What wakes me up without my alarm?

How do our bodies digest all the different things inside us? What is a phantom pregnancy? Why do men get middle-age spread? How do I wake up without an alarm clock? When did white skin first evolve? Plus, a message in a bottle...

Eusebius - Give us a call right now if you want to put a question to Chris for the next 30 minutes. Good morning Chris!

Chris - Hey good morning!

Eusebius - I've got a song in my head, and I blame you - in a good way - for this week's story that we're going to start with. What message in a bottle in my head…

Chris - I think that's probably actually what the person who found this extraordinary thing was also humming away afterwards! This story is truly amazing. So there's a lady and a husband who are from Western Australia and they were driving around along the coast in a remote part of Western Australia and their car got bogged in the sand. So while they were digging it out some of the people who were with them went off for a walk and sticking out of a sand dune on this remote beach was this bottle.

So this lady said, “Well it looks like a nice piece I could put on my mantelpiece when I get back home!” So she took this bottle away because it looked kind of authentic and nice; it wasn't just your average bottle of wine or something. And when they go back to the car one of the other members of the party there got the sand out of the bottle and then they realised there was this thin strip of paper inside.

They got this thin sort of cigarette-sized piece of paper from the bottle out and it was tied up with string. So they delicately unrolled it and dried it out in the oven and read it and they thought it was a hoax because it was a message from the late eighteen hundreds from a German ship apparently! It was put into the water somewhere in the world and for 130-something years had not been seen.

Now the data which is on this piece of paper enabled them - because the writing was still legible - to then go to the German consulate - because it was from a German ship - and look up the original logs for the ship. It was from a ship called “Paula”. It sailed from Cardiff and it was heading for Indonesia.

The Germans had a project for a number of years putting thousands of these messages in bottles overboard; it's sort of the more ancient equivalent really of what people are doing with those rubber ducks that accidentally went overboard a few years ago. They were using this to track where these things went. There were instructions on this piece of paper how to contact your German consulate to tell them you'd found this.

No one had found one of these since the 1930s. So this is the oldest - world record-breaking - Message In A Bottle ever found, and the fact is it was in the water for probably a period of time but then got washed up on this beach and probably buried in the sand was why it was saved. Because it's been in the sand for a very long time, and although the cork had slowly been eroded away by the sand, the actual note inside had remained viable and readable. They've actually put it on display at the Western Australia Museum - bit of a trek to go and see it - but what a wonderful story all the same; Stunning; absolutely stunning!

Eusebius – Caleb, Good morning!

Caleb - How are you?

Eusebius – We’re extremely well; what is your question for the Naked Scientist?

Caleb - You want to know how do our bodies digest the different foods?

Eusebius - What a lovely question. Back to School Chris!

Chris - Hello Caleb. You're quite right, it's not an appetising thought when you consider all those delicious things, which tasted so nice on their own all mixing round down in your stomach and then somehow being processed. But that's basically what happens you swallow things: having munched them up with your teeth and broken them into a pulp, they then meet your stomach acid, which is very concentrated hydrochloric acid, and an enzyme secreted in the stomach called "pepsin" which works in this very acidic pH. This helps to dismantle the proteins and some of the other chemicals in the food because the acid attacks the food, the pepsin attacks the food and then the stomach also has a lot of muscle in its wall so the stomach slowly moves the food around a bit like a cement mixer really to encourage mixing between these initial digestive juices and the enzymes. Then the stomach squirts out small doses of this runny stuff, which is the mixture of everything, into your small intestines.

The first part of your small intestine is the duodenum; that then gives rise to the jejunum, and then to the ileum. The small intestine has a very high surface area. The inside of the intestine is thrown into all these folds, which are then covered in more tiny folds called "villi". And this means there's a huge area for absorption. On the surface of the intestine are more enzymes that can break down individual components of the food - more proteins and sugars - and you also add to the food pancreatic juice and bile from the liver. The pancreatic juice has got more enzymes in it that can break down all the different components of food, and the bile from the liver emulsifies fats. So instead of the fats forming large droplets, these components of bile bind to the fat, break it up into very tiny droplets and then the lipases that eat fat break them down. They can attack these particles of fat and turn them into fatty acids. All these constituents slowly make their way to the wall of the bowl and are soaked up into the blood stream and the blood stream then sends the goodies to what's called your portal vein, which delivers them to your liver.

The liver gets the first look at anything you eat, and that's important because your liver is one of your biggest organs and it's very important for detoxifying things; because you don't want some toxins and some of the things that you eat going straight into your blood supply, because it could actually upset the biochemistry of other parts of the body. So the liver deals with any of those toxins and also extracts some of the things like a lot of the sugar that comes through. And anyone partial to a glass of shiraz with their lunch: it deals with quite a lot of the alcohol in there straight away too;

Then, anything that's left over ends up in your large intestine. And really that's there just to dry things out because everything is very very runny: litres and litres of digestive juices wash around in a small intestine. Having been added to your body from outside and then secreted into the small intestine, you don't want that leaving your body because you'd be dehydrated very quickly. So the large bowel is there to dry things out for you. 

And the other thing that we must mention is you also have more bacteria living in your intestines than there are cells in the rest of your body and they are like an extra organ in and of itself. These bacteria add their biochemistry and their metabolism on top of yours and they help you to extract more calories and more nutrients from the foods than you would otherwise be able to, including making some vitamins for you that you couldn't make with your own body. And you then absorb those additional nutrients and you feed your bacterial passengers to keep them happy at the same time. So a happy microbiome is a happy person!

Eusebius - Even before we take our first break, Bochocko, you've got a question we haven't stumped Chris in weeks go for it.

B - Chris, a question - I'm pregnant and during my third trimester I've found out that my husband was the one who was experiencing the pregnancy symptoms! That's how I found out I was pregnant. So the question would be why would he be the one experiencing all the nausea vomiting or the stuff? 

Chris - Yeah well the answer is do you believe him, for a start? He might just be taking advantage knowing that you're going to get a lot of attention downstream, so it's his turn at the moment may make it that's part of!

I have seen one patient who had the same thing. He came in to an A and E department I was working in, about ten fifteen years ago, and he had also all the same marks on his abdomen - I think he'd just been overindulging though, but he did say he had some of these symptoms that his wife had been experiencing while she was pregnant. We don't know much about this, but there is evidence that a male's behaviour changes and his biochemistry changes his hormone profile changes when his wife is pregnant also once she has had children. So a man who becomes a father often has quite different behaviour. There's an evolutionary advantage to this, because you want to be nurturing and protective towards your offspring to make sure they're okay. Now a nurturing, protective individual isn't necessarily the same individual who is really good at fighting for a mate in the first place, so that there is something - some signals and some behavioural shift that happens in males - not just humans but many species - when they become a parent. We don't know what those signals are but we do know that there are lots of chemicals which are secreted from our bodies into the air around us all the time, and some of these do have effects on other people and women can influence the behaviour of other women. There's evidence that this can happen through some kind of pheromones. Again, this is poorly understood but it has been documented - range of studies showing this - there's no reason why it couldn't have a similar effect on the husband. So maybe you are oozing something out which is getting into the air and, with close personal contact, your exposing him to some signals and this is having a subtle effect on his body. And these are manifesting as some of the symptoms he's describing; but also be careful about attaching significance to coincidence, because it could well be a coincidence and he was going to feel a bit funny anyway and then you say "oh, it must be linked to the fact that I'm pregnant! Must be!". But in fact it's just a coincidence; so be skeptical. But there's a kernel of truth there, possibly, as well. We do see this sort of thing... 

Seth - Good morning Chris. Chris, I'm trying to understand why it is that men - as they approach middle age, going to early old age - they get something called "middle age spread" but some men don't get middle age spread. What exactly is middle age spread, and what causes it? 

Chris - Do you have this?

Seth - My middle age spread started when I was four years old, and early-onset dementia!

Chris - Just wondering if you had a sort of conflict of interest in the question at all? No I'm just kidding! The answer is there's probably a range of factors; we're not going to be able to give one reason for these things because there's a common end point, which is people putting on weight but I don't think you can say that in every case. There is one cause - the commonest reason people gain mass is because they eat too much. And this means that there's more calories coming in to your body than there are calories that actually are being expended by your body, either by staying warm for exercise other activities growing and so on. So if there's an imbalance you will slowly accumulate mass. Now the way we store energy in the body is we convert any excess calories into fat, because it's the most energy-dense way to store calories and the fat is not evenly distributed around the body: it gets preferentially deposited in certain places in the body under the skin, but especially around your viscera - your internal organs in your abdomen - which is what causes a beer gut.

Now why this happens as we get older is probably for a range of reasons as I say, but one of them is that people eat too much. As we get older, we tend to become less active because we get more responsibilities in life, we get more to do so we feel more tired because, by doing more, we're getting tired. And so we don't tend to take as much exercise, and if you don't take as much exercise you then lose your lean tissue, which is what's capable of burning calories. So it becomes a vicious cycle. And this tends to make things really accelerate: because you take less exercise, you've got less lean tissue to burn calories; you're burning fewer calories, so your storing more calories. Because you get a bit fat, you don't feel like doing as much exercise, and you're also busy and a bit tired, but you still carry on eating the same because you've got into the habit of doing that and it builds up and builds up and then, before long, you end up thinking "yes, I've got a bit of a paunch and I really don't know what to do about it!" But then it's really hard to lose excess weight, because you have to do so much exercise just to burn off the energy in an apple, that people just give up and they get very demoralised. On top of that, there are other factors like as you get older your hormone levels change. So testosterone levels change; your level of aggression and excitability changes, and therefore you're burning fewer calories for that reason and biochemically your metabolism is a bit slower so you're burning fewer calories. For that reason, and also you may get other diseases, like diabetes, which again have a metabolic impact. So all these things probably come together and contribute to us gaining weight as we get older. And if you're not careful to offset the effects then it can become a runaway process and make people develop a middle aged spread. The best thing to do is to not let it happen in the first place by being very diligent about eating the right amount, eating the right things and staying active. Can't emphasize enough how beneficial exercise - even modest exercise - is. Take the stairs instead of a lift. You burn off the equivalent of a biscuit going up a few flights of stairs; and if you do that several times a day you've saved on a gym subscription but you've actually benefitted your health and your blood pressure profile enormously!

Eusebius - Brenda, good morning. What is your question.

Chris - good morning!

Brenda - Tell me, is a substitute for soap linament - and they used to use in the war - glycerin water and soap linament -  for cracks and things cause but cold and they said yes but you could work in the garden if you put that on your hand.

Chris - so you're suggesting this is a good alternative to a just normal hand soap?

Brenda - Yes, hand cream doesn't work as well as that.

Chris - Yeah. One of the reasons why, when you damage your skin, it becomes very dry is because you lose layers of skin. You open up cracks in the skin, and then the skin becomes a bit inflamed, and the inflammation is a sort of dermatitis actually causes the skin to become sore because you've got the immune system moving in to try to encourage the skin to repair itself and it becomes a vicious cycle cause cracks in the skin let dirt and other muck in, which makes it more inflamed, which makes it more likely to break down in crack in future. So things which are emollients - things which can encourage the skin to absorb water and to exclude things getting in through these cracks - tend to help the process to recover. And there's no reason why your approach wouldn't work. If it works for you, there's nothing nasty in there - keep using it! But current soaps are very alkaline and they're made by a process called saponification. You take alkaline substances, like sodium hydroxide, you mix it with fat or fatty acids and you get soap, and they're very alkaline, which means they do tend to dry skin out horribly. And if you keep using soap relentlessly again and again and again you can actually end up breaking down your skin because you know the alkaline material in the soap penetrates the skin and damages the cells in the top layers of skin and it makes it sore and cracked and very dry. So if your approach works for you and it doesn't have such an alkaline P.H. probably a good idea.

Eusebius - Let's take one from social media. There's an interesting question here from someone who says "please please please ask Chris the following: I forgot to set my alarm clock, but I woke up exactly at 5:00 o'clock this morning nevertheless, which is the time that I needed to wake up. Who woke me up? And it's not the first time!"

Chris - No. Well what woke him up is his body clock. And in your brain you have a "suprachiasmatic nucleus", which is a cluster of 20-30,000 brain cells that sit just above where the optic nerves which flow underneath the brain from the eyes; it's literally in the middle at the base of your brain. And this cluster of nerve cells set your biological rhythm. They get you out of bed in the morning; they send you to bed at night, because what they're doing is running a genetic "domino effect" where a gene turns on; this turns on a second gene, which turns on a third gene, which feeds back and turns off the first gene; and this "ticks" genetically through a 24 hour cycle taking just a bit more than 24 hours to complete this genetic cycle. And as these different genes are turned on and off, the activity in those nerve cells is changing and the changing activity in the nerve cells is then used to change how the brain responds and also to secrete a very important hormone, called cortisol, out of your pituitary gland into your bloodstream. The effect of this is to tell every cell in your body what time it is, because every cell in your body -  within reason - is also running a time clock which is a slave to this master clock in your brain. And this means that your body can pre-empt the demands of the day ahead and change your metabolism so that the minute the alarm clock goes off, you're already revved up and at full capacity ready to meet the metabolic demands of the day. That's very important, because if you were to get out of bed feeling very sluggish and wait for your metabolism to build up and give you energy it would be lunchtime before you actually really got over that sluggish "I've just got out of bed" feeling. Imagine the worst jetlag you've ever had. That's how you would feel every morning; but your body gets into a rhythm - a pattern - of setting your metabolism based on your habitual behaviour and therefore it's ready to meet the demands of the day. And this includes getting ready to receive your breakfast, because your metabolism to absorb and process calories is already turned on by that time; your muscles are ready to start delivering movements, and your brain is ready to start processing thoughts. By the end of the day, because you get used to going to bed at a certain time,  the hormone cycles have already been reprogrammed and are winding down so you're feeling sleepy to go into bed and go to sleep at the right time so you don't go to bed with your metabolism thundering along preparing you to run a race and fight a fight that you don't need to. And that's why, even though the alarm clock doesn't go off, because all these hormone changes are kicking in and altering your behaviour well ahead of you needing to wake up, you still wake up anyway. Its a human habit!

Eusebius - Etienne - what is your question?

Etienne - I took my boys to Maropeng, and we've being doing some research, and it looks like modern science all concurs that we Homosapiens evolved around about 200-250,000 years ago in Africa.  But our ancestors were all black - so all Chinese; all Indians; all whites - we all have the same black ancestors. When did we become white? How did this happen? We led the change coming in?

Chris - Well actually it's more subtle than that because - in fact - once upon a time our ancient ancient ancestors were all white skinned and that's because they had hair; I had this interesting conversation - because, when I was in South Africa in Grahamstown at Scifest in the late "noughties" I was there with a lady called Nina Jablonski, who works at Penn State University in America; and her studies over her lifetime, her career, have been looking at human migration and human origins and skin colour; and our ancient ancestors. We shared a common ancestor with what are now chimpanzees and bonobos, probably about 6 million years ago. Now those ancient ancestors had hair like chimps do; and because they had dark hair they didn't need to put protective melanin into their skin, because the melanin is in skin to protect us from the effects of the sun. And if there's hair there, the hair soaks up the sun and it protects the underlying skin. So actually once we evolve down the Homo lineage - or actually earlier than that once we evolved down the hominid lineage - actually the first things we had to do was to start to darken our skin, because as we became less hairy then we didn't have the protection afforded by body hair from the sun; so the skin had to evolve to take on that job more and skin became darker. So the first thing we did was to evolve to become dark skinned as we became hair free. And then, as people exited from Africa, because we know that - as far as we can tell - all the lines of evidence point to Africa being the "Garden of Eden" if you like - it's where the earliest ancestors came from - they then had an exodus and populated the rest of the world with anatomically modern humans, 50-60,000 years ago. It may be that they actually left much earlier than that, and we know there were other forms of Homo who were going out before that, but they then populated the rest of the world. But the climes that they encountered, and the environments they encountered, in the rest of the world were quite different than the challenges posed in Africa. Because, in Africa, obviously in many places it's extremely hot - very sunny - and if you have extremely profound sun exposure on your skin, sunlight breaks down folic acid. Now we've heard from a few people who are pregnant on the programme at the moment. And people who are trying to get pregnant, or are pregnant, are encouraged to take folate supplements. Folic acid is very important for the developing nervous system to form correctly, so if you dont have enough folic acid in your body you can't make rapidly-dividing cells divide properly, and you are more prone to getting conditions like spinal bifida and neural tube defects. That's why pregnant women are advised "make sure you take folic acid supplements." So people evolved to be dark skinned not because of the risk of skin cancer - because they probably didn't live long enough to get that - but to defend themselves from problems with folic acid. Then, when they moved out of Africa and went to less sunny places, they didn't need that defense so much. But then they had another problem, which is that you make in your skin vitamin D, which you absolutely need to absorb calcium to have a strong skeleton. If you have too much melanin in your skin, you can't get enough ultraviolet into your skin to make vitamin D. So therefore people evolved to become whiter skinned in order to combat the fact that they were vitamin D deficient and calcium deficient and they then didn't have as much of a problem with the folic acid anymore. So it's a really interesting story of evolution that we went from white to dark to defend ourselves against the sun and then from black back to white in certain environments in order to make sure we didn't get weak bones!

Eusebius -Thank you Chris we'll do it again next week. Have a lovely seven days ahead of you!