Original Communication
European Journal of Clinical Nutrition (2005) 59, 597–602. doi:10.1038/sj.ejcn.1602110 Published online 2 March 2005
Modulation of COX-2 expression in peripheral blood cells by increased intake of fruit and vegetables?
Guarantor: Professor Dr Med M Vatn.
Contributors: None of the authors had any financial conflicts in the preparation or submission of the manuscript. All co-workers took part in proof-reading the manuscript and made suggestions for changes that were implemented. KA conducted all the statistical analyses and wrote most of the paper; AB and LFA designed and carried out the primary study (Brevik et al, 2004a, 2004b); LFA and KA initiated the present study; PAA, HTH and DAN planned the methodological approach for analyzing COX-2 in peripheral blood cells; HTH and DAN did the laboratory work on the blood samples; MV and PAA forwarded the idea of looking at COX-2 as a diet marker; MV provided advice on medical issues relevant to clinical work.
K Almendingen1,2, A Brevik3, D A Nymoen4, H T Hilmarsen4, P A Andresen4, L F Andersen3 and M Vatn1,2
- 1Medical Department, Rikshospitalet University Hospital, Oslo, Norway
- 2Research Institute of Internal Medicine, Rikshospitalet University Hospital, Oslo, Norway
- 3Department of Nutrition, School of Medicine, University of Oslo, Blindern, Oslo, Norway
- 4Department of Pathology, Rikshospitalet University Hospital, Oslo, Norway
Correspondence: K Almendingen, Medical Department, Rikshospitalet University Hospital, 0027 Oslo, Norway. E-mail: kari.almendingen@labmed.uio.no
Received 9 June 2004; Revised 27 October 2004; Accepted 18 November 2004; Published online 2 March 2005.
Abstract
Background:
Enhanced cyclooxygenase-2 (COX-2) expression is associated with carcinogenesis, ischemia, angiogenesis, inflammation, and neurodegeneration. The preventing effect of aspirin and nonsteroidal anti-inflammatory drugs is partly due to inhibition of the COX-2 enzyme. Fruit and vegetables (FVs) contain numerous compounds that may decrease disease risk by several different mechanisms, for example through the inhibition of COX-2 activity.
Objective:
We tested the hypothesis that an increased intake of FVs would modulate the COX-2 expression in peripheral blood cells.
Design:
A strictly controlled dietary crossover study (n=39). After 1 week run-in period with no FVs in the diet, one group was given two portions of FVs (2 FV), while another group was given five portions (5 FV) daily for 14 days. Following a 2 weeks washout period and 1 week run-in, the regimens were switched between the groups. Gene expression analysis of COX-2 mRNA in blood samples was performed by quantitative real-time-PCR.
Results:
No significant treatment effect of diet intervention was found in the crossover analyses (P=0.74). However, the individual variation in response may seem large.
Conclusions:
These data does not contradict the recommendations for an increased intake of FVs. Further studies on expression directly and indirectly, through analysis of factors regulating and being regulated by COX-2, should be carried out. A first step would be to evaluate the correspondence between COX-2 mRNA expression and products of the COX pathway, like prostaglandins. Naturally occurring polymorphisms of COX-2 promoters and coding regions might contribute to functional variations and response to different diets.
Sponsorship:
Norwegian Research Council, National Nutrition Council, Throne Holst Foundation for Nutrition Research, Freia Chokoladefabriks Medisinske Fond and the Norwegian Cancer Society.
Keywords:
COX, blood, crossover, diet, vegetables, fruits
