- A meta-analysis of 43 existing trials evaluating soy protein found it can reduce low-density lipoprotein cholesterol — the so-called "bad" cholesterol — by 3% to 4%. The study, which originally looked at 46 trials but ended up analyzing 43, came from St. Michael's Hospital in Toronto and was funded by the Canadian Institutes of Health Research.
- The researchers said they wanted to examine whether the U.S. FDA's plan to take soy off its list of heart-healthy foods was consistent with current literature. David Jenkins, the study's lead author, said he and his team hope their work is considered in the FDA's evaluation.
- Of the 43 trials, 41 studied soy protein's impact on LDL cholesterol, which contributes to fatty buildup in arteries and increase the risk of heart attack or stroke. Researchers acknowledged the study was limited because it did not expand its scope beyond the 46 trials that the FDA had referred to previously.
Companies such as DuPont, Danone and many others making soy protein and products containing soy are likely watching the FDA closely because touting a connection to heart health on labels can be a big marketing advantage. Heart health is the No. 1 claim consumers look for when grocery shopping, according to the Hartman Group.
This new study could help the argument to allow the claim, but its acknowledged limitation could lessen the impact of the research findings when it comes time for the FDA to move ahead on its proposed rule to revoke the existing authorized label claim.
However, there are chances that even if the FDA takes the claim away, it may still allow a qualified health claim on soy protein products. A qualified health claim requires a lower scientific standard of evidence and permits label claims based on limited evidence linking consumption of soy protein with heart disease risk reduction.
The AP has reported the existing heart health claim is on between 200 and 300 soy products in the U.S. today, so whatever the FDA decides to do could have a major impact on those manufacturers and any competitive advantage they've had from heart-healthy labeling.
Previous studies show mixed conclusions about soy's impact on human health. A 2015 U.S. review of 35 studies on soy found it lowered LDL cholesterol and raised HDL, often called "good" cholesterol. Issues have been raised about soy's effect on breast cancer risk, poor thyroid function and interference with male hormones, but those seem to depend on underlying health conditions, how much soy is eaten and what type.
Soy also has a number of known benefits. It's low in fat, high in protein and has no cholesterol. Drawbacks include being low in calcium — unless fortified with it — and potentially causing allergies. In addition, 93% of soybeans grown in the U.S. are genetically engineered, which is an issue for some people.