Consumption of ultra-processed foods and cancer risk: results from NutriNet-Santé prospective cohort.
BMJ (Clinical research ed.). 2018;360:k322
Plain language summary
Foods that are heavily processed tend to have high levels of total fat, sugar and salt and low levels of fibre and vitamins. They also tend to have high levels of contaminants (caused for example by high heat treatment), food additives and plastic packaging exposure. This large prospective population-based cohort study assessed the association between ultra-processed food consumption and the incidence of cancer. The study found that ultra-processed food intake was associated with a higher overall cancer risk and a higher breast cancer risk. A 10% increase in the consumption of ultra-processed foods was associated with an increase of more than 10% greater risk of overall and breast cancer risk. The authors call for further studies to better understand the different elements of food processing and their association to cancer risk.
OBJECTIVE To assess the prospective associations between consumption of ultra-processed food and risk of cancer. DESIGN Population based cohort study. SETTING AND PARTICIPANTS 104 980 participants aged at least 18 years (median age 42.8 years) from the French NutriNet-Santé cohort (2009-17). Dietary intakes were collected using repeated 24 hour dietary records, designed to register participants' usual consumption for 3300 different food items. These were categorised according to their degree of processing by the NOVA classification. MAIN OUTCOME MEASURES Associations between ultra-processed food intake and risk of overall, breast, prostate, and colorectal cancer assessed by multivariable Cox proportional hazard models adjusted for known risk factors. RESULTS Ultra-processed food intake was associated with higher overall cancer risk (n=2228 cases; hazard ratio for a 10% increment in the proportion of ultra-processed food in the diet 1.12 (95% confidence interval 1.06 to 1.18); P for trend<0.001) and breast cancer risk (n=739 cases; hazard ratio 1.11 (1.02 to 1.22); P for trend=0.02). These results remained statistically significant after adjustment for several markers of the nutritional quality of the diet (lipid, sodium, and carbohydrate intakes and/or a Western pattern derived by principal component analysis). CONCLUSIONS In this large prospective study, a 10% increase in the proportion of ultra-processed foods in the diet was associated with a significant increase of greater than 10% in risks of overall and breast cancer. Further studies are needed to better understand the relative effect of the various dimensions of processing (nutritional composition, food additives, contact materials, and neoformed contaminants) in these associations. STUDY REGISTRATION Clinicaltrials.gov NCT03335644.
Variations of physical activity and sedentary behavior between before and after cancer diagnosis: Results from the prospective population-based NutriNet-Santé cohort.
Physical activity (PA) but also reduced sedentary behavior may be associated with better prognosis and lower risk of recurrence in cancer patients. Our aim was to quantify the variations in PA and time spent sedentary between before and after diagnosis, relying on prospective data in French adults. We also investigated sociodemographic and lifestyle factors associated with these variations.Subjects (n = 942) were incident cancer cases diagnosed in the NutriNet-Santé cohort between 2009 and 2015. PA and sedentary behavior were prospectively collected with the 7-day short version of the IPAQ questionnaire every year since subjects' inclusion (i.e., an average of 2 year before diagnosis). All PA and sitting time points before and after diagnosis was compared by mixed model. Factors associated with decrease in PA and increase in sitting time were investigated using logistic regressions.Overall and vigorous PA decreased after diagnosis (P = 0.006, -32.8 ± 36.8 MET-hour/week on average, in those who decreased their overall PA and P = 0.005, -21.1 ± 36.8 MET-hour/week for vigorous PA, respectively), especially in prostate (-39.5 ± 36.3 MET-hour/week) and skin (-35.9 ± 38 MET-hour/week) cancers, in men (-40.8 ± 46.3MET-hour/week), and in those professionally inactive (-34.2 ± 37.1 MET-hour/week) (all P < 0.05). Patients with higher PA level before diagnosis were more likely to decrease their PA (odds ratio [OR]: 4.67 [3.21-6.81], P < 0.0001). Overweight patients more likely to decrease moderate PA (OR: 1.45 [1.11-1.89], P = 0.006) and walking (OR: 1.30 [1.10-1.70], P = 0.04). Sitting time increased (P = 0.02, +2.44 ± 2.43 hour/day on average, in those who increased their sitting time), especially in women (+2.48 ± 2.48 hour/day), older patients (+2.48 ± 2.57 hour/day), and those professionally inactive (2.41 ± 2.40 hour/day) (all P < 0.05). Patients less sedentary before diagnosis were more likely to increase their sitting time (OR: 3.29 [2.45-4.42], P < 0.0001).This large prospective study suggests that cancer diagnosis is a key period for change in PA and sedentary behavior. It provides insights to target the subgroups of patients who are at higher risk of decreasing PA and increasing sedentary behavior after cancer diagnosis.