Can we survive only on sunlight, water, and carbon dioxide?
You may have heard about many vegan charlatans, like Jasmuheen, trying a new trend called “breatharianism”.
Which is a so-called ‘diet’ suggesting that humans can survive on only light and air, while also claiming that plants have souls and it’s wrong to murder them.
The diet sounds pretty ridiculous, and many Darwin Award winners have already starved to death trying to do it, claiming they could survive on spiritual energy from the sun.
But all mysticism aside, is it scientifically possible for humans to photosynthesize?
We are not auto trowphs, but if we could be, the implications for life extension would be enormous.
The danger of starvation has been an existential threat to human survival since the dawn of time.
And it still is.
According to the United Nations Food and Agriculture Organization, 795 million people worldwide, suffered from chronic undernourishment in 2016.
In addition, massive droughts and new deserts are springing up all around the world.
So it is unclear if we will ever be able to feed the 12 billion people, who will live on this planet by the end of the century.
In fact, at any moment, a nuclear war or economic collapse, could plunge us into a global famine.
All these existential risks could be alleviated, if we could just find a way to get our energy from sunlight, like plants do.
Plants can harness the raw power of the sun, with an organelle called the “chloroplast”, which allows them to undergo photosynthesis, the process of turning sunlight and carbon dioxide, into oxygen and glucose.
The glucose can then be used for energy so that the plant never has to eat.
If humans could add chloroplasts into our cells, we would no longer need farms, mass deforestation, or food supplies for space missions.
Our countless hours spent purchasing, preparing, and eating food, could be redirected elsewhere.
Malnutrition and food born illness would disappear, extending human life expectancy.
Not needing to grow food will also make it easier to establish a colony on Mars.
An idea explored in the popular sci-fi animay series, Knights of Sidonia, where the future human race lives in a multi generation colony ship, and are genetically engineered to feed on starlight.
But just how scientifically practical is this?
And can we do it efficiently?
A review published in the Journal of experimental biology, called “the making of a photosyntetic animal”, outlined a process for capturing chloroplasts called “Kleptoplasty”.
Kleptoplasty is when chloroplasts from Auto trowphes, like plants or algae, are sequestered by animals.
These host organisms will partially digest the algae, but keep the chloroplasts intact, so they can steal the plant’s ability to photosynthesize, and get some of their future food from sunlight.
It turns out, the concept of putting photosynthetic chloroplasts into cells is not a new idea.
Nature has been doing it for 2 billion years and it’s called “Endosymbiosis”.
When the first single-celled animals ate bacteria, the prey cell became part of the predator cell, as an organelle.
Which is how we got mitochondria.
Chloroplasts themselves were once photosynthetic organisms called “Cyanobacteria”, until they were eaten by the ancestors of plants.
Doctor Christina Agapakis is one of many biologists trying to mimic Kleptoplasty, experimenting with zebrafish embryos, injecting them with photosynthetic cyanobacteria.
Astonishingly, the fish didn’t die, and neither did the bacteria.
However, injecting the embryos with other bacteria, like E coli, would kill either the embryo or the bacteria, within an hour.
By that logic, it might theoretically be possible to get these chloroplasts and bacteria, to survive inside our cells too.
In fact, 4 animals have already found ways to feed off sunlight.
These animals include, number 1, the Spotted Salamander.
Number two, a sea slug called Eleezia Chlorotica.
Number 3, the pea A fid.
And lastly, number 4, the Oriental Hornet.
The first photosynthetic animal is the spotted Salamander, which actually lives here, in the united states.
A study published in 2010 was the first to discover that the cells of these salamanders somehow contained Algae, which used their chloroplasts to power the Salamander’s cells.
The salamanders begin photosynthesis early in their lifetimes, as the algae even appear inside their fertilized eggs.
These salamanders spend their entire lives in a symbiotic relationship with the algae, having even adapted their immune system to tolerate them.
The algae enters the developing salamander egg, and becomes a part of the fetus, before the immune system can kick it out.
They then form a sym bi otic relationship, where the algae eats the nitrogen in the Salamander’s waste, while the salamander gets food and oxygen, from the algae’s photosynthesis.
In fact, the algae also acts as an internal source of oxygen, letting the salamander partially breathe underwater.
In 2011, a study published in the proceedings of the natural academy of sciences, explored the possibility of incorporating this algae into human tissue as well.
Which opens the door to future superhumans, that might find themselves swimming at the bottom of an ocean for an hour, with symbiotic algae supplying them oxygen.
Perhaps then, they might dry up on a beach, and feed on the sun for breakfast.
This discovery is the first documented case of a plant living in partnership with a verta brett.
However, the photosynthetic process might not be as efficient for us, as it was for the salamander.
While infusing human cells with algae is an interesting prospect, the problem with this method is that it isn’t really Kleptoplasty.
What we’re looking for is an efficient way to incorporate the chlorplasts into the cells, without taking the entire algae in along with them.
Which brings us to the sea slug.
The Eleezia Chlorotica, famously known as, “The Solar Powered Sea slug”. Uses a different strategy.
Unlike the salamander, the slug has stolen the chloroplasts from algae altogether, without needing the rest of the organism for it to photosynthesize.
The chloroplasts collect in the branches of the slug’s digestive tract, which turns the slug green, conveniently giving them a nice camouflage.
Baby slugs are still brown because they haven’t collected enough chloroplasts, but an adult slug only needs to eat for 2 weeks per year, and lives off sunlight for the other 50.
This is real Kleptoplasty, because the slug is not dependant on the algae for food, it just feeds off sunlight by itself.
Early in 2015, a study published in the biological bulletin, found proof that some of the slug’s genes came from the algae it regularly consumed.
The slug has evolved to hijack genes from the algae, so they could also make the specialized proteins required to maintain the chloroplasts.
This is a paradigm-shifting concept, because no non-bacterial lifeform has ever been able to accomplish horizontal gene transfer, until now.
Juvenile sea slugs establish endosymbiosis of chloroplasts after sucking out the cell contents, and absorbing them into it’s body, through a process called “Fag O cytosis”.
The slug still needs to eat occasionally to consume protein and nutrients, but using photosynthesis, it can still go up to 9 months without food.
The idea of an animal stealing genes is amazing enough, but the fact that isolated chloroplasts can function alone in an animal’s body, is groundbreaking.
So perhaps we humans won’t need to infuse ourselves with algae after all, it might be more efficient to just engineer ourselves with genes that make chloroplast.
Unfortunately, chloroplasts are still energetically expensive to maintain.
But what if we didn’t need the chloroplasts at all?
There might be a way to bypass the chloroplasts, and just build the chlorophyll machinery.
This brings us to the pea A fid, which can even manufacture it’s own pigments.
Pigments, like Carotenoids and Chlorophyll, are powerful compounds that make up the core of photosynthesis, absorbing sunlight to make A T P, or, Adenosine Triphosphate.
The source of all energy in the cell.
We don’t know the exact process yet, but Pea A fids somehow have the genes to make this photosynthetic machinery without Kleptoplasty.
A study published in the Journal Nature, called “Photosynthesis-like process found in insects 2012”, uses carotenoid pigments without needing chloroplasts.
The same concept applies to the Oriental hornet, which uses it’s hard exoskeleton as a solar panel, producing electricity from sunlight.
The Hornet’s exoskeleton contains grooves that split incoming sunlight into diverging beams, as well as pinholes that reduce the amount of sunlight bouncing off the exoskeleton, allowing it to absorb most of the light that strikes it.
The Hornet then makes a pigment called xanthopterin, which can turn light into electrical energy, building up a voltage, which increases the activity of it’s muscles and enzymes.
The hornet gathers solar energy during the day, and the voltage is released as current during the night.
A solar cell was created by Dr. Marian Plotkin, to assess the efficiency of the xanthoperin pigment. While it was found to be inefficient, the project still demonstrated, that the pigment really could create electricity from sunlight.
Overall, the big question is whether or not the knowledge gained from these animals, can help us develop Kleptoplasty or photosynthesis in humans.
Unfortunately, there are some problems.
First, humans also need protein, which we can only get from animals.
This means we’d still need to take supplements for 9 amino acids the human body requires, but the photosynthesis will definitely cover us for sugars and fats.
Second, If humans had chloroplasts in our skin cells, the chlorophyll pigment would probably turn us green, which many people might not like for aesthetic reasons.
Third, photosynthesis is not an efficient process for large organisms like humans, because large creatures have a lower volume to surface area ratio.
Even in plants, photosynthesis only converts about 5 to 9 percent, of the total available energy from the sun’s rays.
Plants can survive on this, because they have paper-thin leaves that maximize their surface area, but humans do not.
So if we wanted it to work, we’d need to absorb a ton of light, so say goodbye to clothes.
Fourth, unlike slugs, insects, and salamanders, humans are complicated, and our physiology doesn’t have many analogs to theirs.
For example, unlike slugs, our thick oily layer of dead skin cells prevents carbon dioxide from getting into our cells.
While we do make Carbon dioxide in our mitochondria, we don’t make enough, and the C O 2 that we do make, is mostly in our brain and muscles cells, rather than our skin cells.
So we would also need to engineer small pores in our skin to let the carbon dioxide in.
C O 2 is crucial in photosynthesis, but if we don’t let enough in, the human body would behave more like a hybrid car, running partially on both food and on sunlight.
Maybe it’s more practical to spend our body’s energy on other biological needs, rather than on micromanaging chloroplasts and photosynthetic sym bee ontz.
So while Kleptoplasty seems like a popular idea in the transhumanist and biohacking community, I just think there are too many problems for a 100 percent solar diet to be feasible.
In fact, Doctor Christina Agapakis’s team did a calculation for the photosynthetic zebrafish and projected that we’d need thousands of algae per cell, to make it run 100 percent on sunlight.
Even the spotted Salamander is not able to survive fully on sunlight, and Kleptoplasty only works in animals like the E Chlorotica slug and the Pea A fid, because they have evolved to look like leaves.
Possessing low volumes and high surface area.
However, don’t give up hope.
While we could never subsist entirely off the sun, who’s to say we can’t supplement our diets with a little solar snack every now and then.
I can still see these body mods being a great backup generator to keep starving people alive just a bit longer, but it will never be a replacement for food.
We may not go full solar anytime soon, but celebrities with green algal hair implants and enhanced athletes with green skin, don’t seem far outside the realm of possibility.
Nor would green astronauts, where a tiny solar meal could be the difference between life or death.
In conclusion, while this research probably won’t make breatharianism a reality, it might still make biopunk ideas, like photosynthetic skin patches, seem a little less science fictional.
Even then, we could always ditch Kleptoplasty altogether, and instead create synthetic chloroplasts with biotechnology, or mechanical ones with nanotechnology.
Who knows what the future of biohacking holds.
Through more research into these unique animals, we can gain a better understanding of how they function, apply that knowledge to our technologies, and most of all.
Let nature’s example, continue to inspire us.