The Possible Role of Melanin and Neuromelanin in Brain Injury—and Recovery?
A wild theory about the loss of melanin from the subtanitia nigra after head trauma
This week I heard what may be the wildest theory yet about the potential causes of post-concussion symptoms. It could be total nonsense. Or there might be some merit to it. Then again, it’s sometimes worthwhile to discuss meritless things if thinking about them yields new ideas that are worthwhile.
How did I stumble upon this theory? Here’s the chain of events.
I listen regularly to the Huberman Lab podcast. One of Huberman’s guests was Rick Rubin. I then listened to Rick Rubin’s podcast (which is called Tetragrammaton). He interviewed Huberman in tandem with a doctor who helped Rick lose a lot of weight and generally be healthier. That doctor is a neurosurgeon named Jack Kruse.
I found Jack Kruse to be almost insufferable. The way he speaks to other people is abusive and demeaning. And to get 10 minutes of actionable information, you have to listen to him speak for three hours.
Nevertheless, sometimes even the insufferable can help ease the suffering of others. With that possibility in mind, here are the core elements of what he said about the brain after head injury.
A Loss of Neuromelanin After a TBI?
Human beings only recently discovered the existence of neuromelanin (as well as other forms of melanin), and we’re still learning how it works and what it does. This frontier aspect is part of what makes Kruse’s claims possible.
According to Kruse, the force of a head trauma can drive neuromelanin out of the substantia nigra in the brainstem. (This seems plausible to me, in part because we know that a TBI drives potassium out of neurons.) This loss of neuromelanin then creates a cascade of problems.
Along with the loss of potassium from neurons after a TBI, the loss of neuromelanin could play a key role in an ongoing energy crisis for the brain (which is how more mainstream doctors like Micky Collins describe the post-concussive state, as an energy crisis).
But what does neuromelanin have to do with energy?
We primarily associate melanin with skin color—we learn this as part of a basic education in human biology. However, the roles of melanin and neuromelanin (and the other forms of melanin) go way beyond the skin.
We know that neuromelanin plays a key role in protecting brain cells from toxins. Specifically the brain cells that produce dopamine and noradrenaline.
Apparently, melanin and neuromelanin may also play key roles in energy storage and distribution throughout the brain and body. This is what Kruse is pounding his fist on the table about.
In Kruse’s view, our modern lifestyle—where we’re rarely outside and our bodies struggle to replenish melanin and neuromelanin storage—is at the root of many ailments, not just TBI.
The Broader Role of Melanin and Neuromelanin
Here are few select quotes about melanin and neuromelanin from the Wikipedia pages about them:
Melanin pigments are produced in a specialized group of cells known as melanocytes. They have been described as "among the last remaining biological frontiers with the unknown".
Melanocytes are melanin-producing neural crest-derived cells located in the bottom layer (the stratum basale) of the skin's epidermis, the middle layer of the eye (the uvea), the inner ear, vaginal epithelium, meninges, bones, and heart.
In addition to their role as UV radical scavengers, melanocytes are also part of the immune system, and are considered to be immune cells.
Note: So melanin is being made and stored in a wide variety of places.
Tyrosine is the non-essential amino acid precursor of melanin. Tyrosine is converted to dihydroxyphenylalanine (DOPA) via the enzyme tyrosinase. Then DOPA is polymerized into melanin.
Note: It’s news to me that melanin is a downstream product of dopamine. So… Tyrosine converts to Dopamine which converts to Melanin.
Side Note: My wife suffered from migraines since childhood and one of the products that can help her prevent a migraine from getting worse contains 3 grams of L-Tyrosine per serving (it’s the Tingle-Free version of the Pre-Workout drink from Promix). I had assumed this L-Tyrosine helped with dopamine production, but I did not know about the potential boost to melanin production and what that might mean, especially if the substantia nigra is involved.
Neuromelanin concentration increases with age, suggesting a role in neuroprotection (neuromelanin can chelate metals and xenobiotics) or senescence.
Note: A xenobiotic is a chemical found within an organism that is not naturally produced or expected to be present in the organism. It could also be a natural substance from another organism that shouldn’t be present in another (such as hormones from other animals). So neuromelanin protects some of our most important brain cells from the constant intrusion of toxins etc. And one of my main complaints is how any exposure to toxins hits me like a ton of bricks.
Neuromelanin is found in large quantities in catecholaminergic cells of the substantia nigra pars compacta and locus coeruleus, giving a dark color to the structures.
Note: A catecholaminergic cell is involved in the production of catecholamines— dopamine and noradrenaline.
Neuromelanin is found in higher concentrations in humans than in other primates.
Note: This fact makes Kruse believe that melanin and neuromelanin are biological bedrocks of our species. To him, melanin not only explains why we don’t need a bunch of body hair (like other primates do) for sun protection, it also helps explain the differences in our brains. He has a whole tangent about the way Neanderthals living in northern latitudes probably evolved to replace lost thermodynamic energy from the sun (available to homo sapiens living nearer to the equator) via enhancements to the catecholamine pathways as well as generating more catecholamines from cold exposure. But they may have had lower baseline dopamine levels, which seems to provide those with Neanderthal genes with some protection from developing schizophrenia. (For what it’s worth, 23andMe tells me I have more Neanderthal genes than 58% of its users. But I digress.)
Neuromelanin and Parkinson’s
If a head trauma does drive neuromelanin out of these brain structures, and you don’t replenish it (Kruse says that’s possible), your brain may lose a critical line of defence against toxins, which is not great in a world where we are exposed to a wide array of toxins almost every day. And this can lead to forms of neuro-degeneration including Parkinson’s. From Wikipedia:
Neuromelanin-containing neurons in the substantia nigra degenerate during Parkinson's disease. Motor symptoms of Parkinson's disease are caused by cell death in the substantia nigra, which may be partly due to oxidative stress. This oxidation may be relieved by neuromelanin. Patients with Parkinson's disease had 50% the amount of neuromelanin in the substantia nigra as compared to similar patients of their same age, but without Parkinson's. Because of this possible connection, neuromelanin has been heavily researched in the last decade.
This makes me think of the scenes in the documentary Still, when Michael J. Fox wakes up and immediately takes medications that increase dopamine. In an earlier part of that documentary, you see the actor suffer a series of head traumas in severe car accidents when he was still a teen. TBI is a risk factor for developing PD.
I don’t want to imply that this substantiates Kruse’s idea. Even though the loss of neuromelanin from the brainstem is a hallmark of Parkinson’s, more complex dysfunctions are also at play. It may be that neuromelanin’s ability to chelate iron goes haywire, for example. So the answer may not be as simple as replacing lost neuromelanin. To use a car metaphor, if something is wrong with the fuel system, adding more fuel won’t solve the problem.
I don’t have Parkinson’s, but one of my main complaints post-concussion was dizziness, which can be viewed as a movement disorder, and movement disorders are linked to these same areas of the brain, and to the oculomotor system, which depends on melanin in the eyes and the brainstem to function optimally.
Melanin, the Sun, and Energy
I didn’t find much on Wikipedia about the role of melanin in energy storage. So I searched for “melanin and energy storage” and was a bit stunned to see that technology companies are experimenting with using melanin for its energy storage capacity for… solar energy. Check it out…
Melanin: A Greener Route To Enhance Energy Storage under Solar Light
Electrodes of melanin on carbon paper were investigated for their morphological, optical, and voltammetric characteristics prior to being assembled into symmetric supercapacitors operating in aqueous electrolytes.
This brings me to one of Kruse’s main actionable takeaways, and that is to get far more sun exposure—to boost melanogenesis. Does it actually work? I don’t know, but he sends his patients to live for months at a time in equatorial regions (plus or minus 10 degrees of latitude from the equator). He claims that by doing this, one can replenish one’s storehouse of melanin and neuromelanin.
I don’t know enough about human biology to say whether neuromelanin replenishment in the substantia nigra via sun exposure is even plausible or not. And even if it is possible for a healthy person, does that mean it’s possible for everyone?
This sunlight prescription made me think about a segment from the old Michael Moore documentary about America’s healthcare system. In the segment, we see a French man sent by his French doctors to recuperate on the beach in the South of France. In short order, the man is tanned and fully recovered.
Rick Rubin is a believer. Before following Kruse’s advice, he was obese. Rubin is now far healthier and spends large parts of his day in the sunshine. He’s set up his house so he can work outside much of the day.
Along with following the sunshine prescription, Kruse advocates fully aligning your biology with the circadian rhythm, which is a more mainstream idea, and something I wrote about here. Rick Rubin is so devoted to circadian alignment, he doesn’t have a single white lightbulb in his house, only red lights.
Along with his sunlight prescription, Kruse also prescribes transcranial magnetic stimulation to the NFL players who seek him out.
The Ink Well
Last but not least, Kruse talks about the octopus and the way the animal can store light energy and later produce bioluminescence. Oh, and octopus ink is dark because it’s… melanin! I looked this latter part up and it’s true, according to Wikipedia:
Cephalopod ink is a dark-coloured or luminous ink released into water by most species of cephalopod, usually as an escape mechanism… Its dark colour is caused by its main constituent, melanin.
It’s the kind of fun fact that would blow the minds of stoned people at a party. “Octopus ink is like, melanin, man!” But then again, The Dude Abides for a reason, right?
So is it time for an extended trip to the equator? Or to a red light sauna? Or a UVB tanning bed? I’m not sure. But I do look at my Vielight and my NeoRhythm and the sunshine on my skin a little differently now. And using my best Neanderthal imitation I say this: Hmph.
Brainwave is a newsletter about brain health, a personal blog about my own journey, and an informational resource for people whose symptoms haven’t resolved after a concussion or mTBI. I aim to present this information clearly and concisely, spelling out what’s backed by science and what remains unknown. Nothing here is meant as a substitute for professional medical advice, diagnosis, or treatment. I am not a physician or a healthcare practitioner of any kind; I’ve had a lot of sports-related head trauma and had to learn this stuff the hard way. If you found this information helpful or know someone who might benefit from it, please share and subscribe to Brainwave.
Just subscribed! Thank you for creating this space!👊🏽🥰
Great article!