Nutrient utilization plays a critical role in determining endurance performance. Mitochondria, the energy factories of muscles, have the ability to convert all three nutrients, carbohydrate, fat and protein, into energy. The mitochondria have developed sophisticated sensing mechanisms to fuel working muscles when nutrient stores are constantly changing. In many ways, nutrient delivery to mitochondria can be likened to a highway. For exercise of short duration, traffic on the mitochondrial highway is primarily carbohydrate. However, since the body’s carbohydrate is limited after 30 minutes, the highway traffic consists of carbs and fat. Longer than 45 minutes and protein starts traveling the highway.


With all this traffic there is clearly a need for a traffic cop to make sure nutrient traffic is orderly and runs smoothly. Recently, scientists in Pennsylvania and Texas identified a specific protein that regulates the roadway traffic. The protein, called MICU1, plays an essential role so that nutrient conversion to energy always operates at peak efficiency.


The discovery of MICU1 has important implications in the management of Type 2 diabetes, obesity and even endurance performance. For example, in obesity the traffic cop could increase fat and sugar utilization so you lose weight. For endurance athletes, by changing the proportion of fat and carbohydrate one could theoretically extend endurance.


It’s a fascinating area of research. Stay tuned for traffic updates on the carb/fat highway.

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