Alimentos ultraprocesados y salud, lo que dicen los estudios observacionales

Continuously and inexorably, although many do not like it, the evidence on the relationship between ultra-processed foods and health is accumulating. Most of it is observational, but little by little it gives us interesting information that should be taken into account when analyzing all of the existing evidence.

Along these lines, a recent review has just been published that precisely attempts to synthesize the results of all the relevant epidemiological research on ultra-processed foods carried out to date. It’s about the study»Ultra-processed foods and chronic non-communicable diseases: a systematic review and meta-analysis of 43 observational studies» (2020) and as stated in the title, it is a systematic review with meta-analysis that compiles the results of 43 different observational studies and nearly a million people, on the relationship between its intake and a wide variety of non-medical diseases. transmissible.

When proposing proposals to explain these results, the authors explain that a diet rich in ultra-processed foods usually causes a higher caloric intake and a lower nutritional quality, with more sugars, salt, trans and saturated fats and a lack of fiber. . However, they add that it is likely that there are more influencing factors, since in the studies in which adjustments have been made for these variables, similar results continued to be reached. And they list some possible candidates: alterations of the food matrix (its destruction during processing could lead to alterations during the metabolization process), presence of additives (especially emulsifiers and sweeteners, whose chronic consumption could negatively affect the microbiota or the inflammation), carcinogenic compounds (such as those created by cooking at very high temperatures) or possible presence of some toxic compounds that migrate from packaging, such as bisphenol A.

On the other hand, the review included a segmented analysis of studies among the child population, reaching conclusions that were much less clear than in the case of adults:

«… Increased consumption of ultra-processed foods was linked to increased waist circumference and dyslipidemia in children, as well as metabolic syndrome in adolescents. However, both prospective and cross-sectional data showed no association or inverse association between different measures of excess weight (BMI, waist circumference, waist-to-height ratio, skinfolds, and body fat percentage) and other risk factors. metabolic (elevated levels of glucose, insulin, triglycerides, HDL and non-HDL cholesterol and blood pressure). Similarly, cross-sectional analysis of normal weight vs. overweight children and adolescents showed no differences in consumption of ultra-processed foods between groups or greater consumption among those with normal weight. «

And these are the hypotheses they propose to explain these very different results among the little ones:

«… these results suggest that a constant intake of ultra-processed foods over time is necessary to cause negative effects of subclinical cardiovascular disease that manifests later, throughout life. However, the lack of clear associations in children and adolescents could be explained in part by the physical developmental changes that take place during these vital stages of the human life cycle, which have the potential, for example, to delay or offset the effects on the body weight of ultra-processed foods. Furthermore, only one of the studies controlled for physical activity and infrared reporting of dietary intake information as potential confounders. (…). Another possible explanation is that most samples came from low-income communities, where physical activity levels may be higher than in higher-income communities.»

As a final summary, the authors close the work with the following paragraph:

«The present meta-analysis provides evidence that higher consumption of ultra-processed foods is associated with a 20% to 81% increase in adults in the risk of various non-communicable diseases when assessed cross-sectionally and a 22% increase when assessed cross-sectionally. 28% in the risk of depression and mortality when examined prospectively. However, evidence of an association between the consumption of ultra-processed foods and adverse health outcomes in children and adolescents was limited. (…) the «The weight of the evidence is sufficient and taking into account the precautionary principle, preventive initiatives should address the issue of the consumption of ultra-processed foods.»

As I said, the evidence is accumulating and it doesn’t look good at all. Although it seems that for the people of AESAN it is not enough, since ultra-processed food is only mentioned in your report with dietary recommendations when talking about other guides.