Vitamin D- The Power of Sunlight

By on October 17, 2013

The Power Of Sun Light

Today I am going to talk about an essential vitamin, which I would say everybody is at least borderline deficient in. This one vitamin is actually produced by your body and it is vital for health, however, in this day and age, where we spend most of our lives indoors, we struggle to produce it and that can cause an array of health problems.

This very vitamin is directly related to the sun and it is vital that we have sun exposure every day if possible to allow our bodies to produce it.

Hands up, who feels great when the sun is out? There are clearly psychological reasons for loving summer days, but what people do not realise are the factors that lie beneath this that people do not understand.

I’ve had many clients complain of eating well, sleeping lots and training hard but never quite feeling their best at certain times of the year. Who usually feels flat after the Christmas period, but has no idea why? Maybe you put it down to too much excess and whilst that is partly true, post Christmas combines with the end of the fun and festivities, there are other factors at play.

Just recently I personally felt myself struggling to ‘get on it’ in training and constantly felt this niggle of not quite being on the right train tracks in life.

This is a strong indicator towards a Vitamin D deficiency!

So what’s the problem?

In winter in the UK the majority get up, leave home in a car, get to work where we work all day indoors with no sunlight, get back in the car, drive to the gym where we have a workout then get back in the car to drive back home where we hit the sack ready to go again the next day!

And even if we do get outside, the sun is so low and far away that we still don’t get any benefit from it.

Then when summer comes everyone smothers themselves in creams which block any chance of getting vitamin D anyway!

There is a general over reaction to the sun these days. Although the sun and its power has to be respected and precautions have to be taken,  it gives incredible benefits and it can affect how we feel as well as how we perform when training.

Contrary to popular belief the sun is one of the most important anti-cancer, anti-obesity tools you can have.


Because it provides us with the nutrient vitamin D.

You see, vitamin D is unique in that it is made in the skin as a result of an exposure to sunlight.

To give you an example, 15-20 minutes exposure to the sun in the summer months between June and August at noon, in a country near the equator is the equivalent to taking around 20,000IU of vitamin D orally.

It is nearly impossible to get adequate levels of vitamin D from your diet. Sunlight is the only reliable way to generate vitamin D in your own body. However the healing rays of sun light that generate vitamin D in your skin cannot penetrate glass, if you are indoors, make sure you get outside as much as possible.

Here’s the thing though, the further away you live from the equator, the longer exposure you need from the sun in order to generate vitamin D. Putting that into perspective, the UK, Canada and certain US states are far from the equator and it may be that even with sun exposure it is not enough. Not only that, the darker your skin type the longer the exposure has to be for the same benefits.

For example, to guarantee adequate levels of vitamin D from the sun in the UK would only occur between the months of June to August, when the sun is at its highest between the hours of 12pm and 3pm. After that you will struggle, as the sun’s rays are not strong enough. That is why it is important to take further measures to top up you levels.cocktail on a tropical beach


Topping up your vitamin D

There are a number of ways to increase your intake of Vitamin D

Food Sources – The best sources that are rich in vitamin D include fish like wild salmon, tuna, mackerel, as well as fish liver oils. Some vitamin D is also present in beef liver and egg yolks.

Sunlight – Exposing your skin to natural sunlight, this acts as a pro hormone, rapidly converting to vitamin D in your skin.

Sun beds/sun lamps – Using a safe home tanning bed to replicate similar results to exposure to natural light. Make sure it is a UVB sunbed and your exposure is no more than 3 times a week for no more than 2 minutes each time

Supplements – Taking an oral Vitamin D3 supplement whenever natural skin exposure is limited

To put things into perspective…..

My good friend and fitness professional Alwyn Cosgrove made a relevant point when I spoke to him regarding supplementation. Alwyn owns one of the top 10 gyms in the United States, ex competitive taekwondo practitioner and cancer survivor and is based in California. He made the point that despite living in the sunshine state, supplementing vitamin D daily, when his bloods are tested, they come back as borderline to ok for vitamin D.  Now compare that to the UK where the sun hardly shines in the summer never mind the winter and Just think what effect that has on us in our normal day to day lives, never mind how it affects your performance?


Health Benefits of Vitamin D

There are numerous health benefits to vitamin D, let’s take a look at a few of them…

  • One key job for Vitamin D is to prevent healthy cells becoming diseased which can lead to any number of diseases resulting from cell degeneration including all forms of cancer, diabetes, osteoporosis and rheumatoid arthritis.
  • Lowers the risk of respiratory infections by 50%
  • Reducing systemic inflammation
  • Vitamin D is essential for liver function. As the liver produces bile which aids in the digestion of fats, a deficiency of Vitamin D may lead to high levels of fat in the blood vessels, ultimately increasing your risk of heart disease.
  • The maintenance of healthy bones; bizarrely, there has been an increasing number of cases of osteomalacia (rickets for adults) caused by Vitamin D deficiency in the past few years. Although this is only caused by a severe shortage of Vitamin D, it is something worth being concerned about.
  • It is a crucial component for healthy immune systems; Very helpful in the fight to keep common winter ailments at bay.
  • Reported to be linked to maintaining a healthy body weight and brain function.


So as you can see, there is already a wealth of information pertaining to your overall day to day health, but what about its effect on your performance.

Lets take a look…


Performance Considerations…

  • Bone Health – Low levels of Vitamin D contribute to more brittle bones and increased risk of breaks and fractures. This is because Vitamin D is important in calcium absorption in the body (remember how you can’t isolate nutrients). A Vitamin D deficiency can therefore lead to weaker bones thus increasing the risk of injury (as well as osteoporosis) and enabling your body to cope with heavy weightlifting sessions.
  • Muscle Strength – Low vitamin D can lead to abnormal muscle contraction and relaxation, which in turn affects force production by the muscles. It has also been shown to aid the production of natural steroid hormones in the human body thus aiding muscle growth. This will clearly effect everything from strength and power to burning body fat more efficiently.
  • Muscle Power and Force – Research has shown that optimum levels of vitamin D improve muscle power development. The ability of the muscles to contract and produce force is impaired with lower vitamin D levels.
  • Lean Body Mass – As discussed low levels of vitamin D affects muscle performance, but it also can allow for increased fat storage.
  • Insulin Sensitivity – Vitamin D supplementation has been shown to increase the sensitivity of insulin (meaning you only need small levels of insulin to provoke a response to lowering blood glucose levels), making your body work more efficiently.
  • Asthma – Vitamin D has been shown to improve respiratory function.
  • Cardiovascular Health – Is known to improve heart function.

How much Vitamin D do you need? 

Research suggests that adults 5000 IU per day to put the majority of people into the recommended level. However, supplementing with vitamin D alone, might not be the best way to increase your levels. There is a relationship between Vitamin A and Vitamin D. Vitamin A helps the body use vitamin D and if you did not supplement then there is a good chance you will become vitamin A deficient, which will have consequences with your health.

This is another indicator that your body works in synergy. You cannot just concentrate on one thing as everything is interlinked, All vitamins and minerals work together to help numerous functions within the body.


Here is your Action Plan

  • Try to expose the skin to 10-20 minutes of sunlight at least every other day (with no creams on the skin)
  • No Sun? Get yourself on holiday 3 months after you summer finishes. The liver stores around 3 months’ worth of vitamin D before it needs a top up.
  • Cannot get Away? Use a UVB sun bed in SHORT bursts. No more than 2 minutes at a time, 3 times a week.
  • Ensure you have a high magnesium intake which encourages D absorption. I recommend supplemental sources of magnesium ending in -ate (e.g magnesium citrate) and transdermal magnesium for great absorption. This will ensure you get enough. Eat enough nuts, bananas and leafy greens for magnesium as well.
  • Supplement with Vitamin D3. Aim for between 3000 and 5000 IU’s per day.
  • Do not smother yourself in sun screen, Check the table to see how long you need before you cover yourself up.



UVB rays are the only rays that help create Vitamin D, these rays are only available when the sun is over head, typically between the hours of 12pm and 3pm

UVB rays are easily blocked and cannot penetrate pollution or cloud, make sure the sky is clear

UVB rays are blocked by sun screens so aim to get the exposure before you put it on.

If it is not possible to be in the sun at these times supplement with fish oils, each more fish and take a Vitamin D Supplement.

Make sure you are getting adequate levels of Vitamin D, to increase your sports performance.


To your strength and Health



Dean Coulson

About Dean Coulson

• International Best Selling Author of the Fit Formula • Feature writer on Nutrition for the Uk’s biggest selling Martial arts magazine – Martial Arts Illustrated • Presenter & speaker - Tour the UK with Bafta Award Winning writer Geoff Thompson. ( ) • Owner and Performance coach at Assert Fitness Ltd. Taking our clients Dreams and makes them a reality, through the realms of coaching all aspects of health and fitness to busy professionals. • ,