A comparison of the effectiveness of soy protein isolate and fish oil for reducing the severity of retinoid-induced hypertriglyceridemia

The effectiveness of soy protein isolate (SPI) to reduce the severity of retinoid-induced hypertriglyceridemia has been demonstrated in the rat, but not in human subjects. Because fish oil has been demonstrated to be effective at lowering serum triglyceride concentration in human subjects undergoing retinoid therapy, a study was conducted to compare the ability of SPI with that of fish oil to reduce the severity of retinoid-induced hypertriglyceridemia in the rat. Male Fischer 344 rats, n = 8/group, were fed one of four isonitrogenous, isoenergetic diets, consisting of a control diet containing 24% casein +20% corn oil (C), and three 13-cis retinoic acid (13cRA)-supplemented diets containing 24% casein +20% corn oil (R), 24% SPI +20% corn oil (SR), and 24% casein +15% fish oil and 5% corn oil (FR). There was no effect of diet on food intake or final body weight. Serum triglyceride concentration for group R was higher (P < 0.001) than for groups C, SR, and FR (7.20 vs. 2.50, 2.84 , and 2.02 mmol/L, respectively); values for groups SR and FR did not differ for this parameter. The serum concentration of 13cRA for group R did not differ from that for groups SR and FR. Thus, SPI was as effective as fish oil in reducing the severity of retinoid-induced hypertriglyceridemia in an animal model, suggesting that it may be effective for this purpose in human subjects.