After comparing results from 24 studies, researchers at the Chinese University of Hong Kong found little evidence that increasing soy intake improves people’s blood sugar levels.
Previous lab research had indicated that soy proteins and estrogen-like compounds called soy isoflavones might help control blood sugar levels. The meta-analysis, designed to see if that is true, looked at 24 studies that had included a total of 1,518 people, some with diabetes. The studies had lasted anywhere from one to 12 months.
While the meta-analysis showed that there might be some benefit from soy-based foods like tofu as opposed to soy supplements, there was not enough evidence to conclude that soy helps blood sugar levels.
Nine of the studies had specifically tested the effects of soy-based foods on blood sugar levels. Participants in those studies experienced an average decrease in blood sugar levels of four mg/dL-statistically insignificant. Even then, researchers said they could not be sure if soy was the deciding factor in those lowered levels.
The meta-analysis results were published in the American Journal of Clinical Nutrition.