According to two large studies, eating lots of highly processed foods such as convenience foods is linked to an increased risk of heart disease, bowel cancer and premature death.
Research offers more reasons to limit the consumption of ultra-processed foods and instead consume more unprocessed or minimally processed foods to reduce the risk of death, disease and poor health. The results were published in the BMJ.
A growing body of evidence suggests that a high intake of ultra-processed foods is associated with a higher risk of several chronic diseases. However, few studies have assessed the association between ultra-processed foods and bowel cancer risk, and previous results have been mixed due to limitations in study design and sample sizes.
Ultra-processed foods include baked goods and packaged snacks, soft drinks, sugary cereals, and ready-to-eat or reheat products, often containing high levels of added sugar, fat, and/or salt. but lacking in vitamins and fiber.
The first study suggests that a high intake of ultra-processed foods in men and certain ultra-processed food subgroups in both men and women are associated with an increased risk of colorectal cancer. The second study found a link with an increased risk of cardiovascular disease and death.
The findings reinforce the importance of reformulating dietary guidelines around the world, paying more attention to the degree of food processing as well as nutrient-based recommendations.
In the first study, researchers examined the association between the consumption of ultra-processed foods and the risk of colorectal cancer in American adults. Their findings were based on 46,341 men and 159,907 women from three large studies of US health professionals whose food 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 three-decade period, taking medical and lifestyle factors into account.
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% higher risk of developing colorectal cancer. The link remained significant even after further adjustment for body mass index or diet quality.
No association was observed between overall consumption of ultra-processed foods and risk of colorectal cancer in women. However, higher consumption of ready-to-eat meat, poultry or seafood products and sugar-sweetened beverages in men – and ready-to-eat or reheated mixed dishes in women – was associated with increased risk. increased colorectal cancer.
The second study was based on 22,895 Italian adults. The quantity and quality of food and drink consumed were assessed and deaths were measured over a 14-year period, taking into account underlying medical conditions.
The results showed that those with the least healthy diets compared to those with the healthiest diets had a 19% higher risk of death from all causes and a 32% higher risk of death from heart disease. .
The risks were similar when the two highest and lowest categories of ultra-processed food intake were compared (19% and 27% higher for all-cause and cardiovascular mortality, respectively).
A significant proportion of the excess mortality risk associated with poor diet was explained by a higher degree of food processing. Consumption of ultra-processed foods remained associated with mortality even after accounting for poor nutritional quality of the diet.
Both studies are observational and therefore cannot establish a cause. Limitations include the possibility that some risks are due to other confounding factors.
Nevertheless, both studies used reliable markers of diet quality and took into account well-known risk factors. The findings confirm other research linking highly processed foods to poor health.