Consideration about the Intake of Conjugated Linoleic Acid in the Japanese

Abstract

Conjugated linoleic acid (CLA) comprises geometrical and positional isomers of linoleic acid and is a fatty acid with a conjugated double bond. The activities of CLA, including anti-obesity and anti-cancer activities, are known, and CLA is now used as a health-food supplement for its beneficial effects. However, there are few reported studies on CLA intake, absorption and metabolism in the Japanese population. Information about CLA intake in Japanese individuals was obtained in the present study by examining the daily intake of CLA, normal blood CLA levels, and the change in blood CLA levels after taking a CLA supplement. Results indicate that the normal dietary intake of CLA for Japanese individuals is 37.5 mg/day. Normal blood CLA levels are 6.4 μmol/L in plasma and 1.7 μmol/L in red blood cells. After taking 2.3 g/day of a CLA supplement for three weeks, blood CLA levels were 7.7-fold higher in plasma and 8.7-fold higher in red blood cells. Although normal dietary intake and blood levels of CLA in Japanese individuals were lower than those in non-Japanese subjects reported in previous studies, Japanese individuals taking a dietary supplement of CLA showed a dramatic increase in blood CLA levels. Therefore, long-term intake of 2.3 g CLA/day as a dietary supplement likely has a positive effect in Japanese individuals.