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Keto and Cancer

Could the secret to curing cancer really be as simple as eating a low carbohydrate, high fat diet? There have been a number of “miracle” cases where dogs have been diagnosed with varying types of cancer, only for the dogs to show signs of remission once they started on a ketogenic diet. How can something as simple as replacing carbohydrates with fat in the diet potentially produce such a drastic improvement in an animal’s health? Is it too good to be true?

The Keto Diet

The basis for the keto diet revolves around altering the balance of energy sources in the diet. This involves lowering the level of carbohydrate inclusion and subsequently increasing the fat content of the diet. The body is then forced to burn and utilize energy from the fat rather than from carbohydrates (1).

Carbohydrates and fats (or lipids) are metabolized in different ways in the body. Upon ingestion, carbohydrates are broken down into a sugar called glucose. This stimulates the hormone, insulin, to be released from the pancreas which packages and stores glucose as glycogen in the liver. The glycogen is stored until it is needed, at which time it is broken back down into glucose available for energy production, also known as ATP (2). 

black and white border collie mix puppy running on brown dirt road during daytime

A different metabolic pathway is used to process lipids for energy. Triglycerides and cholesterol are the most commonly ingested fats and when digested, yield more energy than carbohydrates. The conversion of fat to energy is quite complex but essentially lipids are broken down in a cycle called beta oxidation, which yields acetyl CoA. Acetyl CoA can then be used in another metabolic cycle, called the krebs cycle, to produce energy (3). 

In an individual who is consuming a keto diet, there is less glucose being produced from carbohydrate metabolism and an excess amount of acetyl CoA being produced from lipid metabolism. Acetyl CoA continues to rise to the point where it cannot all be used for energy and is converted into ketones inside of the liver. Ketones can then be converted back into acetyl CoA for energy use in the brain as an alternative to glucose. 

Theory of the Cancer Fighting Keto Diet

The keto diet was originally built on the theory that the replacement of ketones as energy in the brain could help reduce or eliminate epileptic seizures. Besides utilizing ketotic conditions to reduce seizures, there have been cases of cancer patients on the keto diet going into cancer remission (4).

The hypothesis between cancer remission and the keto diet stems from the idea that there is a reduction in the hormone called insulin-like growth factor 1 (IGL-1). When carbohydrates are metabolized into glucose and insulin is stimulated, there is a subsequent hormone cascade which results in the production of IGL-1. This hormone promotes mitosis and the proliferation of cells. The likelihood of DNA mutagenesis, the rate limiting step in cancer formation, rapidly rises with an increase in the proliferation of cells. An increase in glucose transporters as a result of carbohydrate ingestion are also thought to cause an inhibition in protective apoptosis or cell death. This makes cancerous cells more resistant to chemotherapy treatments. Combined, this supports the hypothesis of a high carbohydrate diet being a precursor for cancer formation (5).

For patients on the keto diet, it is thought that while normal cells can use ketones for energy, cancerous cells cannot. Therefore, cancer cells are pushed into remission. This in combination with the proliferative qualities of IGL-1 drive the hypothesis that the keto diet may help prevent and maybe even cure cancer.

Assortment of sliced vegetable and fruits on board

Problems with the Keto Theory

The first problem with relying on a keto diet to cure cancer is that there have been NO clinical trials proving the efficacy of keto diets in combating cancer. The theory that keto may be the golden key to resolving one of the most deadly diseases in mammals, is based solely on a few individual cases and physiological theory. 

In fact, a state of ketosis has actually been shown to have some serious negative health effects. These include low blood pressure, acidosis, kidney stones and heart disease. The keto diet can also cause more minor alterations in health. Dogs on keto diets have been reported to present with “flu-like” symptoms including diarrhea, lethargy and muscle atrophy. This is especially dangerous for individuals with cancer, potentially adding more complications to their conditions and recovery (6). Furthermore, the high fat content of keto diets are not suitable for dogs with pancreatitis as the high fat cannot be digested and may result in abdominal pains and worsening symptoms.

Multiple doctors have actually advised against using the keto diet, including dietician Dr. Rachel Kleinman from the University of Chicago Medicine. Dr. Kleinman states that “Research on the diet’s effectiveness in treating obesity, cancer and diabetes is limited” and “More often than not, it’s not sustainable. Oftentimes weight gain may come back, and you’ll gain more than what you lost” (7).

Red plastic heart with bandaid on top ECG chart

In Conclusion

Cancer is such a complicated, multifactorial disease, with no one cause or treatment. As it stands, simply removing carbohydrates from the diet cannot be the sole means of cancer prevention. Without proper research, the keto diet holds little merit as a cure for cancer in dogs or humans. Eating a balanced and antioxidant rich diet, in combination with exercise and avoiding carcinogenic compounds are still the best ways to reduce cancer risks.

View Sources

  1. Freeman, John M., Eric H. Kossoff, and Adam L. Hartman. "The ketogenic diet: one decade later." Pediatrics 119, no. 3 (2007): 535-543.
  2. Cori, Carl F. "Mammalian carbohydrate metabolism." Physiological Reviews 11, no. 2 (1931): 143-275.
  3. Schulz, Horst. "Beta oxidation of fatty acids." Biochimica et Biophysica Acta (BBA)-Lipids and Lipid Metabolism 1081, no. 2 (1991): 109-120.
  4. Keto Pet “The Ketogenic Diet and Cancer in Dogs” https://www.ketopetsanctuary.com/pages/case-studies
  5. Macaulay, V. M. "Insulin-like growth factors and cancer." British journal of cancer 65, no. 3 (1992): 311.
  6. Sampath, Amitha, Eric H. Kossoff, Susan L. Furth, Paula L. Pyzik, and Eileen PG Vining. "Kidney stones and the ketogenic diet: risk factors and prevention." Journal of child neurology 22, no. 4 (2007): 375-378.
  7. UChicago Medicine Ingalls Memorial “Ketogenic diet: What are the risks?” (2019). https://www.uchicagomedicine.org/forefront/health-and-wellness-articles/ketogenic-diet-what-are-the-risks
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