Conjugated linoleic acid (CLA) is consumed widely as a supplement. It causes hepatomegaly in animals, but toxicological data in humans are limited. We therefore studied the effect of a high daily intake of CLA on liver and kidney function in healthy subjects. Twenty subjects received 14.6 g cis-9,trans-11 CLA and 4.7 g trans-10,cis-12 CLA isomers a day for 3 weeks. Liver and kidney function was measured at 0, 3, 7, 10, 16, and 21 days. Mean values of all tests remained within normal limits. Lactate dehydrogenase (mean+/-SD) increased from 290.9+/-43.6 to 322.5+/-60.7 U/L (p=0.04) on day 21. One subject exceeded the upper limit of normal of 450 U/L on day 21, to 472 U/L and another showed an isolated elevation to 555 U/L on day 7. Gamma-glutamyltranspeptidase increased from 12.1+/-5.9 to 13.5+/-6.2U/L (p=0.002). No one exceeded the upper limit of 50 U/L for men and 40 U/L for women. A daily intake of 19.3 g CLA for 3 weeks does not produce clinically relevant effects on markers of liver and kidney function in healthy volunteers.
Trial registration: ClinicalTrials.gov NCT00449462.
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