IamA IamA Hi. I'm Newcastle University Professor Mark Birch-Machin. My research focuses on the response of human skin to ultraviolet radiation, particularly within the context of skin ageing and cancer. AMA!

I am a glassblower and consistently get sunburn on my face from sodium flare coming off of the glass I'm working in the flame. I wear sunscreen sometimes is there anything else I can do to reduce the risks associated with uv radiation? I do this everyday so its not like the sun where you can just go inside

The sodium flare suggests it is another type of radiation that is causing the effect on your face. Different types of radiation, as you probably know, have different wavelengths and therefore different protection is required. It will be important for you to ascertain the wavelength of radiation that is coming from the sodium flare to match the protection

Is Campus Coffee too expensive?

For 4 Americanos you can buy one bottle of sunscreen. So, it’s not too expensive and if you swapped for a week, you’ll be saving your skin.

I know this isn't specifically regarding skin aging and cancer, but I've a few friends with autoimmune conditions (Lupus and Ulcerative Colitis respectively) and both of them have reported a vicious cycle of their condition flaring up when they're vitamin D deficient. Of course, a marker of their conditions is UV hypersensitivity, and neither absorb vitamin D well when it's administered orally, so they're both stuck constantly dealing with inflammation that vitamin D is known to temper slightly.

With that in mind, how would you recommend tackling that cycle of deficiency and inflammation? Is there a specific type of sunscreen they could use which would be more effective at blocking UV?

Ps: Sorry for the rambling question. I got there in the end.

Great question, as this is a tricky one to answer. We need to protect our skin from excessive sun damage, but at the same time getting enough sun light to generate sufficient quantities of Vitamin D. Although the diet provides Vitamin D, sun light is still the best source. However, many skin cancer charities have tried to answer this question, and one of the best statements comes from Cancer Research UK, which encourages people to receive enough sun light on unprotected skin, but which does not allow you to burn. The summary is – a little bit of sun light goes a long way to producing Vitamin D. In Caucasian skin this approximates to 15 minutes of sun exposure. But remember, get out of the sun well before you burn!

I've been told that Asian sunscreens contain sunblocking ingredients that are not present in US formulations. Do you have any opinion on these types of ingredients?

Different continents have different regulatory organisations, which explains the differences in allowed actives that you find between Asian and US formulations.

I've heard professors say that using sunscreen is actually more harmful than moderate sun exposure in terms of increasing you likelihood of cancer. What is your opinion?

There’s nothing wrong with sunscreen. It’s the way that you use it that counts. Most people don’t put it on correctly, or the right thickness. Thinking that they are protected, when they are not. Sunscreen should always be used as a useful tool in the sun-smart toolbox.

What do you use for sun protection?

How exactly does the mitochondrial complex II enzyme work to keep skin looking smooth?

We’re looking at young first before smooth this is because Complex II is key in keeping the batteries of our skin topped up and providing sufficient bioenergy to slow down the effects of ageing on our skin. The downstream effect of this is that healthy skin with lots of bioenergy will help to reduce fine lines and wrinkles but as we know this is a long process. Complex II is part of the respiratory chain of mitochondria which provides ATP for all cells including skin. As we age, our bioenergy decreases and free radicals increase. Finding actives that reduce the decline in complex II activity will help to slow the signs of ageing.

There's a certain irony that a Newcastle uni professor is studying sunburn. We barely see the thing!

Anyway, what's your thoughts on Newcastle Science central development on the old brewery, do you think more scientific companies will set up shop up here?

I study sun damage/protection – not sunburn! …and the sun does shine here sometimes!! It’s an exciting opportunity but the key for me is attracting a critical mass of companies that will boost the local economy and also attract larger companies to the region. The North East has a lot to offer as we have a historical record of being innovative.

I study sun damage/protection – not sunburn! …and the sun does shine here sometimes!! It’s an exciting opportunity but the key for me is attracting a critical mass of companies that will boost the local economy and also attract larger companies to the region. The North East has a lot to offer as we have a historical record of being innovative.

I’ve heard that the SPF of many sun creams is actually only about half of the SPF given on the label – is this right? So if I’d normally choose a factor 15, should I be choosing 30?

Despite small fluctuations, the SPF labelled on the bottle is pretty good. The biggest problem is that people don’t put enough on. At best they put on half the thickness – it should be a teaspoon per limb!

What should I look for when picking a sun cream? I'm fairly dark skinned and tan easily

Guessing from your username, you’re looking to get a tan. Have you tried fake tans? In terms of protecting your skin, you’d be wanting an SPF of at least 30, because almost everyone puts on sunscreen to half of the recommended thickness at best, which means you’re only getting an equivalent of about SPF 15 (a ballpark figure, as the relationship is not linear).

For clarification, is this the same "complex II" as the one in the electron transport chain? At which stage of gene expression is faulty in the elderly and how does it become faulty?

We’re looking at young first before smooth this is because Complex II is key in keeping the batteries of our skin topped up and providing sufficient bioenergy to slow down the effects of ageing on our skin. The downstream effect of this is that healthy skin with lots of bioenergy will help to reduce fine lines and wrinkles but as we know this is a long process. Complex II is part of the respiratory chain of mitochondria which provides ATP for all cells including skin. As we age, our bioenergy decreases and free radicals increase. Finding actives that reduce the decline in complex II activity will help to slow the signs of ageing.

For clarification, is this the same "complex II" as the one in the electron transport chain? At which stage of gene expression is faulty in the elderly and how does it become faulty?

Yes it is, succinate ubiquinone oxidoreductase.The decline in complex II was found from 7 years to 77 and so it is not just happening in old skin.

What's the best way to treat skin after I've got burnt to minimise damage?

It would obviously be better not to burn in the first place, however it can happen quite easily even on a cloudy summer day. Skin redness is an increase of blood flow to the burnt area, and is part of defence approach that the skin uses. Tanning is also part of this SOS response. Therefore, the damage has already occurred and most people use cooling balms to help reduce the heat.

Congratulations on your discovery!

As a research assistant in the field of Gerontechnology, I'm particularly interested to know if during your research you found any specific patterns involving the enzyme as people age. Perhaps there was an average cutoff point, or unexpected results?

Thank you! We found that Complex II activity declines only in the lower layer of the skin with age. This is the part that is responsible for skin ageing. We noticed that the decline with age was approximately linear over the range studied (7 to 80 years).

How do you combat high UV during summer without using sunscreen as they make you sweat so much?

Depends on what you’re doing outside (sport, chatting with friends). If you’re chatting with friends, the best form of sun protection is a tree (shade )! Of course, wearing a broad-brimmed hat is good, or if you’re out at a social event remember you can always wear a shirt with a collar and turn your back to sun, which protects your face from getting burned. Think about next time you’re going to a concert or sporting event at a stadium and consider whether you’re going to be looking at sun.

how long does sunscreen last - how often should I be reapplying it? how long does it keep in the bottle or does it go off?

If you keep it out of direct of sunlight, sunscreen will certainly work effectively up to the use by date. If you are using a one-day application sunscreen, then be really sure that you’ve not missed any areas. If not, reapplying every 2 hours is always helpful to ensure you’ve not missed any areas, particularly if you are doing vigorous weeding in the garden.

What is the correlation between uv exposure ( tanning, sunburns etc.) and cancer occurrence? Basically how much do sunburns increase the risk of skin cancer on average ? ( I assume there are many variables involved but are there any general figures)

Thanks for doing this AMA!

Yes, there are many variables, but one important variable is pattern and dose of UV exposure. In other words, it’s not just how much sun exposure you get, it depends on the pattern or episode of that exposure (for example, getting it all in one setting, or over a period of time). Then, of course, there is genetic predisposition which is an important variable in cutaneous malignant melanoma.

I tan very easily and always wear high SPFs. Every once in a blue moon I get a bad burn where I forgot to apply sunscreen, or didn't apply enough.

Two questions. First, everyone always recommends Aloe. Is there any medical benifit to this besides reducing pain? Second, how much tolerance does our skin have before it becomes damaged and starts to look bad and or become dangerous? A couple bad suntans? Many?

Aloe has been shown to have antioxidant benefits in skin protection against UV. However, skin protection includes both – SPF, as well as antioxidant benefit, therefore Aloe should not be the only ingredient used as we need to have components like titanium dioxide and zinc oxide and chemical sunscreens to form a shield against the harmful UV rays.

Why does my brown skin temporarily darken as a result of sun exposure (even while wearing sunscreen), but return to its original shade as soon as I get home and shower? Is it possible for a tan to be this temporary?

Why does my brown skin temporarily darken as a result of sun exposure (even while wearing sunscreen), but return to its original shade as soon as I get home and shower? Is it possible for a tan to be this temporary?

Always important to protect against skin damage whatever your skin type. Your skin tone darkens following sun exposure due to the increase in melanin (dark pigment), which serves to protect your skin against further damage. Skin darkening is part of the S.O.S. signal to protect your skin.

There are sun screens with coloured tones to suit different skin types. Which one are you using?

Thank you for your reply! I was just surprised that I can come home and the tan fades so quickly. It looks like I need to get better about re-applying sunscreen during the day!

Yes, re-applying is always a good idea, as sunscreen can be removed when drying off after a swim or sporting activity

Also, re-applying helps to get even coverage and to identify any missed areas of sunscreen application.

What is the best SPF? Is there one?

Different countries give different maximum SPFs. Generally, the maximum is around 50, but there are certainly ones with higher SPFs. The important question again is application, because incomplete application of a high SPF (eg50) could give you lower protection than recommended application of an SPF 15. The recommended application is 2 milligrams per cm2.

I have been very seriously thinking of a cosmetic startup, but not knowing where to look, stalled it so far. Now, I am going to take advantage of your AMA. Please excuse me, Kind Sir.

I am thinking of creating a cosmetic that might have some chance at arresting and even reversing UV radiation-induced premature aging.

Can you give me some pointers what chemicals/agents, etc are most promising? Antioxidants?

Where should I start?

Thank you very much.

I'd love to help you and can do so through the University consultancy services email: [email protected]