Ultra-processed foods may negate Mediterranean diet benefits for type 2 diabetes.

Ultra-processed foods may negate Mediterranean diet benefits for type 2 diabetes.

The Negative Effects of Ultra-Processed Foods on Type 2 Diabetes and Mortality

Mediterranean Diet For people with type 2 diabetes, the negative effects of eating too much ultra-processed foods may cancel out the benefits of healthy eating, such as following a Mediterranean diet.

The Mediterranean diet, known for its emphasis on fiber, healthy fats, and low sugar, is often lauded as one of the best diets for people with type 2 diabetes[^1^]. However, a new study suggests that the negative effects of a diet rich in ultra-processed foods may outweigh the benefits of following a Mediterranean diet[^1^]. This revelation should prompt individuals with type 2 diabetes to not just focus on fiber, fat, and sugar content but reduce or eliminate ultra-processed foods from their diet[^1^].

Understanding the Impact of Ultra-Processed Foods on Type 2 Diabetes

Current advice for managing type 2 diabetes often centers around consuming foods high in fiber, healthy fats, and low in sugar[^1^]. Two diets commonly recommended are the Mediterranean Diet and the DASH Diet, both of which prioritize whole grains, legumes, nuts, fruits, and vegetables[^1^]. Research has shown that higher intakes of fish, whole grains, fiber, and n-3 polyunsaturated fatty acids are associated with lower all-cause mortality in individuals with type 2 diabetes[^1^].

However, a recent study published in the American Journal of Clinical Nutrition reveals that a diet rich in ultra-processed foods significantly increases the risk of death for people with type 2 diabetes, regardless of adherence to the Mediterranean diet[^1^]. These findings add to the mounting evidence that high consumption of ultra-processed foods can lead to premature death[^1^].

While several studies have demonstrated a connection between diets rich in ultra-processed foods and an increased risk of developing type 2 diabetes, this study is the first to examine the relationship between ultra-processed foods and mortality in individuals already diagnosed with the disease[^1^]. Researchers from the Institute for Research, Hospitalization and Health Care (IRCCS) Neuromed in Italy embarked on this investigation, utilizing data from the Moli-sani Study[^1^]. The study collected information from 24,325 individuals aged over 35 residing in the south-central Italian region of Molise between 2005 and 2010[^1^].

Among the cohort, the researchers identified 1,065 individuals with type 2 diabetes who were followed for an average of 11.6 years[^1^]. Using a comprehensive food intake questionnaire, the researchers determined the percentage of ultra-processed foods in the participants’ overall food intake. Additionally, they assessed the quality of each person’s diet using the Mediterranean Diet Score[^1^].

Defining Ultra-Processed Foods

The term “ultra-processed foods” is based on the NOVA food classification system, which categorizes foods based on the extent and purpose of processing, rather than on nutrient content[^1^]. The NOVA system groups foods into four categories:

  1. Unprocessed or minimally processed foods: These foods include edible parts of plants or animals in their natural state[^1^].
  2. Culinary ingredients: This category comprises substances like salt, oil, sugar, and starch derived from Group 1 foods[^1^].
  3. Processed foods: These foods are products obtained by combining Group 1 and Group 2 foods, such as canned vegetables or freshly baked bread[^1^].
  4. Ultra-processed foods: This category refers to heavily processed products made with substances derived from Group 1 foods, which contain various additives like colorings, preservatives, and flavor enhancers[^1^].

Examples of ultra-processed foods include carbonated drinks, packaged snacks, ready-to-heat products, and reconstituted meat products[^1^].

The Impact of Ultra-Processed Foods on Mortality

The study found that, on average, individuals in the cohort consumed 7.4% of their total food intake as ultra-processed foods[^1^]. Those who consumed the highest amounts of ultra-processed foods (≥10.5% for females and ≥9% for males) had a greater risk of death from any cause and from cardiovascular disease compared to those who consumed the least[^1^]. Importantly, this increased mortality risk persisted even when comparing individuals with similar nutritional compositions, as indicated by their Mediterranean Diet Scores[^1^].

Dr. Marialaura Bonaccio, the lead author of the study, highlights potential mechanisms underlying the harmful effects of ultra-processed foods, stating that these effects are not solely due to poor nutritional content[^1^]. Non-nutritional factors, including food additives, contaminants from plastics, and alterations to the food matrix, likely contribute to these adverse health effects[^1^].

Implications and Limitations of the Study

Dr. Bonaccio emphasizes that individuals managing type 2 diabetes should not solely focus on the nutritional composition of foods but also reduce their consumption of ultra-processed products[^1^]. However, not all experts are convinced of the dangers of processing. Professor Michael Lean, a nutrition expert from the University of Glasgow, raises several concerns about the study. He highlights that the research shows associations rather than causation, with other factors potentially influencing mortality rates, such as smoking and medications[^1^].

Additionally, Professor Lean suggests that individuals who consume more processed foods might also consume fewer traditional whole foods, which could explain the study’s findings[^1^]. Furthermore, he proposes that reverse causality could be at play, whereby individuals with more severe diabetes or higher medication requirements might change their diets to include more ultra-processed foods as a result of their condition[^1^].

Though there may be reservations about the study’s conclusions, indulging in whole foods and traditional meals, while limiting processed food consumption, remains a sensible approach according to Professor Lean[^1^].

The Need for Comprehensive Food Labels

To curb the consumption of ultra-processed foods, some experts advocate for the adoption of the NOVA food labeling system, which would inform consumers about the level of food processing (ranging from 1 to 4)[^1^]. Currently, several countries implement the Nutri-Score label, which rates the nutritional value of a product from A to E[^1^].

Dr. Bonaccio supports the idea of incorporating food processing information into front-of-package nutrition labels[^1^]. She notes that current labels solely focus on the nutritional composition of foods, neglecting the degree of processing[^1^].

In conclusion, while the Mediterranean diet is widely regarded as beneficial for individuals with type 2 diabetes, the harmful effects of ultra-processed foods cannot be ignored[^1^]. Eliminating or reducing the consumption of ultra-processed products may help individuals manage their diabetes and mitigate the risk of premature death[^1^]. Further research is necessary to fully understand the complex relationship between ultra-processed foods, type 2 diabetes, and mortality.