Soy May Not Cut LDL ('Bad') Cholesterol
Soy Protein Did Not Reduce LDL Cholesterol in Study of Adults With Mildly High Cholesterol
Opposing Views continued...
The study is "excellent" and in line with findings from her own lab and recent work by other researchers, Lichtenstein tells WebMD.
In a statement emailed to WebMD, Chapman says the study "confirms that soy foods lower total cholesterol even though the drop in LDL cholesterol wasn't significant. She points out that the participants' LDL levels were "nearly" normal when the study started, and that the study might not have picked up on small changes in LDL cholesterol.
Lichtenstein counters, "I don't think you'd find people to study that had extremely high cholesterol levels that were going to be treated just with soy, because it's not consistent with current guidelines," which involve cholesterol-lowering drugs, as well as dietary changes. Lichtenstein also says the 3% drop in total cholesterol wasn't enough to bring participants' total cholesterol down to the normal range.
Chapman says other research has linked soy consumption to cholesterol improvements.
Lichtenstein sees some benefit in soy foods. "If you use a soy burger or a soy frankfurter to displace a hamburger or frankfurter, you would likely see a drop in LDL cholesterol because you're decreasing saturated fat," says Lichtenstein. "From that perspective, using soy-containing foods to displace foods with animal fat is probably advantageous."
But Lichtenstein says no recent data in people with mildly high cholesterol levels show that soy protein or other soy nutrients called isoflavones go above and beyond that to independently reduce heart disease risk.
"I think whenever there is a claim that a food is going to do something positive like lower cholesterol, we all become very enthusiastic and it usually gets embraced without too much hesitation," Lichtenstein says. "However, when data starts emerging that perhaps the original assessment was not accurate, the bar is much higher as far as what's necessary to establish lack of effect as opposed to an effect."