Harmful Effects

HEALTH PROBLEMS FROM OVEREXPOSURE TO THE SUN

Earlier, we mentioned the health problems related to UV Radiation, so now let’s take a closer look at each one.

Dehydration

Overexposure to the sun causes rapid loss of water in the body. We all know water is the essence of life. It is the most important nutrient in our bodies, making up roughly 70 percent of our muscle and brain tissue. Only oxygen is craved more than water.

When we breathe, we lose moisture to the air every time we exhale as much as two cups a day! Furthermore, our bodies lose water through evaporation from the surface of our skin even without doing big exercises, and of course we also pass water in our urine.

During the course of an average day, a healthy adult can lose eight to 10 cups of water. And in exercise, this number rises considerably.

If we fail to replenish the water we lose through these processes, we set off a physiological reaction that can have serious health effects. The following is the natural progression of dehydration and its effects on the body.

Sometimes it can be mild dehydration, look for the following symptoms:

  • Because your kidneys will begin to conserve (save) water, your urine (pee ‘short call’) will become concentrated (darker) and will be amber colored as opposed to a normal light-tinted yellow color.
  • Constipation and / or bloating may be noticed (difficulty in having a ‘long call’)
  • Dry skin, mucous membranes, and lips
  • Thirst, often extreme
  • Flushed face

It can also be moderate dehydration, look for the following symptoms:

  • Fatigue (tired, too much)
  • Sunken eyes or sunken fontanels (soft spot on head) in infants. It’s also referred to as “Kawompo”.
  • Lack of tears in a crying infant
  • “Doughy” skin that doesn’t bounce back when pinched
  • Dizziness / vertigo / light headedness
  • Up to 30% decline in physical labor capacity, muscle cramping (pain in the limbs)
  • Headache
  • Cold hands and feet
  • Problems concentrating (can’t focus at all)
  • Drowsiness (sleepy)
  • Fainting (black outs / off and on)
  • Impatience and extreme irritability (very jumpy and nervous)
  • Major reduction in urine production (little pee, with a dark color)

Dehydration can also be severe, look for the following symptoms:

  • Weak irregular heart beat (often racing) and low blood pressure
  • Rapid breathing
  • Confusion
  • Vomiting and / or diarrhoea (going from both ends)
  • Shock, collapse or unconsciousness
  • Seizures (fits)
  • Coma and death

To prevent dehydration, experts recommend that everyone drinks at least six to eight glasses of water a day. Nutritionists also agree that the best way to fight the heat and the cold is to drink plenty of water.

You can keep cool in the heat by doing the following:

Add two glasses a day to your eight-glass minimum. Also, keep in mind that heavy perspiration from physical activity can result into loss of 12, 14 or even 16 glasses of water per day!

Drink before you get thirsty. If you wait until you’re thirsty, you’re already slightly dehydrated. Thirst is an unreliable indicator of your hydration needs.

Reduce your physical activity level if it is overly hot.

Monitor infants, children, and the elderly. In addition to being more susceptible to dehydration, they are also often unable to express their thirst or to hydrate themselves.

Pregnant women need to drink more water. They need to accommodate the needs of the fetus and the fluid losses due to increased heat production and perspiration. Breast feeding women need to increase water intake to replace fluid lost through nursing.

Don’t count beverages containing caffeine or alcohol toward your eight glasses! Caffeine and alcohol dehydrate your body, so you need to compensate for them. Drink an extra glass of water for each cup of regular coffee or tea, and for each glass of alcoholic beverage that you drink.

Eye Damage

Cataracts and other eye damages can be caused by too much exposure to the sun. This is a kind of eye damage that causes the lens to cloud and you can’t see clearly. If left untreated, it can cause loss of vision, blindness.

Other Forms of eye Damage that can result from UV Radiation

Pteryglium is where tissue grows on the white of the eye and blocks vision. Skin cancers around the eyes and retina damage.

All these eye problems could be prevented if people would wear sunglasses and protect the eyes. Most people don’t use protection and the rate of eye damage is increasing.

There are three (3) million blind people in Uganda. 80% are due to cataracts. These numbers are likely to increase because of the exposure already highlighted above.

Vision is precious and trying to live without your vision will be very difficult. Ugandan people don’t like to wear sunglasses nor do they teach their children to use them. Good sunglasses don’t need to cost a lot of money; they only need to be UV 400. This means they give protection against UVA Radiation. You can buy a good pair of sunglasses for about UShs. 4,000. Money well spent, believe me.

The diagram below shows a normal human eye

eye

Immuno Suppression (Immune system not working well)

Repeated overexposure to ultraviolet radiation can cause long–lasting damage to the body’s immune system. Mild sunburns can suppress immune functions in people of all skin types.

UV radiation causes the alteration of white blood cells (WBC), the cells that fight disease. They somehow fail to do what they were designed to do, due to overexposure to ultraviolet radiation, too much sun on the body. Other form of eye damage that can result from UV radiation is pteryglium, tissue grows on the white of the eye and blocks vision, skin cancers around the retina damage. All these problems would be lessened if people had proper eye protection. But most people can not get the protection there are some many cases that would prevented. There are 3 million blind people in Uganda. 80% are due to cataracts. These are likely to increase because of the exposure already highlighted above. Vision is precious and trying to live without your vision will be difficult. Ugandan don’t like to wear sunglasses nor do they teach their children to use them. sunglasses don’t need to cost a lot of money; they only need to be UV 400. This they give protection against UVA Radiation. The diagram below shows a normal human eye Immune Suppression Repeated over exposure to ultraviolet radiation can cause long–lasting damage body’s immune system. Mild sunburns can suppress immune functions in people skin types.

One of the most important things you can do is to protect and boost your immune system. It’s what keeps you healthy, well and alive. We need our immunity to fight off diseases and to recover once we get sick.

Decreased vaccines efficacy (not working well)

Overexposure to sun rays causes vaccines not to work well as they should. Many vaccine preventable diseases are extremely infectious.

Any factor that causes, even a small decrease in vaccine efficacy (not working well) can have a major impact on public health. The end results are, spreading of diseases. The morbidity (hospitalization), and mortality (death) rates increasing. So we all need protection against UV radiation. All humans need protection. Your dark skin is not enough protection as your brain, eyes, and immune system are not protected by Melanin.

Brain Damage

When earlier studies were done on the harmful effects of UV radiation, they did not consider infants and young children, without any hair, in the sun all day. Brain damage we know, in this case, is caused by overexposure to UVR, excessive heat and lack of protection.

Note; that in some other countries women carry their infants in different ways, but those that do carry them on the back always make sure the infants are protected from the sun, in most cases. In Africa the head is always exposed to the sun, why is that?

Now take a closer look at the infant on the back of the mother without any covering for the head. The infant is strapped to the back and all hair has been shaved off, exposing the infant totally to 100% of the harmful sun rays causing maximum damage to the brain, eyes, skin and immune system. You don’t have to be a doctor or a rocket scientist to understand what is happening to this child.

On the skull of the infant, there are six openings (fontanels, also known as “Kawompo”). The main Kawompo, called Anterior Fontanel, is the largest on the top of the head. It should close at about 18 months of age, under normal conditions. In Uganda the infants in the sun all day working with the mother, well it closes much, much sooner.

The diagram below shows a Human Skullskulls

Skin Cancer

Childhood sunburns and Melanoma have a link. Melanoma is the most serious form of skin cancer. This type of cancer spreads to other parts of the body quickly. When diagnosed early, it can be cured. In most cases, with dark skinned people, the detection is in the late stages. Detection in the late stage is often fatal.

The diagram below shows a Human SkullSkin Cancer Childhood sunburns and melanoma have a link. Melanoma is the most serious skin cancer. This type of cancer spreads to other parts of the body quickly. diagnosed early it can be cured. In most cases we, dark skinned people, wait until late stage, then we go to doctor. In the late stage melanoma is often fatal. There are two other types of skin cancer that are not fatal, but can cause other Basal Cell Carcinomas and Squamous Cell Carcinomas. Early detection is the high cure rate. Watch for signs, i.e. bumps, nodules and moles. When any change size, shape or color, go see a doctor, at once!

There are two other types of skin cancer that are not fatal, but can cause other problems – Basal Cell Carcinomas and Squamous Cell Carcinomas. Early detection is the key for a high cure rate. Watch for signs, i.e. bumps, nodules and moles. When any of these change size, shape or color, go see a doctor, at once!

Did you know there is an increase in cancers in Uganda? There is a 12% increase in cancers across the board. Yes it’s true, dark skin has more melanin giving you more natural protection, but cancers do occur and in most cases detection is in the late stages and the outcome is not good. Just think about this, can you afford hospitals, treatments, medications, and transportation to and from the doctors? The answer is probably no, so just take care of your beautiful dark skin. In the USA people spend Millions of dollars!! per year just to get your color. That’s right they want to look like you! Take care of your skin; it has to last you a lifetime. Yes… black skin is so very beautiful, so who told you it wasn’t? Go take another look in the mirror. You are beautiful just the way you are!

The darker the skin the better! Yes, that’s right; the darker your skin the more natural protection you have. The skin is the largest organ of the body. Keep infants and young children out of the sun. Their skin is just too thin and sunburn is unavoidable.

Why are there holes “Kawompo” on the infant head?

As explained before, Kawompo are the openings on the child’s head. They are there to help in the birthing process and to allow the brain to grow, after birth. The infant in the sun loses neurons (in the brain) that are never replaced.

Sunlight UV damage to skin persists even after dark

“Moving immediately into the shade does not stop sun damage, as UV rays can continue damaging skin cells hours after exposure,” The Guardian reports. Ultraviolet (UV) light is known to cause damage to DNA in skin cells, which increases the risk of the most serious type of skin cancer: melanoma.

This study aimed to examine the biological mechanisms that may be involved in this process.

Researchers used pigment-producing skin cells from mice (melanocytes) and found that it is the pigment melanin that plays a role in the damage process.

Exposure to UV light causes melanin to produce small molecules, called cyclobutane pyrimidine dimers (CPDs). The CPDs form abnormal bonds between the “building blocks” in the DNA helix. These CPDs are formed at the time of UV exposure, but the research showed that the formation of CPDs also continues for three or more hours after UV exposure has stopped (“after dark”). After this, DNA repair mechanisms step in.

Some tests using human melanocytes were also performed. This was said to similarly demonstrate the continued formation of CPDs after dark, but the effects were much more variable. It is unclear whether the situation in humans is completely identical.

Overall, the findings reinforce the risks of over-exposure to sunlight. It is easy to forget that the sun is a giant nuclear fusion reactor that emits radiation. Therefore, it is important to be sun-smart to reduce your risk of skin cancer.

You don’t need to get a suntan, let alone sunburn, to harvest the vitamin D-boosting effect of sunlight.

Where did the story come from?

The study was carried out by researchers from Yale University School of Medicine in the US and other institutions in Brazil, Japan and France. The study was supported by various grants, including those from the Department of Defence and National Institutes of Health. 

The study was published in the peer-reviewed scientific journal Science Magazine.

The UK media’s reporting of the study was accurate, though some of the headlines were potentially confusing. For example, headlines such as The Daily Telegraph’s “Sunlight damages DNA even in the dark” and The Guardian’s “Exposure to sun poses risk of skin cancer even in the dark” could be taken the wrong way. People may be concerned that when they go out at night, the sun is damaging their skin and they need to cover up. The results of the study actually suggest that the damage caused by UV exposure to the skin continues for some hours after the exposure has stopped (e.g. after you have come in for the evening, after a day at the beach). 

What kind of research was this?

This was a laboratory study aiming to see by what processes UV light causes damage to the DNA in skin cells.

Melanin is the pigment in skin and hair cells, which is present in variable amounts across individuals. The amount and type of pigment in your skin, such as pheomelanin and eumelanin, are associated with the risk of developing melanoma –

the most serious type of skin cancer.

People with blonde and red hair have higher amounts of yellow pheomelanin relative to brown eumelanin in their skin and hair, which puts them at higher risk than people with darker skin and hair.

Previous research has demonstrated that when melanin, particularly yellow pheomelanin, is exposed to UV light, this produces reactive oxygen species (ROS) –

molecules that can cause cell damage and “breaks” in the DNA. Looking at the DNA abnormalities present in melanoma, it seems that in most cases there are distortions to the DNA helix. This is due to the presence of molecules called cyclobutane pyrimidine dimers (CPDs), which cause abnormal bonds between the “building blocks” in the DNA.

Ultraviolet A type radiation (UVA) makes up around 95% of the UV entering the atmosphere. However, the researchers say that although UVA is clearly linked to melanoma, UVA is not very good at making these CPDs directly. The researchers therefore aimed to look at the biochemical pathways that cause the pigment-producing skin cells (melanocytes) to produce CPDs.

What did the research involve?

The researchers carried out a variety of laboratory experiments, where melanocytes from mouse and human skin were exposed to UVA and UVB light. They used special laboratory techniques to examine the DNA in the cells, looking for the generation of CPDs at the time of UV exposure and for some time after UV exposure had been discontinued (“after dark”).   

The researchers then carried out further studies to see what biochemical processes may be causing the melanocytes to produce CPDs.

What were the basic results?

The researchers showed that exposure to UVA light causes the immediate production of CPDs. Unexpectedly, CPD generation continued for three or more hours after UVA exposure was stopped. After this, the formation of CPDs was offset by DNA repair mechanisms.

Experiments using melanocytes from albino mice suggested that it was the melanin pigment that was involved in the continued production of CPDs after dark, as pigment-free melanocytes did not continue to produce CPDs after UVA had been stopped.

Half of all CPDs produced after UVA exposure to mouse melanocytes were found to be formed in this “after dark” period, when exposure had stopped. Further tests with UVB light showed that most of the CPDs produced occurred after dark. Further tests in the mice suggested that the red-yellow pigment pheomelanin is both a “poorer shield” against the generation of CPDs at the time of UV exposure, and a stronger generator of CPDs after dark.

Tests with the human melanocytes similarly demonstrated the production of CPDs after dark, but in human cells the response was said to be much more variable. The researchers considered that this could be due to genetic differences, though they could not look into this further due to privacy restrictions on the donated skin.

When looking into the underlying biochemical pathways involved in the production of CPDs after dark, they found that this was due to UV-induced reactive oxygen and nitrogen species combining and causing excitation (the application of energy) of an electron in the melanin pigment. The energy produced during this process is transferred to the DNA and causes the formation of CPDs.

How did the researchers interpret the results?

The researchers conclude that pigment-producing skin cells (melanocytes) cause the production of “dark CPDs”, even after UV exposure ends. They say that melanin, while it may protect against cancer in one respect (e.g. people with darker skin having lower risk), it may also be cancer-causing (carcinogenic).

They also say that their findings “validate the long-standing suggestion that chemically generated excited electronic states are relevant to mammalian biology”.

Conclusion

This laboratory research examined the biochemical processes by which UV exposure causes damage to the DNA in skin cells, and so increases the risk of melanoma.

The research which used mouse pigment cells in the laboratory, confirmed that the melanin pigment plays a role. Exposure to UV light causes melanin to produce CPD molecules, which cause abnormal bonds to form between the “building blocks” in the DNA helix. The research showed that the formation of CPDs continues for three or more hours after UV exposure has stopped (“after dark”) before DNA repair mechanisms step in. The melanin pigment is necessary for the continued formation of CPDs after dark (pigment-free cells did not do this), and there was also the suggestion that different types of melanin could have differing effects. For example, the red-yellow pigment pheomelanin seemed to be a stronger generator of CPDs after dark. 

However, it should be noted that most of these results came from experiments using mouse pigment cells. Although UV exposure to human melanocytes was said to similarly cause the continued formation of CPDs after dark, the effects were reported to be much more variable. The researchers considered that this could be due to genetic differences, but they were not able to explore this further, due to privacy restrictions.

Therefore, these results must be predominantly considered to be applicable to mice. Although this is likely to be a good indication of the biochemical pathways that may occur in human skin cells after UV exposure, it is not know if the results would be completely identical.

Overall, the findings show that at whatever time UV exposure causes most damage to the skin – either at the time of exposure, or in the continuing hours afterwards – it does cause DNA damage to the skin, which is linked to the risk of skin cancer. The study again highlights the importance of safety in the sun, including the use of sunscreen, sunglasses and skin coverage.

Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.

Links To The Headlines

Exposure to sun poses risk of skin cancer even in the dark, study finds. The Guardian, February 19 2015

Could using sunscreen at NIGHT prevent skin cancer? Damage caused by UV light continues for hours after dark, finds study. Mail Online, February 19 2015

Sunlight damages DNA even in the dark, Yale scientists find. The Daily Telegraph, February 19 2015

A day on the beach can lead to cancer-causing damage AFTER the sun has set. Daily Mirror, February 19 2015

Links To Science

Premi S, Wallisch S, Mano CM, et al. Chemiexcitation of melanin derivatives induces DNA photoproducts long after UV exposure. Science. Published online February 20 2015

 

 

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