Fasting, in combination with vitamin C, can help treat some cancers. This has been the discovery of researchers from the International Foundations of Medicine (IFOM) Cancer Institute Milan and the University of Southern California. They found that a diet that mimics fasting combined with high vitamin C delayed the progression of tumors in many colorectal cancer mouse models. The disease regressed in some of the mice.
They published their results in the Nature Communications journal. Senior author biological sciences professor Valter Longo said that they have demonstrated for the first time how non-toxic intervention can treat aggressive cancer effectively. Longo is also the USC Longevity Institute, USC Leonard Davis School of Gerontology director.
The study researchers reiterated that since fasting is still challenging for people living with cancer, there is a safer and more feasible option: a plant-based, low-calorie diet that mimics fasting and elicits the same response from cells as real fasting does.
The study's findings suggest that this low-toxicity treatment may replace conventional toxic therapies.
The results of past research on vitamin C's potential to fight cancer is mixed. However, recent studies have shown that it has some positive effects, especially if it is combined with chemotherapy. The new study was conducted to determine whether combining it with a diet that mimics fasting may enhance the capacity of high vitamin C to fight off tumors. This could be possible if it creates an environment that is toxic to cancer cells but safe for otherwise normal cells.
Longo shared that their first in-vitro experimentation had remarkable results. Used on their own, the diet and vitamin C reduced the growth of cancer cells and also instigated cancer cell death in a minor capacity. Combined, however, they had a synergistic effect, dramatically killing nearly all cancer cells.
The researchers only detected this dramatic effect in cancer cells with mutation, regarded as among the most challenging aspects of cancer research. The KRAS gene mutations signal the body's resistance to most of the cancer-fighting treatments, while also reducing patient survival rate. These mutations are seen in about one-fourth of all cancers in humans and about half of the colorectal cancers.
In addition, the study shared clues why past studies using vitamin C for cancer therapy had limited efficacy. Vitamin C seems to trigger cells that are KRAS-mutated to protect the cancer cells through the increase of ferritin. Ferritin is an iron-binding protein. However, by reducing ferritin levels, the researchers were able to increase the toxicity of vitamin C against cancer cells. They also discovered that survival rates of patients with colorectal cancer lowered when they had high ferritin levels.
Co-author Maira Di Tano said that the scientists observed that cycles of taking the diet increase vitamin C's effect against cancers involving KRAS mutations through iron regulation and oxidative stress mechanisms. It pointed to a specific gene, heme-oxygenase-1, which regulates iron.
The treatment combination was also found to enhance responses against melanoma and breast cancer mouse models. Now, five or more clinical trials currently investigate this diet and combine it with various anti-cancer drugs.