Reducing Cancer Risk Through Healthy Eating
(from American Association for Cancer Research, November 2018)
Following dietary recommendations may reduce risk of several cancers.
More vegetables and fruit. Less alcohol and processed food.
You’ve heard these recommendations before, but a study recently published in Cancer Research, a journal of the American Association for Cancer Research, shows that following such guidelines really could reduce your risk of cancer.
A team of French researchers conducted an analysis of four scientifically validated nutritional recommendations: the WCRF/AICR score; the Alternate Healthy Eating Index; the French Nutrition and Health Program-Guidelines Score; and the MEDI-LITE score.
The researchers found that all the diets were associated with some reduced risk of cancer. The WCRF/AICR recommendations, however, had the strongest association with reduced risk. These recommendations were developed specifically with cancer prevention in mind.
Aside from maintaining a healthy weight and getting regular physical exercise, the WCRF-AICR guidelines call for high consumption of plant-based foods and whole grain cereals, and low consumption of sugary drinks, meats, alcoholic drinks, salt, and salt-preserved foods.
“WCRF/AICR has estimated that in developed countries, around 35 percent of breast cancers and 45 percent of colorectal cancers could be avoided by better adherence to nutritional recommendations. It is, therefore, very important to investigate the role of nutrition in cancer prevention,” said co-author Bernard Srour, PharmD, MPH, and PhD candidate in nutritional epidemiology at EREN-Inserm.
To examine links between the four nutritional indices and cancer risk, researchers drew data from the NutriNet-Santé study, launched in 2009 to investigate associations between nutrition and health in a French cohort. This study included a large sample of 41,543 participants aged 40 or older. Over time, the participants tracked their dietary intakes, and the researchers used statistical modeling to characterize the associations between the four diets and several types of cancer.
The results showed that a one-point increase in the WCRF/AICR score was associated with a 12 percent decrease in overall cancer risk; a 14 percent decrease in breast cancer risk, and a 12 percent decrease in prostate cancer risk.
The authors concluded that the “synergistic contribution” of a healthy diet was more significant than any single dietary recommendation. For example, antioxidants from fruits and vegetables may contribute to counteract some of the oxidative damage to the DNA caused by red meat and processed meat, and exercise could lower blood pressure, partly counteracting the effects of high-sodium foods.
“This emphasizes the role of an overall healthy lifestyle—nutrition and physical activity and alcohol avoidance—in cancer prevention,” Dr. Srour said. “It is, therefore, important to keep in mind that every lifestyle factor counts and it is never too late to adopt a healthy lifestyle.”
The study’s authors said the WCRF/AICR recommendation to avoid alcohol most likely contributed to that diet’s role in reducing cancer risk. They said the findings in this study augment recent research that implicates alcohol as a risk factor in many cancers.
“In its last report, the WCRF stated that there is now strong, convincing evidence that alcohol consumption increases the risks of oropharyngeal, esophagus, liver, colorectal, and post-menopausal breast cancers,” said senior author, Mathilde Touvier, MSc, MPH, PhD, head of the Nutritional Epidemiology Research Team (EREN) of the French National Institute of Health and Medical Research (Inserm), University of Paris 13. She added that there are also apparent links to stomach and premenopausal breast cancers.
The authors said the study’s main limitation is that, as a volunteer-based study, it may have overrepresented women, people with health-conscious behaviors, and those with higher socioeconomic and educational levels. As a result, some unhealthy behaviors may have been underrepresented, and the associations between healthy diets and cancer prevention may be stronger than indicated.
Because previous research has shown that the French consume more fruits and vegetables and fewer sugary beverages and processed foods than the American population, the authors said adhering to the WCRF/AICR recommendations would likely yield more dramatic results in the United States.