Consuming ultra-processed foods and drinks may increase the risk of colorectal cancer

Consuming ultra-processed foods and drinks could increase the risk of developing colorectal cancer. This was the conclusion of a large study undertaken by the Barcelona Institute for Global Health (ISGlobal), a center supported by the “la Caixa” Foundation, based on questionnaires on eating behaviors completed by around 8,000 people in Spain. The study, the first of its kind in the country, also analyzed the relationship between ultra-processed food and drink products and two other cancers; while no association was observed with prostate cancer, in the case of breast cancer, a higher risk was observed in the subgroup of former and current smokers who reported a diet rich in the products ultra-processed.

Social, economic and industrial changes have led to an increase in the consumption of ultra-processed foods and beverages, which currently accounts for between 25% and 50% of total energy intake in diets in Europe and the developing countries. high and middle income. The Nova classification system groups all foods and beverages into four categories according to the degree of processing they undergo. Ultra-processed foods – the ones that go through the most processing – are industrial formulations with more than five ingredients that typically contain additional substances, such as sugar, fats, salt, and additives. Examples of products in this category include sweetened carbonated beverages, ready meals, and industrial mass produced bakery products.

Several studies have linked the consumption of ultra-processed foods and drinks to health risk factors, cardiovascular disease, type 2 diabetes and an increased risk of premature death. There are only a few studies on the relationship of these food products to cancer and the results are not entirely conclusive. A French study found an association between consuming ultra-processed foods and an increased risk of cancer. A Canadian study found an increased risk of developing prostate cancer with higher consumption of processed foods, but not ultra-processed foods.

The aim of the present study was to assess whether consumption of ultra-processed foods and drinks is associated with an increased risk of colorectal, breast or prostate cancer. To this end, the researchers undertook a case-control study of 7,843 adults living in different Spanish provinces: half of the participants had a diagnosis of colorectal (1,852), breast (1,486) or prostate (953) cancer. ); and the other half were people with the same characteristics who did not have cancer. Data were obtained from the MCC-Spain multicase-control study. Dietary data were collected using a validated questionnaire designed to assess the frequency of consumption of usual foods and beverages over a period of one year. The results were then categorized by level of treatment using the Nova classification.

The study, published in Clinical nutrition, concluded that consumption of ultra-processed foods and drinks was associated with an increased risk of colorectal cancer: a 10% increase in consumption of ultra-processed foods and drinks was associated with an 11% increase the risk of developing colorectal cancer.

Dora Romaguera, lead author of the study and researcher at ISGlobal, the Institut d’Investigació Sanitària Illes Balears (IdISBA) and CIBEROBN, says this relationship can be explained, in part, “by low fiber intake , fruits and vegetables, which are known to offer protection against colorectal cancer, in people who consume a lot of ultra-processed foods, but also by additives and other substances with carcinogenic potential generally used in processed food products . “

In the case of breast cancer, no strong relationship was found, but an association was observed in the group of current and former smokers. Romaguera explains that “smoking is a risk factor for breast cancer, and smoking and certain dietary factors, such as consumption of ultra-processed foods and drinks, are known to have synergistic effects on cancer development. . “

No association has been found between prostate cancer and a diet rich in ultra-processed products.

This finding is not surprising and is consistent with the results of previous studies on dietary factors and prostate cancer risk, in which no link was found. “

Dora Romaguera, researcher, ISGlobal

Colorectal and breast cancer: a less healthy diet

The results of the study showed that people with breast and colorectal cancer, but not those with prostate cancer, reported less healthy diets than people without cancer in the control group. “We found differences in terms of energy consumption, fiber, energy density and saturated fatty acids. Consumption of ultra-processed foods and drinks was higher among colorectal and breast cancer cases. than in witnesses, “says Sílvia Fernández, researcher at ISGlobal. first author of the study.

The food groups that accounted for the largest proportion of ultra-processed food consumption were sugary drinks (35%), sugary products (19%), ready-to-eat foods (16%) and processed meats (12%). Processed meats have already been classified as carcinogenic by the International Agency for Research on Cancer (IARC). However, according to Pilar Amiano, researcher at the public health service of Guipúzcoa, who coordinated the study: “Ultra-processed foods and beverages in general are not yet classified as carcinogenic because the aim of the IARC was not to ‘assess the overall risk of an individual’s diet, but rather focus on specific components that could be unsafe, such as processed meats’.

She goes on to say that in light of the results of the present study and the current scientific evidence on the health risks associated with ultra-processed foods and beverages, especially in relation to cancer, the authors believe “that the ‘food and public health policies and the IARC should already take into account food processing and discourage the consumption of ultra-processed products.’