Why we need UV light
Why we need UV light?
Sun exposure in order to get UV light is vital to good health and sun avoidance is causing an epidemic of vitamin D deficiency contributing to a rising incidence of rickets (bone deformity), osteoporosis (brittle bone disease), osteomalacia (bone softening disease), multiple sclerosis, high blood pressure, cardiovascular disease, depression, rheumatoid arthritis, diabetes and some cancers.
Vitamin D receptors are found in most cells and tissues of the body. It is for this reason that vitamin D has such a wide range of therapeutic benefits. It also manages levels of calcium and phosphorous in the blood, bones and gut and helps cells all over the body to communicate properly. In short, vitamin D is vital to our survival. We need exposure to UV light.
The discovery of the importance of UV light
It was during the industrial revolution of northern Europe (during the early 1800s) that UV light was first recognized as playing a crucial role in the production of vitamin D in the body.
As more and more people crowded into cities and towns, leaving their largely agricultural lives behind, the rate of serious bone-related diseases began to increase rapidly. Combined with less time spent outdoors, industrialization lead to smog polluting the atmosphere which cut out large amounts of ultraviolet rays.
By the early 1930s it was recognized that by exposing children to safe levels of UV light, rickets could be avoided.
Very few foods naturally contain vitamin D and only a few foods are fortified with vitamin D. Pre-World War II, once rickets had been identified as resulting from a lack of vitamin D, many foods were fortified which helped to reduce the incidence of rickets, however, post-World War II, the fortification process was not efficiently monitored and led to several cases of vitamin D-overdosing among children. The intoxification of vitamin D led to a ban on fortification of dairy products across Europe, which exists to this day with the exception of margarine which contains vitamin D as required by law. In the US most milk is fortified with vitamin D.
It is now thought that more than 50% of the world’s population is at risk of vitamin D deficiency. As we age this risk increases due to the body’s inability to synthesise vitamin D as efficiently as during the younger years.
How does vitamin D work?
As we absorb
Vitamin D comes in two forms, vitamin D2 – found in plants and vitamin D3 found in animals.
Vitamin D3, also known as 25-hydroxyvitamin D, is created when we expose our skin to UVB rays found in UV light. Vitamin D starts in humans as a substance in the skin called 7-dehydrocholesterol and the UVB rays from the sun convert it into vitamin D3. At this stage, vitamin D3 is inactive.
Infographic showing how 7-dehydrocholesterol becomes active calcitriol
Note that once vitamin D is turned into calcitriol, it becomes a hormone.
Calcitriol is also made in other parts of the body in much smaller amounts and it is thought it acts within the tissues where it is made. These tissues include: cells of the immune system, brain, breast, large intestine, lining of blood vessels, pancreas, parathyroid glands, placenta, prostrate and skin – our largest organ.
Factors which influence how much vitamin D the body creates
The amount of vitamin D each individual creates is due to several factors including skin pigmentation, age, time of year, time of day and latitude (how close to or far away you live from the equator).
Vitamin D and skin types
Melanin (which determines our skin, hair and eye colour) evolved as an effective natural sunscreen and efficiently absorbs UVB protons. It is important to note that people with different skin types will absorb UV rays at different rates. Those with darker skin (more melanin pigmentation) will need longer exposure to sunlight than a person with light skin and red hair.
Prolonged sun exposure does not lead to an overdose of vitamin D because the pre-vitamin D becomes degraded as the skin heats up. Pre-vitamin D is when uv light and 7-dehydrocholesterol in the skin combine. Pre-vitamin D is inactive.
How sunscreen affects vitamin D synthesis
Sunscreens block UVB and some UVA rays and prevent them entering the skin. When we slather on sunscreen, we need to be mindful that we are blocking out UV rays which would otherwise be beneficial for creating vitamin D. A sunscreen with a sun protection factor of 8 reduces the capacity of the skin to produce vitamin D by 95%. A SPF of 15 reduces the skin’s capacity to create vitamin D by 98%.
Ageing and vitamin D production
As we age, the amount of 7-dehydrocholesterol that the skin produces falls. A 70-year-old makes only 25% of the vitamin D3 that a 20 year old will make in the same duration of sun exposure. As we produce less 7-dehydrocholesterol, so our ability to synthesise vitamin D falls.
Vitamin D and geography
Although the sun is closest to earth in winter, the rays of the sun enter the earth’s atmosphere at a flatter angle which causes the UVB photons to pass through a greater distance of ozone layer which absorbs and disperses much of the radiation before it reaches earth’s surface.
Where we live on the planet also makes a difference to how much UVB is available to our bodies. The closer to the equator, the more vitamin D is available. In latitudes above 37 degrees (further from the equator), very little, if any, vitamin D is produced during the winter months.
During the early morning and late afternoon the angle of the rays of the sun penetrating the earth’s atmosphere are significantly reduced, even during summer months, which is why it is important to get safe sun exposure during the hours of 10.00 and 15.00 from March through to the end of October.
Thankfully for those of us who live in chillier climates, the fat in our bodies will store a certain amount of vitamin D to help keep us going during the winter months, although it may not always be sufficient and is often a reason for the tendency to feel blue during the winter months.
One of the best ways to overcome depressive feelings is to invest in a lightbox or schedule a hot holiday to give you that extra boost. Some scientists recommend the use of a sunbed once or twice a week for a few minutes each time. There is a lot of negative talk about the use of sunbeds – the jury is out. Personally I wouldn’t use a sunbed.
I spend a lot of time outdoors and feel strongly that the sunshine is how we were meant to get our sun exposure in a holistic and natural way.
What is safe exposure?
You need to expose as much of your body as possible, ideally naked or a bikini / bathing suit. Stay out in the sun until your skin begins to show a very faint shade of pink. If you have darker skin or a tanned skin, you will need longer exposure. Do not allow your skin to burn.
What are the recommended levels of vitamin D?
This figures below represent the unified views of the British Association of Dermatologists, Cancer Research UK, Diabetes UK, the Multiple Sclerosis Society, the National Heart Forum, the National Osteoporosis Society and the Primary Care Dermatology Society.
Some scientists suggest that sufficient levels are 50nmol/L (20ng/ml) and optimal levels are 70-80nmol/L (28-32ng/ml).
Other scientists and researchers state that these levels are too low and need to be increased by up to a factor of 10!
A study done in Africa on Maasai warriors, who are outside every day, showed they had a blood level of 25-hydroxyvitamin D averaging around 48 ng/ml.
I find it concerning that there is so much apparent confusion among scientists and medical professionals about what constitutes an optimal level, which is where we all should be aiming. Sufficient is better than deficient, but when you consider the important role that vitamin D plays in the body, optimal is best.
If you are concerned about your vitamin D levels, the best option is to consult with your GP. If you spend large amounts of time indoors, the chances are you could have a vitamin D deficiency, and given the importance of this hormone within our bodies, it is worth ensuring your blood contains the “sufficient” amount at the very least.
It is important that the doctor tests for 25-hydroxyvitaimin D levels. You may ask why it is necessary to measure the amount of 25-hydroxyvitamin D instead of the active form of vitamin D, called calcitriol (which is what vitamin D becomes once it has gone via the kidneys). The main reason is that as the body becomes vitamin D deficient, more calcitriol will be produced to make up the shortfall. Only after the body has become significantly deficient in vitamin D, will calcitriol levels begin to fall. Another reason is because 25-hydroxyvitamin D lasts for 2 – 3 weeks, whereas calcitriol lasts only a few hours in the body.
Consequences of vitamin D deficiency
Exposure to UV light is vital to good health. In order to maintain your vitamin D at optimal levels, eating foods containing vitamin D will not suffice, as very few foods contain sufficient amounts of it to make any significant impact on your health.
The natural way to obtain vitamin D, and one I wholly support, is through exposure to the sun on a regular basis. Evolution didn’t have us queuing up at the pharmacy to buy supplements to keep us healthy. Nature requires us to live a healthy, balanced life, taking regular exercise and spending regular time outdoors.
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What about the risk of skin cancer?
There are tomes written about the dangers of over-exposure to the sun and the negative impact it can have on the skin, increasing the risk of some skin cancers as well as wrinkling. In fact there is a growing body of scientific evidence which suggests that we need to spend more of our time absorbing UV light to help maintain a healthy balance within the body.
Non-melanoma basal and squamous cell carcinomas are more likely to occur when sunburn has occurred during childhood and as a young adult. Melanoma is the most serious form of skin cancer and unusually, this tends to occur on parts of the body which are generally protected from overexposure to the sun.
It is interesting to note that people who spend a lot of time outside are at a much lower risk of developing melanoma than those who spend much of the time indoors. Vitamin D actually protects us from several cancers including prostrate, breast, colon, uterus and ovarian cancer. As your vitamin D levels rise, so your risk of developing these cancers falls.
Vitamin D and bones
Vitamin D deficiency is most famously noted for rickets in children. It is also recognized to be responsible for bone-related diseases such as osteoporosis (brittle bone disease) and osteomalacia (bone softening disease). Many people suffering from non-specific aching bones and muscles have been diagnosed eventually to having a lack of vitamin D. Vitamin D is very important for strong bones as it helps the body to metabolize calcium and phosphorous which are essential for creating strong and healthy bones. Without vitamin D, calcium and phosphorous cannot be absorbed by the body.
Vitamin D and multiple sclerosis
There is evidence of higher incidence of MS the further away you were born and spent your early years from the equator. Research has shown there is a 50-70% reduction in MS lesions when UV exposure is at its maximum in summer compared to winter. A study in Tasmania showed that adequate sun exposure, particularly in winter, between the ages of 6-15 reduced the risk of developing MS in later life by about two thirds.
Some cells in the immune and nervous systems have vitamin D receptors which means that vitamin D plays a role within those cells. In laboratory tests, when immune cells are exposed to vitamin D, they become less inflamed, which could mean that vitamin D boosts the immune system, making it less likely to attack other cells in the body. Higher vitamin D levels also suggest a slower progression of MS and reduced degree of disability for those with MS.
Vitamin D and diabetes mellitus
Diabetes mellitus (Type 1) appears to have a close relationship with vitamin D. Type 1 diabetes is an auto-immune disease where the immune system attacks the body. Specifically, the immune system attacks beta-cells which are needed to produce insulin. Even for people with normal blood sugar levels, a lack of vitamin D can lead to pre-diabetes and more than doubles your risk for progressing to type II diabetes.
Vitamin D receptor cells are found in the insulin-producing cells of the pancreas, fat, the liver and muscle tissue, all of which play an important role in synthesizing glucose in your blood. Studies show that as you move closer towards the equator, the risk of developing diabetes mellitus falls by a factor of 15. Also, children who took vitamin D supplements during their first year of life are less likely to develop diabetes mellitus later in life.
Vitamin D and cancer
Several studies have suggested that the incidence of certain cancers decreases the closer you live to the equator. The higher levels of UVB photons appear to help the body fight cancer cells that are found in the breast, colon, ovaries, uterus and prostrate. The reason it is thought that vitamin D helps to stave off cancer in these particular organs is the fact that vitamin D receptor cells are found in these organs, and these cells are important for regulating growth of cells and possibly preventing the cell developing into an unregulated cancer cell.
Some researchers have suggested that development of these types of cancer could be cut by 50% if vitamin D supplements were readily available to help make up the shortfall for people living in higher latitudes (further away from the equator).
Vitamin D and rheumatoid arthritis
Rheumatoid arthritis (RA) is an autoimmune disorder. Often the treatment for RA includes use of steroids which can have a negative effect on vitamin D levels within the body. In the case of this kind of treatment, it should be noted that vitamin D supplements may need to be taken. Many people who suffer from RA have lower levels of vitamin D. Researchers have suggested that vitamin D helps to inhibit inflammation in the body.
Vitamin D and dementia
Studies have suggested that vitamin D deficiency may double the risk of developing dementia. With moderately deficient levels of vitamin D it was predicted that risk of dementia may be increased by 53%, In cases of severe deficiency, the risk of developing dementia was more than doubled. Vitamin D receptor cells are densely located in areas associated with memory and thought processing. It is thought that vitamin D helps to clear plaques in the brain which are responsible for the onset of dementia.
Vitamin D and depression
The lower levels of vitamin D the more likely the risk of developing clinical depression. Vitamin D has an impact on the amount of serotonin produced within the brain. Serotonin helps to lift our mood and to cope during times of difficultly. When treated with vitamin D supplements, depression was significantly improved after a period of 12 weeks.
Vitamin D and cardiovascular disease
Cardiovascular events such as heart failure, myocardial infarction, stroke, or cardiovascular death have been linked to low levels of vitamin D. Studies have shown that vitamin D deficiency can increase the risk of suffering a heart attack by 50%. A much greater risk of dying from a heart attack has been linked to vitamin D deficiency. People who live at higher elevations and closer to the equator have lower occurrences of heart related diseases. People who live further away from the equator have higher risk of developing CVD. There are more CVD related incidences during the winter period. Vitamin D receptors have been found in all the major cardiovascular cell types, including the cardiac muscle found in the heart, arterial wall cells and the immune system.
Symptoms of possible vitamin D deficiency
Other than getting your vitamin D serum levels tested, there is no sure-fire way of determining if you are vitamin D deficient, however, if you are regularly suffering from any of the below, it may point to a vitamin D deficiency:
Sweaty head
If the rest of your body is not sweating, you are not performing any strenuous exercise, your core body temperature is 37C (98.6F), yet your head is sweating, this could be a sign of vitamin D deficiency.
Feeling blue
Serotonin is a neurotransmitter that affects how we feel. When we are feeling down or low, it could be that our serotonin levels are low. Sunshine, because of its production of vitamin D, affects the amount of serotonin we produce, so if we are low on vitamin D, it is likely that our serotonin levels could do with a boost. A lot of people suffer from SAD, seasonal affective disorder, which can be helped by the regular use of a SAD lightbox to help boost vitamin D levels during the winter months.
There is a link at the bottom of this article to information and tips on how to make the right choice when buying a SAD lightbox.
Feeling lethargic
Vitamin D is required for us to feel motivated. If you are constantly feeling tired despite sleeping well, you might be advised to get your vitamin D levels checked
Muscle weakness
Vitamin D deficiency accounts for most muscle weakness. It can lead to you feeling heavy in the legs, tiring easily, having trouble climbing stairs. Muscle weakness due to vitamin D deficiency tends to be most notable in the legs and as people get older, the risk of falling, due to decreased muscle strength becomes an important factor to consider.
Aching bones
Bone pain is an indicator of vitamin D deficiency. Vitamin D is needed for the body to absorb calcium and phosphorous, which are vital for healthy bone development and maintenance. When these levels drop, breakages, joint and bone pain can become long-term problems.
Gut problems
Vitamin D deficiency has a negative impact on the healthy bacteria that live in our gut. The healthy bacteria help to maintain balance within the body, as well as producing B vitamins. In this case, vitamin D deficiency can also lead to vitamin B deficiency. Studies have shown there is a strong link between inflammatory bowel disease such as crohn’s and ulcerative colitis and vitamin D deficiency. It is thought that vitamin D can help to reduce the inflammation caused by inflammatory bowel disease and reduce complications related to the disease such as surgeries, colostomies and colon cancer.
Sources of vitamin D
The sun
The sun is by far the best source of vitamin D. It’s free, readily available, natural and was meant to provide us with what we need.
Cod liver oil
Cod liver oil is by far the most effective way of obtaining vitamin D in supplement format. It contains a much higher density of vitamin D than other foods / supplements and is easily digestible by the body. Many brands of cod liver oil use a process that removes all the natural goodness, so you need to choose wisely. Make sure when choosing a cod liver oil, that you look for a product that is naturally produced, unheated, fermented and made using a filtering process that retains the natural vitamins.
Green Pasture – Fermented Cod Liver Oil – 120 Capsules
Mushrooms
Careful you don’t pick the magic ones! It is reported in many places that mushrooms are a good source of vitamin D, but don’t mushrooms grow in dark places? Apparently some mushrooms can be exposed to the sunlight for a short while to help to create vitamin D, however, I’m not sure how you identify these particular mushrooms in the supermarket and the vitamin D they produce is vitamin D2, which is far less effective for the human body than vitamin D3.
I love mushrooms, but I’m not going to rely on them for my vitamin D boost. Please don’t go picking mushrooms from the wild, unless you really understand what you are doing. With many mushrooms, you don’t get a second chance.
Fatty Fish
Ethically sourced fatty fish such as wild salmon, tuna and mackerel rank among the best food sources of vitamin D. Make sure to buy wild fish as farmed fish contain very little or no vitamin D.
Beef liver, eggs and fortified cereals
Beef liver is a good source of vitamin D as well as egg yolk and fortified cereals, however both egg yolks and beef liver are high in cholesterol, so the trade off is not particularly favourable. Many cereals contain high amounts of sugar, which is very detrimental to our health.
Vitamin D is absolutely necessary for our overall health and welfare
Vitamin D can no longer be thought of exclusively to help promote healthy bone formation. Vitamin D receptor cells are found all over the body and there is clearly a reason for this and vitamin D’s importance in our overall health.
It is easy to adopt a non-healthy lifestyle and assume that supplements are the way forward. They are not. They may help, but from an evolutionary standpoint, we were designed to be fit, active, healthy, outdoors people. Far from the norm of someone sat in an office all day in front of a laptop, going home to eat a microwaved, processed meal. No wonder so many major health problems are increasing at such a fast rate.
The bottom line is to try and do everything you can to stay healthy. A healthy lifestlye includes regular exercise, good sleep, healthy eating, time outdoors and stress management. Vitamin D is absolutely vital for overall health.
Regular exercise, good sleep, healthy eating, uv light and stress management are vital for overall health. Click To TweetNumerous studies have shown how several cancers, diabetes, mental health, auto-immune diseases and neurological diseases respond to vitamin D levels within the body. Isn’t this sufficient to ensure we get the optimal amount?
Vigilance in monitoring serum 25-hydroxyvitamin D concentrations (vitamin D) should be a high, if not vital, priority for ensuring you and your loved ones live long, healthy and happy lives.
How do you maintain your vitamin D levels?
SAD lightbox information: http://www.sad.org.uk/buying-a-sad-light/
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