1: Consumption of ultra-processed foods does not increase prostate cancer risk
Over the past few decades, diets in many countries have shifted towards an increase in the consumption of ultra-processed foods: foods generally characterised by their low nutritional quality, higher content of total and saturated fats, added salt and sugar and lower fibre and vitamin density.
The first study to evaluate the association between the incidence of cancer and the consumption of ultra-processed food was reported last month in the BMJ, which looked at the dietary records of 104,908 participants (21.7% men and 78.3% women; age range 18-72 years, and without cancer at baseline) from the NutriNet-Sante cohort.
During follow-up (a median time of 5 years), 2228 first incident cases of cancer were diagnosed, among these 739 breast cancers, 281 prostate cancers and 153 colorectal cancers. Whilst multi-variate adjusted models showed that ultra-processed food was associated with increased risks of overall cancer (p<0.001) and breast cancer (p=0.02), no association was found between intake of ultra-processed food and prostate cancer (p=0.8). However, the relatively young cohort included in this study (median age 42.8 years) potentially impacted on this, resulting in relatively low numbers of prostate cancer diagnoses and limited statistical power.
Although a large cohort study, the general limitations of food epidemiological research apply, namely that assumptions have been made that the measured food exposure at baseline reflect long-term diets, and that food diaries are unbiased. Furthermore, the authors note that some carcinogenic processes may take several decades to take effect, and so a much longer follow-up period is required to measure the longer-term effect of ultra-processed foods on cancer risk.