Before the arrival of COVID-19, a lot was said about vitamin D. After COVID's arrival, perhaps even more so. Why?
A recent study shows that Low Vitamin D Status Increases Hospitalization and Death from COVID-19.
It's essential to have an optimal vitamin D status to ensure your immune system is working optimally, but its implications reach FAR BEYOND COVID-19.
Unfortunately, daily recommended intakes of vitamin D are, in many cases, not sufficient enough to cover all the health aspects involved.
How important is vitamin D, how much vitamin D per day do you really need and how do accomplish that?
These questions will be answered in this article.
Guidelines around the world vary quite a bit.
The biggest problem I've come across, regarding recommended intakes, is that vitamin D is an incredibly complex multi-factorial topic and sometimes things are left out of the equation.
To come to a complete understanding (as far as is possible) you need to cover ALL the factors involved. I went through more than 100 scientific papers and wrote an almost 6000-word chapter for my book, Immunity Hi, Virus Bye-Bye. That's how complex it is.
I've decided to share the entire chapter here. I've split it up into three parts:
PART 1 explains exactly how significant vitamin D is and forms an introduction to Part 2 & 3. Please don't skip this part as it is an essential part that helps in understanding these subsequent parts.
PART 2 is about why most recommendations fall short and what range is a more optimal range. HINT: it's going to be a lot easier to follow this recommendation than it is to make a healthy breakfast.
PART 3 is all about ideal times of sun exposure and never talked-about strategies for skin protection.
PART 1: Introduction to Vitamin D
Warning messages from authorities to reduce sun exposure are very common because of increased risks of skin cancer. However, sun exposure also enables our body to produce vitamin D.
If our levels of vitamin D are too low, we actually increase our risk for other cancers and all-cause mortality. The irony of the advice to reduce sun exposure is that increasing numbers of people suffer from vitamin D deficiency, which puts them at an increased risk for cancer.1
Has something gone wrong in our evolution, are the recommendations insufficient, or is something else going on?
Vitamin D has been produced by plants and animals almost from the time life began. As plants and animals evolved, the ability to transport and metabolize vitamin D also became more complex.
In many animals and in humans, there is a vitamin D receptor in nearly every cell, and the ability to produce the active form of vitamin D, which is actually a hormone.2
Vitamin D is most known for its ability to affect skeletal and bone health. Calcium can be only sufficiently utilized for our bones in the presence of vitamin D. Low vitamin D status decreases bone density and is strongly associated with increased fracture risk, as becomes apparent from looking at the elderly.3, 4
More recently, some of vitamin D’s other properties have gained more traction. Current research considers reduced vitamin D levels as a potentially significant risk factor for a host of diseases such as cancer, cardiovascular disease, diabetes, hypertension, autoimmune diseases, metabolic disorders, and, last but not least, infectious diseases that are caused by decreased immunity.5
That means cold viruses, influenza viruses, and coronaviruses all have an easier time attaching themselves to the epithelial cells in our airways where they can cause an infection. Bob was very familiar with this:
Bob is a retired engineer who is quite fit for his age of seventy-one. He cycles every day and doesn’t shy away from physical labor. He can often be found in the garden, where he tends to his homegrown vegetables. Bob’s vegetable garden is his great pride. It hosts almost twenty different kinds of vegetables, which provide for him and his wife almost year-round. Bob’s generosity ensures his friends and neighbors frequently enjoy some of his fresh produce. Although Bob feels good for his age, he feels his immune system may be in need of a little boost. Ever since Bob’s gotten older, he’s noticed that he’s been getting sick more often. Every year, when winter comes around, he gets sick at least three times. At first, Bob thought it might be his age, but that didn’t explain why some of his friends seemed to be less affected. As a matter of fact, one of his friends, Sam, leads a way less active lifestyle yet rarely gets sick.
One day, Bob had a talk with his friend Sam, who had done a blood test the other day. Sam shared the results with Bob. “My doctor is particularly impressed with my vitamin D levels. They are higher than most people my age,” Sam said proudly.
Sam’s doctor jokingly said: “Perhaps that’s why you don’t visit me as much during flu season!” Sam’s doctor had told Sam that vitamin D is essential for the immune system, and as we age, we produce less of it. Knowing that Sam isn’t much of an outdoors person, Bob asked Sam how he sustains his healthy vitamin D levels. Sam revealed that he supplemented vitamin D year-round.
Bob initially thought he got enough sun exposure, but he realized that he usually wore some form of sun protection, whether it was sunscreen lotion or clothes covering his skin.
“Why don’t you try some vitamin D supplements?” Sam asked him.
Over the coming days, Bob thought it over and asked his family doctor for advice. His doctor thought it might be a good idea, which made the decision easy for Bob. He started taking vitamin D supplements. This was near the end of summer. Bob wasn’t sure if it would actually help him the coming winter, but trying couldn’t hurt, he thought.
By the time winter came around, Bob just carried on as usual. One weekend, his grandkids came to visit. The youngest, three-year-old Bobby, had a cold and spread a fair amount of virus-carrying droplets around the house with his sneezing and coughing. Bob expected he would get sick, like he usually would when someone was sick around him, but he didn’t bother with it because he was delighted that his grandson wanted to visit Grandpa, despite being sick.
Several days later, Bob was still fine, to his own surprise. That winter, Bob did manage to get sick, though. However, it was only a mild cold. Normally, Bob would get sick not only more often, but also more severely.
Bob continued supplementing his vitamin D, kept an active lifestyle, and made sure he ate sufficient healthy whole plant foods. The following winter, he didn’t even get sick once.
Vitamin D is important for our immune function.
However, the older we get, the less efficient our body becomes in producing vitamin D through sun exposure. Specifically, in people over seventy years of age, there is a fifty percent reduction in the production of vitamin D.6
Since those of us over the age of sixty are at an increased risk for COVID-19 complications, having a good vitamin D status is essential. Before discussing the optimal amount of vitamin D and the best way to obtain it, we are going to look at how vitamin D works and what surprising connections it has to other parts of our body.
As stated earlier, vitamin D receptors are located in almost all cells in our body. This alone indicates the importance of vitamin D.
Can these receptors also be found in our immune system? Yes, in the vast majority of immune cells, or white blood cells. These white blood cells also have an active vitamin D metabolism. That means they can also convert the non-active form of vitamin D to its biologically active form.
All the vitamin D we get into our bodies through sunlight, food, or supplement is not yet activated. It has to be activated within our body.
It is the biologically active form of vitamin D that is involved in the modulation of our immune system and the ability to control our immune function at different levels. One interesting way it does that is by increasing the phagocytic ability of immune cells. This is the process whereby a white blood cell completely engulfs a virus, so that it becomes trapped inside.
As explained in Chapter 2, section 5: “Essential Fatty Acids,” we could compare it to the classic game of Pac-Man, where Pac-Man makes his way through a maze, engulfing all the dots that lay before him. This is an important part of our immune system, enabling it to analyze and neutralize a threat with the variety of tools at its disposal.3, 7
Another important way in which vitamin D can influence our immunity is by reinforcing the epithelial barrier function, particularly of our eyes and intestinal tract.3 The eyes are one gateway for viruses to enter our body,8 and probably one of the least protected areas, since people tend to wear masks but not protective glasses.
We, and even more so our children, rub our eyes on multiple occasions throughout the day, making it easier for viruses to penetrate. You can imagine that when the barrier function is not in optimal condition, we are more easily infected by these viruses.
The epithelial barrier function comprises individual epithelial cells lining the eyes and intestinal tract. It is comparable to an army of individual soldiers. When it gets weakened, it is analogous to replacing the soldier’s firearms with hand-to-hand combat tools, resulting in a more vulnerable defense lining. If it gets weakened further, it’s analogous to the soldiers being completely unarmed.
As discussed in Chapter 5: “The Connecting Link: The Microbiome,” these epithelial cells are a critical aspect of the immune system. They cover the lining of the intestinal tract that prevents pathogens and harmful substances from passing. The beneficial bacteria in the gut help keep this barrier intact, but they are not the only ones.
Vitamin D is essential as well.
Research furthermore suggests that vitamin D plays a role in the complex relationship between the microbiota living in the gut and immune system modulation.3 The correct functioning of this part of the body largely ensures that the immune system is running properly.9, 10
Imagine having bought a remote control airplane that hasn’t been assembled. The instruction manual would allow you to correctly assemble the plane. Vitamin D is the instruction manual for the microbiome to let the immune system function properly and do what it’s supposed to do: defend and protect.
By the same token, the instruction manual helps you to assemble the plane and let it do what it’s supposed to do: fly.
Vitamin D can upregulate specific compounds contributing to a strengthened immune system. One of these compounds, CAMP (cathelicidin antimicrobial peptide), increases the antimicrobial activity of some white blood cells, but also has direct antimicrobial properties itself, even against the virus type to which all coronaviruses belong.11, 12
CAMP is not only increased in our protective barrier of epithelial cells, but also in our corneal (eye) cells and lung cells.3
Lung cells are severely affected in patients who experience complications caused by COVID-19. It is, therefore, best to maintain these areas at all times.13
CAMP, and another upregulated compound called defensin, can decrease the ability of a virus to replicate and reduce the pro-inflammatory particles called cytokines, mentioned in Chapter 2: “Optimizing our Immune Cells,” which cause inflammation that can injure the lining of the lungs.
This is of great significance to reduce potentially life-threatening complications caused by a cytokine storm that can arise in vulnerable people who are infected with COVID-19.14
Other strategies to reduce the risk of these complications are covered in Chapter 2: “Optimizing Our Immune Cells.”
The multiple protective pathways of vitamin D protect against respiratory infections, as high-quality evidence from a meta-analysis of twenty-five randomized controlled trials has demonstrated. Vitamin D supplementation reduced the risk of experiencing at least one acute respiratory tract infection. The protective effects were particularly strong for people who were deficient.15
It is here where we need to pay attention, because low levels of vitamin D are common, as mentioned previously. Vitamin D is unique because our skin can make it from exposure to sunlight,16 unlike other vitamins, hence why vitamin D is technically a hormone.
It serves us to take precautionary steps to ensure adequate levels of vitamin D are always maintained, especially during times when sun exposure is low or when sunlight is not strong enough.
To establish how we can reach an adequate intake of vitamin D, we need to understand why it is different from other vitamins. In nature, vitamin D levels have always been dependent mainly on sunlight.17 The main reason for a lack of vitamin D is a lack of sunshine since only a limited number of foods naturally contain vitamin D.18
Vitamin D production, which is initiated when sunlight touches our skin, is influenced by:
● genetic components;
● skin color; and
● lifestyle, such as the use of sunscreen and clothing.
The further we are away from the equator, the weaker sunlight becomes, especially during the colder months of the year. The darker our skin color, the more sunlight we need to produce an adequate amount of vitamin D.
Because vitamin D levels have been shown to depend on seasons, levels tend to be lowest after winter and highest at the end of summer.19
Perhaps not coincidentally, COVID-19 infections started increasing around the globe when levels tend to be at their lowest.
Establishing an adequate intake of vitamin D is problematic if we rely on recommended levels of vitamin D. We may follow recommendations but still fall short of reaching optimal levels for our immune system. Hence, our immune system won’t be able to function as it should.
PART 2: Recommended Intakes of Vitamin D
On supplement bottles, vitamin D is commonly listed as IU, which stands for International Units. Recommendations are varied, from as low as 200 IU/day in some European countries, 600 to 800 IU for IOM (Institute of Medicine in the U.S.), to as much as 4,000 to 10,000 IU/day for the Vitamin D Council.19
These numbers can be quite confusing. However, the maximum tolerable intake is set at 4,000 IU by various nations, because above that there can be toxic effects.19 The relevance of these numbers will become clearer as we determine a more optimal vitamin D intake.
IUs are generally used instead of micrograms (μg or mcg), so most supplement bottles list IU. If a bottle lists mcg, we can easily convert to IU by multiplying it by 40, e.g., 2.5 mcg is 100 IU.20
General guidelines run into some issues, due to the amount of sun exposure needed to produce adequate vitamin D and the complicated factors that influence the level of UV radiation exposure needed to initiate vitamin D production in the body, as just mentioned.
Some vitamin D researchers suggest that approximately five to thirty minutes of sun exposure between 10 a.m. and 3 p.m. at least twice a week to the face, arms, legs, or back without sunscreen usually leads to sufficient vitamin D synthesis.
Light-skinned people fall in the lower end, and dark-skinned people the higher end, of this range. Individuals with limited sun exposure need to include good sources of vitamin D in their diet or take a supplement to achieve recommended levels of intake.20
Supplements are generally a more reliable way of getting enough vitamin D, since a lot of us don’t get enough sun exposure to produce an adequate amount. If we do get enough sun exposure, sunscreen will lower or stop vitamin D production.
If you live near the equator, this may not be a big deal, but the further away you are from the equator, the higher the chance your vitamin D levels are not adequate, especially in winter, where vitamin D production can be nonexistent.
Combine this with the lockdowns that were put in place near the end of winter for many places across the globe, when people are not inclined to go out as much, and you have the perfect recipe for low vitamin D levels.
For some of us, supplementation of vitamin D may therefore be the best solution to increase our levels, to where they can have immune-protective effects. What should we aim for, then?
These recommended intakes are based on minimal sun exposure. However, this RDA may not be enough to reach optimal vitamin D levels. The reason for this is that most studies on vitamin D were designed with disease prevention in mind.
Obviously, disease prevention is a good thing, but the absence of disease doesn’t automatically equate to good health. The gap between the amount needed to prevent disease and the amount the body can utilize can be quite wide for some nutrients. We’ve seen that for vitamin C, but the gap is likely bigger for vitamin D.21
Compare this to an e-bike with a completely charged battery, which can run at full speed. If you ride long enough, the speed will drop because it’s a way for the e-bike to save energy and prolong battery life. Just because you can still run on a lower battery, that doesn’t mean it’s optimal.
There is practical evidence as well that the RDA of 600–800 IU falls short. For example, 600 IU of vitamin D is believed to be sufficient to protect against osteoporotic fractures. This amount supposedly ensures enough calcium to be absorbed and transported to our bones to keep them healthy and strong.22
However, although this may be sufficient for a part of the population, it is not sufficient for everyone.
An intake of 600 IU will get most people to a level of at least 50 nmol/L (20 ng/mL), which is a unit to measure vitamin D in our blood. Here it gets more interesting.23 In a study where scientists measured vitamin D levels of people who had died in accidents or other unnatural or unexpected causes, they made a crucial observation.
Scientists observed that there were bone mineralization problems in the skeletons of eighteen to thirty-nine percent of the people who had vitamin D levels of 50–75 nmol/L (20-30 ng/mL). Remember, the so-called safe level is 50 nmol/L. Apparently, that is not enough for all of us to support bone health. This is a dilemma.
How can vitamin D levels that might not be enough to obtain optimal bone health be enough to support optimal immune function? And, what about other protective pathways of vitamin D? It is likely that they are impaired as well.
So what amount of vitamin D would be safer?
The scientists observed none of the bone mineralization problems in levels higher than 75 nmol/L (30 ng/mL).24
How much vitamin D would be enough to get to the level of 75 nmol/L?
In most interventional trials, levels of 75 nmol/L were reached with a minimum of 1,800 IU daily.25 That is approximately two to three times the RDA.
It may be safer to aim a little higher than this, since we want everybody to have not only good bone health but also an optimal immune system.
Besides this, there is evidence that higher is indeed better. That’s because natural levels are significantly higher.
Let’s take breast milk as an example.
Breast milk is the perfect food for any newborn baby, or for any newborn mammalian species for that matter.21, 26 It’s easy to imagine we would have run into problems, evolutionarily speaking, if breast milk had any deficits. So why are we giving vitamin D drops to our children?
Because we don’t want our children to develop soft and distorted bones, leading to deformities in their limbs and spine, through a disease called rickets. Rickets results from the body only being able to utilize a small part of calcium in the absence of sufficient vitamin D.27
That means breast milk, ironically, is often deficient in vitamin D, and we try to fix it with a supplement for our children.
How can breast milk be deficient in vitamin D if breast milk is the perfect food for newborns? The problem is not the breast milk itself. Evolution has not abandoned us.
The problem is that the vitamin D status of many mothers and mothers-to-be fails to meet optimal levels, resulting in breast milk with low levels of vitamin D.28
This issue was observed during the increasing urbanization of the seventeenth century.27
People tended to live in crowded places surrounded by more buildings than ever before, restricting their sun exposure needed to produce adequate amounts of vitamin D. Imagine stepping out of your front door and the first thing you’re welcomed by is another house or building that blocks the sun.
If you spend most of your time in that kind of environment, you can imagine how a vitamin D deficiency can easily develop over time as your exposure to the sun is limited, especially if you have no access to supplements. In the mid-seventeenth century, most children who lived in the crowded and polluted industrialized cities of northern Europe developed severe growth retardation, deformities of the legs, bending of the spine, knobby projections of the ribcage, and weak and toneless muscles.
Even during the late nineteenth century, in one of these industrialized places, the Netherlands, there was an alarming eighty to ninety percent of children with rickets.
A classic sign of rickets:27
How much vitamin D would an average mother have to take to get high enough levels in her breast milk so her child would not be deficient?
About ten times more than the recommended amount of 600 IU, namely 6,000 IU.21
Interestingly, although high compared with the adult recommendation, such an intake almost exactly reproduces the measured vitamin D status of contemporary Africans leading ancestral lifestyles. This is basically how we humans used to live a long time ago, spending most of our time outdoors in equatorial regions.
That doesn’t mean we should all live like that now, unless you have a distaste for excessive clothing. But it does say something about the importance of sunlight and the way our physiology has adapted to our surrounding environment, especially considering the fact that most of us wear clothes while being outdoors, compared to not wearing much at all a long time ago.21, 29
Despite 6,000 IU seeming to be a more ideal amount, it is paradoxically also more toxic.
That’s because our bodies can’t regulate vitamin D from supplements in the same way as vitamin D from sun exposure. An abundance of sun exposure, although having potential problems on its own, can’t result in vitamin D toxicity. Our body can regulate vitamin D from sun exposure exceptionally well, unlike from food and supplements.30
It may, therefore, be wise to stay on the safe side and not go beyond 4,000 IU on a daily basis, which is the maximum tolerable limit across most guidelines.
Recommended levels of vitamin D fall short for at least some people regarding bone health, and may fall even shorter for overall health and optimal immune function. The perfect amount of vitamin D is hard to establish, but considering the information presented, it may range anywhere from 1,800 IU to 4,000 IU if we are minimally exposed to sunlight.
Although 1,800 IU seems enough to cover bone health, it’s unclear whether it’s enough to ideally support all facets of our immune system.
Getting sufficient sun exposure to reach these levels is complicated by different factors such as latitude, genetic components, season, skin color, and lifestyle, such as the use of sunscreen and clothing. Despite these complications, there are guidelines we can follow to produce at least 2,000 IU through sun exposure, which makes more than evolutionary sense.
However, there are several caveats. Not only that ...
what about the increased risk of skin cancer?
PART 3: Sun Exposure and Underrecognized Sun Protection Strategies
Included here is a guideline in respect to sun exposure, followed by underrecognized and neglected strategies to increase protection against sunlight, decreasing the risk of developing skin cancer.
The following example serves as a reference point to discuss the caveats.
We know that people living in certain parts of the world can obtain an average daily dose of 2,000 IU by exposing their face, arms, and legs to sunlight without the application of sunscreen for about fifteen minutes (half that if in a bathing suit), two to three times a week between 11 a.m. and 3 p.m. during the months of May through October.
What parts of the world are we talking about?
Any place on Earth located on forty degrees latitude.
The equator is a horizontal line drawn around the middle of the globe. The equator is the most central point and is on zero degrees latitude. If we draw a line forty degrees north of the equator, it will cross through northern California in the U.S., Southern Europe, Turkey, Kazakhstan, Northern China and Northern Japan. If we draw a line forty degrees south of the equator, it will cross through Chile, Argentina, Tasmania and New Zealand.
The first caveat involves skin color. This example just mentioned reflects type II, light-skinned people, but there are actually six skin types. Skin type I is the lightest, which always burns and tans rarely, whereas skin type VI skin is the darkest and virtually never burns.
This means that the times for a skin type I person are slightly shorter than those quoted, whereas darker skin types require a longer time to reach the same 2,000 IU, even twice as long (see the second caveat).
The second caveat is latitude. The further we are from the equator, the more sun exposure we need; the closer we are, the less we need to produce the same amount of vitamin D. More so in winter months.
Around the equator, we can produce an equal amount of vitamin D in both winter and summer, but the further we move away, the less vitamin D we can produce during the winter months.
Darker-skinned people tend to be nearer the equator, which makes evolutionary sense because they need more sun exposure. Based on a study which measured the sun exposure of people living in Canada, darker-skinned people may need up to double the amount of time to produce the same amount of vitamin D.6
The south of Canada is located on fifty degrees latitude. Northern France, Germany, Czech Republic, Ukraine and the far north of Mongolia and China are also on this latitude. Southern Chile and Argentina are positioned fifty degrees south of the equator.
How much sun exposure do people in these places require, according to the study?
First, people from any skin type cannot produce Vitamin D for three months during winter. For the rest of the year, people with skin type II need to expose their arms, face, and neck to the sun for up to thirty minutes every day to generate 1,000 IU. The scientists noted that, in summer, it was fourteen to thirty minutes.
This study shows that it is not unrealistic for somebody with type II skin to produce 2,000 IU within half an hour in summer, if he or she exposes more parts of the body to the sun, such as the legs. Although 2,000 IU is double the amount measured in the study, the time decreases as more of the body gets exposed to sunlight.
However, the difference between living on fifty versus forty degrees latitude is that the sun exposure on fifty degrees latitude is required daily, whereas on forty degrees latitude the exposure is only required two to three times a week.
That’s an enormous difference. Moreover, people with skin type V, which is the second-darkest skin type, needed up to double the time of sun exposure to produce the same amount of vitamin D.
People with the darkest skin type need slightly longer than that.
The third caveat is that, even if you obtain the 2,000 IU from May to October, you require more sun exposure to reach the same 2,000 IU in the other months of the year.
That means you would need more sun exposure than listed here to compensate for the shortfall during the other months, or you would need more through food or supplements.
Underrecognized Sun Protection Strategies
Health warnings to reduce our sun exposure are limited. They focus on avoidance of sunlight, appliance of sunscreen and clothing (to cover the skin), which have their place. But this neglects two relevant protective factors that reduce our risk for sunburn. There is increasing evidence that shows we can protect ourselves in other ways, without having to avoid sun exposure altogether.
In addition, sunscreen may have benefits, but it also has downsides, which are relevant to discuss.
The first protective factor is sun acclimatization. Inadequate acclimatization to UV radiation in daily life carries the risk of sunburn and corresponding increased risk of both nonmelanoma and melanoma skin cancer. Melanoma is the most dangerous form of skin cancer. Slowly acclimatizing to sunlight and its UV radiation decreases sunburn risk and therefore improves overall protection. Sunburns are associated with a doubling of the risk of melanoma.1 Hence the warnings to minimize sun exposure.
The second protective factor is the most underrecognized. Minimizing sun exposure is advised to reduce our risk for skin cancer. Yet, paradoxically, some groups of people have high levels of sun exposure and are in fact more protected against the malignant cancer that is melanoma.
Where do we find these people?
In the Mediterranean region.31
How is that possible?
Emerging evidence points to diet being the protective factor. What dietary factors play a protective role, and how can they offer protection?
A rather unexpected thing happens when we expose ourselves to sunlight.
Penetrating UV radiation, found in sunlight, can damage our cells and DNA. Sunlight has been such a crucial component in our evolution, and yet it can induce damage even before we develop sunburn. Not only that, it lowers the antioxidants stored in our skin and flowing through our blood. The fact that our antioxidant status is affected by the sun is yet another reason to consume more antioxidant-rich foods. And that is exactly what people in the Mediterranean do, whose intake of vegetables, fruits, legumes, and nuts are higher in comparison to more typical Western diets.32
Greece especially stands out. It is also host to one of the blue zones mentioned earlier in Chapter 7: “The Optimal Diet,” which emphasizes consuming a variety of whole plant foods.
Despite higher levels of sun exposure, people in this region are more protected against the dangerous melanoma.
In Italy, they found that the rising incidence of melanoma was associated with lower intakes of antioxidants. This also explains why people on more Western diets in more sunny regions like Australia and New Zealand have an astonishing eighteen times higher risk than the Greeks of developing melanoma. At the same time, Greeks that migrate to these countries and adopt a Western diet show an obvious deterioration in their health.31
Antioxidant-rich food counters the damage caused by the sun, but what about sunburn? During sunburn, our immune system gets activated. It sends out white blood cells called neutrophils, which start to accumulate in the skin affected by sunburn, where they exert pro-inflammatory activities.33
In simple words, that means sunburn increases inflammation. As discussed in Chapter 2: “Optimizing our Immune Cells,” antioxidants have the ability to lower inflammation and the damage that occurs as a result.
If our antioxidant status is low to begin with, it makes sense that we are more prone to developing sunburn. We can see something similar with plants.
Suppose there is one variety of plant spread out over a garden. One side of the garden receives direct sunlight, whereas the other side does not. Plants on both sides seem to do fairly well, although the plants on the sunny side of the garden seem livelier and more colorful. This is about to change. A dry spell is approaching. Blistering heat and scorching sun rays fill up the days. Within a week, the leaves of the plants on the sunny side of the garden start shriveling up. The soil becomes drier and drier until every last bit of moisture has evaporated. The plants on the darker side of the garden now seem to radiate more life force. The soil still contains some moisture and the leaves are slightly dry, but, unlike their sunny neighbors, they don’t look like they are in grave danger.
What happened here?
The plants that normally love the sunshine suddenly can’t seem to handle it anymore. The simple reason for that is because they are deprived of water. What water is for the plants, antioxidants are for us. Plants simply don’t fare well without water, and neither do we fare well without antioxidants.
Sunlight depletes our already low antioxidant stores, making us more prone to developing sunburn. It’s not surprising, therefore, that the emerging evidence points to antioxidants offering better protection and delaying sunburn.31, 34, 35
The third protective factor is omega-3, which has been covered in more detail in Chapter 2, section 5: “Essential Fatty Acids.” The essential fatty acid seems to, at least, offer protection through its anti-inflammatory properties.36
That still leaves us with sunscreen. Sunscreen has advantages because it can prevent sunburn during times when we expose ourselves more to sunlight. However, it also has downsides:1
Sunscreen reduces acclimatization to UV radiation, thus increasing your risk of sunburn when you don’t apply sunscreen.
Sunscreen reduces vitamin D production in the skin, thus potentially contributing to a vitamin D deficiency when using sunscreens excessively.
Despite being able to prevent sunburn, there is no consistent evidence that sunscreen reduces the risk of the most malignant type of skin cancer, melanoma. There is some evidence, though, that it can protect against one form of nonmelanoma skin cancer, namely, squamous cell skin cancer.
If we are minimally exposed to the sun, a total intake of around 2,000 to 4,000 IU of vitamin D is more ideal than the 600 to 800 IU that is still recommended in various guidelines. Although the lower end of the range (2,000 IU) will be good for our bone health, it doesn’t guarantee to be the ideal amount for our immune system. We can get vitamin D through food, supplementation, and sun exposure.
Food alone is generally not a sufficient source of vitamin D, but it may be enough in combination with sufficient sun exposure. If we are minimally exposed to sunlight, we should not rely on food alone.
Sun exposure recommendations are complicated due to a variety of factors that influence vitamin D production. Nonburning sun exposure has a protective effect against a variety of chronic diseases, but also may carry a possible increased risk of nonmelanoma skin cancer because of its association with many thousands or tens of thousands of cumulated hours of lifetime sun exposure. Here is where antioxidant-rich diets come into play, for they increase protection even if we don’t develop sunburn.
Sunscreen may offer some protection against one type of nonmelanoma cancer, but there is no evidence that it protects from the most dangerous skin cancer, melanoma. Moreover, sunscreens increase the risk of vitamin D deficiency and hinder the acclimatization necessary to increase the resistance of our skin to develop sunburn.
If you live in regions of higher latitude, it may be helpful to supplement during the winter months. If you are minimally exposed to the sun during the warmer months of the year, it is helpful to supplement year-round.
This article comes from the book: