Scientists have identified a potential new biological biomarker for the development of obesity. Known as peptide neurotensin (NT), it directly promotes fat absorption and weight gain.
The study, published in the journal Nature, is based on data from fruit flies, mice and humans.
NT is mainly produced in the gastrointestinal tract and central nervous system. It is released with ingestion of fatty foods. It facilitates fatty acid absorption in the intestine, potentially leading to obesity.
Led by Dr Mark Evers, from the University of Kentucky Markey Centre, the research analysed data derived from the Malmo Diet and Cancer Study. This cohort of more than 28,000 men and women was followed for an average of 16 years and included information such as weight and insulin resistance. In 4,632 cohort participants, the scientists showed that obese and insulin-resistant individuals had significantly higher levels of fasting pro-NT - an NT precursor hormone.
For non-obese participants with the most elevated levels, the risk of developing obesity during the follow-up was more than doubled compared to participants with the lowest pro-NT concentrations.
These findings suggest that NT is linked to the development of obesity, insulin resistance and potential ensuing metabolic diseases, like diabetes.
"Our findings have redefined how we view the role of NT," Evers, points out. "NT appears to be a metabolically 'thrifty' peptide which increases the absorption of ingested fats; however, with the abundance of fats in typical Western diets, NT can have a detrimental effect by contributing to increased obesity and related metabolic disorders."
Protection against obesity
In animal models, the scientists investigated whether a deficiency in NT would, on the contrary, offer protection against obesity. They discovered that low levels of NT did reduce the risks associated with high fat consumption, such as obesity, insulin resistance or fatty liver disease.
This shows that NT could be an early biological marker of obesity, and could thus also be an interesting therapeutic target for future drugs.
The researchers say more studies will have to be conducted in the near-future, in particular to understand whether pro-NT levels can also predict future obesity in children and adolescents. Scientists believe there will be 60% of men, 50% of women and 25% of children affected by obesity in the UK by 2050, meaning such research is vital.