Fasting in management and prevention of cancer

 

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Introduction

Cancer is undoubtedly one of the most deadly ailments to befall mankind since ancient times, since there is evidence of a large growth or tumour (an abnormal, solid mass of tissue caused by excessive cell division or failure of cells to die when they are supposed to) in the left femur (the bone between the pelvic joint and the knee joint) of a mediaeval man (1).

A cancer or tumour is developed when abnormal cells grow uncontrollably (2). The human cells are designed to die when they become abnormal in a process called apoptosis or programmed cell death, but sometimes cells avoid this mechanism and grow into a large mass. Malignant tumours, unlike benign tumours that are non-cancerous and grow slowly, grow quickly with the ability to invade nearby tissues and even spread to other parts of the body, a process called metastasis.

Why cancer?

As an ailment of concern due to its severity, cancer has been on the lips of people, ranging from the medical professionals who spend their careers taking care of patients to individuals who have suffered from cancer or have a family or friend with the ailment.

Within these discussions are beliefs concerning cancer, often from the non-professionals concerning its management or treatment. One of these beliefs or claims is the effect of fasting or intermittent fasting (more like a scheduled eating pattern involving fasting to burn fat and improve metabolic health) on cancer.

Before we dive into the subject matter, i.e., the effect of fasting or intermittent fasting on cancer progression or cancer prevention, let us discuss why cancer has been on the lips of the masses, especially while it is like a hard nut to crack, and also the same reason making quick conclusions, especially without a good medical background on cancer and its metabolic components, is not the right thing to do.

 

How tumours survive harsh conditions

Tumours have been known to survive harsh conditions via several mechanisms, of which we would be discussing a few.

a. Tumour or cancer cells are out of control of the signals the body produces to control cells and their growth. For instance, a self-destruct signal is used by cells to destroy itself when they undergo stress that could make them abnormal. So cancer cells keep growing with the aberrations or mutations (a permanent and random change in the sequence of DNA that can affect the genes and the resultant chromosomes).

b. Cells require blood supply to provide the oxygen for metabolic processes as well as nutrients. Since several new abnormal cells are compounding rapidly, more oxygen and nutrients are needed. Tumour cells develop a mechanism of stimulating the growth of new blood cells.

c. Telomere (a compound structure found at the end of a chromosome) which shortens progressively to maintain the lifespan of the cell is manipulated by cancer cells to keep growing.

 

 

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d. These tumour cells have the ability to transform into mobile cells, escape through the blood vessels and migrate to other sites of the body in a process tagged metastasis. This behaviour of cancer cells is the major cause of cancer death. This movement might sometimes occur due to the unfavourable condition of the primary tumour site (where the tumour started growing).

 

Fasting and Cancer

Several studies have been carried out on the effect of fasting on cancer prevention, cancer management, cancer treatment and prevention of cancer reoccurrence (relapse). We would investigate these subtopics one after the other.

 

Effect of fasting on cancer prevention

Several research studies have been done investigating how the lifestyle of fasting or intermittent fasting has affected cancer prevention. In a research paper, the result stated that individuals over 60 years, a 1-hour increment in fasting duration at night was associated with a 9.5% higher risk of colorectal cancer; however, a 1-hour increment in night sleep duration is associated with a 15.2% lower risk of colorectal cancer (3), thereby suggesting a night sleep duration increase instead of a night fasting duration increase for individuals of that age range. This research shifts focus from fasting increment to sleep increment as a mechanism for colorectal cancer risk reduction for individuals over 60 years of age.

The benefits of night sleep stem from the metabolic resetting, detoxification, cell repairs, stress relief, etc., that happen during night sleep.

Another research paper produced a result that further enlightened the above paper on earlier breakfast association in cancer prevention. The research result stated that combining long night fasting and early breakfast may be associated with a lower risk of prostate cancer when compared to short night fasting and late breakfast (4). The study further stated that fasting for more than 11 hours overnight was associated with prostate cancer risk reduction compared to fasting for 11 hours or less. Other factors considered in the study can be found in the paper.

These studies record the possibility of employing nighttime fasting and night sleep duration in possible cancer-risk reduction. That being said, it is worthy to note that there are other factors that affect cancer risk, like inherited genetic configuration; lifestyle components like smoking and drinking; and environmental factors such as pollution and radiation.

 

Fasting and cancer management

According to various studies, fasting and cancer management are controversial topics due to the following reasons.

Evidence that fasting reduces the toxic effect and side effects of chemotherapy is not available (5). The study also stated that there are no beneficial effects of short-period fasting on the quality of life of cancer patients under treatment (5).

Another study stated the lack of an ‘integrated mechanistic model’ to judge how fasting could support conditions that limit cancer cell growth, survival and adaptation (6). This is to say that the processes mentioned above are complicated, and they lack an effective protocol for investigating how they are associated.

Conclusion

There is not enough substantiated evidence on the direct and proven effectiveness of fasting or intermittent fasting on cancer prevention and management. This is because a tumour and its molecular components are complex and require advanced mechanisms in understanding how they are associated, hence numerous studies and research that seek to provide useful information. Yes, there are studies, but those studies are not enough to support the claim of the efficacy of fasting in this field of medicine and are therefore subject to further studies and investigations.

Remember, this article was presented for educational purposes and is strictly not medical advice. This is because research data are only translated by qualified medical personnel into clinical practice. So, you should only consult your doctor for medical advice.

 

References

1. https://www.discovermagazine.com/the-hunt-for-the-prehistoric-roots-of-cancer-29967

2. Tiwari, S., Sapkota, N., & Han, Z. (2022). Effect of fasting on cancer: A narrative review of scientific evidence. In Cancer Science (Vol. 113, Issue 10, pp. 3291–3302). John Wiley and Sons Inc. https://doi.org/10.1111/cas.15492

3. Huang, P., Zeng, B., Li, S., Zhang, K., Li, C., Liang, Y., Liuzhang, B., Wu, X., Xie, S., Li, Y., & Zhang, B. (2026). Exploratory Analysis of Association of Nightly Fasting and Sleep Durations with Colorectal Cancer Risk in Chinese Community-Dwelling Older Adults: A Cross-Sectional Study. Nutrients , 18(5). https://doi.org/10.3390/nu18050861

4. Palomar-Cros, A., Espinosa, A., Straif, K., Pérez-Gómez, B., Papantoniou, K., Gómez-Acebo, I., Molina-Barceló, A., Olmedo-Requena, R., Alguacil, J., Fernández-Tardón, G., Casabonne, D., Aragonés, N., Castaño-Vinyals, G., Pollán, M., Romaguera, D., & Kogevinas, M. (2021). The association of nighttime fasting duration and prostate cancer risk: Results from the multicase-control (mcc) study in Spain. Nutrients, 13(8). https://doi.org/10.3390/nu13082662

5. Drexler, U., Dörfler, J., von Grundherr, J., Erickson, N., & Hübner, J. (2023). Fasting during cancer treatment: a systematic review. In Quality of Life Research (Vol. 32, Issue 5, pp. 1427–1446). Springer Science and Business Media Deutschland GmbH. https://doi.org/10.1007/s11136-022-03300-1

6. Tiwari, S., Sapkota, N., & Han, Z. (2022). Effect of fasting on cancer: A narrative review of scientific evidence. In Cancer Science (Vol. 113, Issue 10, pp. 3291–3302). John Wiley and Sons Inc. https://doi.org/10.1111/cas.15492