High Fat Diets Contribute To Irregularities In The Hypothalamus

This study evaluated how consumption of a high fat diet which specifically including high amounts of fats and carbohydrates, may stimulate hypothalamic inflammation as a physiological response to obesity and malnutrition; findings reaffirmed that inflammation occurs in the hypothalamus as early as 3 days after consuming a high fat diet before the body begins to display signs of obesity. 

"We were intrigued by the fact that these are very fast changes that occur even before the body weight changes, and we wanted to understand the underlying cellular mechanism," said Sabrino Diano, member of the Yale Program in Integrative Cell Signaling and Neurobiology of Metabolism.

Hypothalamic inflammation was observed in animals being fed a high fat diet and changes in physical structure were discovered to be occurring among their microglial cells which act as the first line defense in the central nervous system that regulate inflammation. Activation of microglia was found to be due to changes in their mitochondria organelles that help the body derive energy from consumed food. Mitochondria were observed to be substantially smaller in these animals on the high fat diet; changes in size was due to Uncoupling Protein 2 which regulates mitochondria energy utilization that affects the hypothalamus’ control of energy and glucose homeostasis. 

UCP2 mediated activation of microglia affected neurons in the brain when receiving an inflammation signal due to the high fat diet stimulated the aniamals in this group to eat more and become obese. When this mechanism was blocked by removing the UCP2 protein from the microglia the animals receiving a high fat diet ate less and were resistant to weight gain. 

As published in Cell Metabolism this study demonstrates how following fat diets physically affect us and conveys how following a high fat diet can alter our food intake in a neurological basis. 

"There are specific brain mechanisms that get activated when we expose ourselves to specific type of foods. This is a mechanism that may be important from an evolutionary point of view. However, when food rich in fat and carbs is constantly available it is detrimental."

The team has the objective to gain better understandings of the physiological mechanisms regulating how much food we consume, and the team will continue to investigate how activated microglia can affect various diseases in the brain such neurological disorders associated with changes in the micoglial cells that have been shown to have higher rates of incidences among those who are obese.