According to the results of research carried out by experts from Tufts University and Harvard University (United States), there is strong evidence of the association between the consumption of ultra-processed foods and the risk of developing colorectal cancer in men. The researchers comment that the greatest risk comes especially from processed foods with meat and fish products. It is worth remembering that in 2015 the WHO, and specifically the International Center for Research on Cancer (IARC), determined that red meat processed food was a carcinogenic food, hence it became part of the Group 1 category that pigeonholes what is considered carcinogenic to humans. The new study only supports the results of previous studies, such as the one carried out in 2018 by French and Brazilian researchers.
The new study aimed to examine the association between the consumption of ultra-processed foods and the risk of colorectal cancer in men and women by reviewing data from three large prospective studies, the Health Professionals Follow-up Study and the two Nursing Health studies with a maximum duration of 28 years. The three studies included almost 200,000 participants, 159,907 women and 46,341 men. Of the total number of participants, 3,216 cases of colorectal cancer were documented, 1,922 women and 1,294 men. In all three studies, a similar methodology was followed, every two years the participants had to answer a a questionnaire on lifestyle, diet and consumption habits, health status, etc. When collecting the information, the experts adjusted for possible confounding factors, participants with previously diagnosed cancer were also ruled out, except for those with skin cancer, people with a history of ulcerative colitis, or people who ate very high or very low calories. According to the results, men whose diet was high in ultra-processed foods had up to 29% more risk of developing colorectal cancer compared to those who had a reduced consumption. Experts point out that the risk of suffering from this type of cancer increased with greater consumption of ultra-processed foods. In this case, and in order to carry out a precise quantification, the consumption of ultra-processed foods was classified into quintiles (a quintile is a fifth or 20% of the total) segmenting five degrees. The researchers used the NOVA classification, which classifies foods into four groups, a first group made up of unprocessed or minimally processed foods, foods that may have been modified without the addition of substances, such as fish, meat or frozen vegetable products. A second group made up of products that have been extracted from foods that come from nature or from industrial processes, such as oils or refined flour. The third and fourth group are processed foods that, in turn, are divided into two subgroups, processed and ultra-processed, the latter being those that can imitate the appearance and sensory qualities of different foods, but are not recognizable from the original foods . They contain fats, salt and sugars, and they have involved industrial processes such as hydrogenation, hydrolysis, extrusion, molding or remodeling, among others, in addition, they include other additives such as emulsifiers, colorants, humectants, flavorings, etc. The researchers made the appropriate classifications reaching a consensus, but when there was a discrepancy in the classification of a food, a group of experts, dietary researchers, documentation, etc. were used. After collating the data, it was concluded that colorectal cancer could be the cancer that is more related to diet compared to other types of cancer, than processed meats, which for the most part belong to the category of ultra-processed foods, they are a clear and strong risk factor for suffering from the aforementioned neoplasia. By the way, let us remember that a few days ago we were talking about a study that linked ultra-processed foods with the risk of having worse mental health, and if we add other studies, there are compelling reasons to try to avoid this type of product as much as possible, although it is true that it can cost a bit, especially knowing that up to 70% of the food products that we can find in a supermarket are ultra-processed, as determined in an investigation the consumer organization Foodwatch Holland. Experts comment that ultra-processed foods have a high content of added sugars, fat and little fiber, something that favors overweight and obesity, which are also risk factors for colorectal cancer. It is surprising to know that this relationship was clearly identified in men, while in the case of women, an increased risk of cancer due to higher consumption of ultra-processed foods was not identified. This perceived difference by gender requires further investigation to determine if there is a real difference by gender or if it is simply a fluke, or confounding factors that were not controlled for. More research is needed to better understand how ultra-processed foods contribute to the development of colorectal cancer. The experts conclude in their study (you can read it here) that the findings support the importance of limiting certain types of ultra-processed foods in the diet, in order to reduce the risk of various diseases and enjoy better health.