Intake frequency of fish and serum levels of long-chain n-3 fatty acids: a cross-sectional study within the Japan Collaborative Cohort Study

• Published in: Journal of epidemiology 2005-11, Vol.15 (6), p.211-218
• Main Authors: Wakai, Kenji, Ito, Yoshinori, Kojima, Masayo, Tokudome, Shinkan, Ozasa, Kotaro, Inaba, Yutaka, Yagyu, Kiyoko, Tamakoshi, Akiko
• Format: Article
• Language: English
• Subjects: Adult; Age Distribution; Aged; Animals; Case-Control Studies; Cross-Sectional Studies; Diet; Diet Records; Fatty Acids, Omega-3 - blood; Female; Fishes; Humans; Japan; Male; Middle Aged; Original; Sex Distribution
• ISSN: 0917-5040; 1349-9092
• DOI: 10.2188/jea.15.211

Several investigations have adopted self-reported intake frequency of fish as a surrogate for intake of long-chain n-3 fatty acids, for which protective effects against cancer have been suggested. Whether reported fish consumption reflects the fatty acid intake, however, has to be elucidated. We examined the association between intake frequency of fish and serum long-chain n-3 fatty acids (weight percentage of total fatty acids) among 1,257 control subjects (631 men and 626 women), aged 40-79 years, in case-control studies nested in the Japan Collaborative Cohort Study. All the subjects were not fasting when blood was drawn. Serum fatty acids were determined by gas chromatography. In men, intake frequency of fresh fish and dried or salted fish was significantly but weakly correlated with serum levels of eicosapentaenoic (EPA), docosapentaenoic (n-3) (DPA), and docosahexaenoic (DHA) acids; the age-adjusted Spearman correlation coefficients ranged from 0.11 to 0.18. In women, fresh fish consumption was somewhat associated with serum EPA (Spearman correlation coefficient = 0.12) as was dried or salted fish consumption with serum DPA (0.11). A rising trend in geometric means of serum EPA, DPA, and DHA was found with an increasing intake frequency of fresh or dried/salted fish in both sexes. The geometric means adjusted for age and participating institution in the highest intake category were higher than those in the lowest by 7% to 40%. A population with high self-reported frequency of fish intake, as a group, may have higher bioavailability of long-chain n-3 fatty acids than one with low frequency.