0:00:04 > 0:00:08How often do you stop and really think about your food?
0:00:08 > 0:00:11Look at all this lovely fat and sugar.
0:00:11 > 0:00:12Yummy.
0:00:12 > 0:00:16Do you ever wonder why you eat what you eat?
0:00:16 > 0:00:18What cooking does to food?
0:00:19 > 0:00:21Delicious.
0:00:21 > 0:00:24Or what effect it has on your body?
0:00:24 > 0:00:26I trained as a medical doctor and I'm absolutely obsessed
0:00:26 > 0:00:29by nutrition and the hidden chemistry of food.
0:00:30 > 0:00:34So I've teamed up with botanist James Wong to explore food,
0:00:34 > 0:00:37each of us coming from very different perspectives.
0:00:37 > 0:00:39Truly delicious.
0:00:39 > 0:00:41Together, we have taken over
0:00:41 > 0:00:43the country's leading food science lab...
0:00:45 > 0:00:48..to deconstruct some of our favourite foods...
0:00:48 > 0:00:50It's all sunk to the bottom.
0:00:50 > 0:00:53..and to reveal some truly remarkable secrets.
0:00:53 > 0:00:58I want to find out what affect food has on us and our biology,
0:00:58 > 0:01:00right down to the molecular level.
0:01:02 > 0:01:05As a botanist, I'm fascinated by
0:01:05 > 0:01:08the massive diversity of edible plants on our planet.
0:01:08 > 0:01:11I'm going to put them under the microscope to discover
0:01:11 > 0:01:14exactly how their biology interacts with our own.
0:01:17 > 0:01:21So join us as we seek out the most remarkable food stories
0:01:21 > 0:01:25on the planet and reveal the hidden science of our food.
0:01:39 > 0:01:43Across the world, food comes in a bewildering range of shapes,
0:01:43 > 0:01:46colours and flavours,
0:01:46 > 0:01:51but there was a time early in our lives when things were much simpler,
0:01:51 > 0:01:55when we lived and thrived on just one food.
0:02:00 > 0:02:04Chances are this is the first food you ever consumed -
0:02:04 > 0:02:05it's human breast milk.
0:02:08 > 0:02:10Now, what's amazing about this stuff is that it contains all
0:02:10 > 0:02:13the nutrients a baby needs to grow and thrive.
0:02:13 > 0:02:15Fed on nothing but breast milk,
0:02:15 > 0:02:18a baby will double in weight in just five months.
0:02:20 > 0:02:24So how can this precious liquid provide everything a baby needs
0:02:24 > 0:02:28to grow and prosper? To find out, I'm going to take it apart.
0:02:30 > 0:02:35We start by putting 200ml samples, a few feeds for a new-born,
0:02:35 > 0:02:36into a centrifuge.
0:02:39 > 0:02:43A quick strain and the first ingredient in the milk is visible.
0:02:47 > 0:02:50Now, this contains around 8g of fat,
0:02:50 > 0:02:53about the same amount as you would find in a bag of crisps,
0:02:53 > 0:02:56fat that is essential for building a baby's nervous system
0:02:56 > 0:02:59and the smooth running of their brain.
0:02:59 > 0:03:03What's left is this skimmed milk, which is mainly water,
0:03:03 > 0:03:07but which also includes another vital ingredient.
0:03:07 > 0:03:11I should be able to make it appear by adding a few drops of vinegar.
0:03:12 > 0:03:13Now I need to filter it.
0:03:16 > 0:03:19This is protein, essential for building a baby's body.
0:03:24 > 0:03:27I'm left with a solution of vitamins, minerals
0:03:27 > 0:03:29and one last major component.
0:03:31 > 0:03:33Now I'm going to do something slightly weird
0:03:33 > 0:03:37because I haven't tasted breast milk since I was a baby.
0:03:39 > 0:03:42Surprisingly sweet, although I guess it shouldn't be surprising
0:03:42 > 0:03:47because about 7% of that is made up of lactose, which is a sugar,
0:03:47 > 0:03:48a form of carbohydrate,
0:03:48 > 0:03:53and babies need carbohydrate because they need an instant source
0:03:53 > 0:03:54of accessible energy.
0:03:55 > 0:03:58So this mix of carbs, proteins, fats,
0:03:58 > 0:04:03vitamins and minerals in breast milk is all a baby needs to survive.
0:04:04 > 0:04:08The funny thing is that, as we get older, it doesn't really change.
0:04:08 > 0:04:11They just come to us in different forms of food.
0:04:16 > 0:04:18As adults, we're faced with a huge range
0:04:18 > 0:04:21of different foods to choose from.
0:04:22 > 0:04:27So how do we go about getting the right balance of fat, protein,
0:04:27 > 0:04:29carbs, vitamins and minerals?
0:04:31 > 0:04:35And which are absolutely essential for our survival?
0:04:46 > 0:04:52Every morning, all over the globe, we wake up ready for food.
0:04:52 > 0:04:54COCK CROWS
0:05:05 > 0:05:10We rise with our blood sugar low and the same need - quick energy.
0:05:13 > 0:05:16Be it toast, cereal, or rice,
0:05:16 > 0:05:20it's little wonder that most of us turn to the same type of food
0:05:20 > 0:05:25for that first meal of the day - carbohydrates.
0:05:25 > 0:05:26Did I snore?
0:05:26 > 0:05:28- No.- OK, good.
0:05:31 > 0:05:35Carbohydrates are fantastically diverse.
0:05:35 > 0:05:40It's really sort of a catch-all terminology for a group of chemicals
0:05:40 > 0:05:44that are made up of building blocks of sugar.
0:05:44 > 0:05:49There are many different types - glucose, lactose and probably
0:05:49 > 0:05:52the most exciting one, starch.
0:05:53 > 0:05:57It's what plants use to store away their energies
0:05:57 > 0:06:02in a concentrated format. Round here, it's usually found
0:06:02 > 0:06:05in the form of a seed stolen from a grass.
0:06:09 > 0:06:12Oryza sativa, better known as the rice plant.
0:06:16 > 0:06:20Each seed is a grain of rice, a marvel of nature.
0:06:21 > 0:06:24But rice doesn't give up its energy easily.
0:06:30 > 0:06:33These terraces here in Banaue are called by some
0:06:33 > 0:06:36the eighth wonder of the world.
0:06:39 > 0:06:43The people who live in these mountains have been cultivating rice
0:06:43 > 0:06:45for over 2,000 years.
0:06:51 > 0:06:52- Hello!- Hello!
0:06:56 > 0:06:58'And today, it's my turn.'
0:06:58 > 0:07:01I feel like Superman to be able to do this.
0:07:03 > 0:07:06'As we work the terraces, we're burning calories,
0:07:06 > 0:07:08'a measurement of energy.
0:07:10 > 0:07:14'Even at rest, our body needs fuel to tick over and,
0:07:14 > 0:07:18'just standing here, I'm burning about 100 calories an hour.
0:07:20 > 0:07:25'But while working the fields, that jumps up to around 350.'
0:07:25 > 0:07:29- You're tired?- I'm waiting for my Asian rice farmer genes to kick in.
0:07:30 > 0:07:32I don't think they work!
0:07:36 > 0:07:38We get our energy from our food
0:07:38 > 0:07:42and the carbohydrate-rich ones like the rice I had for breakfast
0:07:42 > 0:07:45give us fuel more quickly than any other type.
0:07:48 > 0:07:52The body breaks down long carbohydrate chains
0:07:52 > 0:07:54into a simple sugar - glucose.
0:07:57 > 0:08:01It's easily absorbed in the blood and transported around the body,
0:08:01 > 0:08:03feeding our muscles and our organs.
0:08:06 > 0:08:08Carbs are the rocket fuel in our diets.
0:08:16 > 0:08:20Growing rice by hand requires a lot of energy.
0:08:26 > 0:08:30So we have to be sure we get a lot more energy from eating it
0:08:30 > 0:08:31than it takes to produce it.
0:08:36 > 0:08:39I mean, even harvesting the stuff is labour-intensive.
0:08:42 > 0:08:45And you can be burning over 400 calories an hour.
0:08:48 > 0:08:53So, after six months of loving care and hundreds of labour hours,
0:08:53 > 0:08:56you end up with this beautiful stuff - raw rice.
0:08:59 > 0:09:01I still wouldn't call it a food, though.
0:09:04 > 0:09:08All this effort begs the question - why do we bother with rice at all?
0:09:11 > 0:09:17The reason why rice is such a phenomenally important food is the
0:09:17 > 0:09:24sheer amount of energy that's packed into each one of these tiny grains.
0:09:24 > 0:09:27And I can actually show you how much energy they have visually
0:09:27 > 0:09:30but, first, I've got to break them open.
0:09:31 > 0:09:36This stuff might not look very exciting,
0:09:36 > 0:09:38but it's packed full of energy.
0:09:41 > 0:09:45You can convert the potential energy that's stored in the rice grains
0:09:45 > 0:09:48into heat and light energy just by doing this.
0:09:51 > 0:09:53'Each puff is around 10g...'
0:09:55 > 0:09:57I could do this all day! '
0:09:57 > 0:10:00'..and contains around 35 calories of energy,
0:10:00 > 0:10:01'all going up in flames.
0:10:03 > 0:10:05'And almost all of it comes from carbohydrates.'
0:10:07 > 0:10:10Now, our bodies might not do this in the exact same way
0:10:10 > 0:10:12because we use complex biochemistry to do it.
0:10:14 > 0:10:17And rice doesn't give up its energy without a fight...
0:10:20 > 0:10:23..but we have discovered how to harness its power.
0:10:26 > 0:10:30Even once fully processed, rice is essentially indigestible
0:10:30 > 0:10:34because starch really stubbornly holds on to its energy -
0:10:34 > 0:10:36until you do this.
0:10:37 > 0:10:40Cooking is the game-changer.
0:10:48 > 0:10:50The starch in the rice is made up of
0:10:50 > 0:10:55two energy-giving carbohydrate molecules - amylose and amylopectin.
0:10:57 > 0:11:00But their long chains are packed together,
0:11:00 > 0:11:02making them mostly indigestible.
0:11:04 > 0:11:07The combination of heat and water
0:11:07 > 0:11:10has the power to break the tangled chains apart.
0:11:18 > 0:11:21This chemistry is going on inside every cell.
0:11:26 > 0:11:30The starch absorbs the boiling water and swells massively...
0:11:33 > 0:11:37..until the moment when the cells burst open
0:11:37 > 0:11:39and the digestible carbs erupt.
0:11:44 > 0:11:48So turning rice into a food is incredibly energy intensive.
0:11:51 > 0:11:55A cupful takes about 70 calories to produce.
0:11:57 > 0:12:02But we got 35 calories from just 10g,
0:12:02 > 0:12:07which means a cup of rice gives us back around 700 calories.
0:12:08 > 0:12:12We get a whopping ten times more energy out than we put in.
0:12:16 > 0:12:20And that's why rice, a cultivated river grass,
0:12:20 > 0:12:24has become such an important staple in the water-rich tropics.
0:12:33 > 0:12:37Where it's too cold or too dry to grow rice,
0:12:37 > 0:12:44we in the western world have turned to another crop for our carb hit -
0:12:44 > 0:12:46wheat.
0:12:55 > 0:12:59Most of the wheat we consume comes in the form of bread
0:12:59 > 0:13:03and this city is famous for one particular type of bread -
0:13:03 > 0:13:05sourdough.
0:13:05 > 0:13:06I've been doing this for 37 years.
0:13:06 > 0:13:08The minute I touched dough,
0:13:08 > 0:13:12I fell in love with it and thought, "This is what I want to do".
0:13:12 > 0:13:14No matter if you're rich, poor, or anything,
0:13:14 > 0:13:17you're making something wonderful for everybody.
0:13:19 > 0:13:22It begins with unprocessed wheat flour...
0:13:26 > 0:13:30..a bland, tasteless powder that, if cooked, would set like concrete.
0:13:33 > 0:13:35To turn it into a tasty food,
0:13:35 > 0:13:38Fernando Padilla employs an army of microbes.
0:13:43 > 0:13:45These microbes live in something
0:13:45 > 0:13:47affectionately known as the mother dough.
0:13:52 > 0:13:55This is where she lives, as you can tell. We say, "Mother dough lives here".
0:13:55 > 0:13:57We're going to put an address here.
0:13:59 > 0:14:02I'm carrying a piece of history here.
0:14:02 > 0:14:05'The mother dough is a mix of water and flour,
0:14:05 > 0:14:07'more commonly known as a starter.'
0:14:09 > 0:14:14Inside it, a community of live yeast cells and bacteria thrive.
0:14:17 > 0:14:20But this is no ordinary starter.
0:14:20 > 0:14:23It's reported to be the oldest in the US.
0:14:25 > 0:14:28And this goes back to 1849?
0:14:28 > 0:14:34Imagine, over 165 years ago, it was the same dough.
0:14:34 > 0:14:37A tiny piece of this dates back to the same family.
0:14:39 > 0:14:43This starter was apparently created by French immigrants
0:14:43 > 0:14:45during the great Gold Rush.
0:14:47 > 0:14:48Inhale.
0:14:48 > 0:14:50Oh, God!
0:14:53 > 0:14:58That's all the sweetness of the flour being fermented.
0:14:58 > 0:15:01It creates this alcohol flavour, but it all evaporates.
0:15:01 > 0:15:03- You see how strong it is? - I was expecting something nice!
0:15:05 > 0:15:09This little thing is going to give us 400 loaves of bread.
0:15:09 > 0:15:10Let's bring it out.
0:15:11 > 0:15:16'Every day, half of the mother dough is fed with flour and water.
0:15:16 > 0:15:19'Then it's locked away overnight, where it regenerates,
0:15:19 > 0:15:23'doubling in size.' Good night, Mummy.
0:15:23 > 0:15:24See you tomorrow.
0:15:25 > 0:15:27This is 200lbs of flour here.
0:15:30 > 0:15:35'The other half of mother will be used to create over 400 loaves of
0:15:35 > 0:15:38- 'of delicious, fresh bread.' - We should have worn the apron.
0:15:41 > 0:15:44Adding water activates enzymes in the flour.
0:15:46 > 0:15:51This in turn starts a complex biochemical cascade,
0:15:51 > 0:15:53which begins with starch in the flour
0:15:53 > 0:15:56turning into a sugar called maltose.
0:15:58 > 0:16:01Mix it for ten minutes.
0:16:01 > 0:16:07Bacteria from the mother dough now feed greedily on the maltose,
0:16:07 > 0:16:09breaking it down into glucose.
0:16:15 > 0:16:18The bacteria have begun to digest the flour for us.
0:16:18 > 0:16:21You hear that? When you hear the dough popping...
0:16:21 > 0:16:23Pop, pop, pop.
0:16:24 > 0:16:27It's saying, "I'm ready, get me out of here".
0:16:27 > 0:16:32'If we baked it now, this would turn out as flat as a pancake.'
0:16:32 > 0:16:34Why is mine not looking like yours?
0:16:34 > 0:16:37- Now we just fold it over.- Yep.
0:16:37 > 0:16:40'Fortunately, another group of microbes will use
0:16:40 > 0:16:42'some of the glucose to transform the dough.'
0:16:44 > 0:16:46OK, this is dried yeast.
0:16:46 > 0:16:49Doesn't look incredibly exciting, does it?
0:16:49 > 0:16:53But every single grain there contains thousands of these
0:16:53 > 0:16:56single-celled organisms and they're held currently
0:16:56 > 0:16:58in a state of suspended animation.
0:16:58 > 0:17:00I am about to bring them back to life.
0:17:02 > 0:17:05To do that, they need food and water.
0:17:05 > 0:17:11So I'm going to add sugar and then water...
0:17:11 > 0:17:14and now I add the yeast.
0:17:14 > 0:17:16If the yeast cells are still alive,
0:17:16 > 0:17:20they'll produce a gas which passes through the pipe to the test tube.
0:17:22 > 0:17:26Those yeast cells are springing back to life,
0:17:26 > 0:17:28and they're going to get stuck into that sugar.
0:17:33 > 0:17:36So it's working. You can see the bubbles being produced.
0:17:36 > 0:17:40They're being created by the yeast gobbling up the sugar
0:17:40 > 0:17:44and producing carbon dioxide gas, which you can see bubbling up.
0:17:44 > 0:17:47And it's this reaction which is absolutely key
0:17:47 > 0:17:50to producing a nice, fluffy loaf.
0:17:51 > 0:17:54With carbon dioxide bubbling through his bread mix,
0:17:54 > 0:17:57Fernando must now stop the gas escaping.
0:17:58 > 0:18:02To do that, he alters the chemical structure of the dough
0:18:02 > 0:18:04by a process called kneading.
0:18:05 > 0:18:08I'm not an expert baker at all,
0:18:08 > 0:18:13but I know the secret to making good bread is
0:18:13 > 0:18:16making really sure you knead it thoroughly.
0:18:19 > 0:18:23When we knead bread, we're forcing two proteins inside the flour,
0:18:23 > 0:18:28gliadin and glutenin, to form bonds, creating a tough new substance -
0:18:28 > 0:18:30gluten.
0:18:32 > 0:18:35And this is where the art of bread-making comes in.
0:18:36 > 0:18:41If you don't knead enough, you won't create enough gluten in your loaf,
0:18:41 > 0:18:44so the gases will escape and it won't rise.
0:18:46 > 0:18:51But get it just right, and the effect on the loaf is magical.
0:18:55 > 0:18:59As it rises, its volume more than doubles as the yeast consume
0:18:59 > 0:19:05the glucose and as they blow bubbles inside their gluten home.
0:19:05 > 0:19:09The bacteria also produce a small amount of lactic acid
0:19:09 > 0:19:11and, with no added sugar,
0:19:11 > 0:19:16the acid gives the loaf the distinctive tang of sourdough bread.
0:19:18 > 0:19:22Baking then seals the air pockets and, thanks to the microbes from
0:19:22 > 0:19:27the mother dough, we end up with a carb-rich, light, fluffy loaf.
0:19:30 > 0:19:32Whoa! Wow.
0:19:35 > 0:19:38- How many loaves is that? - This is about 100 loaves of bread.
0:19:40 > 0:19:42Perfect.
0:19:50 > 0:19:51Mmm. It's incredible.
0:20:02 > 0:20:05Sourdough used to be one of the most popular forms of bread,
0:20:05 > 0:20:09until it got displaced by cheap, mass-produced stuff
0:20:09 > 0:20:13and that seems like a shame because it's tasty and it's also healthier.
0:20:13 > 0:20:17It hasn't got added sugars and the acid in the bread means
0:20:17 > 0:20:19you're much better able to absorb the minerals and vitamins
0:20:19 > 0:20:21that are locked up in the flour.
0:20:21 > 0:20:24In fact, I think I'm going to try baking some when I get home.
0:20:28 > 0:20:32From the east to the west, by unlocking the secrets of rice
0:20:32 > 0:20:36and wheat, our ancestors made the indigestible digestible.
0:20:39 > 0:20:42As a result, these foods became the staples
0:20:42 > 0:20:45that feed our towns and cities.
0:20:47 > 0:20:52Historically, carbs were the foods that fuelled our civilisations,
0:20:52 > 0:20:54a cheap and ready source of energy.
0:21:01 > 0:21:05Energy keeps us moving, but it's protein that builds us.
0:21:08 > 0:21:14Your body makes at least 250,000 different types of protein,
0:21:14 > 0:21:18molecules which are needed to make everything from hormones
0:21:18 > 0:21:20like insulin to the muscles that power you.
0:21:22 > 0:21:25To create all these different proteins,
0:21:25 > 0:21:29you need to eat plenty of protein, around 50g a day.
0:21:32 > 0:21:37And one of my favourite sources of high-quality protein is eggs.
0:21:43 > 0:21:47So I want to take one apart, see just what it is that I'm eating.
0:21:49 > 0:21:54Right, I'm just going to prise off a little bit of shell,
0:21:54 > 0:21:58and there it is. As you can see, it's hard, crystalline,
0:21:58 > 0:22:01made up mainly of calcium carbonate.
0:22:05 > 0:22:08Here, magnified over 2,000 times,
0:22:08 > 0:22:14you can see the surface of the shell is covered in lots of tiny holes,
0:22:14 > 0:22:16there so a developing chick can breathe.
0:22:18 > 0:22:22Each hole is formed over a gap in a lattice of protein
0:22:22 > 0:22:24that the shell grows over.
0:22:24 > 0:22:28Surprisingly, this membrane is partly made from a tough protein
0:22:28 > 0:22:33called keratin, the same stuff our hair and nails made from.
0:22:38 > 0:22:42It protects the contents of the egg from bacteria and dust.
0:22:44 > 0:22:50Inside, the white, or albumen, is a mix of water and 11% protein.
0:22:52 > 0:22:56But it's the egg yolk where most of the goodness resides.
0:22:56 > 0:23:01It's got minerals, vitamins, some fat, some cholesterol,
0:23:01 > 0:23:04but it's also got 17% protein.
0:23:04 > 0:23:07The fact that you find protein in the membrane, the white,
0:23:07 > 0:23:12AND the egg yolk, shows you just how important protein is in us.
0:23:12 > 0:23:15It's responsible for everything,
0:23:15 > 0:23:21from running your immune system to carrying oxygen around your body.
0:23:21 > 0:23:25And eggs are a really beautiful source of protein,
0:23:25 > 0:23:28because almost all the protein there,
0:23:28 > 0:23:31apart, obviously, from the shell, can be readily digested.
0:23:33 > 0:23:38But, once you've eaten it, where does the protein from your food go?
0:23:47 > 0:23:52Mexico City, home to a population of one of the highest consumers
0:23:52 > 0:23:54of eggs on the planet.
0:24:05 > 0:24:08And it's also home to the Lucha Libre.
0:24:12 > 0:24:14BELL RINGS
0:24:27 > 0:24:29When it comes to wrestling,
0:24:29 > 0:24:33Mistico, El Santo and Shocker are all household names.
0:24:40 > 0:24:42The way you look in the ring is very important.
0:24:42 > 0:24:45In my case, I don't wear a mask
0:24:45 > 0:24:50because they call me "El senor mil por ciento guapo",
0:24:50 > 0:24:53which means "1,000% handsome".
0:24:59 > 0:25:02I've been wrestling for 22 years professionally.
0:25:05 > 0:25:09My dad used to be a professional wrestler, too.
0:25:09 > 0:25:13He taught me mostly everything I know
0:25:13 > 0:25:16and he taught me how to eat, too.
0:25:16 > 0:25:19To build and maintain his impressive physique,
0:25:19 > 0:25:21Shocker needs to eat a lot of protein.
0:25:22 > 0:25:25To be a wrestler, you've got to have good nutrition.
0:25:25 > 0:25:29If you don't eat, you don't grow.
0:25:31 > 0:25:36In the UK, on average, we each eat around four eggs a week.
0:25:36 > 0:25:39The average Mexican eats seven,
0:25:39 > 0:25:44but Shocker puts away an incredible 50 every week.
0:25:48 > 0:25:52The eggy proteins are needed because he trains so hard every day.
0:25:52 > 0:25:54With each stretch and lift,
0:25:54 > 0:25:58he is tearing the fibres deep down in his muscles.
0:26:00 > 0:26:03This triggers his body to repair them.
0:26:06 > 0:26:10Enzymes deep in his stomach and intestines break down the protein
0:26:10 > 0:26:14in his food into their individual building blocks,
0:26:14 > 0:26:16molecules called amino acids.
0:26:19 > 0:26:23These enter his bloodstream and travel to where they are needed.
0:26:24 > 0:26:29And, for Shocker, the amino acids join together to build the proteins
0:26:29 > 0:26:32he needs to make bigger, stronger muscles.
0:26:40 > 0:26:41I like my eggs in different ways.
0:26:41 > 0:26:43I like them a la Mexicana.
0:26:43 > 0:26:45They come with tomato, onion and chilli.
0:26:47 > 0:26:49I like them rancheros,
0:26:49 > 0:26:51tortilla under, sunny side up.
0:26:53 > 0:26:56The way we prepare eggs makes a massive difference
0:26:56 > 0:26:59to how easily we can use the protein they contain.
0:27:01 > 0:27:04Contrary to popular belief, eat eggs raw
0:27:04 > 0:27:08and we only benefit from about half the protein.
0:27:11 > 0:27:13Cook them and it's a very different story.
0:27:14 > 0:27:18It fundamentally changes the proteins in an egg.
0:27:18 > 0:27:19You can see it happening.
0:27:21 > 0:27:24If you really want to play around with the texture of the eggs,
0:27:24 > 0:27:26you could invest in a water bath.
0:27:26 > 0:27:28That way, you can control not only the time,
0:27:28 > 0:27:31but also the temperature you cook the eggs at.
0:27:32 > 0:27:37This is a raw egg and, as it slowly cooks, it changes.
0:27:37 > 0:27:41Over here, you can begin to see some of the egg white is setting.
0:27:41 > 0:27:47The protein in it is denaturing, meaning it's easier to absorb.
0:27:48 > 0:27:52The longer eggs cook, the more the protein fibres denature.
0:27:52 > 0:27:55The protein molecules literally unfold.
0:27:56 > 0:28:01That's what's happening when egg white transforms into a gel.
0:28:01 > 0:28:07These cooked egg whites aren't simply more pleasant to eat,
0:28:07 > 0:28:10the untangled protein molecules also make it easier
0:28:10 > 0:28:14for Shocker to absorb the protein his body vitally needs.
0:28:17 > 0:28:20When you work out a lot, when you do a lot of exercise,
0:28:20 > 0:28:24you start building up and you start making your food into muscle,
0:28:24 > 0:28:27all different kinds of muscle.
0:28:27 > 0:28:28Relaxed muscle.
0:28:34 > 0:28:39Shocker's success in the ring is built entirely on the way he trains
0:28:39 > 0:28:42and how his body uses the amino acids,
0:28:42 > 0:28:45the building blocks of every protein,
0:28:45 > 0:28:46to repair his muscles.
0:28:48 > 0:28:51People like champions. We don't like losers.
0:28:52 > 0:28:54You've got to look good. You've got to win.
0:28:59 > 0:29:02BELL RINGS
0:29:16 > 0:29:22Although we're made up of around a quarter of a million different
0:29:22 > 0:29:26proteins, those proteins are comprised of just 20 amino acids.
0:29:29 > 0:29:34The amazing thing is our bodies can just manufacture 11 of those,
0:29:34 > 0:29:38but that leaves nine and we call them the nine essential amino acids.
0:29:42 > 0:29:44We've evolved the cellular machinery
0:29:44 > 0:29:47to produce all but these nine essential ones.
0:29:50 > 0:29:52Those, we must get from our diet.
0:29:54 > 0:29:56But this isn't always easy.
0:29:56 > 0:30:01Eggs, fish and meat contain all nine essential amino acids,
0:30:01 > 0:30:04but there are plenty of foods that don't.
0:30:05 > 0:30:09To survive, we have to carefully mix and match what we eat.
0:30:11 > 0:30:15Look at this. This is real Aztec gold.
0:30:15 > 0:30:19For millennia, corn has been the staple crop
0:30:19 > 0:30:22throughout pretty much the whole of Latin America
0:30:22 > 0:30:26and that's because it's just packed full of the good stuff.
0:30:27 > 0:30:31It's bursting with carbs, vitamins and fibre,
0:30:31 > 0:30:36but crucially, though, it's missing two essential amino acids -
0:30:36 > 0:30:38lysine and tryptophan.
0:30:40 > 0:30:42But in this part of Mexico,
0:30:42 > 0:30:46they've found an ingenious way of eating corn to get all the
0:30:46 > 0:30:51amino acids they need and it's a rather surprising local delicacy.
0:30:52 > 0:30:55I've always wanted to see it in the field.
0:30:55 > 0:30:58You get these massively swollen ears of corn
0:30:58 > 0:31:01and, when you split them open,
0:31:01 > 0:31:05you can see the deformity that lies beneath.
0:31:06 > 0:31:10Huitlacoche has been called "food of the gods",
0:31:10 > 0:31:12but it looks like something from a horror movie.
0:31:15 > 0:31:19It too is lacking essential amino acids, but eat this
0:31:19 > 0:31:23with regular corn, and you get all the amino acids you need.
0:31:23 > 0:31:27This is created by a pathogenic fungus
0:31:27 > 0:31:31and it's a debilitating disease on maize plants around the world,
0:31:31 > 0:31:37but only in Mexico do farmers open this up and get really excited.
0:31:40 > 0:31:44This fungus begins as nothing more than a microscopic spore.
0:31:46 > 0:31:50Carried on the wind, just one could infect an entire crop.
0:31:52 > 0:31:54It germinates and sends out branches
0:31:54 > 0:31:57that pass throughout the ear of corn,
0:31:57 > 0:32:01where it affects every kernel, creating the swollen tumours.
0:32:04 > 0:32:09Other countries would torch these infected fields, but not here.
0:32:17 > 0:32:23What time is it now? 6.30 in the morning and in full swing.
0:32:25 > 0:32:28Huitlacoche has become a delicacy,
0:32:28 > 0:32:33served up in the best restaurants in town.
0:32:33 > 0:32:34It's crazy, no?
0:32:34 > 0:32:40At market, infected corn is worth 50% more than just regular corn,
0:32:40 > 0:32:44so master chef Lalo Garcia arrives early to ensure he gets
0:32:44 > 0:32:45the pick of the bunch.
0:32:46 > 0:32:50- This is where I buy the huitlacoche. - Wow.- Look at that.
0:32:51 > 0:32:55And the smell. The smell is amazing, that of earth.
0:32:55 > 0:32:58It's why I really love this product.
0:32:58 > 0:33:04It's amazing that earth still produces this, this type of beauty.
0:33:07 > 0:33:13So we have a little olive oil here. Onions. We add our huitlacoche.
0:33:18 > 0:33:22We're going to make a very basic salsa to go with our huitlacoche.
0:33:28 > 0:33:31You'd never know to look at it,
0:33:31 > 0:33:34but huitlacoche has the most amazing flavour.
0:33:34 > 0:33:41It's kind of like black truffles meet shiitake mushrooms,
0:33:41 > 0:33:44with that savoury volume whacked up.
0:33:44 > 0:33:48Smoky, rich. It's got to be the world's best comfort food.
0:33:50 > 0:33:52And eaten with corn tortillas,
0:33:52 > 0:33:56I get my hit of all nine of those essential amino acids.
0:34:01 > 0:34:03But the Mexicans aren't the only ones
0:34:03 > 0:34:06to pull off this classic combination.
0:34:07 > 0:34:10From the British favourite of beans on toast...
0:34:12 > 0:34:15..to the Indian Holy Grail of rice and dhal...
0:34:17 > 0:34:22..or the Italian staple of beans and pasta, across the globe,
0:34:22 > 0:34:27we've invented combinations of pulses and beans mixed with grains
0:34:27 > 0:34:31to give us all nine of the amino acids we desperately need.
0:34:33 > 0:34:37We've instinctively become expert nutritionists,
0:34:37 > 0:34:40hunting out exactly what we need from our food.
0:34:44 > 0:34:48And no nutritionist would recommend a diet that didn't have some fat.
0:34:51 > 0:34:55Whether you get it from meat, fish, nuts or vegetables,
0:34:55 > 0:34:59fat, like protein, is essential for health.
0:35:02 > 0:35:05Now, different foods have different forms of fat.
0:35:05 > 0:35:08We've got olives, walnut, avocado.
0:35:09 > 0:35:12Most of these fats are liquid at room temperature.
0:35:12 > 0:35:15The odd one out is this one, which came from the beef.
0:35:15 > 0:35:17It's solid at room temperature.
0:35:17 > 0:35:20And the reason there are so many different types of fat is because
0:35:20 > 0:35:25there are so many different types of building blocks for fat.
0:35:25 > 0:35:28Each fat is in turn made up of something called fatty acids.
0:35:29 > 0:35:32Complex fat chains are built by assembling
0:35:32 > 0:35:35these smaller units of fatty acids.
0:35:38 > 0:35:41Taking a close look at the fat in a piece of salmon
0:35:41 > 0:35:44shows just how many fatty acids there are.
0:35:46 > 0:35:48I'm mashing it up with some acetone,
0:35:48 > 0:35:52stuff more commonly used to remove nail varnish.
0:35:52 > 0:35:55This won't add to the flavour, but it will help separate out the fat.
0:35:56 > 0:36:01There's a lovely layer of pink fat right there on the top.
0:36:01 > 0:36:04Some fancy kit then reveals what I'm looking for.
0:36:04 > 0:36:06You can see lots of different peaks
0:36:06 > 0:36:10and each of these peaks represents a different fatty acid.
0:36:12 > 0:36:16These fatty acids are essential to the smooth running of our bodies.
0:36:17 > 0:36:21Eating salmon is a great way of getting hold of them.
0:36:21 > 0:36:26But we are so dependent on fat that we've evolved cellular machinery
0:36:26 > 0:36:30to build most of the fatty acids that might be missing from our diet.
0:36:30 > 0:36:34There are two types, however, which your body cannot make.
0:36:34 > 0:36:38They are omega-6 and the rather more elusive omega-3.
0:36:40 > 0:36:42These we have to get from food.
0:36:47 > 0:36:51Omega-6 is easy - there's plenty in vegetable oil.
0:36:51 > 0:36:55Omega-3 is rarer. It's found in oily fish, like salmon.
0:36:56 > 0:36:58But where else can you find it?
0:37:05 > 0:37:07We're going roaming. We're looking for the cattle now, are we?
0:37:07 > 0:37:09We are. It can take some time.
0:37:13 > 0:37:15These are Highland cattle.
0:37:15 > 0:37:18There we are, look. There's a cow away down there.
0:37:18 > 0:37:23They're really well adapted to life in Scotland.
0:37:23 > 0:37:26And though they sport the longest hair of any cow,
0:37:26 > 0:37:29that's not what makes them special.
0:37:29 > 0:37:33What marks these cattle out is that, unlike most cattle,
0:37:33 > 0:37:36their meat is rich in elusive omega-3.
0:37:38 > 0:37:41They look like really large dogs with horns!
0:37:43 > 0:37:46Iain MacKay looks after just 50 cattle.
0:37:47 > 0:37:51They're free to roam over a vast expanse of wild moorland.
0:37:53 > 0:37:54Hi, gang.
0:37:55 > 0:37:58The type of breed we've got here utilises this ground.
0:37:58 > 0:38:02They have a massive stomach and they can take on a huge amount of
0:38:02 > 0:38:05this roughage and then just go, lie down, and digest that.
0:38:07 > 0:38:11And it's this natural environment that provides the omega-3
0:38:11 > 0:38:13that we can't live without.
0:38:15 > 0:38:18In fact, it is absolutely vital for building and maintaining
0:38:18 > 0:38:21my favourite organ - the brain.
0:38:21 > 0:38:26Surprisingly enough, a brain is half fat and, of that fat,
0:38:26 > 0:38:29a quarter is made up of omega-3.
0:38:32 > 0:38:36All this omega-3 forms the connections between every nerve cell
0:38:36 > 0:38:42in the brain, cells which send and receive electrical impulses
0:38:42 > 0:38:46from the brain's 80 billion other cells.
0:38:46 > 0:38:50Low levels of omega-3 have been linked with depression and anxiety.
0:38:54 > 0:38:56Fortunately, there's a ready supply of the stuff
0:38:56 > 0:38:59scattered throughout this particular landscape.
0:39:02 > 0:39:05It's found naturally in the oils in the grass.
0:39:09 > 0:39:11But the highest dose can be got
0:39:11 > 0:39:14from a delicious mouthful of Highland clover.
0:39:19 > 0:39:22Magnify the clover 600 times
0:39:22 > 0:39:27and you'd be able to see microscopic globules of omega-3 fat.
0:39:34 > 0:39:37The cattle face the same challenge as us -
0:39:37 > 0:39:40they have to get their omega-3 from their diet.
0:39:42 > 0:39:44It matters what they eat.
0:39:44 > 0:39:46Grain contains very little omega-3,
0:39:46 > 0:39:51so factory farmed meat is lacking in this vital fatty acid.
0:39:54 > 0:39:59But these cows get their fill from grass and clover. Once eaten,
0:39:59 > 0:40:02the essential fatty acids enter the cells in their bodies...
0:40:04 > 0:40:06Look at that!
0:40:10 > 0:40:14..making this grass-fed steak far higher in omega-3
0:40:14 > 0:40:19than beef intensively farmed and fed on grain alone.
0:40:19 > 0:40:20Looks good.
0:40:23 > 0:40:28Both omega-3 and omega-6 are vital for life, but it's a balancing act.
0:40:30 > 0:40:34Too high a ratio of omega-6 to omega-3 has been linked to a whole
0:40:34 > 0:40:39range of inflammatory diseases, from type two diabetes to arthritis.
0:40:41 > 0:40:46And a recent US study found that it wasn't unusual for there to be
0:40:46 > 0:40:5125 times more omega-6 than omega-3 in people's diet,
0:40:51 > 0:40:56most of it coming from the vegetable oil used to cook fast foods,
0:40:56 > 0:40:59like burgers, chips and cookies.
0:41:01 > 0:41:05And as omega-6 is so easy to get, it means we really do
0:41:05 > 0:41:09have to concentrate on getting enough omega-3.
0:41:11 > 0:41:17So keep a look out for good sources of omega-3, like beans,
0:41:17 > 0:41:21salmon, mackerel,
0:41:21 > 0:41:23and grass-fed beef.
0:41:25 > 0:41:26In a macabre sort of way,
0:41:26 > 0:41:29I like the fact that I've met this cow's relatives.
0:41:29 > 0:41:32It had a happy life and it didn't travel very far to get my plate.
0:41:32 > 0:41:36I also really like the fact that it's rich in omega-3.
0:41:38 > 0:41:41And it is incredibly succulent.
0:41:43 > 0:41:46Most of the nutrients we require are found in the carbs,
0:41:46 > 0:41:49proteins and fats hidden inside every meal.
0:41:52 > 0:41:54But not quite all.
0:41:54 > 0:41:58Although only needed in tiny amounts, we need to
0:41:58 > 0:42:03get a constant top-up of vitamins and minerals to keep us healthy.
0:42:05 > 0:42:11And there is one mineral-rich food we rely on from birth -
0:42:11 > 0:42:13milk.
0:42:31 > 0:42:34Here in the Rhodope Mountains of Bulgaria,
0:42:34 > 0:42:39people are 30% more likely to live to 100 than people from the US.
0:43:00 > 0:43:04So could it be their diet that's helping them live so long?
0:43:06 > 0:43:11Well, what unites them is the amount of milk they consume,
0:43:11 > 0:43:16rich in a mineral that our bodies can't make -
0:43:16 > 0:43:18calcium.
0:43:18 > 0:43:23Absorbed from food and passed from our gut into the bloodstream,
0:43:23 > 0:43:28calcium is transported to where it's needed most -
0:43:28 > 0:43:29our bones.
0:43:33 > 0:43:36We're constantly rebuilding our skeletons.
0:43:41 > 0:43:44And to do that, we have to keep eating calcium.
0:43:46 > 0:43:50And the amount we need increases as we get older
0:43:50 > 0:43:52because we just don't repair our bones as easily.
0:44:07 > 0:44:12Each morning, Dobrina sets about a daily food ritual
0:44:12 > 0:44:17which might hold the key to her family's long, healthy lives.
0:44:17 > 0:44:18SHE SPEAKS OWN LANGUAGE
0:44:18 > 0:44:20You must have much better technique than me
0:44:20 > 0:44:24because there's nothing coming out here! I could be here all day.
0:44:28 > 0:44:31Milk, be it human breast or from the cow,
0:44:31 > 0:44:35is a fantastic source of vitamins and minerals.
0:44:36 > 0:44:39We removed all the fat and the protein
0:44:39 > 0:44:42to see just what the other constituents were.
0:44:42 > 0:44:45And we found this incredibly rich,
0:44:45 > 0:44:48chemical soup of all sorts of vitamins and minerals that are
0:44:48 > 0:44:53floating around here. I want to get out one thing that's left in there.
0:44:55 > 0:44:58After warming to 40 Celsius,
0:44:58 > 0:45:01we added a salt solution to kick out what I'm looking for.
0:45:04 > 0:45:08A suction filtration then gave me this gungy stuff.
0:45:08 > 0:45:11That is calcium phosphate.
0:45:11 > 0:45:16It's what your bones are made out of, so it's essential to human life.
0:45:18 > 0:45:19But, for some of us,
0:45:19 > 0:45:23getting enough calcium from milk is harder than you might think.
0:45:26 > 0:45:31By the age of five, some people lose the ability to digest lactose,
0:45:31 > 0:45:33the sugar in milk.
0:45:37 > 0:45:4270% of African-Americans are thought to be lactose-intolerant,
0:45:42 > 0:45:4780% of southern Europeans, but only 5% of Brits.
0:45:51 > 0:45:55It's because, over the centuries, cultures that raise dairy cattle
0:45:55 > 0:46:01adapted and developed the ability to digest lactose,
0:46:01 > 0:46:03while cultures without cows didn't.
0:46:05 > 0:46:10And that's a lot of people who can't drink our main source of calcium.
0:46:11 > 0:46:14But we have learned to unlock the chemistry of milk.
0:46:17 > 0:46:19For people who can't digest lactose,
0:46:19 > 0:46:22drinking milk can turn their stomachs
0:46:22 > 0:46:25and that's because a gene that triggers the production of an enzyme
0:46:25 > 0:46:28called lactase has been turned off.
0:46:29 > 0:46:34Now, lactase would normally break down lactose and, in its absence,
0:46:34 > 0:46:38your body's reaction to the lactose can irritate your gut,
0:46:38 > 0:46:41can make you feel really sick and, as a consequence,
0:46:41 > 0:46:47it eliminates this ridiculously rich calcium source from your diet.
0:46:49 > 0:46:53But long ago, these mountain people discovered
0:46:53 > 0:46:58a bacterium that thrives on lactose, turning milk into yoghurt.
0:46:59 > 0:47:01And, every day,
0:47:01 > 0:47:04Dobrina carries on this family tradition making yoghurt,
0:47:04 > 0:47:06beginning with boiling the milk.
0:47:09 > 0:47:13What it does is effectively sterilises the milk, giving you
0:47:13 > 0:47:17a clean slate until you're ready to add the bacteria that you want.
0:47:18 > 0:47:20Oh, yeah. Perfect!
0:47:21 > 0:47:23Just the right amount.
0:47:24 > 0:47:27The curious thing is quite a lot of bacteria actually also have
0:47:27 > 0:47:31a problem breaking down lactose, except for a few strains
0:47:31 > 0:47:37and this is one of them here, a culture of Lactobacillus Bulgaricus,
0:47:37 > 0:47:39otherwise known as yesterday's yoghurt.
0:47:39 > 0:47:42I think what I do is I just pour it in here.
0:47:42 > 0:47:44Is that what I do?
0:47:44 > 0:47:45Oh, wait, no.
0:47:45 > 0:47:46SHE SPEAKS OWN LANGUAGE
0:47:46 > 0:47:49OK. I take this, I put in there...
0:47:49 > 0:47:50SHE SPEAKS OWN LANGUAGE
0:47:50 > 0:47:52- ..and then I pour it in?- No.
0:47:52 > 0:47:53No? More?
0:47:53 > 0:47:56SHE SPEAKS OWN LANGUAGE
0:47:56 > 0:48:00OK, and I stir it. And then I pour it in?
0:48:00 > 0:48:01OK.
0:48:04 > 0:48:05Once the microbes are added,
0:48:05 > 0:48:10they multiply as they feed on the lactose in milk,
0:48:10 > 0:48:14producing the lactic acid which is vital to making yoghurt.
0:48:17 > 0:48:21This exact process has been happening over and over again
0:48:21 > 0:48:23for potentially thousands of years.
0:48:25 > 0:48:28A lid on to keep any of the bacteria out
0:48:28 > 0:48:31and all we're doing now is insulating the milk,
0:48:31 > 0:48:35to keep the heat in, because the bacteria have a narrow window
0:48:35 > 0:48:38of when they're active in terms of temperature.
0:48:38 > 0:48:39SHE SPEAKS OWN LANGUAGE
0:48:39 > 0:48:42Three hours?
0:48:42 > 0:48:43No. Yes?
0:48:43 > 0:48:45SHE SPEAKS OWN LANGUAGE
0:48:45 > 0:48:48Three hours and we're eating? OK, I can do that!
0:48:50 > 0:48:53I think it's back to Bulgarian school for me.
0:48:59 > 0:49:05As the mixture becomes more acidic, the milk proteins clump together,
0:49:05 > 0:49:09creating a soft, tangy curd - yoghurt.
0:49:11 > 0:49:13Look at that, is that what we made?
0:49:13 > 0:49:14SHE SPEAKS OWN LANGUAGE
0:49:14 > 0:49:15Look at that proud smile!
0:49:15 > 0:49:17Let's open that up.
0:49:17 > 0:49:19You doubted my ability.
0:49:19 > 0:49:21Look at that, it was so simple.
0:49:25 > 0:49:28You can tell me what Bulgarian yoghurt tastes like
0:49:28 > 0:49:29made by an English guy.
0:49:29 > 0:49:32HE SPEAKS OWN LANGUAGE
0:49:32 > 0:49:34It's really good!
0:49:34 > 0:49:36Oh, thank you! That's lovely.
0:49:38 > 0:49:41There's been this amazing transformation
0:49:41 > 0:49:43in only a couple of hours.
0:49:43 > 0:49:47The bacteria have broken down a large proportion of the lactose,
0:49:47 > 0:49:51which means the whole mix is so much more digestible,
0:49:51 > 0:49:55potentially even for people with a lactose intolerance, and that means
0:49:55 > 0:49:59you get more calcium-rich deliciousness back in your diet.
0:50:00 > 0:50:01Mmm.
0:50:03 > 0:50:06Just 300mls of yoghurt will give you
0:50:06 > 0:50:08nearly half your daily calcium needs.
0:50:10 > 0:50:14But eating plenty of this vital mineral won't automatically mean
0:50:14 > 0:50:15that our bodies can use it.
0:50:19 > 0:50:23There's a final bit of chemistry necessary to lay down
0:50:23 > 0:50:24and replace bone.
0:50:26 > 0:50:28To do that, we need the help of vitamins.
0:50:31 > 0:50:35Now, these are strangely hard to classify.
0:50:36 > 0:50:40Vitamins are molecules that in many ways are best defined by
0:50:40 > 0:50:44what they're not. They're not minerals, not fatty acids,
0:50:44 > 0:50:47not amino acids, but they are absolutely essential,
0:50:47 > 0:50:49albeit in very small amounts.
0:50:53 > 0:50:58Magnified over 1,000 times, a beautiful world of crystals appears.
0:51:00 > 0:51:03Our bodies use these vitamins as life-support
0:51:03 > 0:51:05for many of our bodily functions.
0:51:10 > 0:51:14Vitamin C is abundant in citrus fruits.
0:51:14 > 0:51:19It strengthens blood vessels and gives skin its elasticity.
0:51:22 > 0:51:25And there are eight different types of B vitamins.
0:51:26 > 0:51:29B6 is found in nuts and does everything from
0:51:29 > 0:51:34keeping our nervous systems running to processing those amino acids
0:51:34 > 0:51:37into proteins that we need to repair muscles and organs.
0:51:41 > 0:51:44Vitamin E - that we get from foods like avocado.
0:51:44 > 0:51:46It acts as an antioxidant
0:51:46 > 0:51:50and protects our cells from damaging chemicals
0:51:50 > 0:51:52that are formed when we extract energy from food.
0:51:55 > 0:51:59The vitamin A we get from carrots keeps our eyes healthy
0:51:59 > 0:52:01and helps us fight infections.
0:52:04 > 0:52:08And leafy greens supply us with vitamin K,
0:52:08 > 0:52:10helping our blood to clot.
0:52:20 > 0:52:24And the only way we can absorb calcium is with the help
0:52:24 > 0:52:26of another vitamin - vitamin D.
0:52:30 > 0:52:35The key to getting our daily dose of vitamin D is to get enough sunlight.
0:52:37 > 0:52:40When sunlight reacts with cholesterol in our skin,
0:52:40 > 0:52:42the result is the vitamin D molecule.
0:52:47 > 0:52:51But here, high up in the Bulgarian mountains, and places far from
0:52:51 > 0:52:55the equator, like the UK, year-round sunshine is scarce.
0:52:59 > 0:53:03But there is a way through food that Mr Baklarev and his family can get
0:53:03 > 0:53:06the vitamin D they need all year round.
0:53:31 > 0:53:34Surprisingly, we've discovered that mushrooms
0:53:34 > 0:53:37are a potential source of vitamin D.
0:53:39 > 0:53:43Just like us, they need this vitamin to survive
0:53:43 > 0:53:47and they use it as a protection from the sun's harmful rays.
0:53:49 > 0:53:51How's that? Is that good?
0:53:51 > 0:53:54Yeah? A-ha!
0:53:54 > 0:53:59'Sunlight falling on a mushroom turns it into a vitamin D factory.
0:54:02 > 0:54:06'They use a chemical similar to cholesterol called ergosterol...
0:54:08 > 0:54:11'..which reacts with sunlight to make vitamin D.'
0:54:14 > 0:54:19There's something miraculous about what we're doing here because
0:54:19 > 0:54:24these mushrooms that are freshly picked from the dark forest floor
0:54:24 > 0:54:27don't really contain that much vitamin D.
0:54:27 > 0:54:32But putting them out in this intense UV light
0:54:32 > 0:54:34and the mushrooms, which are still alive,
0:54:34 > 0:54:38start to react by churning out that vitamin D.
0:54:41 > 0:54:43And if you put them gill side up,
0:54:43 > 0:54:46the surface area exposed to the sun increases...
0:54:49 > 0:54:51..and they produce even more.
0:54:58 > 0:55:03Just a few hours out in the sun and a couple of portobello mushrooms
0:55:03 > 0:55:06will give us our daily dose of vitamin D.
0:55:08 > 0:55:14Dry them and it stays locked away in the mushroom for up to a year,
0:55:14 > 0:55:18a tasty way of getting vitamin D through those dark winter months.
0:55:24 > 0:55:29This is amazing! I love this stuff.
0:55:29 > 0:55:32You've got bread with cheese, yoghurt, a yoghurt drink.
0:55:32 > 0:55:34There's no lack of calcium here.
0:55:36 > 0:55:38And the vitamin D in these lovely mushrooms
0:55:38 > 0:55:42allows our bodies to absorb that all-important calcium...
0:55:47 > 0:55:49..sending it through the bloodstream
0:55:49 > 0:55:52to cells called osteoblasts in our bones.
0:56:00 > 0:56:05These creep through the skeleton, laying down calcium-rich bone.
0:56:08 > 0:56:12This constant renewal protects us against diseases linked to ageing,
0:56:12 > 0:56:14such as osteoporosis.
0:56:18 > 0:56:23It could be a key factor not only to a healthy life, but also longevity.
0:56:25 > 0:56:27So there are loads of factors at work,
0:56:27 > 0:56:29but I can't help thinking that with air like this,
0:56:29 > 0:56:31running around every day, home-made food,
0:56:31 > 0:56:34and talk about a tonne of calcium - it can't hurt, can it?
0:56:40 > 0:56:44We've found the foods we all need to keep us ticking over.
0:56:49 > 0:56:54Day-to-day, meal-to-meal, we get much pleasure from the food we eat.
0:56:56 > 0:57:02The smells, tastes, colours and textures delight us.
0:57:04 > 0:57:08But what I think also really adds to that pleasure is understanding
0:57:08 > 0:57:11the hidden biochemistry at work.
0:57:11 > 0:57:13It helps us appreciate our food
0:57:13 > 0:57:17and it also means we're able to make the most of the ingredients
0:57:17 > 0:57:21hidden inside every delicious mouthful,
0:57:21 > 0:57:26ingredients which nourish not just the body, but also the mind.
0:57:28 > 0:57:31So if you're adventurous with food and you try a bit of everything,
0:57:31 > 0:57:36not only are your senses rewarded, your body has a greater chance
0:57:36 > 0:57:39of getting hold of all of those essential molecules
0:57:39 > 0:57:41because, ultimately,
0:57:41 > 0:57:44our bodies and everything we are comes from our plates.
0:57:49 > 0:57:53'Next time, we explore the boundaries of taste...'
0:57:53 > 0:57:55They are irresistible.
0:57:55 > 0:58:00'..we revel in the sumptuous food that dazzles our taste buds
0:58:00 > 0:58:02'and excites our noses...'
0:58:02 > 0:58:04HE LAUGHS
0:58:04 > 0:58:08'..as we discover how good taste is all about survival.'
0:58:11 > 0:58:13How does science change your perception of food?
0:58:13 > 0:58:17Find out how instinctive you are and learn even more about what you eat.
0:58:17 > 0:58:20Head to the BBC website onscreen now
0:58:20 > 0:58:22and follow the links to the Open University.