Ultra-processed foods linked to bowel cancer, cardiovascular disease and death

New research has found that consuming large amounts of ultra-processed food increases the risk of cardiovascular disease, colorectal cancer and death.

The research, published by The BMJ, adds to a growing number of studies linking highly processed foods with poor health.

The authors of the studies say the findings present a clear need to limit the consumption of ultra-processed foods in order to improve public health globally.

What is ultra-processed food?

The term ‘processed food’ encompasses all food that has been altered in some way during preparation. This includes food that has been cooked, tinned, frozen, packaged, dried or changed in nutritional composition (e.g. by fortifying or preserving).

Not all processed foods are unhealthy; some foods need processing to make them safe to eat. These foods therefore fall on a spectrum of minimally processed to ultra-processed.

Minimally processed foods include things like tinned tomatoes and tuna, and frozen fruit and vegetables. These foods are processed to lock in their nutritional value and preserve shelf life, and are not linked to poor health.

Other foods which are processed to add flavour and texture include jarred pasta sauce, salad dressing, yoghurt and cake mixes.

Ultra-processed foods, however, contain ingredients that you wouldn’t add when cooking homemade food (e.g. artificial colours or preservatives). These foods also often contain added salt, sugar and fat.

Common ultra-processed foods include microwave or ready-to-eat meals, sugary breakfast cereals, fizzy drinks, reconstituted meat products and confectionary.

Men who ate the highest amounts of ultra-processed foods had a 29% higher risk of developing colorectal cancer

While previous studies have linked ultra-processed foods to higher risks of obesity, high blood pressure, cholesterol, and some cancers, few studies have assessed the association between ultra-processed food intake and colorectal cancer risk.

To address this gap, the researchers analysed data from more than 206,000 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.

While no association was observed between overall ultra-processed food consumption and risk of colorectal cancer among women, men in the highest fifth of ultra-processed food consumption had a 29% higher risk of developing colorectal cancer compared to those in the lowest fifth. This remained significant after adjusting for BMI and dietary quality.

Higher consumption of meat/poultry/seafood based ready-to-eat products and sugar sweetened beverages among men was also associated with an increased risk of colorectal cancer. The same was found for women who ate high amounts of ready-to-eat/heat mixed dishes.

Those with the least healthy diets had a 32% higher risk of death from cardiovascular disease

In a separate study, the researchers analysed data from 22,895 Italian adults (average age 55 years; 48% men) from the Moli-sani study, investigating genetic and environmental risk factors for heart diseases and cancer.

They assessed both the quantity and quality of food and beverages consumed using two food classification systems – the Food Standards Agency Nutrient Profiling System (FSAm-NPS), used to derive the colour-coded Nutri-Score front-of-pack label, and the NOVA scale, which evaluates the degree of food processing.

Over a 14-year period, 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 when the two extreme categories of ultra-processed food intake on the NOVA scale were compared (19% and 27% higher for all-cause and cardiovascular mortality, respectively).

A significant proportion of the excess mortality risk associated with a poor diet was explained by a higher degree of food processing. In contrast, ultra-processed food intake remained associated with mortality even after the poor nutritional quality of the diet was accounted for.

Researchers call for the reformulation of dietary guidelines worldwide

Both studies are observational so can’t establish cause, and limitations include the possibility that some of the risks may be due to other unmeasured (confounding) factors.

Nevertheless, both studies used reliable markers of dietary quality and took account of well-known risk factors, and the findings back up other research linking highly processed food with poor health.

Both research teams are therefore calling for governments around the world to reformulate dietary guidelines, highlighting the dangers of consuming large amount of ultra-processed foods.

Lauren Nicolle

Lauren is a qualified journalist who writes primarily across the health and social care sectors. She is passionate about exposing the injustices faced by people with a learning disability, with a particular focus on equal access to healthcare.

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