This study describes the contribution of changes in trans fatty acid intake in relation to serum lipoproteins. A total of 328 Japanese-Brazilians of the first (Issei) and second (Nisei) generations, aged 40-79 years in 1993, were assessed in two cross-sectional surveys on health and nutritional status in 1993 and 2000. Multiple linear regression models were used with changes (2000/ 1993) in serum lipoproteins as the dependent variable and changes in dietary trans fatty acids (adjusted for total calories) as independent variable. In both genders a significant reduction was observed in total intake of trans fatty acids with lower LDL and increased HDL serum levels during 7-year follow-up. The mean intakes of trans fatty acids (% of total energy) in 1993 and 2000 were: 5.1% and 3.4% for women and 4.7% and 3.3% for men, respectively. Although the association between changes in dietary trans fatty acids and serum lipoprotein was not statistically significant, on average the intake of this trans fat was higher than the WHO recommendation (up to 1% of total energy).