Ultra-processed foods are everywhere. Over the past few decades, their availability and affordability has increased explosively and intentionally, first in high-income countries, and then in the rest. In the United States, and also in the United Kingdom, about 60% of caloric intake already comes from ultra-processed products. In Spain, the proportion of calories obtained from these foods has also increased.
Messages about these products also proliferate. In many press reports they are pointed out as the main responsible for the increase in obesity or type 2 diabetes. There is also no shortage of influencers who advocate abandoning their consumption. But what are ultra-processed foods? And what is the scientific evidence on its effect on health?
What are they?
Pastries, soft drinks, cookies, nuggets, precooked dishes, dairy desserts... All are products made predominantly (or entirely) from industrial ingredients and containing few (or no) natural foods. Therefore, they usually have a high caloric density (due to their amount of sugars and fats) and a low nutritional quality (very little amount of protein or micronutrients). That is, they do not contribute almost anything, except packaged calories.
The term ultra-processed was used, for the first time, by Carlos Monteiro in 2009. Currently, and in the absence of a legal norm that establishes a specific definition, the most accepted (at least in the field of public health) is that of Monteiro himself and collaborators. These define ultra-processed foods as "industrial formulations produced from substances obtained from food or synthesized from other organic sources." They continue: "Normally, they contain little or none of the food intact, are prepared to consume or heat, and are high in fat, salt or sugars and little dietary fiber, protein, various micronutrients and other bioactive compounds."
Read more: Ultra-processed foods harm health: two studies associate them with higher cancer risk and cardiovascular mortality
In summary, ultra-processed foods are edible industrial preparations made from substances derived from other foods. They are improved products to be attractive to the palate and very comfortable to be consumed at any time and place.
To this is added its enormous profitability. Ultra-processed foods have a long shelf life and a very low production cost. In fact, the production of ultra-processed foods (e.g. sugary drinks) has become one of the most lucrative and fastest growing business activities. They are cheaper than fresh or processed foods and are advertised through misleading messages ("high in vitamins") and accompanied by claims that seek to mask possible harm, to direct consumer demand.
What is its effect on health?
Thanks to traceability and food safety systems, it is very difficult for food, ultra-processed or not, to cause immediate damage to health. With the exception of certain poor quality fats and sugars, which do cause direct damage, but which remain unregulated due to the interference of the industry.
The scientific data on the detrimental effect of ultra-processed foods is clear. There are hundreds of studies that have observed an association between the consumption of these products and an increased risk of obesity, diabetes, hypertension, cardiovascular diseases, and also premature death. An editorial, recently published by Miguel Ángel Royo-Bordonada and Maira Bes-Rastrollo in Gaceta Sanitaria, synthesizes this evidence (which also exists in Spain).
In addition to these effects, a recent study, conducted on almost 200,000 adults in the United Kingdom, has concluded that ultra-processed foods also increase mortality from certain types of cancer, especially ovarian cancer in women. And this is not the first. Last year, research conducted in the United States linked ultra-processed foods to colorectal cancer. Adding to this growing evidence are findings on mental health. A longitudinal study, with a follow-up of a decade, has associated the consumption of ultra-processed foods with cognitive decline in more than 10,000 adults in Brazil.
As for the mechanism of action, there are several hypotheses. On the one hand, the damage may be due to the aforementioned low nutritional quality of the most common ingredients of these products: free sugars, refined flours, unhealthy fats, or salt. In turn, the consumption of ultra-processed foods can displace that of others of better nutritional quality, such as fresh or less processed foods. There are studies that suggest additional hypotheses, related to alterations in satiety signals, imbalances in the diversity and composition of the intestinal microbiota, or with the pro-inflammatory and pro-oxidant effects of ultra-processed foods.
Once its effects have been observed, and its plausibility explained at the biological level, it is pending to implement fiscal measures (taxes on sugary drinks), and regulatory measures (limiting the exposure, above all, of children and adolescents to this type of products) that counteract the spread of these products.
NOURISH WITH SCIENCEis a section on food based on scientific evidence and knowledge contrasted by specialists. Eating is much more than a pleasure and a necessity: diet and eating habits are now the public health factor that can help us prevent numerous diseases, from many types of cancer to diabetes. A team of dietitians-nutritionists will help us to better understand the importance of food and to demolish, thanks to science, the myths that lead us to eat badly.
You can follow EL PAÍS Salud y Bienestar on Facebook, Twitter and Instagram.