In 1924, Otto Warburg described a phenomenon in which cancer cells developed a different method of generating energy. He proposed that cancer cells rely primarily on the fermentation of sugar rather than using oxygen and aerobic respiration to produce energy. This process is now called the Warburg effect, in which nearly all tumors take in large amounts of glucose and release lactate. Malfunctioning mitochondria are the culprits for this alteration in energy production, which results in increased growth and decreased rate of cellular death. Warburg’s theory lost popularity for years but was revived in the 1970s by Peter Pedersen Ph.D., of John Hopkins University. Since then, numerous studies have investigated ways in which cancer is affected by lifestyle. Here we explore what is now known and consider certain diets which may help to reduce your overall risk of this all-too-common disease.
In health, as well as disease, it is not one single thing that determines how we are, but a combination of multiple factors. The exposome has been defined as the totality of exposure individuals experience over their lives and how those exposures affect health. We will discuss nutrition in a moment, but first let us consider an individual’s exposome beyond diet, including such things as environmental exposure, hormone balance, medications, body composition, amount of daily physical activity and any underlying inflammation.1 Each element exerts influences on health and risk of disease independently and through interaction with other elements. For example, inflammation is a known risk factor for cancer as it is for other diseases. To reduce cancer risk, we can target chronic inflammation by moving to eliminate inflammatory triggers and also support the body so that it can remove inflammation causing substrates in the body.
Chronic inflammation is further triggered by two conditions directly related to diet and nutrition. Obesity and metabolic syndrome are often the result of a diet of sugar and highly processed foods, combined with poorly managed stress and lack of sleep. These all combine to systematically increase insulin levels in the body. This is fertile ground to cultivate adipocytes, which are the fat cells. Adipocytes are not just storage tanks for fat, but also act as an active endocrine organ that secretes cytokines and hormones that trigger chronic inflammation. 2 Increased inflammation leads to local tissue damage, which, like a local wound, 3 induces an influx of immune cells and growth factors, and triggers tissue remodeling and new blood flow to the area. The resulting microenvironment provides tumor cells with everything they need to grow to take over the mechanisms to support their own growth and tissue invasion.4 To stop this process of chronic inflammation at the source, we must address diet, as well as sleep and stress. The basic tenets for keeping inflammation in check include meditation, movement, proper sleep, and a proper diet.
One of the most often evaluated diets for cancer, as well as heart disease and overall weight balance, is the Mediterranean diet. This diet includes a variety of vegetables as its base, with an emphasis on consuming locally and seasonally available options.
The pyramid for the Mediterranean diet has as its foundation physical activity and community activity5. Every meal should be dominated by vegetables (2 or more servings per meal) and whole grains (1-2 servings per meal), with fruit primarily as dessert (1-2 servings per meal). Also included are olives, nuts and seeds (1-2 servings a day) and dairy on a daily basis. On a weekly basis, is included a variety of protein from fish/seafood (1-2 servings per week), eggs (2-4 servings) and poultry (2 servings), while limiting red meat and processed meat consumption. Again, the focus is on whole foods and any sweets or alcohol are to be included only in moderation.
The fiber content of this type of diet supports the growth of good bacteria in the gut microbiome and increases the production of short chain fatty acids, which have been linked to reduced risk of inflammatory diseases, diabetes, and cardiovascular disease. The emphasis on a variety of colors of vegetables and fruits provides added benefits from the intake of a broad range of micronutrients and phytochemicals. Phytonutrients are both antioxidant and anti-inflammatory, which means they can reduce the effects of free radicals and inflammatory triggers in the body.1 A build-up of free radicals in cells may otherwise cause damage to DNA, RNA, and proteins, and potentially result in cell death.6
Another diet that may be beneficial in prevention and treatment of cancer is the ketogenic diet. This diet was originally developed in the 1920s to treat epilepsy in children. It was used for two decades as a therapeutic option until drugs were developed to treat this condition. The current epidemic of obesity and cancer in America has renewed interest in the ketogenic diet. This diet has helped many lose weight, but it may not be appropriate for everyone and is not necessarily considered ideal as a long-term solution.
The ketogenic diet may also serve a therapeutic purpose when incorporated into cancer treatment regimens. Miriam Kalamian’s book Keto for Cancer assists patients and their families to get started on the ketogenic diet as an adjunct to conventional treatment. The idea with a keto style diet is that you can decrease the amount of glucose available to the cancer cells while maintaining a steady supply of energy from beta hydroxybutyrate, a ketone body, and thereby induce apoptosis (cell directed death) in unhealthy cells. This diet can help sensitize tumor cells to standard-of-care treatments and increase the overall success of those treatments in clearing some tumors.7 Recent studies of the use of the ketogenic diet in glioma cases indicate that not only does the ketogenic diet affect the cancer cells, it also induces genetic and immune changes which benefit overall wellness.8 The ketogenic diet also modulates oxidative stress and reduces the chemicals in the body that trigger inflammation. In general, it seems that a ketogenic diet provides added support to cancer patients and can also be a way to decrease cancer risk overall.
Fasting has been a part of various cultures for centuries and is now entering the mainstream. When you fast, your gut and liver are given time to clear out by-products of digestion and clear the inflammatory process that happens when we eat. It also enables the body to tap into stored fat to use for energy. Further, adaptation to starvation requires the body to divert energy into various protective systems in order to minimize the damage that might come from starvation. It is thought that by triggering these systems, fasting can also increase longevity and decrease cancer risk. Fasting may also protect cancer patients against the harmful side effects of cancer treatments. As long as there is no chronic weight loss, fasting for up to five days, followed by a normal diet prior to treatment may reduce side effects from treatment, without interfering with the beneficial treatment effects. For general cancer prevention, it may be helpful to add intermittent fasting (at least 13 hours without food) to a colorful plant-based diet like the Mediterranean diet discussed above.
The paradigm of cancer prevention and treatment is changing. It is becoming clear that there is much we can do in our day-to-day lives to support our health and avoid receiving a cancer diagnosis.
- Mentella, Maria Chiara, et al. “Cancer and Mediterranean Diet: A Review.” Nutrients, vol. 11, no. 9, 2019, doi:10.3390/nu11092059.
- Cao, Yihai. “Adipocyte and Lipid Metabolism in Cancer Drug Resistance.” Journal of Clinical Investigation, vol. 129, no. 8, 2019, pp. 3006–17, doi:10.1172/JCI127201.
- Iyengar, Neil M., et al. “Obesity and Cancer Mechanisms: Tumor Microenvironment and Inflammation.” Journal of Clinical Oncology, vol. 34, no. 35, 2016, pp. 4270–76, doi:10.1200/JCO.2016.67.4283.
- Avgerinos, Konstantinos I., et al. “Obesity and Cancer Risk: Emerging Biological Mechanisms and Perspectives.” Metabolism: Clinical and Experimental, vol. 92, 2019, pp. 121–35, doi:10.1016/j.metabol.2018.11.001.
- Serra-Majem L., et al. “Updating the Mediterranean Diet Pyramid towards Sustainability: Focus on Environmental Concerns.” International Journal of Environmental Research and Public Health, vol. 17, no. 23, 2020, p. 8758, doi:10.3390/ijerph17238758.
- Klaunig, James E. “Oxidative Stress and Cancer.” Current Pharmaceutical Design, vol. 24, no. 40, 2018, pp. 4771–78, doi:10.2174/1381612825666190215121712.
- Schwartz, Laurent, et al. “Out of Warburg Effect: An Effective Cancer Treatment Targeting the Tumor Specific Metabolism and Dysregulated PH.” Seminars in Cancer Biology, vol. 43, 2017, pp. 134–38, doi:10.1016/j.semcancer.2017.01.005.
- Poff, Angela, et al. “Targeting the Warburg Effect for Cancer Treatment: Ketogenic Diets for Management of Glioma.” Seminars in Cancer Biology, vol. 56, 2019, pp. 135–48, doi:10.1016/j.semcancer.2017.12.011.