The risk of depression skyrockets when ultra-processed foods exceed 30% of the diet

A large amount of the foods sold in supermarkets are ultra-processed.

Pastries, industrial pizzas, many sauces, salty appetizers or cold cuts are in this group that is increasingly consumed.

In Spain, on average, more than 20% of calories come from these types of products and the figure reaches 30% in Mexico and 58% in the US. Concern about the health effects of ultra-processed foods increases, as does which makes its consumption all over the world.

Today, the medical journal

publishes an extensive review of studies that confirms the association between greater consumption of these foods and diseases such as diabetes or mental illness and premature death.

Among the articles reviewed, published in the last three years and which, if their participants are added, include almost ten million people, the authors find “convincing evidence” that a greater intake of ultra-processed food is associated with an increased risk. of dying from cardiovascular disease, about a 50% increase in the risk of anxiety and other mental disorders, and a 12% increase in the risk of type 2 diabetes. At a next level of confidence, an increase of 21% was observed % risk of death from any cause, around 50% increased risk of obesity or sleep problems and a 22% increased risk of depression.

In a work by the same authors, they saw that the risk of depression skyrockets when ultra-processed foods exceed 30% of a person's daily diet.

For gastrointestinal health or cancer risk, the evidence, researchers believe, is limited.

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The work, led by Melissa Lane and Wolfgang Max, from Deakin University, in Australia, consider that the findings collected provide sufficient reasons to implement public health policies that reduce the consumption of ultra-processed foods and thus improve the health of the population.

Although their data does not allow them to compare the health deterioration caused by this type of food with that of tobacco or alcohol, Lane believes that some policies around these substances can show what can be effective in reducing the consumption of ultra-processed foods.

“For example, warning labels on packages, like those on cigarettes, could be effective,” says the researcher.

Miguel Ángel Martínez, professor of Preventive Medicine and Public Health at the University of Navarra, who has not participated in the work, considers that the evidence from the studies included in this review is more than enough to propose “structural, not just educational” measures. , to reduce the consumption of ultra-processed foods.

“We must make them more expensive through taxes, and use the income obtained to lower the price of healthy products such as olive oil or nuts, not for anything else,” he explains.

“It cannot be that healthy foods become more and more expensive, because that will increase the health gap between social classes,” he emphasizes.

The article also advocates progress in the study of the mechanisms that explain why these types of foods are harmful.

For now, it is known that they are less nutritious and worsen the diet of those who take them because, in addition to providing too much salt, fat or sugar, they leave less space in the stomach for foods such as fruits, which contain beneficial compounds, such as polyphenols or phytoestrogens.

They also contain less fiber and protein, and concentrate more calories in less quantity.

This combination can favor the development of chronic diseases that arise due to chronic inflammation or changes in the microbiota.

Martínez criticizes an aspect of the study that leads the authors to consider weak evidence that would perhaps be stronger with another measurement method.

“They use the GRADE system to evaluate the quality of the strength of the evidence and they have made a mistake, because that method was designed for clinical trials and we have known for a long time that NutriGrade, adapted to the specific characteristics of clinical trials, is more appropriate. nutrition,” he points out.

“With GRADE, in many nutrition studies the evidence is going to be weak, because an observational study is going to be bad, and in nutrition we cannot do randomized clinical trials like we do with drugs, giving people ultra-processed foods to see if It hurts them, because it would be unethical,” he summarizes.

Pablo Alonso Coello, researcher at the Sant Pau Research Institute of Barcelona and Scientific Coordinator of Nutrimedia, values ​​the large amount and information gathered in the review, its order and consistency, but warns that nutrition research will always have difficulty reaching a level confidence like that achieved with a drug in a clinical trial.

“It is difficult to assess the influence of each factor and the effects are small,” he points out.

“We will never have the same security as with tobacco and cancer, which has a very large effect, and the researchers themselves recognize the limitations that they cannot put their hand in the fire,” he concludes.

As an intermediate solution, the authors of the article published in

propose short-term studies to test the effects of ultra-processed foods, measuring changes in weight, insulin resistance, microbiota or inflammation levels. .

Doing the same thing long enough to find out whether they accelerate death or the onset of cancer or cardiovascular disease will be impossible.

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