Two new University of Illinois (U of I) studies report that lunasin, a soy peptide often discarded in the waste streams of soy-processing plants, may have important health benefits that include fighting leukemia and blocking the inflammation that accompanies such chronic health conditions as diabetes, heart disease and stroke.

“Significant levels of the peptide in the participants' blood give us confidence that lunasin-rich soy foods can be important in providing these health benefits,” says U of I Professor Elvira de Mejia, who led the research.

In the cancer study, de Mejia's group identified a key sequence of amino acids — arginine, glycine and aspartic acid — that triggered the death of leukemia cells by activating a protein called caspase-3. The scientists also verified lunasin's ability to inhibit an enzyme that marks the development of cancer, and were able to quantify the number of leukemia cells killed after treatment with lunasin in lab experiments.

In another study, the first to report lunasin's potential anti-inflammatory activity, they showed that lunasin blocked or reduced the activation of an important marker called NF-kappa-B, a link in the chain of biochemical events that cause inflammation. Although inflammation is linked in the public mind with chronic health problems such as heart disease, diabetes and rheumatoid arthritis, de Mejia says it also plays a role in the development of cancer.

Soy flour contains high concentrations of the beneficial peptide, she says.

De Mejia studied 144 soy genotypes to learn which varieties contain the most lunasin. “Some genotypes contain very high concentrations of lunasin, others contain no lunasin and some locations yield more lunasin-rich beans than others,” she says.