Emerging evidence suggests that dietary rice bran may have beneficial effects against several types of cancer, such as breast, lung, liver and colorectal cancer. The chemopreventive potential has been related to the bioactive phytochemicals present in the bran portion of the rice, according to a new study published in the journal Advances in Nutrition.
Researchers at the University of Colorado Cancer Center found there is a delicate balance of bioactive components in rice bran that together show anti-cancer activity, including the ability to inhibit cell proliferation, alter cell cycle progression and initiate the programmed cell death known as apoptosis in malignant cells. The researchers showed that bioactive rice bran derived small molecules include, but are not limited to, polyphenolics, ferulic acid, tricin, β-sitosterol, γ-oryzanol, tocotrienols/tocopherols and phytic acid.
“We’re working now to tease apart the ratios of these active molecules required for bioactivity and mechanisms. Previous attempts to isolate one or another compound have been largely unsuccessful and so it looks now as if rather than any one compound giving rice bran its chemopreventive powers, it’s the synergistic activity of multiple components in the whole food that should be studied," the said.
Work with cancer cell lines and animal models shows that the bioactive components of rice bran act not only within cancer cells but around the cells to create conditions in the surrounding tissues that promote the function of healthy cells, while inhibiting the function of cancer cells. This tissue microenvironment activity includes mediating chronic inflammation that provides a ripe landscape for cancer.
The researchers are evaluating how rice bran may also help to promote an anti-cancer immune response and modulate gut microbiota metabolism for protection against cancer.
“There are well over 100,000 varieties of rice in the world, many with their own unique mix of bioactive components and so one major challenge is to discover the optimal composition for chemoprevention. Another challenge is ensuring that people consistently receive the required daily intake amount or ‘dose’ needed to demonstrate these chemo-protective effects. That said, rice is an accessible, low-cost food in most places of the world, and so work with rice bran as a dietary chemopreventive agent has the potential to impact a significant portion of the world’s population," they said.
Current fiber intakes are alarmingly low, with less than 3% of all Americans meeting recommended intakes. Many nutrition authorities believe adding fiber ingredients to commonly consumed foods will help Americans bridge the fiber gap without adding significant calories to the diet.
