Ultra processed light

You’ve heard about ultra processed food. But did you realise that ultra processed light, ie LED and indoor lighting that generally only contains visible (mostly blue/green) light could be even worse for your metabolic (and overall) health?

Natural sunlight, like natural food contains a rich variety light “nutrients” we have evolved under and need for optimal health.


Natural light and its essential “nutrients”

Starting from high energy (short wavelength) to lowest energy (long wavelength):

1. UVB: UVB is essential for vitamin D production. Vitamin D is a hormone made from a cholesterol precursor in the skin. When irradiated by 280-315nm UVB is made into the hormone known as “vitamin D”. Almost every cell in the body has a vitamin D receptor. Vitamin D controls gene expression, immune function and metabolic health. Low solar exposure and low vitamin D is linked to a multitude of chronic health conditions from increase in diabetes and cancer to asthma and autoimmunity.

2. UVA: UVA is responsible for the erythema response (aka getting pink in the sun), and melanin production. Melanin has important properties that allow increased energy production and cell function (through splitting water in free hydrogen, oxygen and electrons), as well as acting as an important metal chelator helping us to rid ourselves of heavy metals (heavy metal load is also linked to diabetes [1]). Melanin can be internalised to support neuromelanin, sensory and brain function. Your dermatologist is wrong, if he says “there is no such thing as a healthy tan”.

UVA promotes nitric oxide release in the body, an essential component in protecting the cardiovascular system, lowering blood pressure and increasing blood flow to tissues. Dr Weller, author of the huge UK biobank study on sunlight and melanoma, says we have a 100X greater risk of dying of a cardiovascular event due to insufficient sunlight than we do of melanoma from too much [2].

3. Visible light: The ratios of blue, red, violet etc visible light spectra present in natural sunlight is constantly changing from sunrise to sunset. This powerfully triggers circadian biology, cortisol, melatonin and sex hormone release, digestive function and neurotransmitter synthesis. Steady state indoor junk light is one of the biggest drivers of poor hormone function and mental health.

[Credit: Dr Alexander Wunsch: 2016 Presentation on Photoendocrinology]

4. Near Infrared: NIR light is low energy long wavelength and can penetrate deeply into the body (even through the skull) to nourish our mitochondria and increase energy production. Near infrared light is one of the most important drivers of intracellular melatonin production which represents about 70% of our total melatonin levels [3]. This type of melatonin is not released in a circadian fashion into the bloodstream like pineal melatonin (which is sensitive to the changing levels of blue light). Melatonin promotes autophagy and mitophagy (cell recycling), is one of the body’s most important endogenous antioxidants, and has been shown to regulate inflammation and provide antiviral benefits among many other essential functions [4, 5]. Check out the learn section of the Circadian app for a deep dive on melatonin.


Light & metabolic health

Did you know similarly to processed food, artificial light can increase blood sugar and insulin levels (without even having a snack) [6, 7, 8, 9]?

Lack of full spectrum sunlight is associated with an increased risk of cancers, cardiovascular, autoimmune, metabolic diseases, and more [10].

Insufficent sun exposure

Red/infrared light lowers blood glucose by 27% [11]. By the way, you don’t need a red light panel, you just need to #gothefuckoutside more. Natural sunlight is 50% red & infrared light.

Light stimulation of mitochondria

Light at night, like eating junk food, increases blood sugar and diabetes [12].

Outdoor LAN

Artificial light at night will ruin your metabolism, make you gain weight and increase your risk for obesity [13, 14, 15].

ruin your metabolism and make you fat

Further, ultra processed light from LEDs and indoor lighting stimulate dopamine release (thats why your phone and laptop are so addictive) which overtime will deplete your reserves, zapping your willpower and leading you to want to overeat the ultra-processed foods.

Indoor lighting is also linked to increased risk of myopia, whereas sunlight does the opposite [x]. Artificial light likely increases the risk of neurodegenerative diseases like Parkinson’s [16]. Sun exposure on the other hand is linked to lower rates of cancer, cardiovascular, neurodegenerative, metabolic and autoimmune diseases [17].

the risks and benefits of sun exposure

Circadian disruption resulting from insufficient bright natural sunlight during the day and exposure to junk light at night is a well known driver of many pathologic conditions, including sleep disorders, cardiovascular disease, metabolic dysfunction, infertility, poor physical performance, as well as cancer [18].

circadian dysfunction

So while we need to avoid ultra processed food, we need to realise that ultra processed light could be as problematic.

If you take the care to eat a natural, unprocessed diet but don’t expose yourself to natural light during the day and stay up up after dark on your laptop or phone (without protection), you are also ruining your metabolic health, so you may as well just all that Easter chocolate.

Mind your rhythm, mind your light and #gothefuckoutside 😉

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