The work was led by teams from the CIBER Area for Diabetes and Associated Metabolic Diseases (CIBERDEM) at the University of Barcelona.

"Palmitic acid, a saturated fatty acid widely found in foods, is associated with impaired insulin sensitivity, whereas oleic acid, abundant in olive oil, may have a protective effect against these metabolic disorders," says Professor Manuel Vázquez-Carrera, from the UB's Faculty of Pharmacy and Food Sciences, the UB Institute of Biomedicine (IBUB), the Sant Joan de Déu Research Institute (IRSJD) and CIBERDEM.

Other contributors include Ricardo Rodríguez-Calvo of CIBERDEM at the Pere Virgili Institute for Health Research (IISPV), Marta Tajes of the CIBER Area for Cardiovascular Diseases (CIBERCV) at the Bellvitge Biomedical Research Institute (IDIBELL), and Walter Wahli of the University of Lausanne (Switzerland).

According to Vázquez-Carrera, the findings suggest that the type of fat people consume may be more important than the overall amount.

"This review highlights the significant role of the quality of dietary fat, rather than the total amount consumed," notes Professor Manuel Vázquez-Carrera, who is a group leader at CIBERDEM at the UB.

How Palmitic Acid May Promote Diabetes

The researchers examined evidence showing that palmitic acid can trigger several biological processes linked to metabolic disease.

As Xavier Palomer (UB-IBUB-CIBER-IRSJD), the article's first author, says, "at the molecular level, palmitic acid promotes the accumulation of potentially toxic bioactive lipids, fosters low-grade chronic inflammation, and contributes to the dysfunction of cellular organelles, such as the endoplasmic reticulum and the mitochondria."

The team notes that these cellular changes "are closely linked to impaired insulin action and the progression of metabolic disease."

Oleic Acid Shows Protective Effects

The picture looks quite different for oleic acid, a monounsaturated fat found in high amounts in olive oil.

According to the review, oleic acid encourages the body to store fats in forms that are metabolically less disruptive and have little effect on normal cellular function. It also helps maintain healthy insulin signaling in important metabolic tissues, including the liver, muscles, and adipose tissue.

Researchers say oleic acid may also offset many of the harmful effects associated with palmitic acid. This could help explain why eating patterns rich in monounsaturated fats, including the Mediterranean diet, are consistently linked to a lower risk of type 2 diabetes and other metabolic disorders.

Improving Nutrition Strategies for Diabetes Prevention

The authors emphasize that more targeted research is needed to better understand differences seen across population studies.

"It is important to consider variables such as the source of fatty acids, their dietary context, interactions with other nutrients, and different food processing methods," says Manuel Vázquez-Carrera.

The researchers believe that gaining a clearer understanding of these factors will improve scientists' ability to evaluate how different fats affect metabolic health. In turn, that knowledge could support the development of more effective dietary approaches for preventing and managing type 2 diabetes.