Findings Add More Evidence in Support of Policies Limiting Ultra-Processed Foods
Two large studies published today by The BMJ find links between high consumption of ultra-processed foods and an increased risk of cardiovascular disease, bowel (colorectal) cancer and death.
The findings add additional evidence in support of policies that limit ultra-processed foods and instead promote the consumption of unprocessed or minimally processed foods to improve public health around the world.
They also reinforce the opportunity to reformulate dietary guidelines around the world, paying more attention to the degree of processing of foods along with nutrient-based recommendations.
Ultra-processed foods include packaged baked goods and snacks, soft drinks, sugary cereals, and ready-to-eat or heat products, which often contain high levels of sugar, fat, and/or salt, but lack vitamins and fiber.
Previous studies have linked ultra-processed foods to increased risks of obesity, high blood pressure, cholesterol, and some types of cancer, but few studies have evaluated the association between ultra-processed food intake and colorectal cancer risk, and the Findings are contradictory due to limitations in study design and sample sizes.
In the first study , researchers examined the association between consumption of ultra-processed foods and the risk of colorectal cancer in American adults.
Their findings are 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 colorectal cancer rates were measured over a period of 24 to 28 years, taking into account medical and lifestyle factors.
The results show that, compared to those in the lowest quintile of ultra-processed food consumption, men in the highest quintile of consumption had a 29% increased risk of developing colorectal cancer , which remained significant after further adjustment for body mass index or diet quality.
No association was observed between overall ultra-processed food consumption and colorectal cancer risk among women. However, higher consumption of meat/poultry/seafood and ready-to-eat products and sugary drinks among men, and ready-to-eat/heat combination meals among women, was associated with an increased risk of colorectal cancer.
In the second study , researchers looked at two food classification systems in relation to mortality: the Food Standards Agency Nutrient Profiling System (FSAm-NPS), used to derive the front label from the color-coded Nutri-Score package, and the NOVA scale, which assesses the degree of food processing.
Their findings are based on 22,895 Italian adults (average age 55; 48% men) from the Moli-sani Study, which investigates genetic and environmental risk factors for heart disease and cancer. Both the quantity and quality of food and drink consumed were assessed and deaths were measured over a 14-year period (2005 to 2019), taking into account underlying medical conditions.
The results showed that those in the highest quarter of the FSAm-NPS index (least healthy diet) compared to the lowest quarter (healthiest diet) had a 19% higher risk of death from any cause and a 32% higher risk of risk of death from cardiovascular disease.
The risks were similar when comparing the two extreme categories of ultra-processed food intake on the NOVA scale (19% and 27% higher for all-cause and cardiovascular mortality, respectively).
A significant proportion of the excess mortality risk associated with a poor diet is explained by a higher degree of food processing. In contrast, the intake of ultra-processed foods remained associated with mortality even after accounting for the poor nutritional quality of the diet.
Both studies are observational, so they cannot establish cause, and limitations include the possibility that some of the risks are due to other unmeasured (confounding) factors.
However, both studies used reliable markers of diet quality and took into account well-known risk factors, and the findings support other research linking highly processed foods to poor health.
As such, both research teams say their findings support the public health importance of limiting certain types of ultra-processed foods for better population health outcomes. The results of the Italian study also reinforce the opportunity to reformulate dietary guidelines around the world, paying more attention to the degree of food processing along with nutrient-based recommendations.
In a linked editorial, Brazilian researchers argue that no sensible person wants foods that cause disease.
The overall positive solution, they say, includes making fresh, minimally processed food supplies available, attractive and affordable. And sustain national initiatives to promote and support freshly prepared meals made with fresh and minimally processed foods, using small amounts of processed culinary ingredients and processed foods. “Enacted, this will promote public health. It will also nourish families, society, economies and the environment,” they conclude.
