The Study

This study was designed to test whether a ketogenic diet with different kinds of fatty acids can inhibit the growth of tumors of the human colon cancer cell. The ketogenic diet used provided average protein and was low in carbohydrates and high in fat enriched with omega-3 fatty acids and MCT (MKD) or with lard only (LKD).

Methods

This study used 36 male nude mice and was placed under a pathogen-free environment. They received adequate nutrition divided into three feeding groups: ketogenic diet, lard diet and standard diet. Ketogenic and lard diet consisted of high levels of polyunsaturated omega-3 fatty acids and medium chain triglycerides comprising of 69% fat, 3% carbohydrate and 20% protein while the standard diet was composed of 5.28% fat, 52% carbohydrate and 22.1% protein. Tumor size and body weight of all animals were measured every second/ third/fourth day.

Results

The difference between the median tumor volume curves of the ketogenic and lard diet compared to the standard diet was significant. In terms of survival rates, the last animal in the standard diet group reached the endpoint on day 29 after tumor cell injection, whereas, the last animal of the ketogenic and lard diet group reached the endpoint on day 45 and 43, respectively. The author concludes that “overall, application of the unrestricted ketogenic diet with different kinds of fatty acid was highly significantly associated with survival.”

The study noted no significant difference between the blood glucose levels of the three diets. The serum insulin levels at the end of experiment were slightly reduced in the ketogenic and lard diet in comparison to standard diet animals, but the difference was not significant. In addition, there were no significant changes in triglycerides in all three diet groups. There was a rise in total cholesterol and high-density lipoprotein cholesterol together with low-density lipoprotein cholesterol in the ketogenic and lard diet group compared to the standard diet group, but the difference was not considered significant.

Conclusion

Compared to the applied standard diet, the unrestricted ketogenic diet had a retarding effect on tumor growth and resulted in larger necrotic areas within the tumors. The authors comment that ”a possible cause of the observed delaying effect of the ketogenic diet on tumor growth is that tumors are largely unable to metabolize ketone bodies for energy due to various deficiencies in one or both of the key mitochondrial enzymes.” Another possible effect on delayed tumor growth was considered to also be the high levels of omega-3 fatty acids and MCT in the diet. In summary, the author states “we demonstrate that a carbohydrate-restricted diet supplemented with lipids rich in omega-3 fatty acids and MCT or lard only delays the growth of glucose fermenting tumors.” And further, that: “The ketogenic diets described here may provide a promisingstrategy for anti-tumor therapy in the future.”

Citation

Hao GW, Chen YS et al (2015). Growth of Human Colon Cancer Cells in Nude Mice is Delayed by Ketogenic Diet. Asian Pac J Cancer Prev, 16 (5), 2061-2068