The Vitamin D Production vs Sun Protection Balance

We all start off with young skin and then as time goes by, we get wrinkles and pigmentation not because of the passage of time but because of the time spent under sunlight.  In order to treat photoaging we have to understand the chemistry of what happens when we are exposed to sunlight.  This knowledge allows us to prevent and treat photoageing.  There is excellent scientific evidence to show that the main reason for photoageing is the depletion of retinyl palmitate, which is the storage form of vitamin A in the skin and an effective cosmetic agent.

Cluver was a pioneer in recognising that Vitamin A played an essential role in counteracting sun-damage.  He showed that every time we go out into sunlight, the photosensitive Vitamin A molecule is denatured, not merely in the skin, but also in the blood.  

ALPHA HYDROXY ACIDS WILL NOT IMPROVE SUN DAMAGE

Many clinicians are unaware of the chemical changes that are involved in photoageing and think that sunscreens are the best way to prevent photoageing and unfortunately, too many believe glycolic acid and other Alpha Hydroxy Acids – (AHA) are the best way to treat it. Alpha hydroxyacids have no physiological role in photo-damage or even in cellular physiology.

FREE RADICALS

While it is certain that sunscreens go a long way in preventing sun-damage, they do not actually treat the fundamental cause of photoageing and may aggravate the free radical challenge to skin. Light consists of a whole spectrum of photons, which are “packets” of energy that vary according to their wavelength.  Essentially light enters into the skin and certain wavelengths can damage the skin on the molecular or on the sub-atomic level because of the photon energy.  

Most people believe that the damage is done by UV light only, but in fact even green, blue and violet light can damage cells.  “Soft” green light damages keratinocytes presumably by the induction of free radicals that then stimulate melanocytes to make more melanin! We should therefore look also at all visible light as a potential cause of melasma.

 

A SIMPLE SUMMARY OF THE MOLECULAR CHANGES IN PHOTOAGING

On the molecular level, photon energy is absorbed into certain molecules that absorb a specific light energy (we call these chromophores*) and consequently are then altered.  The most important example of this is RP that is extremely sensitive to light.  When vitamin A absorbs the energy of photons in the range of about 325 to 334 nm then vitamin A activity is lost.Interestingly enough, most sunscreens do not adequately protect retinyl palmitate. There are many other molecules that are damaged in the same way, e.g. DNA, vitamin C, B12 etc. The pre-cursor of Vitamin D is a chromophore for UV-B that is obligatory to manufacture natural vitamin D.  The biological paradox is that unfortunately vitamin D-3 itself is a chromophore for UV-A and is destroyed by UV-A light!  Maybe this is why we cannot ever become intoxicated with vitamin D after prolonged exposure to sunlight.

*A chromophore is a molecule that contains a colour that makes it absorb certain photons. Technically, sunscreens are chromophores.

At the sub-atomic level, should a photon strike a vulnerable electron in the outer circuit of an atom, the electron is cast out of its circuit and the molecule, in its quest for another electron to stabilise atomic relationships, becomes a free radical. That starts up a destructive chain of chemical reactions, involving tens of thousands of molecules in a fraction of a second, which may damage cellular structures, DNA and other important cellular structures. Chronic damage eventually leads to photoageing.  

PREVENTING AND TREATING PHOTOAGEING

To prevent or treat photoageing it is logical to design a therapeutic regime that replaces damaged chromophores like vitamin A and C.  Most clinicians will immediately think of retinoic acid as the agent to replace vitamin A.   After all, it is the ligand for the nuclear RAR and RXR receptors. However, when one realises that the main form of vitamin A is destroyed when we go out into the sun is Retinyl Palmitate, then the physiologically best form of vitamin A will be Retinyl Palmitate. 

We know that Retinyl Palmitate specifically protects the DNA from damage and, when applied topically in adequate doses, can have DNA protective effects to the same extent as a sunscreen SPF 20. Protecting DNA is essential for the prevention of skin cancer. Retinyl Palmitate blocks UVB rays , but not those required to make Vitamin D – an all round winning combination!

Women have an added disadvantage because blood levels of vitamin A drop when they menstruate.  That means that they are more vulnerable to photo-damage. 

Langerhans cells desperately need vitamin A and its deficiency prevents them from recognising DNA damage. As a result, clones of abnormal cells slowly start to develop and, years later, manifest as keratoses or skin cancer.  Research has shown that low retinyl esters are associated with skin cancers and topical retinoids are a significant prevention against skin cancer.

Cluver also showed that people who suffered bad sunburn could be improved by oral supplementation of 25,000 i.u. Retinyl Palmitate per day for short periods.

Loading the skin with anti-oxidant molecules such as vitamin C and E the day before expected sun exposure, provides better DNA protection than most organic sunscreens molecules. Tomato soup is an excellent way to help prevent sun burn!

THE SUNLIGHT VS VITAMIN D BALANCE

Some people develop a photophobia and avoid sunlight as much as possible in order to avoid the chances of wrinkles, melasma and skin cancer. As a result, they do not make naturally manufactured vitamin D.   A low vitamin D level is associated with osteoporosis, an increased chance for breast cancer, bowel and prostate cancer amongst other conditions. This raises an important dilemma: are the dangers of sun exposure greater or less than the dangers of avoiding sunlight? If one avoids sunlight, especially in summer, then one cannot make natural vitamin D, and that will increase the chances of getting osteoporosis that is common throughout the world.  Vitamin D protects us from UV-A rays and also protects us from various cancers. Is that a good exchange?  I think not.  I believe we have to find a way to get all the benefits of sunlight and minimise the dangers.  This is where Retinyl Palmitate can help us significantly.  Moreover, retinoids share receptors with vitamin D and together they are responsible for the delicate balance required for normal skin.

Conventional sunscreens are not able to give adequate protection from UV- A, and so vitamin A is still damaged by light, even when a person is wearing a sun protection factor of 30, 40 or even 100.

Diet plays only a small part in Vitamin D nourishment because it is mainly supplied to us through our skin.  UV-B rays convert Cholesterol-like molecules into vitamin D-3. Since in most of the developed first world one only gets UV-B rays in significant quantities for manufacturing vitamin D for less than six months on average, that means people have to supplement their vitamin D as well as go out into the mid-day sun for 10 – 20 minutes everyday in late Spring, Summer and early Autumn. That poses risks to us of photodamage but I believe Retinyl Palmitate topical products with antioxidants are the most effective way at this stage to save both the skin and the body at the same time.

CONCLUSION

There is a more intelligent approach to sun safety than merely blocking it out. Topical Retinyl Palmitate will still allow production of Vitamin D and is active in protection and repair for healthy skin. In the end we need to achieve a balance of just enough sun to produce Vitamin D but not so much that it creates sun damage; there is a role for Retinyl Palmitate and another for sun blocking. Because of the central role of vitamin A and D in normal physiology and because too little UV light and too much UV light have such dire complications besides melasma and wrinkles, it has become absolutely necessary for us to search for a way to get enough summer sun to make vitamin D and still prevent the problems of photo-damage. 

 

Professor Des Fernandes and Dr Ernst Eiselen's new books 'Retinyl Palmitate' and 'Skin Care Ingredients' are available from our bookstore. www.fernro.com