancer in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. Int J Cancer 8. doi: 10.1002/ijc.31095.

Thomas R, 2014. A double blind, placebo controlled randomised trial (RCT) evaluating the effect of a polyphenol rich whole food supplement on PSA progression in men with prostate cancer - The UK National Cancer Research Network (NCRN) Pomi-T study. Prostate Cancer Prostatic Dis 17, 180-6

• To determine whether regular tea consumption (+/- added sugar) is linked to the incidence of prostate and /or breast cancer.

• To determine whether the consumption of cruciferous vegetables is linked to the incidence of prostate and/or breast cancer.

• To determine whether tea drinkers (+/- added sugar), plus cruciferous vegetable intake, is linked to the incidence of prostate and / or breast cancer

Professor Derek Renshaw BSc (Jt. Hons), MSc (Research), PhD, PGCertHE, fHEA
Professor of Translational Physiology
Director of Doctoral Training Centre of Applied Biological and Exercise Sciences (ABES)
Faculty of Health and Life Sciences, Room 32, James Starley Building, Priory Street
Coventry University, Coventry.CV1 5FB
Tel: 44 (0) 24 7765 8075
E: derek.renshaw@coventry.ac.uk

Dr Shahzeena Aslam
Consultant Oncologist
Bedford and Addenbrooke’s Cambridge University NHS Hospital Trusts
c/o The Primrose Oncology Unit, Bedford Hospital, Bedford. MK42 9DJ
T: 44 (0) 1234 795 923, Fax: 44 (0) 1234 792 668
E: Shahzeena.Aslam@bedfordhospital.nhs.uk

Dr Anna Bowzyk Al-Naeeb
Consultant Oncologist
Bedford and Addenbrooke’s Cambridge University NHS Hospital Trusts
c/o The Primrose Oncology Unit, Bedford Hospital, Bedford. MK42 9DJ
T: 44 (0) 1234 792 023, Fax: 44 (0) 1234 792 668
E: Anna.BowzykAl-Naeeb@bedfordhospital.nhs.uk

Dr Michael Cauchi AMRSC
Honorary Statistician The Primrose Unit Bedford Hospital
Lecturer in Statistics and Operations Research
Department of Mathematics and Statistics, University of Limerick, Ireland
Tel: 44 (0) 7917 589126
E: Michael.Cauchi@ul.ie

Ms Madeleine Williams BA hONS, PgDip
Research Manager
The Primrose Oncology Research Unit, Bedford Hospital, Bedford. MK42 9DJ
T: 44 (0) 1234 795 787, Fax: 44 (0) 1234 792 668;
E: madeleine.williams@bedfordhospital.nhs.uk

Dr Anna Kirby MRCP FRCR
Consultant Clinical Oncologist
The Royal Marsden NHS Foundation Trust, Fulham Road, London. SW3 6JJ
T: 44 (0) 20 8661 3169
E: Anna.kirby@rmh.nhs.uk