Senior Professor Xu-Feng Huang (front), with Dr Yinghua Yu and Licai Cheng, have found new evidence that saturated fatty acids are harmful to health.
If the world needed further evidence on the link between a diet high in saturated fats and obesity, researchers at the Illawarra Health and Medical Research Institute (IHMRI), based on the UOW campus, have demonstrated that the consumption of palmitic acid – a major source of saturated fatty acids in our diet – induces brain inflammation and impairs the leptin signalling pathways that regulate appetite.
According to the World Health Organization, palmitic acid (PA), found in palm oil, pork fat, beef tallow, butterfat, cocoa butter and other common foods, increases the risk of developing cardiovascular disease, placing it in the same evidence category as trans fatty acids.
In order to understand how PA causes inflammation leading to leptin resistance – when the body becomes resistant to the positive effects of the ‘satiety hormone’ due to over-eating – the research team, led by Senior Professor Xu-Feng Huang, tested if PA directly interferes with central regulation of energy balance using a rodent model.
“The hypothalamus is capable of sensing nutritional status and, as a result, certain nutrients influence brain function,” explained one of the study’s lead authors, Dr Yinghua Yu, from the IHMRI-based Centre for Translational Neuroscience.
“It is well-known that fatty acids [PA] can enter the brain, but tests to determine the mechanisms involved are typically administered orally. We found that, by administering PA into the cerebral ventricle, we were able to get a much better understanding of how these nutrients [fatty acids] influence signalling.”
The results, which are soon to be published in the prestigious Journal of Nutritional Biochemistry, show that elevated central PA concentrations induce inflammation and central leptin resistance, leading to increased food intake and body weight gain in the animal model.
“Our study suggests that the over-consumption of saturated fatty acids increases the level of saturated fatty acids in the brain inducing an inflammatory response which, in turn, leads to central leptin resistance in rodents,” added Dr Yu, who collaborated with researchers at the Schizophrenia Research Institute and Australian Nuclear Science and Technology Organisation on the study.
“Therefore, PA may play a key role in altering how the brain regulates energy.”
The researchers will use the results to further promising research on the benefits of natural compounds extracted from tea, ginseng and fish, to address PA-induced leptin resistance.
“With better understanding the mechanisms by which specific nutrients, such as fatty acids, influence signalling within the brain, we hope to prevent and even treat obesity and other metabolic disorders in the future,” concluded Dr Yu.
The study, entitled “Palmitic acid induces central leptin resistance and impairs hepatic glucose and lipid metabolism in male mice” received funding from the Diabetes Australia Research Trust.
The authors were Dr Yu, Licai Cheng, Dr Alexander Szabo, Yizhen Wu, Hongqin Wang, Danielle Camer and Professor Xu-Feng Huang.
Media enquires: IHMRI Communications Coordinator, Robyn Gower. T + 61 2 4252 8228