Capsaicin, which is the chemical that puts the heat in hot chili peppers, may encourage some kinds of cancer cells to commit suicide; but capsaicin doesn’t seem to have the same effect on healthy cells. This is just one of many ways in which chemicals that are found naturally in plants (phytochemicals) could have an anticancer effect.
Cancer isn’t just one disease. It’s a group of unrelated diseases that all result from the same sort of problem: cells behaving badly. Cancer cells don’t become the kind of cell that they’re supposed to become, and they keep dividing to make new cells long after they were supposed to stop. Sometimes, they travel through the body and settle down in places where they’re not supposed to be. All of these problems result from something going wrong in the cell’s genetic material. Either some genes have been damaged or the switches that are supposed to turn the genes on and off have been stuck in the wrong position. This problem can get started if a cell’s genes are damaged by exposure to radiation or to cancer-causing (carcinogenic) chemicals, such as those in tobacco smoke. The first line of defense against cancer is to reduce the body’s exposure to radiation and other carcinogens.
Even after a cell has gone rogue, the body has several levels of defenses that could stamp out the cancer before it is ever noticed. The first is a self-destruct mechanism that is built into the cell’s genetic instructions. This self-destruction, which is called apoptosis or programmed cell death, causes the cell to break apart into tidy fragments that are quickly and easily devoured by white blood cells. In contrast, when cells die as a result of trauma, they make a mess by spilling their contents into the surrounding fluid.
Programmed cell death plays an important role in sculpting the embryo during early development. If cells are in the wrong place at the wrong time, they get a signal to commit suicide. That’s why most people aren’t born with webbed fingers and toes. Even in a healthy adult, tens of billions of cells undergo programmed cell death every day. Programmed cell death is a natural body process that is supposed to stay in a healthy balance. If too many cells die, the result is tissue shrinkage (atrophy). If too many cells fail to commit suicide, then abnormal cells such as cancer cells can get out of control.
Programmed cell death is a complicated process that can involve several different pathways and that can be stimulated or suppressed by many different signals. However, the end result is always the same: enzymes called caspases are activated, and they break down the protein structures inside the cell. Some kinds of cancer cells fail to undergo programmed cell death because they have a deficiency of or defect in one of their caspases. These cells may need a little extra encouragement to undergo programmed cell death.
Researchers have reported that capsaicin inhibits the growth of colon tumors. Theoretically, capsaicin could have antitumor effects in other parts of the body because it is easily absorbed from the intestine and carried throughout the body by the bloodstream. One study showed that capsaicin promotes programmed cell death in a particular type of liver cancer cells. Another study showed a similar effect in breast cancer cells.
The first line of defense against cancer is to avoid radiation, carcinogenic chemicals, and the viral infections that are known to cause cells to become malignant. The second line of defense is to eat a low-fat, high-fiber, plant-based diet, which acts in several different ways to prevent cells from becoming malignant and to suppress the growth of tumors. The promotion of programmed cell death by hot peppers is just one of the ways in which a plant-based diet could help to suppress cancer.