Obesity and Type 2 diabetes – are metabolic disorders. Both are related to food: Obesity is connected to excessive body fat accumulation, and high blood sugar is connected to diabetes.
Researchers in UCLA’s Metabolism Research Theme are studying the roots of these disorders and designing ways to treat them. Their strategies are novel.
In the case of Type 2 diabetes, they are working with theories that could dramatically revamp conventional understanding of the disease’s cause.
When Metabolism Theme leader Orian Shirihai, MD, PhD, talks about obesity, he envisions mitochondria (the power plants for cells) trying to deal with an excess nutrient environment.
Inside cells, tiny organs called organelles manage highly specialized tasks. Organelles are to the cells what organs are to the body – they function independently, but they are all connected. Mitochondria are a type of organelle that function as little power plants to handle the work of burning nutrients. When it comes to studying metabolism, mitochondria are the stars of the show.
Mitochondria continually change shape depending on whether they are “eating” sugar or fat. The process works this way:
When organelles have problems repairing themselves, the result is a reduced ability to eliminate defective or toxic parts. For example, a toxic by product of cellular metabolism known as reactive oxygen species (ROS) bombards cellular proteins and membranes, damaging their structures. This stress can lead to a cornucopia of disorders. Learn more about mitochondrial quality control.
Dr. Shirihai and other members of the Metabolism Theme are trying to understand whether it is possible to make tissue prefer one nutrient to another. This process could help stem obesity, a condition that affects more than one-third of U.S. adults.
“The only way to increase metabolism is to decrease metabolic efficiency, and the way to do that is to waste the energy that nutrients provide,” Dr. Shirihai says. “To treat obesity, we need to convince the mitochondria to burn nutrients for heat. The cells won’t then warehouse nutrients in the form of fat. Instead, they will look for fat sources to burn.”
- Dr. Orian Shirihai
Metabolic processes in the cell store as many excess nutrients as possible in the form of fat. The cells build a warehouse of energy that might come in handy when a person eats too little.
To survive in the face of nutrient (fuel) loss, the cells in a person on a low-calorie diet become much more efficient. The cells need fewer calories to function.
For dieters, this efficiency means that after the first week and the loss of a few pounds, it becomes increasingly difficult to drop weight.
Choice and preference help to shape everyday life for many of us, and what we eat to fuel our bodies is certainly no exception. Preferring one type of food to another, informing a decision as simple as restaurant choice or selection off a menu, can have repercussions lasting far longer than the few hours it takes to digest the meal.
Interestingly, this concept of fuel preference manifests itself at the cellular level as well. Mitochondria are the power plants of our cells, and these power plans can churn through sugar metabolites, amino acids, and fatty acids to harvest biological energy. It turns out that it’s not just how much biological energy these power plants produce, but also what fuels they’re burning that matters to our bodies.