Soy lowered LDL with or without its isoflavones
Pooling 11 randomised trials, isolated isoflavones lowered LDL, the cholesterol that drives artery disease, by 5.0 mg/dL; soy protein without them by 3.9, with them by 7.0.
What the study found
Soy protein with the isoflavones stripped out still lowered LDL
Pooling 11 randomised trials, isolated soy isoflavones lowered LDL, the cholesterol fraction that drives artery disease, by 5.0 mg/dL. Soy protein with its isoflavones removed lowered it by 3.9, and soy protein with them added by 7.0. No dose of either predicted how far it fell.
The caveat · Under 5% of a typical LDL level
The largest of those changes is 7 mg/dL, under 5 percent of a typical level. Reductions were bigger in people who started with high cholesterol, so anyone starting from normal should expect less. Only 11 trials, none of them published after 2006.