Two studies report that lunasin, a soy peptide present in effluents from 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.

In the cancer study, de Mejia's group identified a key sequence of amino acids—arginine, glycine, and aspartic acid, (the RGD motif)—that triggered the death of leukemia cells by activating a protein called caspase-3.

"Other scientists have noted the cancer-preventive effects of the RGD sequence of amino acids so it's important to find proteins that have this sequence," she said.

The scientists also verified lunasin's ability to inhibit topoisomerase 2, an enzyme that marks the development of cancer, and they were able to quantify the number of leukemia cells that were killed after treatment with lunasin in laboratory 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.

They also found statistically significant reductions in interleukin-1 and interleukin-6, both important players in the inflammatory process. The reduction in interleukin-6 was particularly strong, she said.

Although inflammation is linked in the public mind with chronic health problems such as heart disease, diabetes, and rheumatoid arthritis, de Mejia said it also plays a role in the development of cancer. "We know that chronic inflammation is associated with an increased risk of malignancies, that it's a critical factor in tumor progression," she said.

The authors of these stuides published in the the Journal of Agricultural and Food Chemistry suggest that daily consumption of lunasin-rich soy protein may help to reduce chronic inflammation and cancer risk.