Regular peanut consumption may be linked to a lower risk of developing type 2 diabetes, with researchers identifying a distinctive pattern of blood fats that could help explain the relationship.
The study, published in The American Journal of Clinical Nutrition, found that people with a particular lipid profile associated with peanut consumption had a lower risk of type 2 diabetes. Body mass index (BMI) appeared to account for much of this association.
Peanuts are nutrient-rich legumes that provide protein, fibre, healthy unsaturated fats, vitamins and minerals. Although commonly grouped with nuts, they belong to the same plant family as beans and lentils.
Researchers led by Dr Inés Domínguez-López and Professor Matthias Schulze of the German Institute of Human Nutrition Potsdam-Rehbruecke, in collaboration with scientists from the University of Barcelona, investigated how peanut consumption affects fats circulating in the blood.
Unlike conventional cholesterol tests, which measure only selected blood lipids, a technique known as lipidomics provides a more detailed picture of the different types of fats in the bloodstream.
The researchers first conducted the ARISTOTLE randomised controlled trial involving 63 healthy adults aged 18 to 33.
For six months, participants consumed either 25 grams of skin-roasted peanuts, 32 grams of peanut butter or 32 grams of a control butter containing peanut oil daily.
Using high-resolution mass spectrometry, the team identified a distinctive pattern of blood fats associated with peanut consumption, which they named the Peanut Lipidomic Signature (PeLS).
The analysis showed significant increases in certain very long-chain saturated fatty acids, particularly C24:0 and C22:0. These fats were incorporated into specific lipid groups, including ceramides, through processes involving enzymes that lengthen fatty acid chains.
Lead author Domínguez-López described the changes as a complex remodelling of the blood lipid profile rather than simply an increase in fat levels.
The researchers subsequently examined data from the EPIC-Potsdam long-term population study, involving more than 27,000 participants.
The analysis included 774 cases of type 2 diabetes and 545 cases of cardiovascular disease.
They found that the peanut-related lipid signature was associated with a lower risk of type 2 diabetes, but no similar association was observed for cardiovascular disease.
BMI statistically explained much of the relationship between the lipid signature and diabetes risk, suggesting that body weight or metabolic processes linked to body fat may play an important role in the association.
Schulze said the findings offered insight into how the quality of dietary fats could influence metabolic health.
The researchers noted that peanuts could be a practical addition to a balanced diet, given their nutritional value and affordability.
However, the findings demonstrate an association rather than proof that eating peanuts directly prevents type 2 diabetes. Further research is needed to understand the biological mechanisms involved and establish how peanut consumption influences long-term metabolic health.