Skin Nutrition: Vitamin A
There have been plenty of articles in the beauty media regarding different vitamins and the fact that they are beneficial to the skin. More often than not they don’t go any further than saying that they are of benefit to you or important, but don’t explain how they work. I was having a conversation recently with a client who made the observation that without having that information she is less inclined to actually use a product – she might purchase it but it tends to sit on the shelf as she is confused as to what it is actually doing for her.
One question that can come up is that “surely if a person is eating a healthy balanced diet with plenty of fresh fruit and vegetables, then aren’t they going to get enough vitamins through their diet and so products containing vitamins aren’t necessary?” In answer, by all means you should be eating a healthy balanced diet for a variety of reasons including benefit to the skin, but the body will be assigning nutrients to where it feels it’s necessary (meaning vital organs first), and the skin is the last place on the list to get fed. By applying them topically, they are going exactly where you want them to go.
Vitamin A
I am starting with A not because I’m working in alphabetical order, but because it is one every person needs for optimum functioning of the skin. It has implications for acne and problematic skin, collagen production and also the prevention of skin cancer. It is what the skin cell uses to control the normal activity of the DNA of the cell’s nucleus, as well as that of the mitochondria (organelles within the cell which produce energy).
The functions of vitamin A in the skin
1. Increases collagen type 1 production, increasing skin firmness.
2. Normalises basal (the lowest layer of cells in the epidermis) cell function and replication, restoring cellular homeostasis – i.e. it governs the normal replication of skin cells and therefore guards against cancer.
3. Compacts the horny layer (stratum corneum), resulting in a smooth skin texture that reflects light evenly, creating a radiant appearance.
4. Normalises oil secretion.
5. Corrects the polarity of keratinocytes, (making them less sticky and therefore less liable to clump together, reducing the formation of comedones (blackheads).
6. Decreases the levels of transglutaminase, an enzyme responsible for cross-linking cell membrane proteins of the keratinocytes, which contributes to keratinocytes blocking pores and forming blackheads.
7. Reduces clumping of melanin (the skin’s pigment that creates both a tan and pigmentation patches) in basal cells, resulting in a reduction in the appearance of hyper pigmentation.
8. Reduces lipid peroxidation (the oxidation of oils in the skin), which has a wide range of skin benefits including treating acne, pigmentation and premature aging.
9. Reduces oxidative stress (acts as an antioxidant).
You can see from this list that vitamin A has multiple benefits and is therefore important to include in almost any effective skincare treatment program.
The pathway of vitamin A into the skin cell via the digestive system
Beta carotene from food is converted into vitamin A when absorbed through the small intestine into the lymphatic system, and is transported to and stored in the liver as the ester retinyl palmitate until required.
When needed it is released from the liver, converted into retinol, attached to proteins in the bloodstream and in this way carried to the skin.
Upon arrival in the extracellular spaces of the dermis/epidermis it reverts back to retinyl palmitate so it can enter the cell via its receptors. On moving through the cell membrane it is further converted to retinol, then retinaldehyde and finally to retinoic acid by the mitochondria, which is the form that the cell uses for DNA synthesis and to support cellular structures.
As the body will use vitamin A for the vital organs before the skin, it makes sense to apply this essential nutrient topically. Provided it is active and in a form that can penetrate the skin, it will be going directly to the cells that need it.
How vitamin A influences collagen formation
There are three main ways in which vitamin A has a positive influence on collagen formation:
1. Retinol causes an increase in the number of fibroblasts (cells that produce collagen) in the dermal layer, and therefore an increase in collagen.
2. As retinyl palmitate it has an SPF 20, which protects against the decrease in collagen production caused by UV exposure.
3. An enzyme called matrix metalloproteinase (MMP) is produced by the skin to degrade old collagen and therefore make way for new, healthy collagen. UV exposure however causes a great increase in this enzyme, resulting in too much degradation, and therefore accelerates aging. Retinoids counteract this by slowing down the expression of this enzyme.
Vitamin A and sun protection
Retinyl palmitate gives a natural sun protection factor of 20 by absorbing UV radiation. This means that (in the UK certainly, and other countries where the UV index is regularly lower than 4) you don’t actually need to wear sunscreen daily to protect your skin from photo-aging. You can in fact combine sun protection with all the other benefits listed above, in just one product. Come the summer months where the UV index can be higher - and its easy to check online - wear an SPF if you are going to be outdoors for longer than 20 minutes in the middle part of the day.
Why it is important to replenish supplies of vitamin A to
prevent premature aging and skin cancer caused by UV exposure
Vitamin A in the skin is destroyed by UV radiation, so it makes sense to top up the supply regularly. It takes around 7 days for it to be replenished naturally (i.e. for the body to get sufficient into the skin via diet alone), while if you use a good topical treatment it only takes hours.
It is common knowledge that prolonged unprotected sun exposure is linked to the development of skin cancer. This is because UV radiation causes damage to the nucleus of the cell and the mitochondria (the energy producing organelle in the cell), inducing mutations in cellular DNA and by destroying vitamin A which is used to normalise cell replication. Damage to the DNA causes cellular mutations that lead to uncontrolled replication, resulting in a tumour. Do remember, this is why we tan. Melanin pigment is produced to act as a barrier defence between UV radiation and the nucleus of the cell.
The skin cell membrane is selectively permeable, meaning it allows certain things like oxygen and nutrients through, while keeping out harmful substances like toxins or bacteria. It lets each molecule through via receptor sites that are unique to that molecule, including vitamin A. When we are born we have an abundance of vitamin A receptor sites, but these are destroyed over the years by UV radiation (along with the vitamin that they recognise). To put it another way, baking yourself in the sun destroys the vitamin that protects you against skin cancer and premature aging as well as the delivery system by which it enters the cell – something to bear in mind next time you want to get a healthy tan.
Please note! This doesn’t mean avoid the sun like the plague – just be sensible and don’t bake yourself for hours during the hottest time of the day with little or no sun protection and expect to look good when you are 50. Skin cancer is only a possibility, premature aging and pigmentation issues are guaranteed – and for younger readers please realise that you will care when you are older, and you are older for a much longer time than you are young.
It’s not all bad news, however. Even if you have had a lifetime of sun exposure, if you re-introduce vitamin A to the skin slowly then you will encourage your skin to make more receptor sites and allow the skin to repair some of the damage that has been done to it. It is honestly never too late to start caring for your skin, at any age and with any amount of damage present you can bring about an improvement if you understand what has gone wrong and apply the appropriate corrective measures.
Vitamin A and acne/problematic skin
Blocked pores are the first step towards the formation of inflamed spots. In acne patients there is a tendency for the keratinocytes to be “stickier” and therefore more likely to form blackheads due to two reasons.
1. Firstly, the effects of positive and negative charges on the cells make them stick to each other more readily, and
2. there is a higher level of transglutaminase present, which is an enzyme responsible for cross linking cell membrane proteins in the keratinocytes.
Retinoids reduce both the positive and negative charges and the levels of transglutaminase, meaning that the pores are less prone to blockages as the keratinocytes exfoliate more easily and naturally.
Another positive effect on acneic skin is that retinoids reduce the production of sebum by decreasing sebaceous gland activity.
Vitamin A and hyperpigmentation
Pigmentation is always linked to UV exposure, so all the sun protection benefits of retinoids apply. Also, in theory, the increased cell turnover of keratinocytes in the presence of retinoids means that the melanin pigment might be spread more evenly throughout the epidermis which reduces the patchy appearance.
Vitamin A acts as an antioxidant and protects against lipid peroxidation
Beta carotene is a potent oil soluble antioxidant which, amongst others, helps protect the cell membrane from oxidative stress. This is a complicated subject and will be dealt with in more depth in a future post, but in brief if the lipid components in the cellular membrane become oxidised then this will start a cascade of events leading to mitochondrial DNA damage. This means the cell won’t be able to reproduce easily and may lead to permanent damage, cellular mutation or cellular death (apoptosis).
Any cell can be affected in this way; therefore all skin conditions will be negatively affected.
Oxidative stress is what precedes skin and other cancers, as well as a host of other conditions, so it makes sense to always have antioxidants present in your products.
Formats of vitamin A in cosmetic/cosmeceutic products
There are many formats of this active ingredient in cosmetic and cosmeceutic skin care today. Most commonly it is found as retinyl palmitate, but retinyl acetate and retinol can also be used in popular brands (there are several more but these are what I have encountered most frequently.
Beta carotene
Also known as pro vitamin A, this is a precursor to vitamin A (as explained in the digestive pathway). It is a member of the carotenoid family and a powerful antioxidant, with a single molecule being effective against a vast number of free radicals. It also reduces UV induced redness (or the visible effects of sunburn), so is a very useful ingredient in sun protection products as well as after sun care. If your skin is very sensitive to even the gentlest form of vitamin A due to a lack of receptor sites, using beta carotene will encourage the formation of these with no adverse side effects except in very rare extreme cases.
Retinyl palmitate
This form is the most common found in skincare products and the least aggressive. It amounts to about 80% of the total vitamin A found in the skin which is why it is easily accepted by most skin types and rarely causes irritation.
Retinyl palmitate has been shown to have an SPF of 20, preventing sunburn and the formation of free radicals.
Retinol
Retinol is the alcohol form of vitamin A, and many consider it to be the “true” form, or the most usable by the skin. It has an advantage in that it is absorbed more quickly through the skin on surface application, but it still has to change back into retinyl palmitate in order to penetrate the cell’s membrane. A disadvantage is that it has a much shorter shelf life and is very unstable in sunlight, and some feel that it can make your skin more sun sensitive.
Another slight disadvantage for some – not everyone – regarding retinol is that it can reduce the skin’s ability to produce ceramide 1, which forms part of the skin’s lipid bilayers and barrier defence system. A lack of it leads to extremely dry, tight, dehydrated and uncomfortable skin (as water in the skin evaporates out too quickly without sufficient oil within it to slow down its progress). It can also then tend to sensitivity, as outside allergens aren’t being kept out effectively. I have found that should this happen the only answer is to drop down to a milder form of vitamin A and the problem resolves itself. For some reason certain skins just don’t tolerate the more aggressive forms, but they will still get huge benefit from retinyl palmitate and shouldn’t be discouraged into thinking that unless they are using retinol they might as well try something else. This is a vitamin EVERYONE needs.
It is also worth mentioning that during the winter months our skin seems to produce less ceramides than in the summer months, particularly on our necks (if I find the reason for this I will happily post it, but at the time of going to press I honestly don’t know why this is). This means that during the winter, if you are using retinol based products, you may find that your neck is a bit itchy. If this is a problem avoid wearing woollen polo neck jumpers and scarves, protect your neck with a silk scarf, or alternatively don’t use retinol on your neck during the winter. That said, I have had at least one client who was reacting to high strength retinol have a huge improvement in her toleration when introducing products that encouraged the production of ceramide 1. It so far is only one case, but interesting to note.
Retinoic acid
This is the form that the cell ultimately converts vitamin A into, and is found in pharmaceutical preparations on prescription only. It is a highly aggressive form and will cause redness, flaking and extreme dryness if your skin is not acclimatised. All that considered it also delivers faster results for people who are willing to stick it out through the less desirable side effects, although you will ultimately get the same benefits with retinyl palmitate without any of unpleasantness if you have patience.
How much should you be looking for in your product?
Therapeutic dose is an important point, as a product can say it has retinol in it but if it’s in too small a dose then it won’t really be doing much. Vitamin A is measured in international units (IU) per gram, and when expressed as a percentage in solution 10 000IU/g is the equivalent of 1% per gram.
The recommended effective dose of topical application is between 500 IU and 10 000 IU.
Anything less than 500 IU (0.2% per gram) is generally of no therapeutic value.
Processing and packaging of vitamin A is an important consideration, as vitamin A is destroyed by light and air
To further complicate the issue, when choosing a product containing vitamin A, you must also consider how the product is processed, packaged and transported. This is an important fact to note, as all products which contain this ingredient should be in either a collapsible tube (such as an aluminium one) or more preferably in an airtight, opaque pump dispenser. If you are purchasing a beautiful pot of anti-aging cream which advertises one of its active ingredients as vitamin A, unfortunately shortly after you have opened it the cream won’t be doing the job you bought it for. It still contains the vitamin, but it is inactive and of no benefit to you.
There is also some concern that this vitamin is damaged by X-rays, so when taking your products abroad it is advisable to carry them in your hand luggage as the X-rays used may be weaker than those used to scan hold luggage.
The correct delivery system greatly enhances the effectiveness of the product
This could possibly be a post on its own. Our skin is a selectively permeable membrane, so consequently doesn’t allow everything through (when working correctly), and the best cocktail of ingredients in the world will be pretty useless if it isn’t getting to the cells that need it.
Standard good cosmetic preparations will deliver around 2% of active vitamin A to the skin, increasing to 7% in the better cosmeceutic products. However, retinyl palmitate in a liposome or nanoparticle delivery system will penetrate the skin’s barrier as well or better than retinol that isn’t in one of these formats.
And finally, don’t be shy with your treatment product!
This is an active ingredient with a short shelf life. Standard protocol states that once you have opened your pump or tube you should aim to get through it in around 3 months. After this there is a reduction in efficacy so I wouldn’t recommend trying to make your product last 6 months – that is a false economy. I have seen over the years the difference in the skin of people who use their products correctly and those who haven’t – the results may not seem dramatic in the short term but are incredible when looked at over decades, justifying the effort put in on a daily basis.
