Two large studies found links between high consumption of ultra-processed foods and increased risks of cardiovascular disease, bowel (colorectal) cancer and death. The findings add further evidence in support of policies that limit ultra-processed foods and instead promote eating unprocessed or minimally processed foods to improve public health worldwide, according to the BMJ, which published the studies. They also reinforce the opportunity to reformulate dietary guidelines worldwide, by paying more attention to the degree of processing of foods along with nutrient-based recommendations.

Ultra-processed foods include packaged baked goods and snacks, fizzy drinks, sugary cereals, and ready-to-eat or heat products, often containing high levels of added sugar, fat, and/or salt, but lacking in vitamins and fiber. Previous studies have linked ultra-processed foods to higher risks of obesity, high blood pressure, cholesterol, and some cancers, but few studies have assessed the association with colorectal cancer risk.

The first study was based on 46,341 men and 159,907 women from three large studies of US health professionals whose dietary intake was assessed every four years using detailed food frequency questionnaires. Foods were grouped by degree of processing and rates of colorectal cancer were measured over a period of 24-28 years, taking account of medical and lifestyle factors.

Results show that compared with those in the lowest fifth of ultra-processed food consumption, men in the highest fifth had a 29% greater risk of developing colorectal cancer, which remained significant after further adjustment for body mass index and dietary quality. Furthermore, higher consumption of meat/poultry/seafood based ready-to-eat products and sugar sweetened beverages among men - and ready-to-eat/heat mixed dishes among women - was associated with an increased risk of colorectal cancer.

In the second study, researchers analyzed two food classification systems in relation to mortality - the Food Standards Agency Nutrient Profiling System (FSAm-NPS), used to derive the color-coded Nutri-Score front-of-pack label, and the NOVA scale, which evaluates the degree of food processing. Their findings are based on 22,895 Italian adults (average age, 55; 48% men).

Both the quantity and quality of food and beverages consumed were assessed and deaths were measured over a 14-year period, taking account of underlying medical conditions. Those in the highest quarter of the FSAm-NPS index (least healthy diet) compared with the lowest quarter (healthiest diet) had a 19% higher risk of death from any cause and a 32% higher risk of death from cardiovascular disease. Risks were similar for the NOVA scale.

Although the studies were observational, so can't prove cause and effect, both research teams say their findings support the public health importance of limiting certain types of ultra-processed foods for better health outcomes in the population.

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To download the US study, click here
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