In a special themed issue of the Journal of the Academy of Nutrition and Dietetics, nutritionists and other heath professionals explore the association between nutrition, obesity and cancer prevention, treatment and survival. They also identify areas where research into future prevention strategies could be improved.
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In 2016, a report by the International Agency for Research on Cancer stated that excess body fatness increases the risk for 13 types of cancer. Lead investigator Stephen Hursting from the University of North Carolina and colleagues reviewed the mechanisms underlying this association and assessed the dietary interventions that are being used in preclinical and clinical trials.
Hursting says that obesity-associated metabolic perturbations are emerging as major drivers of obesity-related cancer, including alterations in growth factor signaling, inflammation, and angiogenesis.
Preclinical evidence suggests that dietary interventions, such as calorie restriction, intermittent fasting, low-fat diet and the ketogenic diet, have the potential to reverse some of these obesity-associated alterations; however, more clinical data are needed to confirm translation to human subjects.”
Stephen Hursting, The University of North Carolina
In adults, dietary energy density (DED) has been linked to weight gain. DED is the ratio of energy intake to food weight and serves as a measure of diet quality.
Cynthia Thomson (Mel and Enid Zuckerman College of Public Health) and colleagues present the findings of an investigation into the link between baseline DED and obesity-associated cancers in over 90,000 postmenopausal women enrolled in trials of the Women's Health Initiative.
A higher DED was shown to be associated with an increased risk of any obesity-related cancer. This increased risk was restricted to women with a normal BMI.
Thomson says the finding suggests that weight management alone may not protect against obesity-related cancers if women prefer a diet pattern indicative of high energy density: “Higher DED in normal-weight women may promote metabolic dysregulation independent of body weight, an exposure known to increase cancer risk.”
In a review of the evidence linking diet and cancer, dietician nutritionists from the National Institutes of Health explain the inconsistencies in the literature and the issues that registered dietitian nutritionists (RDNs) face when translating this complex information for patients:
Despite the best efforts of nutrition science researchers, inconsistencies exist across the diet-cancer prevention scientific literature. Clinical trials are the gold standard of research, but the body of scientific data should be compelling before translating scientific findings to our at-risk, presumed healthy patients for disease prevention and patients with a good prognosis undergoing treatment."
Nancy Emenaker and Ashley Vargas, National Institutes of Health