By Joseph E. Scherger, MD, MPH

Core Faculty, Eisenhower Health Family Medicine Residency Program, Eisenhower Health Center, La Quinta, CA; Clinical Professor, Keck School of Medicine, University of Southern California, Los Angeles

Dr. Scherger reports no financial relationships relevant to this field of study.

SYNOPSIS: In a recent analysis, investigators noted a correlation between a diet loaded with processed red meat and various types of cancers.

SOURCE: Zhang FF, Cudhea F, Shan Z, et al. Preventable cancer burden associated with poor diet in the United States. JNCI Cancer Spectrum. Published May 22, 2019. Available at: http://bit.ly/2XnfALL. Accessed June 20, 2019.

A team from the Friedman School of Nutrition Science and Policy at Tufts University used some databases from multiple sources to conduct a comparative risk assessment of diet and cancer in the United States. Zhang et al found an estimated 80,110 new cancer cases attributable to a suboptimal diet. A total of 67,488 of these were direct dietary associations and 12,589 were obesity-mediated associations. Colorectal cancer accounted for both the highest number of new cancer cases (52,225) and the highest proportion of cases (38.3%). Other cancers associated with a poor diet were cancers of the mouth, pharynx, and larynx (14,421) as well as endometrial (3,165), breast (3,059), kidney (2,017), stomach (1,564), liver (1,000), pancreatic (538), and esophagus (475). The authors noted that a high intake of processed meat carried the highest association with these cancers. A low consumption of whole grains and dairy also increased the risk. The authors did not study food that might prevent cancer, such as a plant-based diet.

COMMENTARY

This study adds to growing evidence showing that the modern industrial diet leads to a heavy cancer burden. In 2010, an oncology fellow named Siddhartha Mukherjee published The Emperor of All Maladies: A Biography of Cancer.1 In it, he reported that early in human history, cancer was a rare disease. However, over time, cancer has become increasingly common, especially since the Industrial Revolution. This increase cannot be blamed on genetics; it has to do with the environment, including what we eat.

Empiric and epidemiologic research has shown that food can cause cancer.2,3 Other research suggests that healthy foods prevent cancer and may even reverse the disease.4,5 Still, clinicians lack data from large clinical trials of nutrition and cancer that could reveal more information. Until more researchers conduct such trials, it is important for clinicians to include nutrition education based on current evidence as part of discussions about cancer.

Certainly, it would be foolish to recommend that a patient reject cancer treatment and follow only a modified nutrition and lifestyle approach. There are instances of cancer reversals with a healthy diet and lifestyle changes; still, overall, those who choose only that route die more often than those who choose cancer treatment.6 Cancer treatment is moving away from using only the toxic and damaging drugs of chemotherapy to include health-enhancing methods such as immunotherapy. Everyone should eat a healthy diet, exercise daily, manage stress, engage in restorative sleep, and create social connections that can lead to meaning and purpose in life. Along with new health-enhancing cancer treatments, we could return to an earlier time when cancer was a rare disease.

REFERENCES

  1. Mukherjee S. The Emperor of All Maladies: A Biography of Cancer. New York: Simon and Schuster; 2010.
  2. Doll R, Peto R. The causes of cancer: Quantitative estimates of avoidable risks of cancer in the United States today. J Natl Cancer Inst 1981;66:1191-1308.
  3. Blot WJ, Tarone RE. Doll and Peto’s quantitative estimates of cancer risks: Holding generally true for 35 years. J Natl Cancer Inst 2015;107(4). pii: djv044. doi: 10.1093/jnci/djv044.
  4. Campbell TC, Jacobson H. Whole: Rethinking the Science of Nutrition. Dallas: BenBella Books; 2013.
  5. Campbell TC, Campbell II TM. The China Study: Revised and Expanded Edition: The Most Comprehensive Study of Nutrition Ever Conducted and the Startling Implications for Diet, Weight Loss, and Long-Term Health. Dallas: BenBella Books; 2016.
  6. The National Academies of Science, Engineering, and Medicine. A healthy diet alone will not cure cancer. Available at: http://bit.ly/2L1xDAE. Accessed June 20, 2019.