STORY AT-A-GLANCE
Vitamin D is a potent immunomodulator, influencing both your innate and adaptive immune responses. As such, vitamin D deficiency has been linked to health conditions such as osteoporosis, autoimmune diseases, cardiovascular diseases and cancer
Vitamin D is also crucial for the maintenance of healthy bones and nervous system function
Sun exposure is the primary source of vitamin D, and while sunburn needs to be avoided, this risk needs to be balanced with the need for vitamin D production
In the critically ill, vitamin D deficiency has been shown to increase infection and mortality rates, and is associated with longer hospital stays
Chinese researchers concluded that vitamin D status can predict your risk of death from COVID-19, as well as the severity of your symptoms in the acute phase. Having a vitamin D level lower than 36.04 ng/mL was predictive for death
For decades, the conventional medical establishment and media have downplayed if not entirely ignored evidence showing that sun exposure is a crucial part of a healthy lifestyle that prevents, as opposed to creates, diseases — including cancer.
Is that about to change? It’s too early to tell, but surprisingly supportive scientific papers and mainstream media articles have recently highlighted the benefits of sun exposure and vitamin D optimization.
Scientific Review Highlights Importance of Vitamin D
Among them is a scientific review published in the peer-reviewed journal Cureus, in which the authors highlight "the intricate relationship between Vitamin D and patient outcomes." An excerpt from the paper, "The Sunlight-Vitamin D Connection: Implications for Patient Outcomes in the Surgical Intensive Care Unit," reads:1
The paper goes on to stress that vitamin D’s "crucial role in maintaining human health" goes well beyond its classical role in bone health (by regulating calcium and phosphorus homeostasis).
"Emerging evidence suggests that vitamin D exerts a much broader influence on various physiological processes," the authors note. For example, they point out that vitamin D is "a potent immunomodulator, influencing the innate and adaptive immune responses":
As such, vitamin D deficiency has been linked to health conditions such as osteoporosis, autoimmune diseases, cardiovascular diseases, and cancer. According to this paper, vitamin D is also "crucial for the functioning of the nervous system and has been associated with mental health disorders."
Vitamin D is also a key regulator of cell growth and differentiation, and "Proper cell growth and differentiation regulation is crucial for maintaining tissue health and preventing abnormal cell proliferation, often associated with cancer," the authors state.
Sensible Sunlight Exposure Is the Primary Source of Vitamin D
Importantly, the authors accurately stress that sunlight is the primary source of vitamin D, and while sunburn needs to be avoided, this risk needs to be balanced with the need for vitamin D production:2
Vitamin D in Critical Illness
The authors also review the clinical implications of vitamin D in critically ill ICU patients, where the scientific evidence shows vitamin D deficiency:3
Increases infection rates, including hospital-acquired nosocomial infections
May increase mortality rates in SICU patients
Is associated with longer hospital stays
Conversely, higher vitamin D levels in SICU patients have been shown to:
To improve outcomes in SICU patients, the authors recommend taking an individualized approach, where patients with documented vitamin D deficiencies are given vitamin D supplements, with vitamin D3 (the active form) being preferred over D2 (the synthetic version), as it raises levels more effectively.
The authors also accurately recommend assessing the patient’s baseline vitamin D level through blood testing before supplementing, to determine the extent of the deficiency, and to monitor the level during and after supplementation. This is the only way to ensure vitamin D sufficiency, because it’s the blood level that matters, not the individual dose. In conclusion, the authors made the following comments:4
Vitamin D Status Can Predict COVID-19 Mortality Rate
In November 2020, I coauthored a scientific review on vitamin D’s impact on COVID-19. That paper, "Evidence Regarding Vitamin D and Risk of COVID-19 and Its Severity" was published in the journal Nutrients.5
Media vilified me for my stance on vitamin D, and one journalist went so far as to claim she "couldn’t verify" that I was the author of this peer-reviewed paper, all in an effort to discredit me.
Since then, the evidence for vitamin D against COVID has only grown stronger. Most recently, an observational study6,7 from China concluded that vitamin D status can predict your risk of death from COVID-19, as well as the severity of your symptoms in the acute phase.
The study, published in the Virology Journal, analyzed data from 399 COVID patients hospitalized between December 2022 and February 2023. The patients were categorized into three groups based on their vitamin D blood levels at admission (normal: 30 ng/mL or higher, insufficient: 20-29 ng/mL, or deficient: less than 20 ng/mL).
Analysis revealed that vitamin D deficiency was associated with more severe symptoms and having a vitamin D level lower than 36.04 ng/mL was predictive for death.
The predictability of COVID-19 mortality was even greater when vitamin D levels were considered together with levels of interleukin-5 (IL-5) and eosinophil. Patients with vitamin D below 36.04 ng/mL, IL-5 higher than 1.7 pg/mL, and an eosinophil count of less than 0.015 had the highest risk of death.
What’s particularly notable here is that 36.04 ng/mL is within the "normal" range for vitamin D, clearly illustrating that "normal" is far from optimal, and not enough when your life hangs in the balance. Most vitamin D experts consider 30 ng/mL half of what an optimum vitamin D level should be, which is 60 to 80 ng/mL.
‘Unexpected’ Life Extension Benefits
October 1, 2023, The Guardian also ran an article8 highlighting some of the "unexpected" benefits of sun exposure, including longer life expectancy and a reduced risk of death from skin cancer. Of course, anyone who has spent any amount of time investigating the matter will not be surprised. That said, here’s an excerpt from that article, written by science correspondent Linda Geddes:
Your Skin Has Built-In Protective Mechanisms
Geddes accurately describes how melanin, the pigment that gives your skin its dark color, protects your skin cells from DNA damage by absorbing ultraviolet sun rays. This is what causes you to develop a tan. She also explains how melanin production is activated by the release of beta-endorphins in response to sunlight, which have stress- and pain relieving effects all of their own.
And, while skin cancer can be triggered by repeated sunburn that damages your skin, people who get lots of sun exposure still have longer life expectancy than those who avoid the sun. So, clearly, routine sun exposure is not a prescription for death by skin cancer. Quite the opposite.
The key, really, is to avoid the skin damage caused by sunburns,11 and the easiest way to do that is by gradually building up a tan. Start by exposing large portions of skin for only five to 15 minutes if you’re fair-skinned, and longer if you have naturally darker skin, around solar noon.
You want your skin to develop just the slightest hint of pink, then cover back up. Each day after that, add a few more minutes. This will allow your melanin to do its job and protect your skin cells from UV damage. If you start in the spring, by mid-summer, you’ll be able to spend hours outside without burning, and your risk of skin cancer will then be minimal.
Vitamin D Supplements Do Not Confer the Same Benefits
Thankfully, Geddes also accurately notes that vitamin D supplements do not confer the same benefits as sun exposure, and that your vitamin D level is a biomarker of sun exposure, which is something I’ve been stressing for quite some time. Never in the history of mankind have we relied on pills for vitamin D production, and there’s no evidence to suggest that it would be wise to do so. Geddes writes:12
The one drawback with using sun exposure to maintain a protective vitamin D level is that there’s simply not enough sunlight hitting the earth year-round in some areas. If you live north of 37 degrees North latitude, you may still need a vitamin D supplement to get you through the winter.
Cancer Organizations Trade Skin Cancer for Internal Cancers
Indeed, the U.S. Surgeon General,14,15 the American Academy of Dermatology (AAD) and many other cancer organizations recommend complete and total sun avoidance in order to prevent skin cancer. The AAD will not even acknowledge different recommendations based on skin type.
This is a disastrous recommendation, as having a vitamin D blood level of 40 ng/mL or higher is a key prevention tool for all types of cancer, including internal cancers that are far deadlier than melanoma (malignant skin cancer). Studies have repeatedly demonstrated that it can significantly reduce your cancer risk, and increase your chances of surviving cancer if you do get it.16,17
For example, researchers at the University of California found that women with a vitamin D serum level of 40 ng/mL or greater had a 67% lower risk of cancer compared to women with levels of 20 ng/mL or less.18,19
The study included ALL invasive cancers, except for skin cancer, and had a follow-up period of nearly four years. Higher vitamin D is also associated with lower all-cause mortality.20,21 So, essentially, the recommendation to avoid all sun exposure trades the low risk of skin cancer for a far greater risk of deadly internal cancers.
By adhering to sensible sun exposure guidelines and making sure you do not get burned, you can maximize your benefits and minimize the risks of skin damage that could lead to skin cancer.
On the whole, overexposure to the sun, not all sun exposure, is the real problem when it comes to raising your risk for skin cancer.22 Meanwhile, optimizing your vitamin D via regular UV exposure can help decrease your risk of well over a dozen different cancers that are far more common and far more deadly than melanoma.
Brittle Bones Is a Serious Problem
Optimizing your vitamin D with sensible sun exposure will also protect you against osteopenia (brittle bones) and osteoporosis (bone loss), the prevalence of which is on the rise among younger people.
As of 2020, an estimated 12.3 million Americans over 50 were affected by osteoporosis, and an additional 47 million younger Americans were in the early stages.23 If your bones are getting compromised in your 40s or even 30s, what life expectancy, not to mention quality of life, can you really expect?
Fosamax and other bisphosphonate drugs are not the answer to this, as they are incredibly toxic and can raise your risk of bone fractures, particularly in the thigh bone.24
The reason for this is because these drugs strengthen your bones, but they do that by inhibiting your body’s ability to absorb old bone. As a result, the bone becomes harder, but also more brittle. Truly healthy bone is hard yet flexible.
Other side effects of bisphosphonate drugs include gastrointestinal problems, gastric ulcers, flu-like symptoms, severe bone, joint and muscle pain, and osteonecrosis of the jawbone.
Optimizing your vitamin D and getting sufficient exercise is a far better route for most people. KAATSU, or blood flow restriction (BFR) training is a great option if you’re frail and/or out of shape, as you don’t need heavy weights.
Recent research25 has confirmed that BFR increases not only muscle mass but also bone mass, "primarily through several hormonal pathways at the same time it enhances cardiovascular function."
As noted by the authors, "The improvements in mobility and gait are indicators of greater health-related quality of life minimizing disability in older adults." For more details on how BFR works its magic, see my previous article "How to Stay Fit for Life."
Analysis by Dr. Joseph Mercola
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