Why our mitochondria need sunlight

Many people were taught in school that the mitochondria are those little organelles that act as the powerhouses in our cells. Besides playing a key role in bioenergetics like ATP production, mitochondria are also responsible for glycolysis (the metabolic pathway that converts food into pyruvate) and cellular respiration (transfer of protons and electrons to create ATP), and the number of mitochondria in each cell can range from a few to thousands per cell depending on factors like age, nutrition, and exercise.

Mitochondria malfunction is involved in basically all chronic diseases and conditions: Alzheimer’s disease, heavy metal toxicity, chronic fatigue syndrome, etc.

They also have several other health functions, much of which are controlled by light.

Mitochondria are light-controlled

Bet you weren’t taught that in biology class!

As I mentioned in my previous post about the health benefits of proper sunlight exposure, light can penetrate certain organelles in our cells like mitochondrion and the nucleus. In short, light is the cheapest and most effective way to change your health.

The retina of our eyes has a high concentration of mitochondria and is therefore susceptible to oxidative stress. Certain wavelengths of light affect mitochondrial function differently.

A variety of studies suggest that short-wave blue light causes reduced ATP production and increased reactive oxygen species (ROS), which is just fancy for saying oxidative stress that eventually damages cells. The result is then cell death (apoptosis) and DNA damage. So excessive blue light, which is what all screens emit = bad for eye health.

On the other hand, long-wave red light can increase ATP and nitric oxide production and reduces ROS, inflammation, and cell death. So overall, red light enhances eye health thanks to better mitochondrial function. These findings can hopefully help prevent and possibly treat eye diseases like glaucoma and improve vision in older adults.

The melatonin-mitochondria connection

As previously mentioned in my earlier post about the benefits of sun exposure, light exposure affects our levels of circulatory melatonin that is produced in the pineal gland of our brains which produces a ton of health benefits. Our mitochondria also produce melatonin. In fact, only 5% of melatonin is produced in the pineal gland.

Near-infrared light is invisible long-wavelength (wavelengths from 650 nm to 1200 nm) light that can penetrate tissues, and near-infrared light therapy, also called photobiomodulation, has been shown to benefit the mitochondria most. For example, near-infrared light from sunlight or artificial sources stimulates the production of melatonin in the mitochondria where it has antioxidant effects (i.e. reducing oxidative stress). Melatonin exerts a myriad of health benefits such as:

stabilizing the mitochondria by triggering mitophagy and apoptosis
promotes the activity of the enzyme pyruvate dehydrogenase (PDH) which enhances mitochondrial uptake of pyruvate resulting in the production of acetyl coenzyme A, a necessary co-factor for melatonin synthesis
increases mitochondrial biogenesis (production of more mitochondria) in stem cells

On the other hand, Acetyl-CoA in the mitochondria is a co-factor for the enzyme involved in melatonin synthesis N-acetyltransferase (AANAT), which enables adequate melatonin production in the mitochondria of normal cells.

The mutual relationship between melatonin and the mitochondria is very important for our health as it controls the amount of ROS inside the mitochondria so it doesn’t get out of control and thus helps keep healthy cells (eye, skin, etc) alive. Fun fact: mitochondria originated from melatonin-producing bacteria. Yet another reason to not hate microbes.

How red light benefits the mitochondria

Red light therapy at low doses, such as near-infrared, has been shown to have beneficial effects on muscles, bones, skin, joints, and connective tissue. Other health benefits include an increase in nitric oxide which improves circulation, better cell survival, increased ATP production, and reduced ROS.

Additionally, near-infrared light changes the structure of the water inside the mitochondria which leads to more energy production. Cellular respiration, also called oxidative phosphorylation, contains the electron transport chain and ATP synthase, which are proteins within the inner mitochondrial membrane. The enzyme cytochrome C oxidase (COX) is within complex IV of the electron transport chain (see the image above), and regulates electron transfers and consequently cellular energy production. The viscosity of the water inside the inner mitochondrial matrix affects the rate at which ATP synthase makes ATP by changing the electron gradient, i.e. the charge, by infusing protons across the inner mitochondrial matrix. Near-infrared light reduces the viscosity of this water which decreases the friction of ATP synthase rotation so it can turn smoother and pump out more ATP.

The intermembrane space matrix is where the mitochondrion’s water is contained.

Here’s where it gets interesting, melatonin within the mitochondria also reduces the inner mitochondrial matrix water viscosity which also enhances ATP synthase function and thus energy production, but also allows melatonin to scavenge free radicals which reduces ROS. This change in water viscosity has been called exclusion zone (EZ) or structured water by Dr. Gerald Pollack, researcher and author of the book The Fourth Phase of Water. Basically, the structure of water changes in such a way that it “excludes” impurities like ROS. An excess of ROS can make water “sticky” which “clogs up” the ATP synthase motor rotation. EZ water also holds a charge which creates an electrical gradient and allows for better cell-to-cell communication.

Overall, we can see the various mechanisms by which sunlight directly leads to energy production within humans. Maybe we need to start thinking of ourselves more as plants and accept that we also convert sunlight into energy. We all know that plants that don’t receive light don’t survive, and I would argue that human health also depends on proper sunlight exposure.

Sources

https://www.cell.com/action/showPdf?pii=S1043-2760%2812%2900136-1

https://www.frontiersin.org/articles/10.3389/fphys.2017.00319/full

https://www.sciencedirect.com/science/article/pii/S1567724916302586

https://www.azolifesciences.com/article/Enhancing-the-Function-of-Mitochondria-Using-Deep-Red-Light.aspx

https://www.mdpi.com/1420-3049/23/2/509

https://www.nature.com/articles/s41598-021-02311-1

https://journals.physiology.org/doi/full/10.1152/physiol.00034.2019

https://www.mdpi.com/1420-3049/23/2/509

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2790317/

https://www.frontiersin.org/articles/10.3389/fnagi.2020.00089/full

https://pubmed.ncbi.nlm.nih.gov/26154113/