0:00:05 > 0:00:10We're constantly being told how to live our lives.
0:00:10 > 0:00:13But what's the health advice you can really trust?
0:00:17 > 0:00:21In this series, we use our expertise to guide you...
0:00:22 > 0:00:26..through the contradictions and the confusions.
0:00:32 > 0:00:35We'll get to the heart of the debate...
0:00:36 > 0:00:39..and ensure you get the information you need.
0:00:46 > 0:00:49We're here when you don't know where to turn.
0:00:52 > 0:00:53I'm Michael Mosley.
0:00:53 > 0:00:56In this series, I'm joined by a team of doctors.
0:00:58 > 0:01:03Together, we'll cut through the hype, the headlines and the health claims.
0:01:03 > 0:01:05This is Trust Me, I'm A Doctor.
0:01:11 > 0:01:14This time, we're going to test some brand-new science.
0:01:14 > 0:01:18Can we lose weight without changing what we eat?
0:01:18 > 0:01:20We actually don't know what's going to happen.
0:01:20 > 0:01:25Alcohol - the new guidelines are out, but what is a safe level?
0:01:26 > 0:01:29We find out why diet foods could be making you fat.
0:01:29 > 0:01:32- It's a shocking result. - It really, really is shocking.
0:01:32 > 0:01:38Which is healthier - microwaving or stove cooking?
0:01:38 > 0:01:41And why cleaning your house could be bad for your health.
0:01:41 > 0:01:43I think I'll be moving out!
0:01:43 > 0:01:44THEY CHUCKLE
0:01:45 > 0:01:47Welcome to Guildford.
0:01:47 > 0:01:49We're here to do an experiment
0:01:49 > 0:01:53to see if you can get healthier, perhaps lose a bit of weight,
0:01:53 > 0:01:57not by changing what you eat, but when you eat.
0:01:57 > 0:01:58But first...
0:01:58 > 0:02:03over to surgeon Gabriel Weston, who has a very surprising proposition.
0:02:05 > 0:02:10Diet products promise all the sweetness with none of the sugar -
0:02:10 > 0:02:12a win-win situation for those of us
0:02:12 > 0:02:15with a passion for the sweeter things in life.
0:02:15 > 0:02:21But could low-calorie food and drink actually be making us fatter
0:02:21 > 0:02:24and increasing our risk of diabetes?
0:02:24 > 0:02:27Come January, after the festive excesses,
0:02:27 > 0:02:30many of us seek out low-sugar products.
0:02:30 > 0:02:34But all of these contain artificial sweeteners instead,
0:02:34 > 0:02:37and there's the potential problem.
0:02:37 > 0:02:41There's some new research that suggests that artificial sweeteners
0:02:41 > 0:02:43could be making us less healthy
0:02:43 > 0:02:46by interfering with the way that our bodies process sugar.
0:02:46 > 0:02:49So we want to put them to the test.
0:02:49 > 0:02:52Are sweeteners actually bad for us?
0:02:54 > 0:02:57To find out, we're going to give this group of volunteers
0:02:57 > 0:03:00artificial sweeteners for one week.
0:03:01 > 0:03:05Before they begin, we're measuring their blood sugar levels.
0:03:05 > 0:03:08We'll do the same at the end to see if there's a change.
0:03:08 > 0:03:12High blood sugar can cause health problems like diabetes -
0:03:12 > 0:03:15and many people take sweeteners instead of sugar
0:03:15 > 0:03:17to try and avoid these,
0:03:17 > 0:03:22as Dr James Brown of Aston University explains.
0:03:22 > 0:03:24A high blood sugar level can be quite dangerous -
0:03:24 > 0:03:27it can cause damage to tissues in the body, like the eye,
0:03:27 > 0:03:29like the kidney, like blood vessels,
0:03:29 > 0:03:30and this is why it's really important
0:03:30 > 0:03:34that the body maintains blood sugar levels in a very narrow band.
0:03:34 > 0:03:37So where do the artificial sweeteners fit into this?
0:03:37 > 0:03:39Artificial sweeteners are interesting,
0:03:39 > 0:03:41because people tend to consume them instead of sugar
0:03:41 > 0:03:45in the belief that they won't cause an increase
0:03:45 > 0:03:47in their blood sugar levels.
0:03:47 > 0:03:49I would imagine that people take artificial sweeteners
0:03:49 > 0:03:51almost thinking that having an artificial sweetener
0:03:51 > 0:03:53is like not having anything at all.
0:03:53 > 0:03:55I think that's the general consensus,
0:03:55 > 0:03:57is that it's a replacement for sugar which is inert -
0:03:57 > 0:03:59it doesn't do anything to the body.
0:04:00 > 0:04:02But is that the case?
0:04:02 > 0:04:05Our volunteers don't normally take sweeteners,
0:04:05 > 0:04:07so our tests over the next week
0:04:07 > 0:04:12will show whether these substances affect their blood sugar levels.
0:04:12 > 0:04:15There are several artificial sweeteners on the market,
0:04:15 > 0:04:19and we're going to test two very different ones.
0:04:19 > 0:04:2350% of our volunteers will get this, benzoic sulfimide,
0:04:23 > 0:04:26known on the street as saccharin.
0:04:26 > 0:04:31Now, we've been using this as a sugar substitute for over 100 years.
0:04:32 > 0:04:37Saccharin is, like most artificial sweeteners, a synthetic chemical
0:04:37 > 0:04:41that tastes sweet but is supposed not to have the downsides of sugar.
0:04:42 > 0:04:45We're going to test this granddaddy of all sweeteners
0:04:45 > 0:04:49against the new kid on the block, stevia.
0:04:49 > 0:04:54Stevia prides itself on being derived from natural sources -
0:04:54 > 0:04:58but the question is, will either of these sweeteners affect
0:04:58 > 0:05:01our volunteers' response to sugar?
0:05:03 > 0:05:07Over the next week, our volunteers are taking the daily
0:05:07 > 0:05:10safe limit of either saccharin or stevia.
0:05:10 > 0:05:13And we're testing their blood sugar levels
0:05:13 > 0:05:15to see whether there's any change.
0:05:16 > 0:05:18This is the saccharin group.
0:05:18 > 0:05:23And James has been taken aback by what saccharin has done to them.
0:05:24 > 0:05:27Now, what we saw when we looked at the data from the saccharin group
0:05:27 > 0:05:29was that after one week of taking saccharin,
0:05:29 > 0:05:32their blood sugar had increased from a healthy level
0:05:32 > 0:05:35to a level that suggests a risk of developing diabetes.
0:05:35 > 0:05:40Wow! Now, that's not what I would have expected.
0:05:40 > 0:05:45And that seems really, really scary, because people take sweeteners
0:05:45 > 0:05:48because they think it's the healthy option.
0:05:48 > 0:05:51The interesting thing is, numbers three, four, five and six
0:05:51 > 0:05:54had a marked response to taking saccharin.
0:05:54 > 0:05:57Their blood sugar really did increase.
0:05:57 > 0:06:00The other individuals didn't see the same responses.
0:06:00 > 0:06:03- It's a shocking result.- Really. It really, really is shocking.
0:06:05 > 0:06:09So whilst the group as a whole suffered raised blood sugar levels,
0:06:09 > 0:06:15for four individuals, saccharin had a particularly bad effect.
0:06:15 > 0:06:16Moving on to stevia,
0:06:16 > 0:06:19we see a very different picture.
0:06:19 > 0:06:22The effects of natural plant extract stevia
0:06:22 > 0:06:25have never been studied like this before.
0:06:26 > 0:06:29The individuals who took stevia for a week
0:06:29 > 0:06:31didn't see any real change in their blood sugar levels.
0:06:31 > 0:06:35- Nothing at all?- Nothing which was marked or noticeable.
0:06:35 > 0:06:39So for the first time, we seem to be demonstrating
0:06:39 > 0:06:42a dramatic difference between these two sweeteners.
0:06:42 > 0:06:46While stevia didn't affect any of our volunteers badly,
0:06:46 > 0:06:50saccharin sent some people's blood sugar skyrocketing.
0:06:50 > 0:06:53So why might this be?
0:06:54 > 0:06:59Well, it seems the answer might lie inside our own bodies.
0:06:59 > 0:07:03One theory as to why sweeteners might change our response to sugar
0:07:03 > 0:07:05is that they alter our gut bacteria.
0:07:06 > 0:07:09So we did some more tests on our volunteers
0:07:09 > 0:07:14to see if their gut bacteria changed over the week they took sweeteners.
0:07:16 > 0:07:18Joining us with the results
0:07:18 > 0:07:21is Dr Paul Cotter from the Teagasc Food Research Centre
0:07:21 > 0:07:23in Cork, Ireland.
0:07:23 > 0:07:26He's found distinct changes in the gut bacteria
0:07:26 > 0:07:29of all the volunteers taking saccharin.
0:07:29 > 0:07:32And there was a noticeable pattern in the four individuals
0:07:32 > 0:07:35who had the biggest rise in blood sugar.
0:07:38 > 0:07:40Very surprisingly, when we looked at the gut microbiota
0:07:40 > 0:07:43of these individuals, it was very much similar to one another,
0:07:43 > 0:07:47and following the treatment with the saccharin, they also seemed
0:07:47 > 0:07:50to undergo a particularly dramatic change during that period of time.
0:07:50 > 0:07:52- And were you surprised by that? - Um...
0:07:52 > 0:07:55usually it's quite difficult to change microbial population -
0:07:55 > 0:07:57it takes quite an amount of time -
0:07:57 > 0:08:00and so to see changes over a short period is quite unusual.
0:08:00 > 0:08:03It suggests there's a significant proportion of the population
0:08:03 > 0:08:05who may be at risk of harm,
0:08:05 > 0:08:08making themselves less well by consuming these sweeteners.
0:08:08 > 0:08:11So there's a group out there that really is vulnerable
0:08:11 > 0:08:14- to the ill effects of taking sweeteners?- Absolutely.
0:08:14 > 0:08:17And without checking out, for example, their gut microbiome,
0:08:17 > 0:08:19it's very difficult to tell who those people are.
0:08:21 > 0:08:24Our results, then, backed up by another recent study,
0:08:24 > 0:08:29suggest that about half of us can be badly affected by saccharin,
0:08:29 > 0:08:33found in many popular sweeteners, diet drinks and foods.
0:08:33 > 0:08:34So we should all be aware.
0:08:36 > 0:08:41The evidence is mounting that for some, saccharin is a bad thing.
0:08:41 > 0:08:44It can significantly alter your gut bacteria
0:08:44 > 0:08:47and increase your risk of developing diabetes -
0:08:47 > 0:08:50the exact opposite of what you might think.
0:08:50 > 0:08:54And it looks like other sweeteners like aspartame could be the same.
0:08:56 > 0:08:58We don't know why these chemicals have this effect
0:08:58 > 0:09:01but in our small study, it seems if you are looking
0:09:01 > 0:09:06for an alternative to sugar, stevia may be a safer option.
0:09:16 > 0:09:20Back in Surrey, we're setting up another brand-new experiment.
0:09:21 > 0:09:23Most of us would like to eat more healthily,
0:09:23 > 0:09:26but we find it difficult to change.
0:09:26 > 0:09:29So Dr Chris van Tulleken has been testing, for the first time,
0:09:29 > 0:09:33a novel approach which involves altering not what you eat,
0:09:33 > 0:09:35but when you eat.
0:09:39 > 0:09:40Thank you.
0:09:40 > 0:09:43Like most people, I'd like to eat healthier, but unfortunately,
0:09:43 > 0:09:47I can't stop eating the food that I love, which isn't that healthy.
0:09:47 > 0:09:48Things like cheeseburgers.
0:09:48 > 0:09:51So I want to try out a new theory - one that will allow me to eat
0:09:51 > 0:09:55as many cheeseburgers as I want and still get healthier.
0:10:00 > 0:10:03These days, we tend to eat throughout the day, snacking right
0:10:03 > 0:10:07up until bedtime and giving our body a break only when we're asleep.
0:10:09 > 0:10:12But scientific research suggests that giving ourselves
0:10:12 > 0:10:15longer periods without eating could be very good for us.
0:10:17 > 0:10:22So could simply packing our mealtimes together and, as a result,
0:10:22 > 0:10:25lengthening the periods of time when we're not eating
0:10:25 > 0:10:26really make us healthier?
0:10:28 > 0:10:31To find out, we've recruited 16 volunteers
0:10:31 > 0:10:34for a ground-breaking experiment.
0:10:34 > 0:10:37They're going to take part in our unique ten-week study
0:10:37 > 0:10:39here at the University of Surrey.
0:10:41 > 0:10:42Service, please.
0:10:42 > 0:10:46- And they're about to find out what's involved.- Whoo!- Look at that!
0:10:46 > 0:10:48LAUGHTER AND CHATTER
0:10:48 > 0:10:49Right, good morning, everyone.
0:10:49 > 0:10:51Thank you for coming in. Now, I know it's early,
0:10:51 > 0:10:56so we have done the right thing and we've got you all a bacon sandwich.
0:10:56 > 0:10:58But you guys haven't got yours yet.
0:10:58 > 0:11:01And that represents what we're doing over the next ten weeks.
0:11:01 > 0:11:03Because you guys are a control group.
0:11:03 > 0:11:05You are going to keep living your lives as normal,
0:11:05 > 0:11:08eating what you like to eat at the times you want to eat it.
0:11:08 > 0:11:10You guys are going to start your breakfast
0:11:10 > 0:11:13an hour and a half later every day.
0:11:13 > 0:11:17So you've still got about an hour and 28 minutes before
0:11:17 > 0:11:19- your bacon sandwich arrives. - LAUGHTER
0:11:19 > 0:11:23And you're going to move dinner an hour and a half earlier,
0:11:23 > 0:11:25so you're going to crunch your meals together.
0:11:25 > 0:11:28And that means you're going to have three extra hours each day
0:11:28 > 0:11:29where you're not eating.
0:11:29 > 0:11:32You're looking really unhappy.
0:11:32 > 0:11:34It's a form of really advanced torture, isn't it?
0:11:34 > 0:11:37Being made to watch someone else eat a bacon sandwich.
0:11:37 > 0:11:39- It's the smell.- Yeah, the smell.
0:11:39 > 0:11:42- How are the bacon sandwiches? - Brilliant.- Very good.- Very nice.
0:11:46 > 0:11:49So, for the next ten weeks, the blue group can carry on having
0:11:49 > 0:11:52an early breakfast and eat as late at night as they like.
0:11:53 > 0:11:57But the red group will have a late breakfast and early dinner,
0:11:57 > 0:12:01so they have a much longer period when they're having no food at all.
0:12:01 > 0:12:04But it does mean no late-night nibbles.
0:12:04 > 0:12:07No midnight snacks, no late-night doughnuts,
0:12:07 > 0:12:11no bowls of cereal before bed, no wine, no beer, no calories.
0:12:11 > 0:12:13LAUGHTER
0:12:13 > 0:12:17But on the plus side, we're saying you can eat whatever you want!
0:12:17 > 0:12:20I find it hard that it's going to make much difference, really.
0:12:20 > 0:12:22Yeah, I'll be really interested to see if it works.
0:12:24 > 0:12:27Moving mealtimes seems like a small change.
0:12:27 > 0:12:29Could it really make much of a difference
0:12:29 > 0:12:31to the health of our red team?
0:12:32 > 0:12:35Leading the research is Dr Jon Johnston
0:12:35 > 0:12:37from the University of Surrey.
0:12:38 > 0:12:41We're not asking people to change what they eat.
0:12:41 > 0:12:44We're just saying, "Change the times that you eat"?
0:12:44 > 0:12:47Exactly, it's just the time that counts in this case.
0:12:47 > 0:12:50So I'm going to be honest - that sounds a bit unlikely to work.
0:12:50 > 0:12:52I can see why you're saying that, but actually,
0:12:52 > 0:12:55there's some really very good data now from studies in mice,
0:12:55 > 0:12:57and even in flies, to suggest that
0:12:57 > 0:13:01if you simply restrict the timing at which an individual eats,
0:13:01 > 0:13:04that actually has beneficial effects for their metabolism.
0:13:04 > 0:13:08- You do realise that people are not fruit flies or even mice?- Well, yes.
0:13:08 > 0:13:10Their metabolism is different. Er,
0:13:10 > 0:13:13there are different social contexts, of course, for eating,
0:13:13 > 0:13:15but what we're trying to do here is actually to find out,
0:13:15 > 0:13:19"Can we translate the basic data from animals into humans?"
0:13:19 > 0:13:22So, we're not just recreating science that you've already done -
0:13:22 > 0:13:24we actually don't know what's going to happen?
0:13:24 > 0:13:27That's right, we really don't know. We're very excited.
0:13:27 > 0:13:29- OK, that is very exciting. - It is very exciting.
0:13:29 > 0:13:31- DUCKS QUACK - Even they're excited!
0:13:33 > 0:13:36And to see if the health of our volunteers improves when we change
0:13:36 > 0:13:41their mealtimes, we're doing a whole range of baseline tests on them -
0:13:41 > 0:13:44from their levels of body fat...
0:13:44 > 0:13:47to their blood, cholesterol and sugar levels.
0:13:48 > 0:13:49And in ten weeks' time,
0:13:49 > 0:13:53we'll find out whether these measures have improved.
0:13:53 > 0:13:56Could a rule as simple as eating breakfast a little bit later
0:13:56 > 0:14:00and eating dinner a bit earlier really help us all be healthier?
0:14:00 > 0:14:03We'll find out later in the programme.
0:14:03 > 0:14:06But first, over to Dr Saleyha Ahsan.
0:14:16 > 0:14:19Do you choose the fresh scents of citrus or pine
0:14:19 > 0:14:21for your cleaning products?
0:14:21 > 0:14:24Do you use air fresheners or scented plug-ins?
0:14:24 > 0:14:28Well, we've all seen the adverts.
0:14:28 > 0:14:30So here comes the science.
0:14:31 > 0:14:34And it might make you think twice.
0:14:34 > 0:14:37We've uncovered some new research
0:14:37 > 0:14:41that suggests using scented products in our homes could be dangerous.
0:14:41 > 0:14:46They contain chemicals to give them the smells we find so appealing.
0:14:46 > 0:14:52And it seems those chemicals could be doing us no good at all, so...
0:14:52 > 0:14:57I want to find out - how big a problem are they for our health?
0:14:57 > 0:14:58And what can we do about it?
0:15:00 > 0:15:02The first thing we need to know is,
0:15:02 > 0:15:07what exactly does using scented products do to the air in our homes?
0:15:07 > 0:15:10So, over the next week, we're going to measure just that,
0:15:10 > 0:15:13with the help of six families from York,
0:15:13 > 0:15:17Professor Ally Lewis, an atmospheric chemist,
0:15:17 > 0:15:19and some rather scary-looking kit
0:15:19 > 0:15:22that will sample the chemicals in the air.
0:15:22 > 0:15:23- Hello!- Hello!
0:15:23 > 0:15:27'The air from each house will be analysed.
0:15:27 > 0:15:31'When Ally looks at the levels of chemicals in the different houses,
0:15:31 > 0:15:34'he can immediately see differences.
0:15:34 > 0:15:38'Three have moderate levels of chemicals in the air.
0:15:38 > 0:15:40'And their cleaning habits are similar too.'
0:15:43 > 0:15:46We do a deep clean once a week, um, and then, the kitchen
0:15:46 > 0:15:49and the rooms we regularly use probably every day.
0:15:51 > 0:15:57But the Kings and Harrisons are much higher, and we think we know why.
0:15:57 > 0:16:00We do like using scented candles.
0:16:00 > 0:16:03We have them on, er, certainly daily.
0:16:04 > 0:16:08And then came the Bissell family.
0:16:08 > 0:16:13So high that Ally had to adjust the monitor inside their house.
0:16:13 > 0:16:16And it turns out they use a lot of cleaning products.
0:16:17 > 0:16:19I keep wiping round all the cupboards and...
0:16:19 > 0:16:21- Polish the table. - ..polish the table.
0:16:21 > 0:16:24I take the dog out four times a day.
0:16:24 > 0:16:27Then this floor gets washed constantly from mucky feet
0:16:27 > 0:16:29when he comes in from a walk.
0:16:29 > 0:16:32So what exactly are the chemicals
0:16:32 > 0:16:36that these everyday household products are leaving in the air?
0:16:36 > 0:16:38But you can see the stand-out chemicals here are
0:16:38 > 0:16:42- the big orange ones.- Yeah. - This is a chemical called limonene.
0:16:42 > 0:16:44Limonene's got a very distinctive smell.
0:16:44 > 0:16:47You can tell by the name - it's a lemony sort of smell -
0:16:47 > 0:16:51- and it's used very, very widely to perfume things.- Are they dangerous?
0:16:51 > 0:16:55So, in themselves, almost all of these chemicals are perfectly safe.
0:16:55 > 0:16:57However, a lot of these compounds are actually quite reactive
0:16:57 > 0:17:01in the atmosphere, so once you release a compound like limonene,
0:17:01 > 0:17:03it doesn't stay as limonene for ever.
0:17:05 > 0:17:07When it gets into the air,
0:17:07 > 0:17:11limonene reacts to form a chemical called formaldehyde.
0:17:13 > 0:17:18And formaldehyde is toxic and even cancer-causing,
0:17:18 > 0:17:21so not something we want in our houses.
0:17:22 > 0:17:25For every two molecules of limonene we put into a home,
0:17:25 > 0:17:29we form roughly one molecule of formaldehyde as a product.
0:17:29 > 0:17:33We've measured formaldehyde as well in three of our houses and found
0:17:33 > 0:17:38that the more limonene they use, the higher their formaldehyde levels.
0:17:38 > 0:17:42So, do we need to throw out all scented products?
0:17:42 > 0:17:46Well, we found the hint of an alternative solution,
0:17:46 > 0:17:48and it comes from Nasa.
0:17:48 > 0:17:52MUSIC: Also sprach Zarathustra by Richard Strauss
0:17:52 > 0:17:56Faced with the problem of keeping the air inside an enclosed space station
0:17:56 > 0:18:01chemical free, they tested a homely possibility -
0:18:01 > 0:18:02house plants.
0:18:04 > 0:18:08It seems they can absorb chemicals through the pores in their leaves
0:18:08 > 0:18:09and break them down.
0:18:11 > 0:18:13- There we are.- Thank you.
0:18:13 > 0:18:16So we're going to put them to the test here on Earth too.
0:18:17 > 0:18:20- So, we have some plants for you. - Oh, fantastic, some plants.
0:18:20 > 0:18:23'We're giving our six families some house plants
0:18:23 > 0:18:25'to place around their homes.
0:18:25 > 0:18:28'They don't yet know our initial results,
0:18:28 > 0:18:32'so they're still using all their normal household products.
0:18:32 > 0:18:35'And, over a four-week period,
0:18:35 > 0:18:37'we're taking more tests of the levels of limonene
0:18:37 > 0:18:42'and formaldehyde in their homes to see if the plants make a difference.
0:18:45 > 0:18:49'Finally, we welcome all the families to the local pub...'
0:18:49 > 0:18:52So, thank you, everybody, for having our samplers in your home.
0:18:52 > 0:18:54'..to discover the results.
0:18:55 > 0:18:58'First, we share the baseline level of chemicals
0:18:58 > 0:19:01'we found at the start of the experiment.
0:19:01 > 0:19:03'Rather a shock for the Bissells.'
0:19:03 > 0:19:07House four, the Bissells' house, holds a world record with us.
0:19:07 > 0:19:10It's the highest concentration of limonene we have ever recorded.
0:19:10 > 0:19:11I think I'll be moving out!
0:19:11 > 0:19:13- LAUGHTER - I think I might be as well!
0:19:13 > 0:19:15I'm coming to your house!
0:19:15 > 0:19:17'So, what happened to these very high limonene levels
0:19:17 > 0:19:19'when we put the plants in?'
0:19:19 > 0:19:22Well, compared with the start of the experiment,
0:19:22 > 0:19:25it turns out they're actually higher.
0:19:25 > 0:19:28But Ally can guess why.
0:19:28 > 0:19:30There is a small increase in limonene in most homes
0:19:30 > 0:19:33and that's potentially reflecting the fact that we've gone into winter
0:19:33 > 0:19:35and people have begun to seal up their homes -
0:19:35 > 0:19:37they've begun to close windows and doors
0:19:37 > 0:19:39and make their homes more airtight.
0:19:39 > 0:19:44The nights are closing in, so more scented candles being burned
0:19:44 > 0:19:47I suspect is...the reason why it's increased a little bit.
0:19:48 > 0:19:52Just closing windows a bit more, and lighting more candles,
0:19:52 > 0:19:55have made limonene levels rise.
0:19:55 > 0:19:59And this should, in turn, cause a rise in toxic formaldehyde as well.
0:20:00 > 0:20:03But our results show quite the opposite.
0:20:03 > 0:20:06What we do see is that the formaldehyde is lower
0:20:06 > 0:20:10in all the homes after the plants were introduced than before.
0:20:10 > 0:20:14In each of the three houses in which we measured formaldehyde,
0:20:14 > 0:20:18over the course of our experiment, the levels fell.
0:20:19 > 0:20:24It suggests that the plants might really have absorbed formaldehyde.
0:20:25 > 0:20:29The plants must be doing summat, by the look on the graph here.
0:20:29 > 0:20:32It is unusual that the limonene has gone up in lots of homes
0:20:32 > 0:20:34and we haven't seen that increase in formaldehyde,
0:20:34 > 0:20:37so I think it's something worth exploring in the future.
0:20:37 > 0:20:40All our volunteers are now much more aware
0:20:40 > 0:20:43of what they are using in their houses.
0:20:43 > 0:20:45It's opened my eyes because I didn't think nothing of going round
0:20:45 > 0:20:47the house giving it a good pshhh!
0:20:47 > 0:20:50I think I would probably keep the houseplants
0:20:50 > 0:20:53if there's a chance that they might be doing some good.
0:20:53 > 0:20:55Definitely going to keep the plants, yeah.
0:20:59 > 0:21:03This study has really surprised everyone who's been involved in it.
0:21:03 > 0:21:08Just how high our levels of chemical pollution in our houses can be
0:21:08 > 0:21:10and, by our own behaviour,
0:21:10 > 0:21:14a few simple steps can actually bring that down.
0:21:14 > 0:21:18I'm off to buy myself a new houseplant.
0:21:19 > 0:21:23To find out which plants are best at absorbing chemicals,
0:21:23 > 0:21:24go to our website...
0:21:24 > 0:21:28bbc.co.uk/trustme
0:21:28 > 0:21:31And on our website you can also ask us
0:21:31 > 0:21:33any health questions you'd like answered.
0:21:33 > 0:21:36And hundreds of you have done just that,
0:21:36 > 0:21:39and our first question is...
0:21:41 > 0:21:43What's the best way to treat dandruff?
0:21:46 > 0:21:49Half the nation suffers from dandruff.
0:21:49 > 0:21:53OK, so you do have a very small amount - do you see that there?
0:21:53 > 0:21:54OK, yeah.
0:21:54 > 0:21:57And apparently a third have actually avoided going out
0:21:57 > 0:21:59because they're so embarrassed.
0:21:59 > 0:22:02No dandruff that I can see in there.
0:22:02 > 0:22:04So, how can we fix the problem?
0:22:04 > 0:22:07Do you see, just a few little bits?
0:22:07 > 0:22:09How would you react
0:22:09 > 0:22:13if I told you that dandruff was actually caused by a fungus?
0:22:13 > 0:22:16- It sounds like mould, doesn't it? - Yeah, it's gross.- It is, isn't it?
0:22:17 > 0:22:21Dandruff is caused by this fungus, Malassezia globosa,
0:22:21 > 0:22:24and we all have it on our scalps.
0:22:24 > 0:22:27It feeds off sebum, or skin oil,
0:22:27 > 0:22:30and produces a by-product called oleic acid.
0:22:30 > 0:22:34Now, the problem is, this acid can irritate some people's skin.
0:22:34 > 0:22:36And when this happens,
0:22:36 > 0:22:42their immune system responds with a turbocharged skin cell turnover.
0:22:43 > 0:22:47This means that bits of skin flake off your scalp
0:22:47 > 0:22:49far more frequently than they should.
0:22:49 > 0:22:51So, what can we do about this?
0:22:51 > 0:22:55Well, air pollution can make the flaky immune reaction worse,
0:22:55 > 0:22:58so maybe try a hat as protection.
0:22:58 > 0:23:02But take it off when the sun comes out, as it seems a small amount
0:23:02 > 0:23:05of ultraviolet light can tone down that immune response.
0:23:05 > 0:23:08But it dandruff is still turning up in your hair,
0:23:08 > 0:23:12and on your shoulders, how do you get rid of it?
0:23:13 > 0:23:16Now, you might think that the flakiness is due to dryness,
0:23:16 > 0:23:20but because the oil is the food of the dandruff fungus,
0:23:20 > 0:23:22you need to wash your hair regularly -
0:23:22 > 0:23:24at least two or three times a week -
0:23:24 > 0:23:28to get rid of the excess grease and build-up of flakes.
0:23:28 > 0:23:32There are plenty of anti-dandruff shampoos out there,
0:23:32 > 0:23:34but which should you use?
0:23:34 > 0:23:37Well, there are the coal tar shampoos.
0:23:37 > 0:23:41They work by slowing down the renewal of skin cells on the scalp
0:23:41 > 0:23:44and they can be great if you are itchy.
0:23:44 > 0:23:47A word of warning, though - if you're fair, like me,
0:23:47 > 0:23:49it can discolour your hair.
0:23:49 > 0:23:52Then there are those with salicylic acid.
0:23:52 > 0:23:55They basically exfoliate your scalp,
0:23:55 > 0:23:59meaning the flakes end up in the water rather than your shoulder.
0:23:59 > 0:24:02But these won't get to the root of the problem.
0:24:02 > 0:24:05For that, you need an anti-fungal treatment.
0:24:06 > 0:24:08The best anti-dandruff shampoos
0:24:08 > 0:24:11are those that target the fungus directly.
0:24:11 > 0:24:14And the most effective off-the-shelf anti-fungals
0:24:14 > 0:24:17are miconazole and ketoconazole.
0:24:17 > 0:24:21Ketoconazole shampoos are widely available from chemists,
0:24:21 > 0:24:26while miconazole shampoos are widely available from...vets.
0:24:26 > 0:24:31Because, in shampoo form, it's only licensed for cats and dogs.
0:24:31 > 0:24:35So whilst we can't advise you use that, it has been approved
0:24:35 > 0:24:41for human use in skin creams, which can be useful for a flaky scalp,
0:24:41 > 0:24:43if you're bald.
0:24:43 > 0:24:47Now, unfortunately, even after a few flake-free weeks,
0:24:47 > 0:24:51the fungus can become resistant to these anti-fungal treatments.
0:24:51 > 0:24:55And if that happens to you, you should swap to a shampoo
0:24:55 > 0:24:58that contains zinc or selenium, which, although milder,
0:24:58 > 0:25:01do contain anti-fungal properties.
0:25:04 > 0:25:07So, if you're trying to shift dandruff, remember,
0:25:07 > 0:25:10it's the fungus you need to target.
0:25:10 > 0:25:13Wash your hair to keep it grease-free,
0:25:13 > 0:25:16look out for the anti-fungal ingredients on shampoo bottles
0:25:16 > 0:25:19and enjoy the sun.
0:25:33 > 0:25:37Earlier in the programme, we embarked on our big experiment
0:25:37 > 0:25:41to see whether just shifting our mealtimes can make us healthier.
0:25:41 > 0:25:44Our group of volunteers are moving their breakfast later
0:25:44 > 0:25:47and their dinner times earlier, packing their mealtimes together
0:25:47 > 0:25:51to give them a longer period overnight when they are not eating.
0:25:51 > 0:25:54And we are testing whether this is good for their health.
0:25:54 > 0:25:57But there's something else I want to try out for myself.
0:25:57 > 0:26:02Over the last ten years, average dinner times have shifted much later,
0:26:02 > 0:26:05from 5.30pm till nearly 8pm.
0:26:05 > 0:26:09And some scientists believe that eating this late in the evening
0:26:09 > 0:26:11isn't doing us any good at all.
0:26:11 > 0:26:16So I'm going to do an experiment on myself to find out if that is true.
0:26:16 > 0:26:19And curiously, it starts first thing in the morning.
0:26:19 > 0:26:22OK, so here we have a nice old-fashioned English fry-up.
0:26:22 > 0:26:24It's my first meal of the day
0:26:24 > 0:26:28and I'm going to have any other meal exactly like it in 12 hours' time.
0:26:28 > 0:26:31On the face of it, it's not the worst experiment I've ever done,
0:26:31 > 0:26:33except that in the intervening 12 hours
0:26:33 > 0:26:35I'm going to have an awful lot of blood taken out of me.
0:26:38 > 0:26:40After both my morning and evening meals,
0:26:40 > 0:26:44the levels of fat and sugar in my blood will be measured.
0:26:45 > 0:26:48Prolonged high levels of either are bad for you.
0:26:48 > 0:26:52And this test will show if the time of day I eat makes a difference.
0:26:54 > 0:26:58So, that was the first blood I've had taken since breakfast time.
0:26:58 > 0:27:00And what should be happening is
0:27:00 > 0:27:05my levels of fat in my blood should be beginning to surge upwards.
0:27:05 > 0:27:07We'll find out shortly.
0:27:10 > 0:27:15For the next 12 hours, it's no food, but plenty of blood sampling.
0:27:23 > 0:27:28Exactly 12 hours later, I have exactly the same meal.
0:27:28 > 0:27:32But will it have exactly the same effect on my body
0:27:32 > 0:27:34at this time of night?
0:27:35 > 0:27:38What the blood tests reveal is that when I ate in the morning,
0:27:38 > 0:27:42my blood sugar got back to normal within two hours.
0:27:43 > 0:27:47And the fat in my blood started to drop after about three hours.
0:27:50 > 0:27:53But after exactly the same meal in the evening,
0:27:53 > 0:27:56my blood sugar stayed high for much longer.
0:27:59 > 0:28:02And the fat levels in my blood were still rising
0:28:02 > 0:28:04even four hours after eating.
0:28:04 > 0:28:07This is a quite startling result.
0:28:07 > 0:28:10Clearly, eating this late at night isn't good for us.
0:28:10 > 0:28:12So, what's going on?
0:28:12 > 0:28:15Well, it seems we have an internal body clock
0:28:15 > 0:28:18that makes us process food differently throughout the day.
0:28:18 > 0:28:22So, what's the optimum cut-off point for meals?
0:28:22 > 0:28:24There's only one way to find out.
0:28:26 > 0:28:30Here at Surrey University, they study circadian rhythms -
0:28:30 > 0:28:33what happens inside your body over the course of a day.
0:28:33 > 0:28:37I volunteered to go into an isolation chamber for 24 hours.
0:28:37 > 0:28:39I imagine it's going to be like a desert island -
0:28:39 > 0:28:43except no view, no sunshine and no sea.
0:28:44 > 0:28:49# If you're fond of sand dunes and salty air... #
0:28:49 > 0:28:54In fact, I'm going to have my body monitored in every possible way
0:28:54 > 0:28:57while I'm shut in the chamber.
0:28:59 > 0:29:02Now, I'm not actually looking forward to this,
0:29:02 > 0:29:05but it will be really interesting to see what happens.
0:29:06 > 0:29:11Keeping me isolated from the outside world for a whole day and a night
0:29:11 > 0:29:13allows the researchers to measure
0:29:13 > 0:29:16my own internal body clock's natural rhythm.
0:29:16 > 0:29:19I don't get any proper meals,
0:29:19 > 0:29:22just regular small snacks to keep me going.
0:29:22 > 0:29:25And every hour for 24 hours,
0:29:25 > 0:29:29my blood is taken to measure levels of fat and sugar.
0:29:32 > 0:29:35This is not one of my best self experiments.
0:29:35 > 0:29:38There's one just down the bottom there.
0:29:38 > 0:29:43The idea is to try and understand what our bodies do naturally,
0:29:43 > 0:29:45so we can find out their rhythms
0:29:45 > 0:29:48and discover what time is best for us to eat.
0:29:50 > 0:29:52Finally, it's over.
0:29:54 > 0:29:56I certainly hope it will be worth it.
0:29:56 > 0:29:57Right...
0:29:58 > 0:30:00And it was.
0:30:00 > 0:30:02As evening approached,
0:30:02 > 0:30:06the fat and sugar levels in my blood started to rise,
0:30:06 > 0:30:08even though I'd had no meal,
0:30:08 > 0:30:11and then fell again when it came to morning.
0:30:11 > 0:30:15This was tied to the levels of a hormone in my blood called melatonin,
0:30:15 > 0:30:17which tells us when to sleep.
0:30:19 > 0:30:21So when I had a fry-up in the evening,
0:30:21 > 0:30:25this was adding to a natural rise in my blood sugar and fat levels.
0:30:25 > 0:30:28Dr John Johnson can explain why this happens.
0:30:30 > 0:30:33OK, so, if you like, our bodies have developed
0:30:33 > 0:30:36to be prepared for having food at a certain time of day
0:30:36 > 0:30:38and to be fasting at another time of day,
0:30:38 > 0:30:41geared towards taking nutrients from the blood,
0:30:41 > 0:30:44storing them away in your metabolic tissues
0:30:44 > 0:30:48and then at night, when you are supposedly fasting,
0:30:48 > 0:30:52these metabolic stores then release energy into the blood,
0:30:52 > 0:30:55so that tissues like your brain still have a good supply of energy.
0:30:55 > 0:30:59- So your fat levels are rising in the early evening.- Yes.
0:30:59 > 0:31:02If you reach into the fridge and you grab, you know,
0:31:02 > 0:31:05your bacon burger or whatever at 11 o'clock at night,
0:31:05 > 0:31:07is that a bad thing?
0:31:07 > 0:31:11Generally yes, because your body isn't expecting you to be eating
0:31:11 > 0:31:14at that time of day. It's expecting you to be fasting.
0:31:14 > 0:31:18And so what you find is that during that time,
0:31:18 > 0:31:21when people eat a meal, the spike of things like sugar
0:31:21 > 0:31:24and fat that you see in the blood after a meal is higher
0:31:24 > 0:31:25if you eat at night
0:31:25 > 0:31:30and that spike takes a bit longer to get down to background levels.
0:31:30 > 0:31:32So if you eat most of your calories
0:31:32 > 0:31:34certainly during the early part of the day
0:31:34 > 0:31:37and fewer calories in the late afternoon and evening,
0:31:37 > 0:31:39that will actually help your metabolism
0:31:39 > 0:31:41and potentially help you to lose weight
0:31:41 > 0:31:43and maintain weight loss as well.
0:31:46 > 0:31:49So, there is good evidence that eating earlier can help us
0:31:49 > 0:31:52be healthier and maybe even lose weight.
0:31:53 > 0:31:57There's an old adage - breakfast like a king, lunch like a prince,
0:31:57 > 0:31:59dine like a pauper.
0:31:59 > 0:32:02And it would certainly be a good idea to avoid that fatty,
0:32:02 > 0:32:07sugary food late at night when your body is least able to deal with it.
0:32:07 > 0:32:10If you have to have that fry-up, have it for breakfast.
0:32:19 > 0:32:21And now for another question sent in by a viewer.
0:32:21 > 0:32:23And this one really surprised us.
0:32:24 > 0:32:30Hi, my question is can I use WD-40 to treat psoriasis?
0:32:30 > 0:32:34When you first hear about this idea, it sounds ludicrous,
0:32:34 > 0:32:37using a household lubricant to treat a skin condition.
0:32:39 > 0:32:43However, it turns out that quite a lot of people are claiming online
0:32:43 > 0:32:47that WD-40 can cure all sorts, including skin conditions.
0:32:47 > 0:32:50When you think about it more deeply, it's not that stupid.
0:32:50 > 0:32:53So, many of the emollients, moisturising creams
0:32:53 > 0:32:57that we use to treat dry, flaky skin conditions contain paraffin
0:32:57 > 0:32:59or paraffin-like substances.
0:32:59 > 0:33:03And that is probably the main ingredient in WD-40.
0:33:03 > 0:33:05But there's the rub.
0:33:05 > 0:33:09I say "probably" because actually the ingredients are a trade secret.
0:33:09 > 0:33:12My money, though, is on the fact that some of them
0:33:12 > 0:33:16are not going to be good for your skin if used long term.
0:33:16 > 0:33:19And talking about money, this stuff is more expensive
0:33:19 > 0:33:22than creams designed to treat dry skin.
0:33:22 > 0:33:25So why would you even be tempted to try it?
0:33:25 > 0:33:29Is using a scummy can from the shed somehow more manly?
0:33:29 > 0:33:31Come on, guys!
0:33:31 > 0:33:33It shouldn't be used to treat skin conditions,
0:33:33 > 0:33:36it shouldn't be used to treat your aching joints,
0:33:36 > 0:33:39however, it is a very effective lubricant, although I should say
0:33:39 > 0:33:42that other water displacement products are available.
0:33:49 > 0:33:50Still to come...
0:33:50 > 0:33:55Is cooking food in a microwave bad for our health?
0:33:55 > 0:33:58And how much alcohol should we be drinking?
0:33:58 > 0:34:00But first...
0:34:07 > 0:34:11Allergies are incredibly common, and worldwide they are on the rise.
0:34:11 > 0:34:14Some can be fatal. So what can you do about it?
0:34:14 > 0:34:17Well, here in the UK, children with a peanut allergy
0:34:17 > 0:34:20are about to go through a pioneering new treatment.
0:34:23 > 0:34:25Connie is 12 years old.
0:34:25 > 0:34:27When she was just two,
0:34:27 > 0:34:31her mother discovered that she was allergic to peanuts.
0:34:31 > 0:34:35She has a life-threatening peanut allergy,
0:34:35 > 0:34:40which means that her airways could constrict,
0:34:40 > 0:34:44which means that she wouldn't be able to breathe properly
0:34:44 > 0:34:48and ultimately she could die because of actually eating a peanut.
0:34:49 > 0:34:54For Connie, even the smallest trace of peanut could trigger a reaction.
0:34:54 > 0:34:57So things the rest of us take for granted can cause
0:34:57 > 0:35:00both her and her family serious anxiety.
0:35:00 > 0:35:03When we're eating out at restaurants,
0:35:03 > 0:35:06then I get nervous or a bit frightened
0:35:06 > 0:35:10cos it's not my mum cooking the food.
0:35:11 > 0:35:16Allergies like Connie's can't be cured and are rarely outgrown.
0:35:16 > 0:35:20So those who have them have to learn to cope with them
0:35:20 > 0:35:21for the rest of their lives.
0:35:24 > 0:35:28It's hard to imagine how worrying it must be to have a serious allergy,
0:35:28 > 0:35:31let alone being the parent of a child
0:35:31 > 0:35:33who could have a fatal reaction.
0:35:33 > 0:35:38But, for Connie and her family, that anxiety could soon be over.
0:35:38 > 0:35:41And that's because Connie is one of the very first children
0:35:41 > 0:35:46trying out a ground-breaking new treatment for her peanut allergy.
0:35:48 > 0:35:51The treatment is being offered at Addenbrooke's Hospital
0:35:51 > 0:35:56in Cambridge, a world-renowned centre for allergy research.
0:35:56 > 0:36:00Here, doctors are investigating what causes allergic reactions
0:36:00 > 0:36:02and how they can be treated.
0:36:02 > 0:36:04And push. Keep going, keep going...
0:36:04 > 0:36:08Today, they are setting out to trigger a controlled reaction
0:36:08 > 0:36:10in Richard, who has a peanut allergy.
0:36:12 > 0:36:14Dr Shelley Dua is supervising.
0:36:17 > 0:36:19What's actually going on inside Richard's body
0:36:19 > 0:36:22when he's having this allergic reaction?
0:36:22 > 0:36:26The body is recognising the peanut as something foreign
0:36:26 > 0:36:30and your immune system is launching an allergic reaction against it,
0:36:30 > 0:36:33which basically means that your allergic cells,
0:36:33 > 0:36:36which are in your mouth, your throat, your stomach,
0:36:36 > 0:36:39they're getting activated and releasing chemicals
0:36:39 > 0:36:42that cause symptoms of an allergic reaction.
0:36:42 > 0:36:45So, just inside my throat still.
0:36:46 > 0:36:47You're struggling to breathe,
0:36:47 > 0:36:50it feels like you're going to vomit all the time.
0:36:50 > 0:36:55Your throat feels like it's swelling and closing up on you.
0:36:56 > 0:37:00Now, the doctors have decided to stop this reaction taking place
0:37:00 > 0:37:02at this point by giving medication.
0:37:04 > 0:37:07The drug stops Richard's immune reaction
0:37:07 > 0:37:10against the proteins in the peanut.
0:37:10 > 0:37:12- Yeah, now that's... - Are you feeling a bit woozy?
0:37:13 > 0:37:16The latest research suggests
0:37:16 > 0:37:20that allergies like this start in infancy.
0:37:20 > 0:37:22Remarkably, they may even develop
0:37:22 > 0:37:25before a baby has ever eaten a peanut.
0:37:25 > 0:37:30It's thought they may arise when a baby's earliest contact with peanuts
0:37:30 > 0:37:34is through their skin in products like skin creams or oils,
0:37:34 > 0:37:38as the immune system doesn't learn that peanuts are OK to eat.
0:37:39 > 0:37:42But the team here believe that they have a treatment
0:37:42 > 0:37:45that can retrain children's immune systems.
0:37:46 > 0:37:49And in many ways, it's beautifully simple.
0:37:49 > 0:37:52Patients are given a tiny dose of peanut protein,
0:37:52 > 0:37:56too small for their bodies to even recognise it as a toxin,
0:37:56 > 0:37:59and then that dose is built up very, very slowly
0:37:59 > 0:38:05until patients can tolerate one, two, or even five peanuts
0:38:05 > 0:38:07without having an allergic reaction.
0:38:09 > 0:38:13This principle has already been used to treat allergies like hay fever,
0:38:13 > 0:38:17but Dr Andrew Clark is now attempting to apply it
0:38:17 > 0:38:21to potentially fatal food allergies in children like Connie.
0:38:21 > 0:38:25The aim for us is that you are able to then eat foods
0:38:25 > 0:38:28that haven't got buckets of peanuts in.
0:38:28 > 0:38:31But it's actually to say, you know, we've got this food that says,
0:38:31 > 0:38:34"This may contain traces of peanuts." Is it safe to eat?
0:38:34 > 0:38:38- And we think that will be safe for you to eat once you're treated.- OK.
0:38:38 > 0:38:42What people with peanut allergies are actually reacting to
0:38:42 > 0:38:46are particular proteins that form a large part of the nut.
0:38:48 > 0:38:50For the treatment,
0:38:50 > 0:38:53the team have pharmaceutically made peanut protein,
0:38:53 > 0:38:56and Connie will start by eating the equivalent
0:38:56 > 0:39:00of just one-hundredth of a nut mixed into yoghurt.
0:39:05 > 0:39:09For the first time in ten years, she's knowingly eating peanut.
0:39:09 > 0:39:12But she doesn't react.
0:39:12 > 0:39:14Well done, well done.
0:39:14 > 0:39:18- You're brilliant! You're an absolute star.- Well done, Connie.
0:39:18 > 0:39:20Over the next few months,
0:39:20 > 0:39:22Connie will take a daily dose of peanut,
0:39:22 > 0:39:24gradually increasing the amount
0:39:24 > 0:39:28in the hope of building up her body's tolerance to it.
0:39:28 > 0:39:31And the technique looks promising.
0:39:31 > 0:39:33We performed a really large trial
0:39:33 > 0:39:35of over 100 children with peanut allergy.
0:39:35 > 0:39:39We found in the trial that we could get about 80 to 90% of them
0:39:39 > 0:39:41to eat peanuts on a regular basis.
0:39:41 > 0:39:45When it worked, it really improved their quality of life.
0:39:50 > 0:39:53Five weeks later, on her third visit,
0:39:53 > 0:39:57the team up Connie's dose to one-tenth of a peanut.
0:39:57 > 0:40:01But amazingly, she still doesn't have a reaction.
0:40:01 > 0:40:04This is really encouraging.
0:40:04 > 0:40:07It shows her immune system is becoming more tolerant.
0:40:07 > 0:40:10And it's giving her new hope.
0:40:12 > 0:40:14If this works, when I go on school trips
0:40:14 > 0:40:17and I'm having lunch there, then it will be good
0:40:17 > 0:40:21not to have the constant worry in the back of your mind -
0:40:21 > 0:40:23does this have peanuts in?
0:40:23 > 0:40:25Am I going to react to it?
0:40:27 > 0:40:31Connie's treatment will last for years, perhaps a lifetime.
0:40:31 > 0:40:33But the hope is that there could be
0:40:33 > 0:40:35even greater potential in the future.
0:40:35 > 0:40:38The principle of what we are doing is really important
0:40:38 > 0:40:40and it can be applied to earlier in life.
0:40:40 > 0:40:44And it's possible that eventually, one day, we'll have a treatment
0:40:44 > 0:40:45that infants perhaps could have
0:40:45 > 0:40:48to prevent this happening in the first place.
0:40:51 > 0:40:54Treatments like this one happening here in Cambridge
0:40:54 > 0:40:57have the potential to change the lives of thousands of patients
0:40:57 > 0:41:00suffering from severe allergic reactions.
0:41:00 > 0:41:04And who knows - this research might even one day be able to
0:41:04 > 0:41:08get to the bottom of what causes allergy in the first place.
0:41:08 > 0:41:12But for now, what do we do if we witness an allergic reaction?
0:41:12 > 0:41:14Over to Saleyha.
0:41:14 > 0:41:17As an emergency medicine doctor,
0:41:17 > 0:41:21I know that a severe allergic reaction can be frightening.
0:41:21 > 0:41:24But you can save someone's life if you know what to do.
0:41:24 > 0:41:29The group most at risk of a fatal reaction are 17-to-27-year-olds,
0:41:29 > 0:41:31like these students.
0:41:31 > 0:41:35And it's not just nuts that can cause reactions.
0:41:35 > 0:41:40So, anyone here suffering from allergies to anything?
0:41:40 > 0:41:42I'm allergic to penicillin.
0:41:42 > 0:41:44I remember having a rash all over my body.
0:41:44 > 0:41:46Funny story - originally thought it was Super Noodles
0:41:46 > 0:41:49- because I was eating Super Noodles at the time.- OK.
0:41:49 > 0:41:52- Staple student diet, Super Noodles. - Would have been a nightmare.
0:41:54 > 0:41:57Apart from nuts and drugs like penicillin,
0:41:57 > 0:42:01fish and shellfish, eggs and dairy, insect stings
0:42:01 > 0:42:06and natural latex can all cause a severe reaction called anaphylaxis.
0:42:08 > 0:42:12The symptoms can include an itchy or swollen mouth,
0:42:12 > 0:42:14problems breathing,
0:42:14 > 0:42:18a fast pulse, nausea or a skin rash.
0:42:18 > 0:42:21These red flags can be symptoms of a reaction
0:42:21 > 0:42:25that could quickly become life-threatening.
0:42:25 > 0:42:28But there are things that you can do that could save a life.
0:42:28 > 0:42:33Most people at risk of dangerous reactions will be prescribed
0:42:33 > 0:42:36a device which contains an adrenaline injection.
0:42:36 > 0:42:40It might sound a bit scary, but they're actually very easy to use.
0:42:41 > 0:42:44A really important thing before you begin anything
0:42:44 > 0:42:47is to get the person to sit or lie down.
0:42:47 > 0:42:52Remove the cap and make a fist around the device.
0:42:52 > 0:42:56The injection should always go into the outer thigh,
0:42:56 > 0:42:58two-thirds of the way down.
0:42:58 > 0:43:01With some pens, you jab firmly.
0:43:01 > 0:43:04With others, you simply place and push.
0:43:05 > 0:43:08They always have the instructions on the side.
0:43:08 > 0:43:12Hold it in place for as long as the instructions state,
0:43:12 > 0:43:14then massage the area.
0:43:16 > 0:43:19It's been proven that injecting adrenaline early
0:43:19 > 0:43:23is the most effective way of treating anaphylaxis.
0:43:27 > 0:43:29If an adrenaline device isn't available,
0:43:29 > 0:43:31then keep the sufferer calm
0:43:31 > 0:43:34and get them to lie down and raise their legs.
0:43:35 > 0:43:39If they lose consciousness, put them in the recovery position.
0:43:39 > 0:43:43And you should always call the emergency services.
0:43:43 > 0:43:45This is really important
0:43:45 > 0:43:49because one in 12 victims will see their symptoms return.
0:43:49 > 0:43:53To spot anaphylaxis, look out for the red flags.
0:43:53 > 0:43:56The most important ones are associated with airway,
0:43:56 > 0:43:59breathing and circulation.
0:43:59 > 0:44:02And there might be some characteristic skin rashes.
0:44:02 > 0:44:05If you spot someone with these symptoms,
0:44:05 > 0:44:08look to see if they are carrying an adrenaline pen.
0:44:08 > 0:44:11And if they are, don't be afraid to use it.
0:44:11 > 0:44:13And then call 999.
0:44:13 > 0:44:16If you do these things, you could save a life.
0:44:16 > 0:44:20For more information about dealing with anaphylaxis
0:44:20 > 0:44:24and the new treatments for peanut allergy, go to our website...
0:44:37 > 0:44:38When it comes to our health,
0:44:38 > 0:44:41it seems we are constantly walking a tightrope.
0:44:42 > 0:44:44We're told something is good for us.
0:44:44 > 0:44:46Then it's claimed too much is bad.
0:44:48 > 0:44:49Take alcohol.
0:44:50 > 0:44:52One of life's guilty pleasures.
0:44:52 > 0:44:54But is there any amount that's safe to drink?
0:44:54 > 0:44:57Could it be positively good for you?
0:44:57 > 0:44:59And how much is too much?
0:44:59 > 0:45:02New UK guidelines have just been announced.
0:45:02 > 0:45:05Now, both men and women are advised to drink
0:45:05 > 0:45:09no more than 14 units a week, spread over three or more days.
0:45:09 > 0:45:12That's less than five pints of strong lager
0:45:12 > 0:45:15or five large glasses of wine in a week.
0:45:15 > 0:45:17But the experts disagree about
0:45:17 > 0:45:21whether this amount is bad for us or perhaps beneficial.
0:45:21 > 0:45:24I'm off to hear the opinions of two leading experts
0:45:24 > 0:45:27on the impact of alcohol on health.
0:45:27 > 0:45:30And they happen to have very different points of view.
0:45:32 > 0:45:35First up is Dr Alexander Jones, a consultant cardiologist
0:45:35 > 0:45:40and clinical scientist at University College, London.
0:45:40 > 0:45:43He believes alcohol can have benefits for heart health.
0:45:44 > 0:45:48So what evidence is there for the benefit of drinking alcohol on heart?
0:45:48 > 0:45:53Well, the best evidence comes from the large epidemiological studies.
0:45:53 > 0:45:56There are large prospective studies in many thousands of people
0:45:56 > 0:45:58in different parts of the world
0:45:58 > 0:46:01that show that if you drink modest amounts of alcohol -
0:46:01 > 0:46:05up to, say, two to three units of alcohol a day -
0:46:05 > 0:46:08that you are less likely to develop
0:46:08 > 0:46:12coronary heart disease or stroke later on in life.
0:46:12 > 0:46:13And have there been trials where
0:46:13 > 0:46:17- you allocate people to alcohol or not drinking alcohol?- There have.
0:46:17 > 0:46:20There have been a couple of studies which showed that
0:46:20 > 0:46:24if they were randomised to either just eating a Mediterranean diet
0:46:24 > 0:46:25or eating a Mediterranean diet
0:46:25 > 0:46:28AND drinking a glass of red wine a night,
0:46:28 > 0:46:31that those who drank a glass of red wine a night
0:46:31 > 0:46:33had better cardiac function over time.
0:46:33 > 0:46:35If there is a protective effect,
0:46:35 > 0:46:38is it the alcohol or is it something else?
0:46:38 > 0:46:42At the very least, alcohol itself is one of the substances.
0:46:42 > 0:46:45In red wine, there are polyphenolic compounds
0:46:45 > 0:46:47which are beneficial to health.
0:46:47 > 0:46:51But the evidence for that is weaker than it is for alcohol itself.
0:46:51 > 0:46:53In terms of the effect of alcohol on bio-markers,
0:46:53 > 0:46:56like blood pressure and things like that, what do you see?
0:46:56 > 0:46:59If you drink to excess, heavy drinkers actually have
0:46:59 > 0:47:01a much higher risk of cardiovascular disease.
0:47:01 > 0:47:04- But moderate drinkers, it tends to go down?- It tends to decrease.
0:47:04 > 0:47:09You also see changes in the level of good cholesterol, if you like.
0:47:09 > 0:47:13And that increases in moderate drinkers.
0:47:13 > 0:47:15And it is possible that that's beneficial
0:47:15 > 0:47:18because there is an association between the level of that
0:47:18 > 0:47:22and having a lower risk of heart disease and stroke.
0:47:22 > 0:47:24What are the ways in which alcohol
0:47:24 > 0:47:28could potentially be having a beneficial effect?
0:47:28 > 0:47:32It may be that alcohol is promoting the production of nitric oxide,
0:47:32 > 0:47:35which is a compound that makes the arteries in the body dilate
0:47:35 > 0:47:40and reduces the stress on the heart and improves its oxygen supply.
0:47:40 > 0:47:42OK, so how much is too much alcohol?
0:47:42 > 0:47:45I think the guidelines are reasonable.
0:47:45 > 0:47:46From the big epidemiological studies,
0:47:46 > 0:47:50drinking around two to three units per day
0:47:50 > 0:47:54seems about the level that is probably beneficial.
0:47:55 > 0:47:59Dr Jones believes there IS a safe level of alcohol consumption
0:47:59 > 0:48:04and the evidence that moderate drinking has a positive effect on heart health stands up.
0:48:04 > 0:48:06But others disagree.
0:48:08 > 0:48:13Professor Tim Stockwell is Director of the Centre for Addiction Research
0:48:13 > 0:48:15at the University of Victoria in Canada.
0:48:15 > 0:48:19He has advised the UK Government on alcohol guidelines
0:48:19 > 0:48:23and is sceptical about the supposed benefits of drinking.
0:48:24 > 0:48:27If you're going for a zero-risk approach, nobody should drink.
0:48:27 > 0:48:30There's 60 different ways at least
0:48:30 > 0:48:34that alcohol can make you unwell or kill you.
0:48:34 > 0:48:37And drinking at about the UK drinking guidelines
0:48:37 > 0:48:40of three or four units a day for a man,
0:48:40 > 0:48:44there's a 23% increased risk of prostate cancer at that level.
0:48:44 > 0:48:47And there'd be 10% fewer deaths from breast cancer
0:48:47 > 0:48:49if there was no drinking in the world.
0:48:49 > 0:48:53Do you think alcohol is beneficial at all?
0:48:53 > 0:48:57I think it's important that we take a sceptical look at the evidence
0:48:57 > 0:49:00because there's a lot of bad science out there.
0:49:00 > 0:49:04So, you think the studies which suggest that moderate drinking
0:49:04 > 0:49:07is protective of the heart are deeply flawed?
0:49:07 > 0:49:08They are too simple.
0:49:08 > 0:49:11It seems to be too good to be true.
0:49:11 > 0:49:13If you follow up people over many years
0:49:13 > 0:49:16and find they're light drinkers, hey presto,
0:49:16 > 0:49:20you find they have a lower risk of many disease than does an abstainer.
0:49:20 > 0:49:24However, there are studies coming out of the UK
0:49:24 > 0:49:27looking at young adults who have never drunk,
0:49:27 > 0:49:29and what's different about them,
0:49:29 > 0:49:32it appears that the abstainers tend to have poorer health
0:49:32 > 0:49:35and be poorer - they have less income.
0:49:35 > 0:49:38So, already, before you start off on this journey,
0:49:38 > 0:49:40where you may get selected
0:49:40 > 0:49:43to be part of one of these medical studies later in life,
0:49:43 > 0:49:47the abstainer group is full of people in poor health already.
0:49:47 > 0:49:50So when they get to be compared with these moderate drinkers
0:49:50 > 0:49:54who are cutting the fat off their bacon and exercising every day,
0:49:54 > 0:49:56they've got an even less good chance.
0:49:56 > 0:49:59But we've now got more decent studies
0:49:59 > 0:50:01where they didn't have that bias.
0:50:01 > 0:50:05And in those studies, there was no evidence of protection.
0:50:05 > 0:50:07It's such a wonderful thing to believe,
0:50:07 > 0:50:11if only it was true, that alcohol was really prolonging our lives.
0:50:11 > 0:50:15- And do you drink? - I do, yeah.- In spite of this.
0:50:15 > 0:50:18- But more cautiously than I used to. - OK, how cautious is cautious?
0:50:18 > 0:50:22- Probably seven or eight drinks a week.- OK.
0:50:22 > 0:50:25You've been in the field for a long time. One piece of advice -
0:50:25 > 0:50:29- what would it be?- Abstinent days. Possibly abstinent months.
0:50:29 > 0:50:33And if you actually don't miss the stuff, abstinent years.
0:50:33 > 0:50:35THEY LAUGH
0:50:35 > 0:50:38But assuming you do occasionally want a drink, how much?
0:50:39 > 0:50:43I think it's probably fine to have three or four drinks
0:50:43 > 0:50:47on an occasion and not to do that more than once or twice a week.
0:50:47 > 0:50:51- And just otherwise have one or two drinks now and again.- Thank you.
0:50:51 > 0:50:54Abstinent years. Abstinent decades!
0:50:55 > 0:50:57- That's going to be a challenge.- Yes.
0:50:57 > 0:50:59So, for Professor Stockwell,
0:50:59 > 0:51:02the evidence for health benefits just doesn't stack up.
0:51:02 > 0:51:05And abstinence is a good thing.
0:51:05 > 0:51:07But what do I now believe?
0:51:07 > 0:51:09Having listened to both of them,
0:51:09 > 0:51:12I do understand this is a really confusing picture.
0:51:12 > 0:51:15I do believe that the equivalent of, say,
0:51:15 > 0:51:17a glass of red wine every so often
0:51:17 > 0:51:19is not going to do you any harm
0:51:19 > 0:51:22and might, just might, do you some good.
0:51:22 > 0:51:26So I shall sip my wine and feel good about it.
0:51:34 > 0:51:37And now another question you've sent in for us.
0:51:37 > 0:51:41Does microwaving my food make it any less healthy?
0:51:42 > 0:51:46I'm not at all surprised that people want an answer to this question.
0:51:46 > 0:51:50The internet is full of reports, articles and blogs
0:51:50 > 0:51:55claiming that microwaves pose a serious threat to our health.
0:51:55 > 0:51:57If all these stories are to be believed,
0:51:57 > 0:52:02the humble microwave is actually responsible for damaging proteins,
0:52:02 > 0:52:07poisoning us with toxins and sucking all the nutrients out of our food.
0:52:07 > 0:52:10It all sounds pretty sinister.
0:52:10 > 0:52:14But what does this mean, and is any of it actually true?
0:52:14 > 0:52:17Well, like most conspiracy theories,
0:52:17 > 0:52:19this one comes with a tiny grain of truth
0:52:19 > 0:52:22mixed in with a lot of misunderstanding
0:52:22 > 0:52:25and some pretty dubious interpretations
0:52:25 > 0:52:27of what microwaves actually do.
0:52:27 > 0:52:30# I'm spinning around... #
0:52:30 > 0:52:36The aptly named microwave oven uses microwave radiation to heat food.
0:52:36 > 0:52:37All that these microwaves do
0:52:37 > 0:52:40is cause water molecules in the food to vibrate,
0:52:40 > 0:52:44generating heat that spreads through the surrounding molecules.
0:52:44 > 0:52:48Now, it has been claimed that this damages proteins
0:52:48 > 0:52:50and destroys nutrients in our food.
0:52:50 > 0:52:52But is any of this true?
0:52:53 > 0:52:55Well, the short answer is yes.
0:52:57 > 0:53:01But that's not as terrible or as unusual as it sounds.
0:53:03 > 0:53:06Actually, what happens in a microwave is no different
0:53:06 > 0:53:08from what happens on a stove.
0:53:08 > 0:53:12Heating by any method changes proteins and nutrients.
0:53:12 > 0:53:15In fact, when you boil vegetables in water,
0:53:15 > 0:53:17you can lose even more goodness
0:53:17 > 0:53:20because the nutrients that were in the veg
0:53:20 > 0:53:23tend to end up in the water, which you then throw away.
0:53:23 > 0:53:27So, if you want to cook in a way that best preserves nutrients,
0:53:27 > 0:53:30what you actually need are shorter cooking times
0:53:30 > 0:53:32that limit the exposure to heat
0:53:32 > 0:53:37and a cooking method that uses as little water as possible.
0:53:37 > 0:53:41And when you look at it like that, a microwave is a good bet.
0:53:41 > 0:53:45In fact, studies looking at vitamin C have shown
0:53:45 > 0:53:49that levels in food can be higher after microwave cooking
0:53:49 > 0:53:51than after boiling.
0:53:51 > 0:53:54So if you like using the microwave, carry on.
0:53:54 > 0:53:58In some cases, your food might actually be more nutritious.
0:54:14 > 0:54:19Ten weeks ago, we put 16 volunteers on a diet with a difference.
0:54:19 > 0:54:23After measuring their body fat, their cholesterol levels
0:54:23 > 0:54:26and their blood sugar levels, we split them into two groups.
0:54:27 > 0:54:30The blue group changed absolutely nothing.
0:54:30 > 0:54:33They ate whatever they wanted whenever they wanted.
0:54:33 > 0:54:37But the reds brought their meal times closer together
0:54:37 > 0:54:39and banned snacking in the evening,
0:54:39 > 0:54:43giving them three extra hours in the day when their bodies are fasting.
0:54:45 > 0:54:47We're testing a new scientific theory
0:54:47 > 0:54:51that this can make you healthier and maybe even lose fat.
0:54:52 > 0:54:55It works in animals, but how did our human guinea pigs get on?
0:54:56 > 0:55:00I found it really hard not being able to have a glass of wine
0:55:00 > 0:55:04in the evening or have nibbles in the evening,
0:55:04 > 0:55:06mindlessly watching telly.
0:55:06 > 0:55:07That's the hardest part.
0:55:07 > 0:55:10It's quite hard to get all your wine drinking done by 6pm.
0:55:10 > 0:55:12It is, it is.
0:55:13 > 0:55:16But Dr Jon Johnston from the University of Surrey
0:55:16 > 0:55:19has now taken their body measurements and blood samples again
0:55:19 > 0:55:22and has the all-important results.
0:55:22 > 0:55:25Have their efforts been worthwhile?
0:55:25 > 0:55:29Well, it's good news for the restricted-time feeding group,
0:55:29 > 0:55:32who ended up looking healthier in some of our measures.
0:55:32 > 0:55:36So, what do we mean by that? They look healthy to me.
0:55:36 > 0:55:38- Well, of course... - But so do these guys.
0:55:38 > 0:55:43So, firstly, they had lower percent body fat.
0:55:43 > 0:55:47Secondly, they had lower fasting blood sugar.
0:55:47 > 0:55:51- And thirdly, they had lower fasting blood cholesterol.- Wow!
0:55:51 > 0:55:53Amazing!
0:55:53 > 0:55:57So, by simply bringing their mealtimes closer together,
0:55:57 > 0:55:59our red group's blood sugar, cholesterol
0:55:59 > 0:56:02and body fat all fell significantly
0:56:02 > 0:56:03in just a few weeks.
0:56:03 > 0:56:05It's an outstanding result.
0:56:06 > 0:56:10These are very important things to change.
0:56:10 > 0:56:12I mean, these are big risk factors
0:56:12 > 0:56:15for dying of things like strokes and heart attacks.
0:56:15 > 0:56:18That's right, these are certainly some of the major risk factors
0:56:18 > 0:56:20for cardiovascular disease and even diabetes.
0:56:20 > 0:56:23So, if these effects can be maintained over time,
0:56:23 > 0:56:25potentially they have very important benefits.
0:56:25 > 0:56:29Why does simply changing those mealtimes work? Do we know?
0:56:29 > 0:56:32There are probably two possible explanations for this at the moment.
0:56:32 > 0:56:35My personal favourite because of my research interest
0:56:35 > 0:56:37is that you are eating at a time of day
0:56:37 > 0:56:41when your body metabolism rhythms are expecting you to be eating food.
0:56:41 > 0:56:44So your body can deal with those calories more efficiently
0:56:44 > 0:56:48than if you eat, for example, during the night.
0:56:48 > 0:56:52However, these guys have also had a longer fasting duration every day
0:56:52 > 0:56:55and it may be that the fasting in itself
0:56:55 > 0:56:58is having some important effect. At the moment, we just don't know.
0:56:58 > 0:57:01But I think it's great we're actually seeing a positive result.
0:57:01 > 0:57:04Is this a thing you're going to keep doing?
0:57:04 > 0:57:06I will definitely carry on.
0:57:06 > 0:57:10I think it's fantastic to have such positive changes. It's fantastic.
0:57:10 > 0:57:14THEY CHEER AND LAUGH
0:57:17 > 0:57:20I love things like this because it's such a simple rule of thumb.
0:57:20 > 0:57:22And you don't have to do it the whole time.
0:57:22 > 0:57:25But for mornings where you don't have much on, or evenings
0:57:25 > 0:57:29when you're not out socialising or eating with friends,
0:57:29 > 0:57:32it's just planted that little seed in my mind that
0:57:32 > 0:57:36maybe at 11 o'clock at night I won't reach for another cheeseburger.
0:57:47 > 0:57:49That's it from Guildford. Next time we're in Glasgow,
0:57:49 > 0:57:52looking at the secrets of the Mediterranean diet
0:57:52 > 0:57:56and carrying out a huge experiment to see if you can get
0:57:56 > 0:58:00the benefits of that diet while making very little effort.
0:58:00 > 0:58:04We'll be finding out whether we should all become vegetarian
0:58:04 > 0:58:07and whether beards are really unhygienic.
0:58:15 > 0:58:19# I just made an appointment for a special rendezvous
0:58:20 > 0:58:24# To see a man of miracles and all that he can do
0:58:29 > 0:58:32# Doctor, I want you
0:58:32 > 0:58:34# Mm, my doctor, wanna do
0:58:34 > 0:58:36# I can't get over you
0:58:36 > 0:58:39# Doctor, do anything that you wanna do... #