For years, cancer researchers have been baffled by a phenomenon called the “Japanese lung cancer paradox.”
American men who smoke have a 40 times greater risk of lung cancer than men who don’t smoke.
But Japanese men who smoke have a much lower incidence of lung cancer than American smokers. Their risk is still high—6.3 times greater than nonsmokers—but it’s just a fraction of the threat faced by American tobacco users.
Researchers at the American Chemical Society set out to solve the puzzle.
They studied mice who were genetically predisposed to lung cancer. Left untreated, virtually all of these animals develop cancer.
They divided the rodents into three groups. For five months, researchers fed one group of mice capsaicin, the chemical that makes hot peppers spicy. The second group was fed 6-gingerol, the compound that gives fresh ginger it’s pungent flavor. The third group was fed both.
Scientists have long noted that both compounds offer potential health benefits. Capsaicin is used topically to treat psoriasis, joint pain, and neuropathy. Gingerol has shown potential as a treatment for rheumatoid arthritis and for cancer suppression.
Of the mice fed capsaicin, all got cancer. Of those eating 6-gingerol, half developed tumors. But among the mice who ate a combination of capsaicin and 6-gingerol, the cancer rate was only 20%.
Researchers say 6-gingerol and capsaicin slow cancer by binding to a receptor on tumors linked to cell growth. The combination works synergistically to lessen the incidence of cancer.
The findings were published in the American Cancer Society’s Journal of Agricultural and Food Chemistry.