Red hot Chilli peppers and cancer
In 2017 capsaicin, the active ingredient of chilli peppers was found by German researchers - Ruhr-University Bochum’s Dr. Habil Hanns Hatt and Dr. Lea Weber - to cause cancer cell death while not harming healthy cells.
What was particularly interesting was that they used Triple Negative Breast Cancer (TNBC) cells, on which no drug seems to have an effect.
Active ingredient in chilli uniquely targets cancer cells in several ways
But it was nothing new. Back in 2007 Dr. Timothy Bates and a team at Nottingham University showed that the bioactive ingredient in chilli, capsaicin, attacks an enzyme in the mitochondrial energy production system of cancer cells. Since this cancer energy production system is unique and does not occur in healthy cells, Bates’ team were not surprised to see that while capsaicin killed lung cancer cells, it did not harm healthy cells.
The interesting finding by Hatt and Weber for capsaicin, as a member of the vanilloid family, was that it also binds to a receptor called the vanilloid receptor subtype 1 (TRPV1), on cancer cell membranes. This helps ions to cross the cell membrane. When capsaicin acts on TRPV1, calcium and sodium levels inside the cancer cell fluctuate and cause cancer cell death.
Capsaicin and the capiscum plant
Capiscum is the general name for plants in the Solanaceae family (nightshade). The whole plant may be either Capsicum annum or Capsicum frutescens, and these yield cayenne, chilli pepper, hot pepper, red pepper, paprika, pimiento, long pepper and conoids.
The plants are native to Mexico and Central America although they are now cultivated the world over.
The most studied active ingredient is a phenol, from the vanilloid family, capsaicin. It is anti-inflammatory and an analgesic. It has been approved by the U.S. FDA for use on the skin. However, in some research experiments, researchers handling the concentrated compound wear gloves – it can burn!!!
Capsaicin has also been studied in oral and topical forms. Several studies have shown that capsaicin may be helpful in managing pain related to surgery and mouth sores due to chemotherapy and radiation therapy.
Prior to 2002, results on the natural compound were mixed. Some researchers suggested it could cause cancer cell death, while others suggested it could even promote cancer.
Capsaicin, mitochondria and PMOR
However, in 2002 two researchers, Hail and Lotan, showed that capsaicin had several different mechanisms of action against mitochondrial problems (1). In healthy cells an enzyme (PMOR) transfers electrons from the cytoplasm to the mitochondrial power stations via Coenzyme Q10. PMOR is thought to be involved in the control of cell growth and proliferation. In healthy cells it is responsive to growth factors and hormones, whereas in tumour tissues and transformed cells it is not. Somehow, capsaicin seems to reboot this action. The researchers found that when cancer cells were treated with either capsaicin or resiniferatoxin, more than half underwent apoptosis (cancer cell death).
But. One study in 2010 (Cancer Research) by researchers at The Hormel Institute, University of Minnesota, linked capsaicin to a higher risk of skin cancer, although the molecular mechanisms of the cancer-promoting effects were not clear at all. Memorial Sloan-Kettering is of the view that this result may simply be dose-dependent.
Capsaicin and breast, bladder, prostate and lung cancer
Three studies have shown that it is, however, effective against breast (2), bladder (3) and prostate cancer (4) cell lines.
In 2007 researchers from Nottingham University (Biochemical and Biophysical Research Communications) found that vanilloids bind to proteins in the cancer cell mitochondria to trigger apoptosis, or cell death, in lung cancer cells without harming surrounding healthy cells. The researchers called it ‘cancer’s Achilles heel’.
Lead researcher, Dr. Bates, said: "Capsaicin, for example, is already found in treatments for muscle strain and psoriasis - which raises the question of whether an adapted topical treatment could be used to treat certain types of skin cancer. It’s also possible that cancer patients or those at risk of developing cancer could be advised to eat a diet which is richer in spicy foods to help treat or prevent the disease."
So, it uniquely damages cancer cells, it binds to unique proteins in cancer cells and their energy production systems and it binds to TRPV1. Maybe it has a number of actions only with cancer cells, or maybe it is not 100% understood yet. But it does cause cancer cell death without harming healthy cells.
The major issue is that almost all the research is on cell lines, with nothing really on cancer in a living human.
Capsaicin and anti-fungal, anti-yeast benefits
Capsaicin and related compounds are called capsaicinoids and it is know that they can burn animal tissue they come into contact with. This can be serious if in contact with the eyes, for example).
However, this property makes capsaicin an effective anti-fungal and anti-yeast agent. It is known that in countries such as Mexico or Thailand, the population naturally control yeast infection by consuming large amounts of chilli in spicy food.
Capsaicin also has a hyper-sensitising and pain relieving effect.
References:
1. Hail N, Lotan R. Examining the role of mitochondrial respiration in vanilloid-induced apoptosis. J Natl Cancer Inst 2002;94:1281–92.
2. Thoennissen NH, O’Kelly J, Lu D, et al. Capsaicin causes cell-cycle arrest and apoptosis in ER-positive and -negative breast cancer cells by modulating the EGFR/HER-2 pathway. Oncogene.Jan 14 2010;29(2):285-296.
3. Yang ZH, Wang XH, Wang HP, et al. Capsaicin mediates cell death in bladder cancer T24 cells through reactive oxygen species production and mitochondrial depolarization. Urology. Mar 2010;75(3):735-741.
4. Mori A, Lehmann S, O’Kelly J, et al. Capsaicin, a component of red peppers, inhibits the growth of androgen-independent, p53 mutant prostate cancer cells. Cancer Res. Mar 15 2006;66(6):3222-3229.