Omega-3 vetzuren verminderen kans op darmkanker flink.*
Uit
een onderzoek onder 460 mensen waarvan 178 mannen met darmkanker blijkt dat zij
met de de hoogste bloedwaarde aan omega-3 vetzuur wel 66 % minder kans hebben op
het krijgen van darmkanker. Omega-3 vetzuren remmen het COX-2 enzym en daardoor
ontstekingsreacties met de goede gevolgen. Aspirine doet hetzelfde als omega-3
vetzuren met het COX-2 enzym, vandaar dat gebruikers van aspirine in deze studie
geen extra voordeel hadden. Omega-3 vetzuren zitten vooral in vette vis
en lijnzaad.
Blood
Levels of Long-Chain Polyunsaturated Fatty Acids, Aspirin, and the Risk of Colorectal
Cancer
Megan N. Hall1,2, Hannia Campos1,
Haojie Li3, Howard D. Sesso4,
Meir J. Stampfer1,2,3,4, Walter
C. Willett1,2,3 and Jing Ma3
Departments of 1 Nutrition and 2
Epidemiology, Harvard School of Public Health; 3
Channing Laboratory and 4 Division of Preventive Medicine, Department
of Medicine, Harvard Medical School and Brigham and Women's Hospital, Boston,
Massachusetts
Requests for reprints: Jing Ma, Channing Laboratory,
Department of Medicine, Brigham and Women's Hospital and Room 336,
Harvard Medical School, 181 Longwood Ave, Boston, MA 02115. Phone: 617-525-2708;
Fax: 617-525-2008. E-mail: jing.ma@channing.harvard.edu
Background:
N-3
fatty acids may decrease risk of colorectal cancer by inhibiting
the cyclooxygenase-2 enzyme and production of proinflammatory
eicosanoids derived from arachidonic acid (20:4n-6). Aspirin
also inhibits the cyclooxygenase-2 enzyme and may share with n-3
fatty acids a potential mechanism to decrease the risk of colorectal
cancer.
Methods:
We conducted a nested case-control analysis using blood samples
collected from the Physicians' Health Study participants in 1982 to
1984. N-3
and n-6 fatty acid levels were measured using gas-liquid
chromatography for 178 men who developed colorectal cancer through
December 31,
1995 and 282 age- and smoking-matched controls. We used conditional
logistic regression to examine associations. All statistical tests
were two-sided.
Results:
Total long-chain n-3 fatty acids were nonsignificantly inversely
associated with colorectal
cancer risk [relative risk (RR) for highest versus lowest quartile,
0.60; 95% confidence interval (95% CI), 0.32
to 1.11; Ptrend = 0.10], after adjustment for
possible confounders. We observed potential interaction between
randomized aspirin assignment and long-chain n-3
fatty acid levels (Pinteraction = 0.04). Among men
not on aspirin, RRs (95% CI) for increasing quartiles of long-chain n-3
fatty acids were 1.00 (reference), 0.60 (0.28-1.28), 0.51
(0.22-1.17), and 0.34
(0.15-0.82), Ptrend = 0.006. For participants taking aspirin,
there was no additional benefit of increasing n-3 fatty acid levels. The RR (95%
CI) for the highest versus lowest quartile of n-6 fatty acids
was 0.64 (0.35-1.17).
Conclusions: Blood levels of long-chain n-3 fatty acids were associated with decreased risk of colorectal cancer among men not using aspirin. N-6 fatty acids were nonsignificantly inversely associated with colorectal cancer risk. (Cancer Epidemiol Biomarkers Prev 2007;16(2):314–21) (Maart 2007) (Opm. Meer over voeding en vetzuren)