<p>The brain has a lot of a fatty substance called <strong><a href="https://www.webmd.com/multiple-sclerosis/myelin-sheath-facts" rel="nofollow noreferrer">myelin</a></strong>. It wraps around nerve fibers and enhances the speed of electrical communication between neurons (source: <a href="http://www.brainfacts.org/Brain-Anatomy-and-Function/Anatomy/2015/Myelin" rel="nofollow noreferrer">Brain Facts</a>), and increases transmission efficiency (Fig. 1). It is produced by supporting cells in the brain called <strong><a href="https://qbi.uq.edu.au/brain-basics/brain/brain-physiology/types-glia" rel="nofollow noreferrer">oligodendrocytes</a></strong>. Myelin is really just many wraps of membrane, and since neurons have long axons and dendrites, too, they also have a lot more membrane than if they were just spherical cells - all of this membrane is "fat" called <a href="https://en.wikipedia.org/wiki/Phospholipid" rel="nofollow noreferrer">phospholipid</a>.</p>

<p>Now on to your questions -</p>

<blockquote>
  <p>Is this fatty tissue structural building material? Or does it just serve as an energy source for the mitochondria?</p>
</blockquote>

<p>Myelin and cell membranes are the most abundant fatty substances in the brain - they are structural fatty substances found around cells and neuronal axons, respectively, and they are not fuel.</p>

<blockquote>
  <p>[I]s there also a water in our brain?</p>
</blockquote>

<p>Every cell contains water, as nearly all biochemical reactions take place in a watery solution. An early report found the water content of neurons to be 55% <a href="https://www.ncbi.nlm.nih.gov/pubmed/3973594" rel="nofollow noreferrer">(Saubermann &amp; Scheid, 1985)</a></p>

<blockquote>
  <p>[W]hat percentage of the brain is actually a neuron?</p>
</blockquote>

<p>Scientific American performed a review on this and settles on a ratio of neurons : glia cells of 1:1 (although numbers of 10:1 have been reported). <strong><a href="https://qbi.uq.edu.au/brain-basics/brain/brain-physiology/types-glia" rel="nofollow noreferrer">Glia</a></strong> are the brain's supportive cells and include the oligodendrocytes as mentioned above that produce the myelin <a href="https://blogs.scientificamerican.com/brainwaves/know-your-neurons-what-is-the-ratio-of-glia-to-neurons-in-the-brain/" rel="nofollow noreferrer">(Jabr, 2012)</a>. </p>

<p><br>  </p>

<p><a href="https://i.sstatic.net/6skCh.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/6skCh.png" alt="Myelin"></a><br>
<sup>Fig. 1. Schematic showing a myelin sheath around an axon. source: <a href="https://www.webmd.com/multiple-sclerosis/myelin-sheath-facts" rel="nofollow noreferrer">WebMD</a></sup>  </p>

<p><sub><strong>References</strong><br>
 - <a href="https://blogs.scientificamerican.com/brainwaves/know-your-neurons-what-is-the-ratio-of-glia-to-neurons-in-the-brain/" rel="nofollow noreferrer">Jabr, <em>Sci Am</em> (2012), June 2012</a><br>
 - <a href="https://www.ncbi.nlm.nih.gov/pubmed/3973594" rel="nofollow noreferrer">Saubermann &amp; Scheid, <em>J Neurochem</em> (1985); <strong>44</strong>(3): 825-34</a></sub></p>

CC BY-SA 4.0
2018-10-26T19:30:06.813Z
2018-10-26T20:13:54.387Z
2018-10-26T20:13:54.387Z
AliceD
<p>I read an <a href="https://www.reference.com/science/brain-made-fat-95ce6711baa7fce6" rel="nofollow noreferrer">article</a> that stated that the human brain contains 60% fat. Is this fatty tissue structural building material? Or does it just serve as an energy source for the mitochondria? </p>

<p>Since our body are also made out of 70% water, is there also a water in our brain? </p>

<p>And the most important question I want to ask is: what percentage of the brain is actually a neuron? </p>

CC BY-SA 4.0
2019-06-16T02:24:29.270Z
Regarding energy sources, the brain can only metabolize glucose and (to a lesser extent) beta-hydroxybutyrate. Its ability to process lipids is negligible.
forest
<neuroscience><brain>
What is the human brain made of?
java person
# What is the human brain made of?

(Asked by: username_0 on 2018-10-26)

I read an [article](https://www.reference.com/science/brain-made-fat-95ce6711baa7fce6) that stated that the human brain contains 60% fat. Is this fatty tissue structural building material? Or does it just serve as an energy source for the mitochondria?

Since our body are also made out of 70% water, is there also a water in our brain?

And the most important question I want to ask is: what percentage of the brain is actually a neuron?

**Tags:** neuroscience, brain

> **Comments:**
> **username_1**: Regarding energy sources, the brain can only metabolize glucose and (to a lesser extent) beta-hydroxybutyrate. Its ability to process lipids is negligible.  

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## 1 answers

### Answer by username_2 on 2018-10-26. Score: 5 | Accepted answer

The brain has a lot of a fatty substance called **[myelin](https://www.webmd.com/multiple-sclerosis/myelin-sheath-facts)**. It wraps around nerve fibers and enhances the speed of electrical communication between neurons (source: [Brain Facts](http://www.brainfacts.org/Brain-Anatomy-and-Function/Anatomy/2015/Myelin)), and increases transmission efficiency (Fig. 1). It is produced by supporting cells in the brain called **[oligodendrocytes](https://qbi.uq.edu.au/brain-basics/brain/brain-physiology/types-glia)**. Myelin is really just many wraps of membrane, and since neurons have long axons and dendrites, too, they also have a lot more membrane than if they were just spherical cells - all of this membrane is "fat" called [phospholipid](https://en.wikipedia.org/wiki/Phospholipid).

Now on to your questions -

> Is this fatty tissue structural building material? Or does it just serve as an energy source for the mitochondria?

Myelin and cell membranes are the most abundant fatty substances in the brain - they are structural fatty substances found around cells and neuronal axons, respectively, and they are not fuel.

> [I]s there also a water in our brain?

Every cell contains water, as nearly all biochemical reactions take place in a watery solution. An early report found the water content of neurons to be 55% [(Saubermann & Scheid, 1985)](https://www.ncbi.nlm.nih.gov/pubmed/3973594)

> [W]hat percentage of the brain is actually a neuron?

Scientific American performed a review on this and settles on a ratio of neurons : glia cells of 1:1 (although numbers of 10:1 have been reported). **[Glia](https://qbi.uq.edu.au/brain-basics/brain/brain-physiology/types-glia)** are the brain's supportive cells and include the oligodendrocytes as mentioned above that produce the myelin [(Jabr, 2012)](https://blogs.scientificamerican.com/brainwaves/know-your-neurons-what-is-the-ratio-of-glia-to-neurons-in-the-brain/).

[![Myelin](https://i.sstatic.net/6skCh.png)](https://i.sstatic.net/6skCh.png)  
Fig. 1. Schematic showing a myelin sheath around an axon. source: [WebMD](https://www.webmd.com/multiple-sclerosis/myelin-sheath-facts)

**References**  
- [Jabr, *Sci Am* (2012), June 2012](https://blogs.scientificamerican.com/brainwaves/know-your-neurons-what-is-the-ratio-of-glia-to-neurons-in-the-brain/)  
- [Saubermann & Scheid, *J Neurochem* (1985); **44**(3): 825-34](https://www.ncbi.nlm.nih.gov/pubmed/3973594)


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