Soy products have long been touted for their many health-promoting phytochemicals. But a recent article published in Cancer Letters talks about a discovery made by Elvira Gonzalez de Mejia and Vermont P. Dia of the University of Illinois in Urbana of a benefit from lunasin, a peptide that occurs in soy, in preventing the spread of colon cancer to the liver.

With colon cancer, the liver is the predominant site of metastasis.  "When lunasin was used in combination with the chemotherapy drug oxaliplatin, we saw a six-fold reduction in the number of new tumor sites," revealed Dr de Mejia, who is an associate professor of food chemistry and food toxicology at UI.

The study used mice bred to develop colon cancer that metastasizes to the liver. The researchers divided the animals to receive daily injections of lunasin, lunasin plus the chemotherapy drug oxaliplatin, oxaliplatin alone or neither compound.  "The group that received lunasin alone had 50 percent fewer metastatic sites,” reported Dr de Mejia.  “But an even more exciting result was seen in the group that received both lunasin and the chemotherapy drug—only 5 new cancer sites when compared with 28 in the control group.”

"This huge reduction in metastasis was achieved with the amount of lunasin in only 25 daily grams of soy protein, the amount recommended in the FDA health claim," noted Dr Dia, who is a University of Illinois postdoctoral fellow.  "In this study, we have learned that lunasin can penetrate the cancer cell, cause cell death, and interact with at least one type of receptor in a cell that is ready to metastasize."