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What Energy the Brain Runs On
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The brain runs on glucose, the sugar that circulates in the blood, and that sugar is its main energy source. The blood keeps delivering it around the clock.
The proportion is surprising. The brain is about 2% of body weight, and even so it takes about 20% of all the energy the body gets from glucose. Out of every five energy coins the body draws from glucose, the brain takes one.
Where does it go? Mostly into what the brain does for a living: the computations neurons carry out and the processing of information, that is, neurons sending signals to one another and handling them.
And its own pantry is small. The brain's only energy reserve is glycogen, which is glucose linked into chains, and it forms in astrocytes, brain cells that surround and support neurons.
In brief
The brain depends on glucose as its main energy source, and the blood delivers it nonstop.
The brain is about 2% of body weight and uses about 20% of the energy the body gets from glucose.
Two parts in every hundred of body weight, and one in every five energy coins the body draws from glucose.
Most of that goes to the computations neurons perform and to processing information.
The brain's only energy reserve is glycogen, formed in astrocytes.
Sources (1)
- Trends in Neurosciences, via PubMed CentralSugar for the brain: the role of glucose in physiological and pathological brain functionPublished
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