Why being naked in the sun could be the most important (and free) Health Interventions we should all embrace…

Most of us will agree, the warm sun on our skin feels great.  It boosts our mood, improves our immune system, lowers our blood pressure, and can improve our metabolic health.  Sun exposure raises our vitamin D levels, which protects us against autoimmune diseases, diabetes, and many types of cancer. Many people think that taking a vitamin D3 supplement to boost blood serum levels is a good replacement for the sun; im here to convince you, this is absolutely not the case.

Vitamin D

I've been in clinical practice now for almost 15 years. As a med student in 2006, the research about vitamin D and its link to all-cause mortality- from heart disease to cancer began to emerge.  I began my practice in 2010 and living in Canada, was very excited about the multitude of health benefits I could impart to my patients by simply dosing them with this cheap supplement.

Vitamin D is important, don’t get me wrong. We make vitamin D from LDL cholesterol in the skin on exposure to sunlight. It’s crucial for so many aspects of health, but there is much more to sunlight than JUST vitamin D production. If you live in high or low latitudes, like us in NZ, the angle of the sun to the earth isn’t low enough to generate the production of Vitamin D 3 all year, so it may be useful to use supplements in the winter. It’s also important to load up on vitamin D3 from the sun when you can in this environment. A good tool to use is Dminder- this app takes into account your latitude and allows you to estimate vitamin D production from the sun.

Research shows that vitamin D is important for:

Calcium Absorption: Vitamin D is crucial for the absorption of calcium in the gut, which is essential for maintaining healthy bones and teeth. Adequate vitamin D levels may also prevent arterial calcification.

Osteoporosis Prevention: Adequate levels of vitamin D can help in the prevention of osteoporosis and fractures.

Immune Modulation: Vitamin D has immunomodulatory properties and can help in the proper functioning of T cells. It has been shown to improve innate immunity while reducing the risk of autoimmune conditions

Infection Resistance: Some studies have suggested that vitamin D can help in reducing the risk of infections, including respiratory infections.

Blood Pressure Regulation: There is evidence to suggest that vitamin D may play a role in regulating blood pressure and improving heart health, 

Mood Regulation: Vitamin D receptors are found in the brain, and some research has linked vitamin D deficiency to mood disorders like depression and anxiety.

Cognitive Function: Preliminary research suggests that adequate levels of vitamin D may be associated with maintained cognitive function in older adults.

Insulin Sensitivity: Some research indicates that vitamin D can improve insulin sensitivity and help regulate blood sugar levels, which is important in preventing type 2 diabetes.

Cancer Risk: Some studies have suggested that adequate vitamin D levels may be associated with a lower risk of certain types of cancer, including breast, prostate, and colon cancer, 

Healthy Pregnancy: Adequate vitamin D levels are important for a healthy pregnancy and may reduce the risk of complications such as gestational diabetes and preterm birth.

Multiple Sclerosis (MS) and Rheumatoid Arthritis: Some research suggests that adequate vitamin D levels may be protective against the development of certain autoimmune diseases, although more research is needed.

Asthma and COPD: There’s some evidence that vitamin D supplementation could improve the severity and frequency of symptoms in chronic obstructive pulmonary diseases (COPD) and asthma, particularly in individuals who are deficient in vitamin D.

Muscle Strength: Vitamin D is thought to play a role in muscle function, and deficiency has been linked to reduced muscle strength.

BUT,  The sun is much MORE than D3…

I started measuring people's vitamin D levels and supplementing almost everyone from my patients with autoimmunity to those with elevated cardiometabolic risk factors as the evidence seemed solid that if your level was in a high normal range, you'd be happy and healthy in no time. 

In fairness, for my sickest patients with the lowest levels, I did see some benefit; for those with acute viral illnesses, or autoimmune conditions, they did do better when vitamin D levels were improved. For the most part, however, I was underwhelmed.  Most of the vitamin D research at the time was done on those with optimal levels due to lifestyle factors, not supplementation.  Those with the highest vitamin D levels had protection against most chronic diseases, yet I and many of my colleagues found that just by giving vitamin D supplements we didn't see people become universally healthier. 

I began to realize that many of the positive epidemiological studies and associations with high serum D3 and health, were not due to supplements at all it wasn't about vitamin D per se.

Vitamin D levels were rather a proxy for the amount of time people spent outside in the sun.

Circadian Biology

The 2017 Nobel Prize in Physiology or Medicine was awarded jointly to Jeffrey C. Hall, Michael Rosbash, and Michael W. Young for their discoveries of molecular mechanisms controlling the circadian rhythm. 

These rhythms are essentially internal clocks that regulate various physiological processes, including sleep-wake cycles, feeding, hormone production, and cellular regeneration, among others. Optimal Circadian Biology is important for almost every aspect of health, and when our circadian biology is disrupted our risk of almost every chronic condition goes up. 

A decade before the prize was won for circadian biology, the  World Health Organization's (WHO) International Agency for Research on Cancer (IARC) classified "shift work that involves circadian disruption" as "probably carcinogenic to humans" (Group 2A) in 2007. This decision was based on evidence from both human and animal studies that suggested a link between night shift work and an increased risk of cancer, particularly breast cancer.

Since 2017 research into the mechanisms that control our circadian biology as well as the conditions linked to its disruption has exploded.

Light is the main controller of circadian rhythms. We evolved on a planet with 24-hour light-dark cycles and our biology is incredibly sensitive to its presence in our eyes and on our skin.  When we miss out on sufficient natural daylight and are exposed to light at night- common for most of us, every system in the body suffers.

We do not sleep well, we overproduce stress hormones, and our sex hormones get thrown out of balance (contributing to the massive epidemic of infertility and low sperm count worldwide and potentially playing a role in the rise in gender confusion). Circadian disruption affects our immune system and risk of cancer, we have a higher risk of metabolic issues including fatty liver, our risk of heart disease increases, and if we do get sick, it’s harder for us to get better.  

Enter POMC…

In the 1970’s a gene called POMC was isolated.  It codes for a protein also called POMC thats stands for "Proopiomelanocortin”.  POMC is synthesized in the hypothalmus and pituitary gland (brain) and also in the skin. Its production is stimulated by UV light on the skin and in the eye and it plays an incredibly important role in our health:

POMC protein is broken down into a number of important peptides including: 

1. Adrenocorticotropic hormone (ACTH)

ACTH stimulates the adrenals to release cortisol, a steroid hormone that plays a role in our stress response, immune function, metabolism, and other physiological processes.  It needs to be high in the morning to give us energy and low in the evening so we can sleep soundly. Many people think of work or psychological stress as the main cause of “adrenal fatigue” or burnout but light plays a major though its modulation of ACTH. Light stimulates ACTH, which stimulates cortisol and but it is all about balance (high in the morning/day on exposure to light, low when the light goes away). Light into the eyes at night also stimulates ACTH, which begins to cause problems as our cortisol levels never fall, and our melatonin levels (separate blog later) never rise.

2. α-MSH

Alpha MSH is best known for its role in stimulating melanin - which gives our skin a brown color when we have been in the sun as well as regulating immune function.  Melanin is our primary defense against the negative effects of excessive UV damage and helps to protect the skin and deeper tissues. In terms of its role in immunity, the general takeaway is that with sun exposure and alpha MSH upregulation, we see a reduction of inflammation through specific cell-mediated functions as well as improving barrier function (gut, lungs, and brain).   Additionally, alpha MSH improves our ability to fight and clear infections and cancer cells, while reducing our risk of autoimmunity. 

Specific Immunological Roles Include:

Anti-Inflammatory Effects: α-MSH has been shown to reduce the production of pro-inflammatory cytokines like tumor necrosis factor-alpha (TNF-α) and interleukin-1 (IL-1), among others. It can also increase the production of anti-inflammatory cytokines such as IL-10. This means that not only can it benefit thouse with chronic low grade inflammation, as is linked to cardiovascular disease and diabetes, but also those with overt inflammatory conditions including Rhumatoid arthritis and Inflamatory bowel disease. Inflammation in the brain in the short term can cause depression, anxiety and insomnia and in the longer term is one of the main porcess that leads to neurodegeneraitve conditions like dementia and Parkinsons. 

Modulation of T-Cell Responses: Alpha-MSH can affect the differentiation and function of T cells, which are crucial components of the adaptive immune system. This means we are better able to fight infections and rid our body of cancer cells, as well as imporve our outcome if we are diagnosed with cancer. 

Autoimmunity and Tolerance: Studies suggest that α-MSH is  involved in promoting immune tolerance and could potentially be used in the treatment of autoimmune diseases.

Endothelial Cell Interactions: α-MSH has been shown to inhibit the adhesion of leukocytes (white blood cells) to vascular endothelial cells, an essential step in inflammation and immune response. This means that it plays an important role in our risk of arterial disease linked to heart diease. 

Inhibition of Nitric Oxide Production: α-MSH can inhibit the production of nitric oxide by activated macrophages. While nitric oxide is essential for some antimicrobial actions, excessive production can be harmful and damage the body.  

Neuroimmune Interactions: α-MSH is important for our mood and risk of neurodegenerative dieases through modulation of the brains immune system, reducing brain inflammation, improving the integrity of the blood brain barrier.  It also provides neuroprotection against heavy metals and toxins that do cross the blood brain brain brrier.

Mucosal Barrier Protection:  α-MSH, strengthens the barriers of the body. Many of us understand that the gut is important for our health, but many dont realise that at any time about 90% of our immune cells reside in the lymphatic tissue across the gut lining.  When this barrier breaks down (intestinal hyperpermebility) our immune system lose the ability to tolerate our healthy gut microbes and we see chronic levels of inflammaiton that link to many chorinc dieases. 

3. β-Endorphin

B-endorphin acts as an endogenous opioid, contributing to pain relief and feelings of well-being. It’s our body’s natural feel-good hormone and helps to prevent overeating as well as playing a role in our sleep-wake cycle and protection from neurodegenerative disease. This is the main reason we feel so good being outside. When our beta-endorphin levels are low we are more prone to depression and addictions. It’s no wonder that lockdowns resulted in a huge increase in addictive behaviors, from overeating to alcohol and drug use.  When we understand how the sun plays a role in our production of mood-boosting opioids we can also see why being stuck inside significantly increases rates of depression and suicide. 

It also raises an important question: Why has evolution made the sun (quite literally) addictive? I don’t think nature makes mistakes, and hopefully, the information in this blog helps you understand why for our overall health it would be important for us to be very driven to seek out the sun on our skin.

Its Key functions Include:

Analgesic Effects: Beta-endorphin is released in response to stress and pain and acts as an endogenous analgesic. It binds to opioid receptors in the brain and spinal cord, inhibiting the release of neurotransmitters like substance P, which is involved in pain signaling.

Emotional Well-being: Beta-endorphin can produce a feeling of well-being or even euphoria, especially under conditions of stress or pain. This is thought to be a protective biological mechanism to help cope with difficult situations.

Regulation of Appetite: Beta-endorphin also plays a role in feeding behavior, although the mechanisms are not fully understood.

4. β-Melanocyte-Stimulating Hormone (β-MSH)

 Less is known about β-MSH compared to α-MSH, but it is also thought to play a role in pigmentation and potentially in the central control of feeding.

5. γ-Melanocyte-Stimulating Hormone (γ-MSH)

Like α- and β-MSH, γ-MSH also originates from POMC. Its roles are less well understood but may include some regulatory functions in the kidney.

6. Corticotropin-like Intermediate Peptide (CLIP)

Generated as a product of ACTH cleavage, the physiological role of CLIP is not completely understood.

7. Lipotropin (β-Lipotropin)

The precursor to β-Endorphin has roles in lipid and fat metabolism. We don’t know much about Lipotropin, but I predict that it will be one of the mechanisms that underlie the relationship between our body composition and sun exposure.

Sun on our skin, hormones, and libido

Sun on our skin has also been shown to stimulate what’s referred to as the skin-hypothalamic-gonadal axis, meaning that UVB light on our skin can increase our sex hormone levels (testosterone, progesterone, and estrogen), improve women’s ovarian function and influence our libido.  Studies even show that being in the sun makes us seem more attractive to the opposite sex (oh lala as well as our receptivity towards sex).  Anyone involved in animal husbandry already knows this, it is foolish to think we are not animals, affected by seasonal changes in our light environment

More on (amazing) melanin

It’s not a coincidence that people look healthier with a tan. They probably are.  Melanin is an incredible antioxidant (protecting the skin from damage and also is present inside the body where it also plays a vital role in protecting our sense organs (eyes, inner ear, brain) from oxidative stress).  It is produced through the stimulation of POMC and a-MSH with sun exposure, and if someone has upregulated MSH from the sun (read above) they will also have produced the other peptides linked to good immune system function and overall health.

Interestingly melanin may also play a crucial role in detoxification through its ability to bind heavy metals. We see this in animals who live in toxic environments (they tend to have darker plumage or coats) and biosynthetic melanin is currently being studied for its ability to remove heavy metals in polluted water.  Melanin may bind heavy metals which are then deposited on the surface of the body and sloughed off as skin cells die, thus potentially protecting the kidneys from damage on excretion.

Melanins are also present in other areas of the body where they play numerous roles:

Safe sun exposure

I hope now im slowly beginning to convince you that exposing your bum to the sun may be a crucial step in your journey to optimal health.

When we realize the sun is our friend, not our foe like centralized medicine may have us believe, we can optimize our health naturally and for free. It is important to remember though that we must respect the sun!

We don’t want to overwhelm our body’s ability to produce melanin and thus end up with a nasty sunburn.

Start slowly, and if you live in a high UV environment avoid excessive exposure between 10-2 p.m. when the sun is the strongest. Preconditioning the skin with infrared light as is present in the early morning before the UV increases OR using a red light therapy device will upregulate your melanocytes so they can cope with more UV.  Staying outside at sunset with skin exposed also has this function, it reduces the inflammation in the skin from the earlier UV and helps heal sunburn.

A sunburn at the end of the day is not much more than excessive oxidative stress and inflammation in the skin, so consuming a healthy diet rich in colorful plant pigments/antioxidants (like anthocyanins- in blackcurrants are plants own sunscreen and protect berries from harsh UV) as well as an anti-inflammatory diet rich in omega 3 fats and low in trans or excessive omega 6 fats can also protect you against sunburn to some degree. 

The natural spectrum of light present in the sun includes primarily Infrared, UVA, and UVB.  These work together to allow the body to benefit from the sun without excessive damage (and cancer). This is why i dislike sunscreens. Most chemical sunscreens block IR and UVB light, allowing UVA to penetrate deep into the skin causing damage to cells. Without the immunomodulatory effects of UVB-producing vitamin D or the antiinflammatory effects of IR light, we end up staying outside too long and potentially causing more damage to the skin.

So, grab a blanket, your favorite book, and a hat, and sun those buns (all year round!)

For a MUCH deeper dive into POMC, Melanin and all things light, read any of Dr Jack Kruse’s work, or watch this video.