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Investigating the effects of lycopene and green tea on the metabolome of men at risk of prostate cancer: The ProDiet randomised controlled trial
Author(s) -
Bey Rhona A.,
Richmond Rebecca C.,
Santos Ferreira Diana L.,
Ness Andrew R.,
May Margaret,
Smith George Davey,
Vincent Emma E.,
Adams Charleen,
AlaKorpela Mika,
Würtz Peter,
Soidinsalo Sebastian,
Metcalfe Christopher,
Donovan Jenny L.,
Lane Athene J.,
Martin Richard M.
Publication year - 2018
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.31929
Subject(s) - lycopene , medicine , prostate cancer , green tea extract , mendelian randomization , odds ratio , cancer , endocrinology , metabolome , metabolite , physiology , carotenoid , food science , biology , green tea , biochemistry , genetic variants , gene , genotype
Lycopene and green tea consumption have been observationally associated with reduced prostate cancer risk, but the underlying mechanisms have not been fully elucidated. We investigated the effect of factorial randomisation to a 6‐month lycopene and green tea dietary advice or supplementation intervention on 159 serum metabolite measures in 128 men with raised PSA levels (but prostate cancer‐free), analysed by intention‐to‐treat. The causal effects of metabolites modified by the intervention on prostate cancer risk were then assessed by Mendelian randomisation, using summary statistics from 44,825 prostate cancer cases and 27,904 controls. The systemic effects of lycopene and green tea supplementation on serum metabolic profile were comparable to the effects of the respective dietary advice interventions ( R 2 = 0.65 and 0.76 for lycopene and green tea respectively). Metabolites which were altered in response to lycopene supplementation were acetate [ β (standard deviation difference vs . placebo): 0.69; 95% CI = 0.24, 1.15; p = 0.003], valine ( β : −0.62; −1.03, −0.02; p = 0.004), pyruvate ( β : −0.56; −0.95, −0.16; p = 0.006) and docosahexaenoic acid ( β : −0.50; −085, −0.14; p = 0.006). Valine and diacylglycerol were lower in the lycopene dietary advice group (β: −0.65; −1.04, −0.26; p = 0.001 and β : −0.59; −1.01, −0.18; p = 0.006). A genetically instrumented SD increase in pyruvate increased the odds of prostate cancer by 1.29 (1.03, 1.62; p = 0.027). An intervention to increase lycopene intake altered the serum metabolome of men at risk of prostate cancer. Lycopene lowered levels of pyruvate, which our Mendelian randomisation analysis suggests may be causally related to reduced prostate cancer risk.