1 00:00:04,040 --> 00:00:08,000 How often do you stop and really think about your food? 2 00:00:08,000 --> 00:00:11,080 Look at all this lovely fat and sugar. 3 00:00:11,080 --> 00:00:12,920 Yummy. 4 00:00:12,920 --> 00:00:16,640 Do you ever wonder why you eat what you eat? 5 00:00:16,640 --> 00:00:18,200 What cooking does to food? 6 00:00:19,960 --> 00:00:21,600 Delicious. 7 00:00:21,600 --> 00:00:24,200 Or what effect it has on your body? 8 00:00:24,200 --> 00:00:26,920 I trained as a medical doctor and I'm absolutely obsessed 9 00:00:26,920 --> 00:00:29,160 by nutrition and the hidden chemistry of food. 10 00:00:30,400 --> 00:00:34,240 So I've teamed up with botanist James Wong to explore food, 11 00:00:34,240 --> 00:00:37,720 each of us coming from very different perspectives. 12 00:00:37,720 --> 00:00:39,560 Truly delicious. 13 00:00:39,560 --> 00:00:41,040 Together, we have taken over 14 00:00:41,040 --> 00:00:43,240 the country's leading food science lab... 15 00:00:45,360 --> 00:00:48,800 ..to deconstruct some of our favourite foods... 16 00:00:48,800 --> 00:00:50,400 It's all sunk to the bottom. 17 00:00:50,400 --> 00:00:53,800 ..and to reveal some truly remarkable secrets. 18 00:00:53,800 --> 00:00:58,360 I want to find out what affect food has on us and our biology, 19 00:00:58,360 --> 00:01:00,040 right down to the molecular level. 20 00:01:02,400 --> 00:01:05,200 As a botanist, I'm fascinated by 21 00:01:05,200 --> 00:01:08,040 the massive diversity of edible plants on our planet. 22 00:01:08,040 --> 00:01:11,240 I'm going to put them under the microscope to discover 23 00:01:11,240 --> 00:01:14,480 exactly how their biology interacts with our own. 24 00:01:17,240 --> 00:01:21,840 So join us as we seek out the most remarkable food stories 25 00:01:21,840 --> 00:01:25,640 on the planet and reveal the hidden science of our food. 26 00:01:39,160 --> 00:01:43,720 Across the world, food comes in a bewildering range of shapes, 27 00:01:43,720 --> 00:01:46,320 colours and flavours, 28 00:01:46,320 --> 00:01:51,800 but there was a time early in our lives when things were much simpler, 29 00:01:51,800 --> 00:01:55,800 when we lived and thrived on just one food. 30 00:02:00,160 --> 00:02:04,120 Chances are this is the first food you ever consumed - 31 00:02:04,120 --> 00:02:05,640 it's human breast milk. 32 00:02:08,080 --> 00:02:10,960 Now, what's amazing about this stuff is that it contains all 33 00:02:10,960 --> 00:02:13,840 the nutrients a baby needs to grow and thrive. 34 00:02:13,840 --> 00:02:15,400 Fed on nothing but breast milk, 35 00:02:15,400 --> 00:02:18,160 a baby will double in weight in just five months. 36 00:02:20,280 --> 00:02:24,200 So how can this precious liquid provide everything a baby needs 37 00:02:24,200 --> 00:02:28,480 to grow and prosper? To find out, I'm going to take it apart. 38 00:02:30,000 --> 00:02:35,040 We start by putting 200ml samples, a few feeds for a new-born, 39 00:02:35,040 --> 00:02:36,360 into a centrifuge. 40 00:02:39,680 --> 00:02:43,920 A quick strain and the first ingredient in the milk is visible. 41 00:02:47,320 --> 00:02:50,000 Now, this contains around 8g of fat, 42 00:02:50,000 --> 00:02:53,520 about the same amount as you would find in a bag of crisps, 43 00:02:53,520 --> 00:02:56,920 fat that is essential for building a baby's nervous system 44 00:02:56,920 --> 00:02:59,720 and the smooth running of their brain. 45 00:02:59,720 --> 00:03:03,800 What's left is this skimmed milk, which is mainly water, 46 00:03:03,800 --> 00:03:07,400 but which also includes another vital ingredient. 47 00:03:07,400 --> 00:03:11,040 I should be able to make it appear by adding a few drops of vinegar. 48 00:03:12,400 --> 00:03:13,920 Now I need to filter it. 49 00:03:16,040 --> 00:03:19,680 This is protein, essential for building a baby's body. 50 00:03:24,080 --> 00:03:27,960 I'm left with a solution of vitamins, minerals 51 00:03:27,960 --> 00:03:29,960 and one last major component. 52 00:03:31,440 --> 00:03:33,240 Now I'm going to do something slightly weird 53 00:03:33,240 --> 00:03:37,880 because I haven't tasted breast milk since I was a baby. 54 00:03:39,400 --> 00:03:42,200 Surprisingly sweet, although I guess it shouldn't be surprising 55 00:03:42,200 --> 00:03:47,240 because about 7% of that is made up of lactose, which is a sugar, 56 00:03:47,240 --> 00:03:48,960 a form of carbohydrate, 57 00:03:48,960 --> 00:03:53,040 and babies need carbohydrate because they need an instant source 58 00:03:53,040 --> 00:03:54,400 of accessible energy. 59 00:03:55,520 --> 00:03:58,560 So this mix of carbs, proteins, fats, 60 00:03:58,560 --> 00:04:03,160 vitamins and minerals in breast milk is all a baby needs to survive. 61 00:04:04,720 --> 00:04:08,880 The funny thing is that, as we get older, it doesn't really change. 62 00:04:08,880 --> 00:04:11,880 They just come to us in different forms of food. 63 00:04:16,840 --> 00:04:18,840 As adults, we're faced with a huge range 64 00:04:18,840 --> 00:04:21,680 of different foods to choose from. 65 00:04:22,720 --> 00:04:27,600 So how do we go about getting the right balance of fat, protein, 66 00:04:27,600 --> 00:04:29,760 carbs, vitamins and minerals? 67 00:04:31,240 --> 00:04:35,120 And which are absolutely essential for our survival? 68 00:04:46,960 --> 00:04:52,520 Every morning, all over the globe, we wake up ready for food. 69 00:04:52,520 --> 00:04:54,440 COCK CROWS 70 00:05:05,640 --> 00:05:10,800 We rise with our blood sugar low and the same need - quick energy. 71 00:05:13,400 --> 00:05:16,600 Be it toast, cereal, or rice, 72 00:05:16,600 --> 00:05:20,640 it's little wonder that most of us turn to the same type of food 73 00:05:20,640 --> 00:05:25,000 for that first meal of the day - carbohydrates. 74 00:05:25,000 --> 00:05:26,880 Did I snore? 75 00:05:26,880 --> 00:05:28,360 No. OK, good. 76 00:05:31,160 --> 00:05:35,520 Carbohydrates are fantastically diverse. 77 00:05:35,520 --> 00:05:40,120 It's really sort of a catch-all terminology for a group of chemicals 78 00:05:40,120 --> 00:05:44,520 that are made up of building blocks of sugar. 79 00:05:44,520 --> 00:05:49,480 There are many different types - glucose, lactose and probably 80 00:05:49,480 --> 00:05:52,080 the most exciting one, starch. 81 00:05:53,800 --> 00:05:57,000 It's what plants use to store away their energies 82 00:05:57,000 --> 00:06:02,080 in a concentrated format. Round here, it's usually found 83 00:06:02,080 --> 00:06:05,760 in the form of a seed stolen from a grass. 84 00:06:09,600 --> 00:06:12,600 Oryza sativa, better known as the rice plant. 85 00:06:16,040 --> 00:06:20,280 Each seed is a grain of rice, a marvel of nature. 86 00:06:21,800 --> 00:06:24,200 But rice doesn't give up its energy easily. 87 00:06:30,080 --> 00:06:33,400 These terraces here in Banaue are called by some 88 00:06:33,400 --> 00:06:36,120 the eighth wonder of the world. 89 00:06:39,800 --> 00:06:43,360 The people who live in these mountains have been cultivating rice 90 00:06:43,360 --> 00:06:45,800 for over 2,000 years. 91 00:06:51,320 --> 00:06:52,960 Hello! Hello! 92 00:06:56,200 --> 00:06:58,560 'And today, it's my turn.' 93 00:06:58,560 --> 00:07:01,520 I feel like Superman to be able to do this. 94 00:07:03,240 --> 00:07:06,480 'As we work the terraces, we're burning calories, 95 00:07:06,480 --> 00:07:08,160 'a measurement of energy. 96 00:07:10,920 --> 00:07:14,600 'Even at rest, our body needs fuel to tick over and, 97 00:07:14,600 --> 00:07:18,840 'just standing here, I'm burning about 100 calories an hour. 98 00:07:20,680 --> 00:07:25,760 'But while working the fields, that jumps up to around 350.' 99 00:07:25,760 --> 00:07:29,680 You're tired? I'm waiting for my Asian rice farmer genes to kick in. 100 00:07:30,880 --> 00:07:32,280 I don't think they work! 101 00:07:36,080 --> 00:07:38,520 We get our energy from our food 102 00:07:38,520 --> 00:07:42,360 and the carbohydrate-rich ones like the rice I had for breakfast 103 00:07:42,360 --> 00:07:45,080 give us fuel more quickly than any other type. 104 00:07:48,960 --> 00:07:52,280 The body breaks down long carbohydrate chains 105 00:07:52,280 --> 00:07:54,840 into a simple sugar - glucose. 106 00:07:57,320 --> 00:08:01,360 It's easily absorbed in the blood and transported around the body, 107 00:08:01,360 --> 00:08:03,400 feeding our muscles and our organs. 108 00:08:06,240 --> 00:08:08,720 Carbs are the rocket fuel in our diets. 109 00:08:16,680 --> 00:08:20,840 Growing rice by hand requires a lot of energy. 110 00:08:26,480 --> 00:08:30,040 So we have to be sure we get a lot more energy from eating it 111 00:08:30,040 --> 00:08:31,720 than it takes to produce it. 112 00:08:36,160 --> 00:08:39,160 I mean, even harvesting the stuff is labour-intensive. 113 00:08:42,240 --> 00:08:45,360 And you can be burning over 400 calories an hour. 114 00:08:48,000 --> 00:08:53,320 So, after six months of loving care and hundreds of labour hours, 115 00:08:53,320 --> 00:08:56,560 you end up with this beautiful stuff - raw rice. 116 00:08:59,560 --> 00:09:01,840 I still wouldn't call it a food, though. 117 00:09:04,200 --> 00:09:08,600 All this effort begs the question - why do we bother with rice at all? 118 00:09:11,920 --> 00:09:17,200 The reason why rice is such a phenomenally important food is the 119 00:09:17,200 --> 00:09:24,480 sheer amount of energy that's packed into each one of these tiny grains. 120 00:09:24,480 --> 00:09:27,760 And I can actually show you how much energy they have visually 121 00:09:27,760 --> 00:09:30,160 but, first, I've got to break them open. 122 00:09:31,840 --> 00:09:36,360 This stuff might not look very exciting, 123 00:09:36,360 --> 00:09:38,680 but it's packed full of energy. 124 00:09:41,120 --> 00:09:45,280 You can convert the potential energy that's stored in the rice grains 125 00:09:45,280 --> 00:09:48,240 into heat and light energy just by doing this. 126 00:09:51,320 --> 00:09:53,520 'Each puff is around 10g...' 127 00:09:55,520 --> 00:09:57,160 I could do this all day! ' 128 00:09:57,160 --> 00:10:00,240 '..and contains around 35 calories of energy, 129 00:10:00,240 --> 00:10:01,520 'all going up in flames. 130 00:10:03,200 --> 00:10:05,720 'And almost all of it comes from carbohydrates.' 131 00:10:07,480 --> 00:10:10,240 Now, our bodies might not do this in the exact same way 132 00:10:10,240 --> 00:10:12,600 because we use complex biochemistry to do it. 133 00:10:14,600 --> 00:10:17,160 And rice doesn't give up its energy without a fight... 134 00:10:20,920 --> 00:10:23,840 ..but we have discovered how to harness its power. 135 00:10:26,000 --> 00:10:30,520 Even once fully processed, rice is essentially indigestible 136 00:10:30,520 --> 00:10:34,800 because starch really stubbornly holds on to its energy - 137 00:10:34,800 --> 00:10:36,000 until you do this. 138 00:10:37,840 --> 00:10:40,120 Cooking is the game-changer. 139 00:10:48,400 --> 00:10:50,360 The starch in the rice is made up of 140 00:10:50,360 --> 00:10:55,040 two energy-giving carbohydrate molecules - amylose and amylopectin. 141 00:10:57,360 --> 00:11:00,000 But their long chains are packed together, 142 00:11:00,000 --> 00:11:02,080 making them mostly indigestible. 143 00:11:04,520 --> 00:11:07,440 The combination of heat and water 144 00:11:07,440 --> 00:11:10,760 has the power to break the tangled chains apart. 145 00:11:18,280 --> 00:11:21,640 This chemistry is going on inside every cell. 146 00:11:26,480 --> 00:11:30,760 The starch absorbs the boiling water and swells massively... 147 00:11:33,960 --> 00:11:37,040 ..until the moment when the cells burst open 148 00:11:37,040 --> 00:11:39,320 and the digestible carbs erupt. 149 00:11:44,280 --> 00:11:48,400 So turning rice into a food is incredibly energy intensive. 150 00:11:51,640 --> 00:11:55,040 A cupful takes about 70 calories to produce. 151 00:11:57,640 --> 00:12:02,440 But we got 35 calories from just 10g, 152 00:12:02,440 --> 00:12:07,240 which means a cup of rice gives us back around 700 calories. 153 00:12:08,520 --> 00:12:12,840 We get a whopping ten times more energy out than we put in. 154 00:12:16,520 --> 00:12:20,440 And that's why rice, a cultivated river grass, 155 00:12:20,440 --> 00:12:24,680 has become such an important staple in the water-rich tropics. 156 00:12:33,960 --> 00:12:37,680 Where it's too cold or too dry to grow rice, 157 00:12:37,680 --> 00:12:44,000 we in the western world have turned to another crop for our carb hit - 158 00:12:44,000 --> 00:12:46,200 wheat. 159 00:12:55,480 --> 00:12:59,480 Most of the wheat we consume comes in the form of bread 160 00:12:59,480 --> 00:13:03,200 and this city is famous for one particular type of bread - 161 00:13:03,200 --> 00:13:05,000 sourdough. 162 00:13:05,000 --> 00:13:06,880 I've been doing this for 37 years. 163 00:13:06,880 --> 00:13:08,360 The minute I touched dough, 164 00:13:08,360 --> 00:13:12,280 I fell in love with it and thought, "This is what I want to do". 165 00:13:12,280 --> 00:13:14,480 No matter if you're rich, poor, or anything, 166 00:13:14,480 --> 00:13:17,440 you're making something wonderful for everybody. 167 00:13:19,440 --> 00:13:22,040 It begins with unprocessed wheat flour... 168 00:13:26,120 --> 00:13:30,280 ..a bland, tasteless powder that, if cooked, would set like concrete. 169 00:13:33,120 --> 00:13:35,280 To turn it into a tasty food, 170 00:13:35,280 --> 00:13:38,440 Fernando Padilla employs an army of microbes. 171 00:13:43,240 --> 00:13:45,160 These microbes live in something 172 00:13:45,160 --> 00:13:47,400 affectionately known as the mother dough. 173 00:13:52,400 --> 00:13:55,480 This is where she lives, as you can tell. We say, "Mother dough lives here". 174 00:13:55,480 --> 00:13:57,840 We're going to put an address here. 175 00:13:59,800 --> 00:14:02,840 I'm carrying a piece of history here. 176 00:14:02,840 --> 00:14:05,680 'The mother dough is a mix of water and flour, 177 00:14:05,680 --> 00:14:07,800 'more commonly known as a starter.' 178 00:14:09,800 --> 00:14:14,000 Inside it, a community of live yeast cells and bacteria thrive. 179 00:14:17,800 --> 00:14:20,600 But this is no ordinary starter. 180 00:14:20,600 --> 00:14:23,960 It's reported to be the oldest in the US. 181 00:14:25,200 --> 00:14:28,920 And this goes back to 1849? 182 00:14:28,920 --> 00:14:34,080 Imagine, over 165 years ago, it was the same dough. 183 00:14:34,080 --> 00:14:37,160 A tiny piece of this dates back to the same family. 184 00:14:39,560 --> 00:14:43,040 This starter was apparently created by French immigrants 185 00:14:43,040 --> 00:14:45,120 during the great Gold Rush. 186 00:14:47,440 --> 00:14:48,640 Inhale. 187 00:14:48,640 --> 00:14:50,000 Oh, God! 188 00:14:53,320 --> 00:14:58,000 That's all the sweetness of the flour being fermented. 189 00:14:58,000 --> 00:15:01,040 It creates this alcohol flavour, but it all evaporates. 190 00:15:01,040 --> 00:15:03,920 You see how strong it is? I was expecting something nice! 191 00:15:05,400 --> 00:15:09,160 This little thing is going to give us 400 loaves of bread. 192 00:15:09,160 --> 00:15:10,480 Let's bring it out. 193 00:15:11,480 --> 00:15:16,000 'Every day, half of the mother dough is fed with flour and water. 194 00:15:16,000 --> 00:15:19,920 'Then it's locked away overnight, where it regenerates, 195 00:15:19,920 --> 00:15:23,560 'doubling in size.' Good night, Mummy. 196 00:15:23,560 --> 00:15:24,840 See you tomorrow. 197 00:15:25,960 --> 00:15:27,800 This is 200lbs of flour here. 198 00:15:30,520 --> 00:15:35,000 'The other half of mother will be used to create over 400 loaves of 199 00:15:35,000 --> 00:15:38,600 'of delicious, fresh bread.' We should have worn the apron. 200 00:15:41,520 --> 00:15:44,360 Adding water activates enzymes in the flour. 201 00:15:46,280 --> 00:15:51,160 This in turn starts a complex biochemical cascade, 202 00:15:51,160 --> 00:15:53,720 which begins with starch in the flour 203 00:15:53,720 --> 00:15:56,280 turning into a sugar called maltose. 204 00:15:58,520 --> 00:16:01,600 Mix it for ten minutes. 205 00:16:01,600 --> 00:16:07,360 Bacteria from the mother dough now feed greedily on the maltose, 206 00:16:07,360 --> 00:16:09,120 breaking it down into glucose. 207 00:16:15,080 --> 00:16:18,960 The bacteria have begun to digest the flour for us. 208 00:16:18,960 --> 00:16:21,920 You hear that? When you hear the dough popping... 209 00:16:21,920 --> 00:16:23,360 Pop, pop, pop. 210 00:16:24,760 --> 00:16:27,840 It's saying, "I'm ready, get me out of here". 211 00:16:27,840 --> 00:16:32,120 'If we baked it now, this would turn out as flat as a pancake.' 212 00:16:32,120 --> 00:16:34,720 Why is mine not looking like yours? 213 00:16:34,720 --> 00:16:37,040 Now we just fold it over. Yep. 214 00:16:37,040 --> 00:16:40,040 'Fortunately, another group of microbes will use 215 00:16:40,040 --> 00:16:42,400 'some of the glucose to transform the dough.' 216 00:16:44,480 --> 00:16:46,320 OK, this is dried yeast. 217 00:16:46,320 --> 00:16:49,120 Doesn't look incredibly exciting, does it? 218 00:16:49,120 --> 00:16:53,320 But every single grain there contains thousands of these 219 00:16:53,320 --> 00:16:56,640 single-celled organisms and they're held currently 220 00:16:56,640 --> 00:16:58,760 in a state of suspended animation. 221 00:16:58,760 --> 00:17:00,920 I am about to bring them back to life. 222 00:17:02,240 --> 00:17:05,160 To do that, they need food and water. 223 00:17:05,160 --> 00:17:11,160 So I'm going to add sugar and then water... 224 00:17:11,160 --> 00:17:14,520 and now I add the yeast. 225 00:17:14,520 --> 00:17:16,440 If the yeast cells are still alive, 226 00:17:16,440 --> 00:17:20,360 they'll produce a gas which passes through the pipe to the test tube. 227 00:17:22,080 --> 00:17:26,160 Those yeast cells are springing back to life, 228 00:17:26,160 --> 00:17:28,760 and they're going to get stuck into that sugar. 229 00:17:33,480 --> 00:17:36,120 So it's working. You can see the bubbles being produced. 230 00:17:36,120 --> 00:17:40,360 They're being created by the yeast gobbling up the sugar 231 00:17:40,360 --> 00:17:44,720 and producing carbon dioxide gas, which you can see bubbling up. 232 00:17:44,720 --> 00:17:47,960 And it's this reaction which is absolutely key 233 00:17:47,960 --> 00:17:50,040 to producing a nice, fluffy loaf. 234 00:17:51,240 --> 00:17:54,440 With carbon dioxide bubbling through his bread mix, 235 00:17:54,440 --> 00:17:57,640 Fernando must now stop the gas escaping. 236 00:17:58,800 --> 00:18:02,480 To do that, he alters the chemical structure of the dough 237 00:18:02,480 --> 00:18:04,720 by a process called kneading. 238 00:18:05,880 --> 00:18:08,640 I'm not an expert baker at all, 239 00:18:08,640 --> 00:18:13,360 but I know the secret to making good bread is 240 00:18:13,360 --> 00:18:16,800 making really sure you knead it thoroughly. 241 00:18:19,080 --> 00:18:23,560 When we knead bread, we're forcing two proteins inside the flour, 242 00:18:23,560 --> 00:18:28,960 gliadin and glutenin, to form bonds, creating a tough new substance - 243 00:18:28,960 --> 00:18:30,400 gluten. 244 00:18:32,400 --> 00:18:35,320 And this is where the art of bread-making comes in. 245 00:18:36,320 --> 00:18:41,120 If you don't knead enough, you won't create enough gluten in your loaf, 246 00:18:41,120 --> 00:18:44,840 so the gases will escape and it won't rise. 247 00:18:46,040 --> 00:18:51,360 But get it just right, and the effect on the loaf is magical. 248 00:18:55,400 --> 00:18:59,960 As it rises, its volume more than doubles as the yeast consume 249 00:18:59,960 --> 00:19:05,480 the glucose and as they blow bubbles inside their gluten home. 250 00:19:05,480 --> 00:19:09,160 The bacteria also produce a small amount of lactic acid 251 00:19:09,160 --> 00:19:11,200 and, with no added sugar, 252 00:19:11,200 --> 00:19:16,680 the acid gives the loaf the distinctive tang of sourdough bread. 253 00:19:18,360 --> 00:19:22,520 Baking then seals the air pockets and, thanks to the microbes from 254 00:19:22,520 --> 00:19:27,720 the mother dough, we end up with a carb-rich, light, fluffy loaf. 255 00:19:30,880 --> 00:19:32,960 Whoa! Wow. 256 00:19:35,200 --> 00:19:38,480 How many loaves is that? This is about 100 loaves of bread. 257 00:19:40,680 --> 00:19:42,040 Perfect. 258 00:19:50,080 --> 00:19:51,880 Mmm. It's incredible. 259 00:20:02,640 --> 00:20:05,600 Sourdough used to be one of the most popular forms of bread, 260 00:20:05,600 --> 00:20:09,440 until it got displaced by cheap, mass-produced stuff 261 00:20:09,440 --> 00:20:13,520 and that seems like a shame because it's tasty and it's also healthier. 262 00:20:13,520 --> 00:20:17,120 It hasn't got added sugars and the acid in the bread means 263 00:20:17,120 --> 00:20:19,680 you're much better able to absorb the minerals and vitamins 264 00:20:19,680 --> 00:20:21,640 that are locked up in the flour. 265 00:20:21,640 --> 00:20:24,640 In fact, I think I'm going to try baking some when I get home. 266 00:20:28,000 --> 00:20:32,040 From the east to the west, by unlocking the secrets of rice 267 00:20:32,040 --> 00:20:36,520 and wheat, our ancestors made the indigestible digestible. 268 00:20:39,520 --> 00:20:42,560 As a result, these foods became the staples 269 00:20:42,560 --> 00:20:45,240 that feed our towns and cities. 270 00:20:47,160 --> 00:20:52,440 Historically, carbs were the foods that fuelled our civilisations, 271 00:20:52,440 --> 00:20:54,200 a cheap and ready source of energy. 272 00:21:01,880 --> 00:21:05,720 Energy keeps us moving, but it's protein that builds us. 273 00:21:08,880 --> 00:21:14,080 Your body makes at least 250,000 different types of protein, 274 00:21:14,080 --> 00:21:18,160 molecules which are needed to make everything from hormones 275 00:21:18,160 --> 00:21:20,720 like insulin to the muscles that power you. 276 00:21:22,640 --> 00:21:25,040 To create all these different proteins, 277 00:21:25,040 --> 00:21:29,160 you need to eat plenty of protein, around 50g a day. 278 00:21:32,880 --> 00:21:37,080 And one of my favourite sources of high-quality protein is eggs. 279 00:21:43,600 --> 00:21:47,840 So I want to take one apart, see just what it is that I'm eating. 280 00:21:49,400 --> 00:21:54,120 Right, I'm just going to prise off a little bit of shell, 281 00:21:54,120 --> 00:21:58,520 and there it is. As you can see, it's hard, crystalline, 282 00:21:58,520 --> 00:22:01,280 made up mainly of calcium carbonate. 283 00:22:05,200 --> 00:22:08,560 Here, magnified over 2,000 times, 284 00:22:08,560 --> 00:22:14,160 you can see the surface of the shell is covered in lots of tiny holes, 285 00:22:14,160 --> 00:22:16,680 there so a developing chick can breathe. 286 00:22:18,400 --> 00:22:22,400 Each hole is formed over a gap in a lattice of protein 287 00:22:22,400 --> 00:22:24,680 that the shell grows over. 288 00:22:24,680 --> 00:22:28,720 Surprisingly, this membrane is partly made from a tough protein 289 00:22:28,720 --> 00:22:33,360 called keratin, the same stuff our hair and nails made from. 290 00:22:38,440 --> 00:22:42,120 It protects the contents of the egg from bacteria and dust. 291 00:22:44,960 --> 00:22:50,560 Inside, the white, or albumen, is a mix of water and 11% protein. 292 00:22:52,640 --> 00:22:56,440 But it's the egg yolk where most of the goodness resides. 293 00:22:56,440 --> 00:23:01,240 It's got minerals, vitamins, some fat, some cholesterol, 294 00:23:01,240 --> 00:23:04,480 but it's also got 17% protein. 295 00:23:04,480 --> 00:23:07,760 The fact that you find protein in the membrane, the white, 296 00:23:07,760 --> 00:23:12,720 AND the egg yolk, shows you just how important protein is in us. 297 00:23:12,720 --> 00:23:15,520 It's responsible for everything, 298 00:23:15,520 --> 00:23:21,640 from running your immune system to carrying oxygen around your body. 299 00:23:21,640 --> 00:23:25,360 And eggs are a really beautiful source of protein, 300 00:23:25,360 --> 00:23:28,280 because almost all the protein there, 301 00:23:28,280 --> 00:23:31,920 apart, obviously, from the shell, can be readily digested. 302 00:23:33,280 --> 00:23:38,160 But, once you've eaten it, where does the protein from your food go? 303 00:23:47,040 --> 00:23:52,840 Mexico City, home to a population of one of the highest consumers 304 00:23:52,840 --> 00:23:54,840 of eggs on the planet. 305 00:24:05,520 --> 00:24:08,520 And it's also home to the Lucha Libre. 306 00:24:12,440 --> 00:24:14,000 BELL RINGS 307 00:24:27,080 --> 00:24:29,080 When it comes to wrestling, 308 00:24:29,080 --> 00:24:33,720 Mistico, El Santo and Shocker are all household names. 309 00:24:40,600 --> 00:24:42,960 The way you look in the ring is very important. 310 00:24:42,960 --> 00:24:45,600 In my case, I don't wear a mask 311 00:24:45,600 --> 00:24:50,400 because they call me "El senor mil por ciento guapo", 312 00:24:50,400 --> 00:24:53,000 which means "1,000% handsome". 313 00:24:59,440 --> 00:25:02,400 I've been wrestling for 22 years professionally. 314 00:25:05,680 --> 00:25:09,240 My dad used to be a professional wrestler, too. 315 00:25:09,240 --> 00:25:13,160 He taught me mostly everything I know 316 00:25:13,160 --> 00:25:16,320 and he taught me how to eat, too. 317 00:25:16,320 --> 00:25:19,280 To build and maintain his impressive physique, 318 00:25:19,280 --> 00:25:21,480 Shocker needs to eat a lot of protein. 319 00:25:22,760 --> 00:25:25,920 To be a wrestler, you've got to have good nutrition. 320 00:25:25,920 --> 00:25:29,400 If you don't eat, you don't grow. 321 00:25:31,320 --> 00:25:36,400 In the UK, on average, we each eat around four eggs a week. 322 00:25:36,400 --> 00:25:39,720 The average Mexican eats seven, 323 00:25:39,720 --> 00:25:44,280 but Shocker puts away an incredible 50 every week. 324 00:25:48,000 --> 00:25:52,880 The eggy proteins are needed because he trains so hard every day. 325 00:25:52,880 --> 00:25:54,840 With each stretch and lift, 326 00:25:54,840 --> 00:25:58,560 he is tearing the fibres deep down in his muscles. 327 00:26:00,960 --> 00:26:03,040 This triggers his body to repair them. 328 00:26:06,240 --> 00:26:10,360 Enzymes deep in his stomach and intestines break down the protein 329 00:26:10,360 --> 00:26:14,280 in his food into their individual building blocks, 330 00:26:14,280 --> 00:26:16,720 molecules called amino acids. 331 00:26:19,840 --> 00:26:23,440 These enter his bloodstream and travel to where they are needed. 332 00:26:24,920 --> 00:26:29,120 And, for Shocker, the amino acids join together to build the proteins 333 00:26:29,120 --> 00:26:32,120 he needs to make bigger, stronger muscles. 334 00:26:40,080 --> 00:26:41,520 I like my eggs in different ways. 335 00:26:41,520 --> 00:26:43,200 I like them a la Mexicana. 336 00:26:43,200 --> 00:26:45,360 They come with tomato, onion and chilli. 337 00:26:47,120 --> 00:26:49,760 I like them rancheros, 338 00:26:49,760 --> 00:26:51,880 tortilla under, sunny side up. 339 00:26:53,600 --> 00:26:56,600 The way we prepare eggs makes a massive difference 340 00:26:56,600 --> 00:26:59,560 to how easily we can use the protein they contain. 341 00:27:01,960 --> 00:27:04,920 Contrary to popular belief, eat eggs raw 342 00:27:04,920 --> 00:27:08,120 and we only benefit from about half the protein. 343 00:27:11,000 --> 00:27:13,600 Cook them and it's a very different story. 344 00:27:14,720 --> 00:27:18,080 It fundamentally changes the proteins in an egg. 345 00:27:18,080 --> 00:27:19,880 You can see it happening. 346 00:27:21,200 --> 00:27:24,400 If you really want to play around with the texture of the eggs, 347 00:27:24,400 --> 00:27:26,280 you could invest in a water bath. 348 00:27:26,280 --> 00:27:28,960 That way, you can control not only the time, 349 00:27:28,960 --> 00:27:31,520 but also the temperature you cook the eggs at. 350 00:27:32,920 --> 00:27:37,200 This is a raw egg and, as it slowly cooks, it changes. 351 00:27:37,200 --> 00:27:41,920 Over here, you can begin to see some of the egg white is setting. 352 00:27:41,920 --> 00:27:47,120 The protein in it is denaturing, meaning it's easier to absorb. 353 00:27:48,440 --> 00:27:52,920 The longer eggs cook, the more the protein fibres denature. 354 00:27:52,920 --> 00:27:55,680 The protein molecules literally unfold. 355 00:27:56,880 --> 00:28:01,120 That's what's happening when egg white transforms into a gel. 356 00:28:01,120 --> 00:28:07,200 These cooked egg whites aren't simply more pleasant to eat, 357 00:28:07,200 --> 00:28:10,760 the untangled protein molecules also make it easier 358 00:28:10,760 --> 00:28:14,680 for Shocker to absorb the protein his body vitally needs. 359 00:28:17,240 --> 00:28:20,120 When you work out a lot, when you do a lot of exercise, 360 00:28:20,120 --> 00:28:24,200 you start building up and you start making your food into muscle, 361 00:28:24,200 --> 00:28:27,080 all different kinds of muscle. 362 00:28:27,080 --> 00:28:28,360 Relaxed muscle. 363 00:28:34,680 --> 00:28:39,720 Shocker's success in the ring is built entirely on the way he trains 364 00:28:39,720 --> 00:28:42,400 and how his body uses the amino acids, 365 00:28:42,400 --> 00:28:45,240 the building blocks of every protein, 366 00:28:45,240 --> 00:28:46,680 to repair his muscles. 367 00:28:48,840 --> 00:28:51,920 People like champions. We don't like losers. 368 00:28:52,960 --> 00:28:54,920 You've got to look good. You've got to win. 369 00:28:59,920 --> 00:29:02,280 BELL RINGS 370 00:29:16,480 --> 00:29:22,160 Although we're made up of around a quarter of a million different 371 00:29:22,160 --> 00:29:26,520 proteins, those proteins are comprised of just 20 amino acids. 372 00:29:29,880 --> 00:29:34,280 The amazing thing is our bodies can just manufacture 11 of those, 373 00:29:34,280 --> 00:29:38,560 but that leaves nine and we call them the nine essential amino acids. 374 00:29:42,320 --> 00:29:44,760 We've evolved the cellular machinery 375 00:29:44,760 --> 00:29:47,920 to produce all but these nine essential ones. 376 00:29:50,240 --> 00:29:52,800 Those, we must get from our diet. 377 00:29:54,600 --> 00:29:56,880 But this isn't always easy. 378 00:29:56,880 --> 00:30:01,880 Eggs, fish and meat contain all nine essential amino acids, 379 00:30:01,880 --> 00:30:04,200 but there are plenty of foods that don't. 380 00:30:05,160 --> 00:30:09,360 To survive, we have to carefully mix and match what we eat. 381 00:30:11,680 --> 00:30:15,800 Look at this. This is real Aztec gold. 382 00:30:15,800 --> 00:30:19,880 For millennia, corn has been the staple crop 383 00:30:19,880 --> 00:30:22,880 throughout pretty much the whole of Latin America 384 00:30:22,880 --> 00:30:26,120 and that's because it's just packed full of the good stuff. 385 00:30:27,560 --> 00:30:31,920 It's bursting with carbs, vitamins and fibre, 386 00:30:31,920 --> 00:30:36,480 but crucially, though, it's missing two essential amino acids - 387 00:30:36,480 --> 00:30:38,160 lysine and tryptophan. 388 00:30:40,440 --> 00:30:42,160 But in this part of Mexico, 389 00:30:42,160 --> 00:30:46,320 they've found an ingenious way of eating corn to get all the 390 00:30:46,320 --> 00:30:51,200 amino acids they need and it's a rather surprising local delicacy. 391 00:30:52,760 --> 00:30:55,000 I've always wanted to see it in the field. 392 00:30:55,000 --> 00:30:58,880 You get these massively swollen ears of corn 393 00:30:58,880 --> 00:31:01,400 and, when you split them open, 394 00:31:01,400 --> 00:31:05,000 you can see the deformity that lies beneath. 395 00:31:06,480 --> 00:31:10,240 Huitlacoche has been called "food of the gods", 396 00:31:10,240 --> 00:31:12,600 but it looks like something from a horror movie. 397 00:31:15,000 --> 00:31:19,160 It too is lacking essential amino acids, but eat this 398 00:31:19,160 --> 00:31:23,720 with regular corn, and you get all the amino acids you need. 399 00:31:23,720 --> 00:31:27,600 This is created by a pathogenic fungus 400 00:31:27,600 --> 00:31:31,840 and it's a debilitating disease on maize plants around the world, 401 00:31:31,840 --> 00:31:37,560 but only in Mexico do farmers open this up and get really excited. 402 00:31:40,040 --> 00:31:44,160 This fungus begins as nothing more than a microscopic spore. 403 00:31:46,040 --> 00:31:50,040 Carried on the wind, just one could infect an entire crop. 404 00:31:52,160 --> 00:31:54,800 It germinates and sends out branches 405 00:31:54,800 --> 00:31:57,960 that pass throughout the ear of corn, 406 00:31:57,960 --> 00:32:01,840 where it affects every kernel, creating the swollen tumours. 407 00:32:04,960 --> 00:32:09,120 Other countries would torch these infected fields, but not here. 408 00:32:17,520 --> 00:32:23,280 What time is it now? 6.30 in the morning and in full swing. 409 00:32:25,360 --> 00:32:28,400 Huitlacoche has become a delicacy, 410 00:32:28,400 --> 00:32:33,080 served up in the best restaurants in town. 411 00:32:33,080 --> 00:32:34,520 It's crazy, no? 412 00:32:34,520 --> 00:32:40,000 At market, infected corn is worth 50% more than just regular corn, 413 00:32:40,000 --> 00:32:44,480 so master chef Lalo Garcia arrives early to ensure he gets 414 00:32:44,480 --> 00:32:45,960 the pick of the bunch. 415 00:32:46,960 --> 00:32:50,120 This is where I buy the huitlacoche. Wow. Look at that. 416 00:32:51,920 --> 00:32:55,920 And the smell. The smell is amazing, that of earth. 417 00:32:55,920 --> 00:32:58,080 It's why I really love this product. 418 00:32:58,080 --> 00:33:04,760 It's amazing that earth still produces this, this type of beauty. 419 00:33:07,400 --> 00:33:13,040 So we have a little olive oil here. Onions. We add our huitlacoche. 420 00:33:18,160 --> 00:33:22,520 We're going to make a very basic salsa to go with our huitlacoche. 421 00:33:28,920 --> 00:33:31,120 You'd never know to look at it, 422 00:33:31,120 --> 00:33:34,760 but huitlacoche has the most amazing flavour. 423 00:33:34,760 --> 00:33:41,160 It's kind of like black truffles meet shiitake mushrooms, 424 00:33:41,160 --> 00:33:44,200 with that savoury volume whacked up. 425 00:33:44,200 --> 00:33:48,200 Smoky, rich. It's got to be the world's best comfort food. 426 00:33:50,480 --> 00:33:52,440 And eaten with corn tortillas, 427 00:33:52,440 --> 00:33:56,120 I get my hit of all nine of those essential amino acids. 428 00:34:01,360 --> 00:34:03,880 But the Mexicans aren't the only ones 429 00:34:03,880 --> 00:34:06,600 to pull off this classic combination. 430 00:34:07,920 --> 00:34:10,760 From the British favourite of beans on toast... 431 00:34:12,920 --> 00:34:15,440 ..to the Indian Holy Grail of rice and dhal... 432 00:34:17,680 --> 00:34:22,960 ..or the Italian staple of beans and pasta, across the globe, 433 00:34:22,960 --> 00:34:27,800 we've invented combinations of pulses and beans mixed with grains 434 00:34:27,800 --> 00:34:31,960 to give us all nine of the amino acids we desperately need. 435 00:34:33,760 --> 00:34:37,400 We've instinctively become expert nutritionists, 436 00:34:37,400 --> 00:34:40,040 hunting out exactly what we need from our food. 437 00:34:44,640 --> 00:34:48,760 And no nutritionist would recommend a diet that didn't have some fat. 438 00:34:51,080 --> 00:34:55,840 Whether you get it from meat, fish, nuts or vegetables, 439 00:34:55,840 --> 00:34:59,000 fat, like protein, is essential for health. 440 00:35:02,040 --> 00:35:05,480 Now, different foods have different forms of fat. 441 00:35:05,480 --> 00:35:08,280 We've got olives, walnut, avocado. 442 00:35:09,560 --> 00:35:12,880 Most of these fats are liquid at room temperature. 443 00:35:12,880 --> 00:35:15,400 The odd one out is this one, which came from the beef. 444 00:35:15,400 --> 00:35:17,200 It's solid at room temperature. 445 00:35:17,200 --> 00:35:20,600 And the reason there are so many different types of fat is because 446 00:35:20,600 --> 00:35:25,000 there are so many different types of building blocks for fat. 447 00:35:25,000 --> 00:35:28,520 Each fat is in turn made up of something called fatty acids. 448 00:35:29,840 --> 00:35:32,880 Complex fat chains are built by assembling 449 00:35:32,880 --> 00:35:35,440 these smaller units of fatty acids. 450 00:35:38,920 --> 00:35:41,920 Taking a close look at the fat in a piece of salmon 451 00:35:41,920 --> 00:35:44,680 shows just how many fatty acids there are. 452 00:35:46,240 --> 00:35:48,840 I'm mashing it up with some acetone, 453 00:35:48,840 --> 00:35:52,160 stuff more commonly used to remove nail varnish. 454 00:35:52,160 --> 00:35:55,400 This won't add to the flavour, but it will help separate out the fat. 455 00:35:56,800 --> 00:36:01,080 There's a lovely layer of pink fat right there on the top. 456 00:36:01,080 --> 00:36:04,640 Some fancy kit then reveals what I'm looking for. 457 00:36:04,640 --> 00:36:06,880 You can see lots of different peaks 458 00:36:06,880 --> 00:36:10,800 and each of these peaks represents a different fatty acid. 459 00:36:12,600 --> 00:36:16,400 These fatty acids are essential to the smooth running of our bodies. 460 00:36:17,920 --> 00:36:21,320 Eating salmon is a great way of getting hold of them. 461 00:36:21,320 --> 00:36:26,120 But we are so dependent on fat that we've evolved cellular machinery 462 00:36:26,120 --> 00:36:30,760 to build most of the fatty acids that might be missing from our diet. 463 00:36:30,760 --> 00:36:34,120 There are two types, however, which your body cannot make. 464 00:36:34,120 --> 00:36:38,960 They are omega-6 and the rather more elusive omega-3. 465 00:36:40,240 --> 00:36:42,200 These we have to get from food. 466 00:36:47,600 --> 00:36:51,040 Omega-6 is easy - there's plenty in vegetable oil. 467 00:36:51,040 --> 00:36:55,360 Omega-3 is rarer. It's found in oily fish, like salmon. 468 00:36:56,640 --> 00:36:58,360 But where else can you find it? 469 00:37:05,080 --> 00:37:07,720 We're going roaming. We're looking for the cattle now, are we? 470 00:37:07,720 --> 00:37:09,640 We are. It can take some time. 471 00:37:13,120 --> 00:37:15,120 These are Highland cattle. 472 00:37:15,120 --> 00:37:18,360 There we are, look. There's a cow away down there. 473 00:37:18,360 --> 00:37:23,040 They're really well adapted to life in Scotland. 474 00:37:23,040 --> 00:37:26,600 And though they sport the longest hair of any cow, 475 00:37:26,600 --> 00:37:29,280 that's not what makes them special. 476 00:37:29,280 --> 00:37:33,000 What marks these cattle out is that, unlike most cattle, 477 00:37:33,000 --> 00:37:36,680 their meat is rich in elusive omega-3. 478 00:37:38,000 --> 00:37:41,200 They look like really large dogs with horns! 479 00:37:43,960 --> 00:37:46,480 Iain MacKay looks after just 50 cattle. 480 00:37:47,800 --> 00:37:51,880 They're free to roam over a vast expanse of wild moorland. 481 00:37:53,280 --> 00:37:54,480 Hi, gang. 482 00:37:55,600 --> 00:37:58,400 The type of breed we've got here utilises this ground. 483 00:37:58,400 --> 00:38:02,440 They have a massive stomach and they can take on a huge amount of 484 00:38:02,440 --> 00:38:05,080 this roughage and then just go, lie down, and digest that. 485 00:38:07,560 --> 00:38:11,560 And it's this natural environment that provides the omega-3 486 00:38:11,560 --> 00:38:13,520 that we can't live without. 487 00:38:15,000 --> 00:38:18,680 In fact, it is absolutely vital for building and maintaining 488 00:38:18,680 --> 00:38:21,440 my favourite organ - the brain. 489 00:38:21,440 --> 00:38:26,160 Surprisingly enough, a brain is half fat and, of that fat, 490 00:38:26,160 --> 00:38:29,040 a quarter is made up of omega-3. 491 00:38:32,640 --> 00:38:36,800 All this omega-3 forms the connections between every nerve cell 492 00:38:36,800 --> 00:38:42,440 in the brain, cells which send and receive electrical impulses 493 00:38:42,440 --> 00:38:46,560 from the brain's 80 billion other cells. 494 00:38:46,560 --> 00:38:50,360 Low levels of omega-3 have been linked with depression and anxiety. 495 00:38:54,040 --> 00:38:56,440 Fortunately, there's a ready supply of the stuff 496 00:38:56,440 --> 00:38:59,120 scattered throughout this particular landscape. 497 00:39:02,280 --> 00:39:05,040 It's found naturally in the oils in the grass. 498 00:39:09,280 --> 00:39:11,240 But the highest dose can be got 499 00:39:11,240 --> 00:39:14,840 from a delicious mouthful of Highland clover. 500 00:39:19,520 --> 00:39:22,760 Magnify the clover 600 times 501 00:39:22,760 --> 00:39:27,440 and you'd be able to see microscopic globules of omega-3 fat. 502 00:39:34,480 --> 00:39:37,680 The cattle face the same challenge as us - 503 00:39:37,680 --> 00:39:40,560 they have to get their omega-3 from their diet. 504 00:39:42,120 --> 00:39:44,280 It matters what they eat. 505 00:39:44,280 --> 00:39:46,840 Grain contains very little omega-3, 506 00:39:46,840 --> 00:39:51,000 so factory farmed meat is lacking in this vital fatty acid. 507 00:39:54,400 --> 00:39:59,360 But these cows get their fill from grass and clover. Once eaten, 508 00:39:59,360 --> 00:40:02,720 the essential fatty acids enter the cells in their bodies... 509 00:40:04,440 --> 00:40:06,600 Look at that! 510 00:40:10,200 --> 00:40:14,280 ..making this grass-fed steak far higher in omega-3 511 00:40:14,280 --> 00:40:19,160 than beef intensively farmed and fed on grain alone. 512 00:40:19,160 --> 00:40:20,520 Looks good. 513 00:40:23,320 --> 00:40:28,760 Both omega-3 and omega-6 are vital for life, but it's a balancing act. 514 00:40:30,960 --> 00:40:34,920 Too high a ratio of omega-6 to omega-3 has been linked to a whole 515 00:40:34,920 --> 00:40:39,720 range of inflammatory diseases, from type two diabetes to arthritis. 516 00:40:41,320 --> 00:40:46,080 And a recent US study found that it wasn't unusual for there to be 517 00:40:46,080 --> 00:40:51,880 25 times more omega-6 than omega-3 in people's diet, 518 00:40:51,880 --> 00:40:56,440 most of it coming from the vegetable oil used to cook fast foods, 519 00:40:56,440 --> 00:40:59,040 like burgers, chips and cookies. 520 00:41:01,560 --> 00:41:05,680 And as omega-6 is so easy to get, it means we really do 521 00:41:05,680 --> 00:41:09,560 have to concentrate on getting enough omega-3. 522 00:41:11,480 --> 00:41:17,840 So keep a look out for good sources of omega-3, like beans, 523 00:41:17,840 --> 00:41:21,600 salmon, mackerel, 524 00:41:21,600 --> 00:41:23,720 and grass-fed beef. 525 00:41:25,000 --> 00:41:26,280 In a macabre sort of way, 526 00:41:26,280 --> 00:41:29,000 I like the fact that I've met this cow's relatives. 527 00:41:29,000 --> 00:41:32,920 It had a happy life and it didn't travel very far to get my plate. 528 00:41:32,920 --> 00:41:36,360 I also really like the fact that it's rich in omega-3. 529 00:41:38,360 --> 00:41:41,120 And it is incredibly succulent. 530 00:41:43,240 --> 00:41:46,560 Most of the nutrients we require are found in the carbs, 531 00:41:46,560 --> 00:41:49,880 proteins and fats hidden inside every meal. 532 00:41:52,400 --> 00:41:54,960 But not quite all. 533 00:41:54,960 --> 00:41:58,680 Although only needed in tiny amounts, we need to 534 00:41:58,680 --> 00:42:03,320 get a constant top-up of vitamins and minerals to keep us healthy. 535 00:42:05,920 --> 00:42:11,840 And there is one mineral-rich food we rely on from birth - 536 00:42:11,840 --> 00:42:13,120 milk. 537 00:42:31,040 --> 00:42:34,480 Here in the Rhodope Mountains of Bulgaria, 538 00:42:34,480 --> 00:42:39,960 people are 30% more likely to live to 100 than people from the US. 539 00:43:00,760 --> 00:43:04,920 So could it be their diet that's helping them live so long? 540 00:43:06,880 --> 00:43:11,160 Well, what unites them is the amount of milk they consume, 541 00:43:11,160 --> 00:43:16,400 rich in a mineral that our bodies can't make - 542 00:43:16,400 --> 00:43:18,680 calcium. 543 00:43:18,680 --> 00:43:23,600 Absorbed from food and passed from our gut into the bloodstream, 544 00:43:23,600 --> 00:43:28,360 calcium is transported to where it's needed most - 545 00:43:28,360 --> 00:43:29,600 our bones. 546 00:43:33,560 --> 00:43:36,880 We're constantly rebuilding our skeletons. 547 00:43:41,760 --> 00:43:44,440 And to do that, we have to keep eating calcium. 548 00:43:46,160 --> 00:43:50,160 And the amount we need increases as we get older 549 00:43:50,160 --> 00:43:52,920 because we just don't repair our bones as easily. 550 00:44:07,640 --> 00:44:12,400 Each morning, Dobrina sets about a daily food ritual 551 00:44:12,400 --> 00:44:17,080 which might hold the key to her family's long, healthy lives. 552 00:44:17,080 --> 00:44:18,840 SHE SPEAKS OWN LANGUAGE 553 00:44:18,840 --> 00:44:20,880 You must have much better technique than me 554 00:44:20,880 --> 00:44:24,280 because there's nothing coming out here! I could be here all day. 555 00:44:28,640 --> 00:44:31,440 Milk, be it human breast or from the cow, 556 00:44:31,440 --> 00:44:35,040 is a fantastic source of vitamins and minerals. 557 00:44:36,440 --> 00:44:39,240 We removed all the fat and the protein 558 00:44:39,240 --> 00:44:42,200 to see just what the other constituents were. 559 00:44:42,200 --> 00:44:45,120 And we found this incredibly rich, 560 00:44:45,120 --> 00:44:48,880 chemical soup of all sorts of vitamins and minerals that are 561 00:44:48,880 --> 00:44:53,680 floating around here. I want to get out one thing that's left in there. 562 00:44:55,600 --> 00:44:58,200 After warming to 40 Celsius, 563 00:44:58,200 --> 00:45:01,320 we added a salt solution to kick out what I'm looking for. 564 00:45:04,000 --> 00:45:08,080 A suction filtration then gave me this gungy stuff. 565 00:45:08,080 --> 00:45:11,560 That is calcium phosphate. 566 00:45:11,560 --> 00:45:16,120 It's what your bones are made out of, so it's essential to human life. 567 00:45:18,600 --> 00:45:19,880 But, for some of us, 568 00:45:19,880 --> 00:45:23,400 getting enough calcium from milk is harder than you might think. 569 00:45:26,960 --> 00:45:31,880 By the age of five, some people lose the ability to digest lactose, 570 00:45:31,880 --> 00:45:33,080 the sugar in milk. 571 00:45:37,840 --> 00:45:42,480 70% of African-Americans are thought to be lactose-intolerant, 572 00:45:42,480 --> 00:45:47,400 80% of southern Europeans, but only 5% of Brits. 573 00:45:51,720 --> 00:45:55,880 It's because, over the centuries, cultures that raise dairy cattle 574 00:45:55,880 --> 00:46:01,160 adapted and developed the ability to digest lactose, 575 00:46:01,160 --> 00:46:03,400 while cultures without cows didn't. 576 00:46:05,600 --> 00:46:10,040 And that's a lot of people who can't drink our main source of calcium. 577 00:46:11,840 --> 00:46:14,880 But we have learned to unlock the chemistry of milk. 578 00:46:17,280 --> 00:46:19,560 For people who can't digest lactose, 579 00:46:19,560 --> 00:46:22,240 drinking milk can turn their stomachs 580 00:46:22,240 --> 00:46:25,800 and that's because a gene that triggers the production of an enzyme 581 00:46:25,800 --> 00:46:28,480 called lactase has been turned off. 582 00:46:29,680 --> 00:46:34,440 Now, lactase would normally break down lactose and, in its absence, 583 00:46:34,440 --> 00:46:38,440 your body's reaction to the lactose can irritate your gut, 584 00:46:38,440 --> 00:46:41,800 can make you feel really sick and, as a consequence, 585 00:46:41,800 --> 00:46:47,320 it eliminates this ridiculously rich calcium source from your diet. 586 00:46:49,680 --> 00:46:53,280 But long ago, these mountain people discovered 587 00:46:53,280 --> 00:46:58,280 a bacterium that thrives on lactose, turning milk into yoghurt. 588 00:46:59,880 --> 00:47:01,120 And, every day, 589 00:47:01,120 --> 00:47:04,280 Dobrina carries on this family tradition making yoghurt, 590 00:47:04,280 --> 00:47:06,200 beginning with boiling the milk. 591 00:47:09,840 --> 00:47:13,480 What it does is effectively sterilises the milk, giving you 592 00:47:13,480 --> 00:47:17,400 a clean slate until you're ready to add the bacteria that you want. 593 00:47:18,440 --> 00:47:20,200 Oh, yeah. Perfect! 594 00:47:21,720 --> 00:47:23,040 Just the right amount. 595 00:47:24,400 --> 00:47:27,600 The curious thing is quite a lot of bacteria actually also have 596 00:47:27,600 --> 00:47:31,320 a problem breaking down lactose, except for a few strains 597 00:47:31,320 --> 00:47:37,480 and this is one of them here, a culture of Lactobacillus Bulgaricus, 598 00:47:37,480 --> 00:47:39,400 otherwise known as yesterday's yoghurt. 599 00:47:39,400 --> 00:47:42,360 I think what I do is I just pour it in here. 600 00:47:42,360 --> 00:47:44,120 Is that what I do? 601 00:47:44,120 --> 00:47:45,160 Oh, wait, no. 602 00:47:45,160 --> 00:47:46,640 SHE SPEAKS OWN LANGUAGE 603 00:47:46,640 --> 00:47:49,240 OK. I take this, I put in there... 604 00:47:49,240 --> 00:47:50,640 SHE SPEAKS OWN LANGUAGE 605 00:47:50,640 --> 00:47:52,320 ..and then I pour it in? No. 606 00:47:52,320 --> 00:47:53,680 No? More? 607 00:47:53,680 --> 00:47:56,080 SHE SPEAKS OWN LANGUAGE 608 00:47:56,080 --> 00:48:00,080 OK, and I stir it. And then I pour it in? 609 00:48:00,080 --> 00:48:01,560 OK. 610 00:48:04,240 --> 00:48:05,920 Once the microbes are added, 611 00:48:05,920 --> 00:48:10,440 they multiply as they feed on the lactose in milk, 612 00:48:10,440 --> 00:48:14,400 producing the lactic acid which is vital to making yoghurt. 613 00:48:17,400 --> 00:48:21,120 This exact process has been happening over and over again 614 00:48:21,120 --> 00:48:23,360 for potentially thousands of years. 615 00:48:25,120 --> 00:48:28,240 A lid on to keep any of the bacteria out 616 00:48:28,240 --> 00:48:31,240 and all we're doing now is insulating the milk, 617 00:48:31,240 --> 00:48:35,040 to keep the heat in, because the bacteria have a narrow window 618 00:48:35,040 --> 00:48:38,080 of when they're active in terms of temperature. 619 00:48:38,080 --> 00:48:39,720 SHE SPEAKS OWN LANGUAGE 620 00:48:39,720 --> 00:48:42,000 Three hours? 621 00:48:42,000 --> 00:48:43,440 No. Yes? 622 00:48:43,440 --> 00:48:45,640 SHE SPEAKS OWN LANGUAGE 623 00:48:45,640 --> 00:48:48,640 Three hours and we're eating? OK, I can do that! 624 00:48:50,680 --> 00:48:53,560 I think it's back to Bulgarian school for me. 625 00:48:59,160 --> 00:49:05,200 As the mixture becomes more acidic, the milk proteins clump together, 626 00:49:05,200 --> 00:49:09,200 creating a soft, tangy curd - yoghurt. 627 00:49:11,280 --> 00:49:13,200 Look at that, is that what we made? 628 00:49:13,200 --> 00:49:14,520 SHE SPEAKS OWN LANGUAGE 629 00:49:14,520 --> 00:49:15,760 Look at that proud smile! 630 00:49:15,760 --> 00:49:17,720 Let's open that up. 631 00:49:17,720 --> 00:49:19,240 You doubted my ability. 632 00:49:19,240 --> 00:49:21,040 Look at that, it was so simple. 633 00:49:25,640 --> 00:49:28,080 You can tell me what Bulgarian yoghurt tastes like 634 00:49:28,080 --> 00:49:29,800 made by an English guy. 635 00:49:29,800 --> 00:49:32,200 HE SPEAKS OWN LANGUAGE 636 00:49:32,200 --> 00:49:34,160 It's really good! 637 00:49:34,160 --> 00:49:36,120 Oh, thank you! That's lovely. 638 00:49:38,560 --> 00:49:41,560 There's been this amazing transformation 639 00:49:41,560 --> 00:49:43,360 in only a couple of hours. 640 00:49:43,360 --> 00:49:47,480 The bacteria have broken down a large proportion of the lactose, 641 00:49:47,480 --> 00:49:51,920 which means the whole mix is so much more digestible, 642 00:49:51,920 --> 00:49:55,800 potentially even for people with a lactose intolerance, and that means 643 00:49:55,800 --> 00:49:59,080 you get more calcium-rich deliciousness back in your diet. 644 00:50:00,520 --> 00:50:01,800 Mmm. 645 00:50:03,560 --> 00:50:06,000 Just 300mls of yoghurt will give you 646 00:50:06,000 --> 00:50:08,680 nearly half your daily calcium needs. 647 00:50:10,400 --> 00:50:14,000 But eating plenty of this vital mineral won't automatically mean 648 00:50:14,000 --> 00:50:15,600 that our bodies can use it. 649 00:50:19,760 --> 00:50:23,040 There's a final bit of chemistry necessary to lay down 650 00:50:23,040 --> 00:50:24,280 and replace bone. 651 00:50:26,000 --> 00:50:28,600 To do that, we need the help of vitamins. 652 00:50:31,960 --> 00:50:35,320 Now, these are strangely hard to classify. 653 00:50:36,760 --> 00:50:40,080 Vitamins are molecules that in many ways are best defined by 654 00:50:40,080 --> 00:50:44,200 what they're not. They're not minerals, not fatty acids, 655 00:50:44,200 --> 00:50:47,680 not amino acids, but they are absolutely essential, 656 00:50:47,680 --> 00:50:49,680 albeit in very small amounts. 657 00:50:53,280 --> 00:50:58,760 Magnified over 1,000 times, a beautiful world of crystals appears. 658 00:51:00,160 --> 00:51:03,320 Our bodies use these vitamins as life-support 659 00:51:03,320 --> 00:51:05,840 for many of our bodily functions. 660 00:51:10,360 --> 00:51:14,360 Vitamin C is abundant in citrus fruits. 661 00:51:14,360 --> 00:51:19,400 It strengthens blood vessels and gives skin its elasticity. 662 00:51:22,120 --> 00:51:25,200 And there are eight different types of B vitamins. 663 00:51:26,840 --> 00:51:29,320 B6 is found in nuts and does everything from 664 00:51:29,320 --> 00:51:34,080 keeping our nervous systems running to processing those amino acids 665 00:51:34,080 --> 00:51:37,720 into proteins that we need to repair muscles and organs. 666 00:51:41,320 --> 00:51:44,720 Vitamin E - that we get from foods like avocado. 667 00:51:44,720 --> 00:51:46,560 It acts as an antioxidant 668 00:51:46,560 --> 00:51:50,120 and protects our cells from damaging chemicals 669 00:51:50,120 --> 00:51:52,920 that are formed when we extract energy from food. 670 00:51:55,760 --> 00:51:59,280 The vitamin A we get from carrots keeps our eyes healthy 671 00:51:59,280 --> 00:52:01,520 and helps us fight infections. 672 00:52:04,800 --> 00:52:08,160 And leafy greens supply us with vitamin K, 673 00:52:08,160 --> 00:52:10,040 helping our blood to clot. 674 00:52:20,760 --> 00:52:24,360 And the only way we can absorb calcium is with the help 675 00:52:24,360 --> 00:52:26,560 of another vitamin - vitamin D. 676 00:52:30,680 --> 00:52:35,080 The key to getting our daily dose of vitamin D is to get enough sunlight. 677 00:52:37,200 --> 00:52:40,200 When sunlight reacts with cholesterol in our skin, 678 00:52:40,200 --> 00:52:42,400 the result is the vitamin D molecule. 679 00:52:47,000 --> 00:52:51,120 But here, high up in the Bulgarian mountains, and places far from 680 00:52:51,120 --> 00:52:55,720 the equator, like the UK, year-round sunshine is scarce. 681 00:52:59,200 --> 00:53:03,560 But there is a way through food that Mr Baklarev and his family can get 682 00:53:03,560 --> 00:53:06,080 the vitamin D they need all year round. 683 00:53:31,680 --> 00:53:34,880 Surprisingly, we've discovered that mushrooms 684 00:53:34,880 --> 00:53:37,600 are a potential source of vitamin D. 685 00:53:39,200 --> 00:53:43,200 Just like us, they need this vitamin to survive 686 00:53:43,200 --> 00:53:47,320 and they use it as a protection from the sun's harmful rays. 687 00:53:49,200 --> 00:53:51,240 How's that? Is that good? 688 00:53:51,240 --> 00:53:54,440 Yeah? A-ha! 689 00:53:54,440 --> 00:53:59,080 'Sunlight falling on a mushroom turns it into a vitamin D factory. 690 00:54:02,360 --> 00:54:06,480 'They use a chemical similar to cholesterol called ergosterol... 691 00:54:08,840 --> 00:54:11,640 '..which reacts with sunlight to make vitamin D.' 692 00:54:14,840 --> 00:54:19,760 There's something miraculous about what we're doing here because 693 00:54:19,760 --> 00:54:24,640 these mushrooms that are freshly picked from the dark forest floor 694 00:54:24,640 --> 00:54:27,360 don't really contain that much vitamin D. 695 00:54:27,360 --> 00:54:32,040 But putting them out in this intense UV light 696 00:54:32,040 --> 00:54:34,600 and the mushrooms, which are still alive, 697 00:54:34,600 --> 00:54:38,640 start to react by churning out that vitamin D. 698 00:54:41,320 --> 00:54:43,320 And if you put them gill side up, 699 00:54:43,320 --> 00:54:46,720 the surface area exposed to the sun increases... 700 00:54:49,280 --> 00:54:51,520 ..and they produce even more. 701 00:54:58,640 --> 00:55:03,400 Just a few hours out in the sun and a couple of portobello mushrooms 702 00:55:03,400 --> 00:55:06,520 will give us our daily dose of vitamin D. 703 00:55:08,080 --> 00:55:14,400 Dry them and it stays locked away in the mushroom for up to a year, 704 00:55:14,400 --> 00:55:18,680 a tasty way of getting vitamin D through those dark winter months. 705 00:55:24,760 --> 00:55:29,120 This is amazing! I love this stuff. 706 00:55:29,120 --> 00:55:32,680 You've got bread with cheese, yoghurt, a yoghurt drink. 707 00:55:32,680 --> 00:55:34,120 There's no lack of calcium here. 708 00:55:36,240 --> 00:55:38,880 And the vitamin D in these lovely mushrooms 709 00:55:38,880 --> 00:55:42,240 allows our bodies to absorb that all-important calcium... 710 00:55:47,360 --> 00:55:49,720 ..sending it through the bloodstream 711 00:55:49,720 --> 00:55:52,320 to cells called osteoblasts in our bones. 712 00:56:00,560 --> 00:56:05,520 These creep through the skeleton, laying down calcium-rich bone. 713 00:56:08,440 --> 00:56:12,960 This constant renewal protects us against diseases linked to ageing, 714 00:56:12,960 --> 00:56:14,840 such as osteoporosis. 715 00:56:18,480 --> 00:56:23,960 It could be a key factor not only to a healthy life, but also longevity. 716 00:56:25,760 --> 00:56:27,400 So there are loads of factors at work, 717 00:56:27,400 --> 00:56:29,640 but I can't help thinking that with air like this, 718 00:56:29,640 --> 00:56:31,600 running around every day, home-made food, 719 00:56:31,600 --> 00:56:34,760 and talk about a tonne of calcium - it can't hurt, can it? 720 00:56:40,280 --> 00:56:44,400 We've found the foods we all need to keep us ticking over. 721 00:56:49,040 --> 00:56:54,520 Day-to-day, meal-to-meal, we get much pleasure from the food we eat. 722 00:56:56,960 --> 00:57:02,400 The smells, tastes, colours and textures delight us. 723 00:57:04,000 --> 00:57:08,480 But what I think also really adds to that pleasure is understanding 724 00:57:08,480 --> 00:57:11,120 the hidden biochemistry at work. 725 00:57:11,120 --> 00:57:13,280 It helps us appreciate our food 726 00:57:13,280 --> 00:57:17,600 and it also means we're able to make the most of the ingredients 727 00:57:17,600 --> 00:57:21,520 hidden inside every delicious mouthful, 728 00:57:21,520 --> 00:57:26,160 ingredients which nourish not just the body, but also the mind. 729 00:57:28,880 --> 00:57:31,920 So if you're adventurous with food and you try a bit of everything, 730 00:57:31,920 --> 00:57:36,200 not only are your senses rewarded, your body has a greater chance 731 00:57:36,200 --> 00:57:39,920 of getting hold of all of those essential molecules 732 00:57:39,920 --> 00:57:41,480 because, ultimately, 733 00:57:41,480 --> 00:57:44,680 our bodies and everything we are comes from our plates. 734 00:57:49,960 --> 00:57:53,280 'Next time, we explore the boundaries of taste...' 735 00:57:53,280 --> 00:57:55,000 They are irresistible. 736 00:57:55,000 --> 00:58:00,640 '..we revel in the sumptuous food that dazzles our taste buds 737 00:58:00,640 --> 00:58:02,440 'and excites our noses...' 738 00:58:02,440 --> 00:58:04,200 HE LAUGHS 739 00:58:04,200 --> 00:58:08,160 '..as we discover how good taste is all about survival.' 740 00:58:11,200 --> 00:58:13,880 How does science change your perception of food? 741 00:58:13,880 --> 00:58:17,760 Find out how instinctive you are and learn even more about what you eat. 742 00:58:17,760 --> 00:58:20,080 Head to the BBC website onscreen now 743 00:58:20,080 --> 00:58:22,640 and follow the links to the Open University.