NARRATOR: HOW OFTEN DO YOU STOP AND REALLY THINK ABOUT YOUR FOOD?

WHY DOES IT TASTE THE WAY IT DOES, AND HOW DOES IT AFFECT YOUR BODY AND YOUR MIND?

WOMAN: HA HA HA!

NARRATOR: IN SEARCH OF ANSWERS, TWO EXPERTS WILL TAKE YOU ON A GLOBAL CULINARY ADVENTURE.

MEDICAL DOCTOR MICHAEL MOSLEY... MOSLEY: MY EYES ARE REALLY BEGINNING TO WATER, AND MY PULSE IS SHOOTING UP.

NARRATOR: AND BOTANIST JAMES WONG...

I COULD DO THIS ALL DAY.

WILL DISCOVER THE HIDDEN SCIENCE IN EVERY MOUTHFUL.

WONG: AND IT IS INCREDIBLE.

IT'S LIKE EATING IN TECHNICOLOR.

NARRATOR: THIS TIME, THEY'RE ON A MISSION TO GO DEEP INSIDE THE FOODS WE SIMPLY CAN'T LIVE WITHOUT-- THE CARBOHYDRATES THAT GIVE US ENERGY... AHH... NARRATOR: THE FATS THAT INSULATE OUR BRAIN CELLS...

THE PROTEINS THAT BUILD OUR BODIES... WONG: IT'S GOT TO BE THE WORLD'S BEST COMFORT FOOD.

NARRATOR: AND THE VITAMINS AND MINERALS THAT ARE VITAL TO OUR HEALTH.

HOW DO WE GET THE RIGHT BALANCE, AND WHY ARE THEY SO ESSENTIAL TO OUR SURVIVAL?

MOSLEY: THIS IS DELICIOUS SCIENCE.

NARRATOR: ACROSS THE WORLD, FOOD COMES IN A BEWILDERING RANGE OF SHAPES, COLORS, AND FLAVORS, BUT THERE WAS A TIME EARLY ON IN OUR LIVES WHEN THINGS WERE MUCH SIMPLER, WHEN WE LIVED AND THRIVED ON JUST ONE TYPE OF FOOD.

MOSLEY: CHANCES ARE, THIS IS THE FIRST FOOD YOU EVER CONSUMED.

IT'S HUMAN BREAST MILK.

NOW, WHAT'S AMAZING ABOUT THIS STUFF IS THAT IT CONTAINS ALL THE NUTRIENTS A BABY NEEDS TO GROW AND THRIVE.

FED ON NOTHING BUT BREAST MILK, A BABY WILL DOUBLE IN WEIGHT IN JUST 5 MONTHS.

NARRATOR: SO HOW CAN THIS PRECIOUS LIQUID PROVIDE EVERYTHING A BABY NEEDS TO GROW AND PROSPER?

TO FIND OUT, MICHAEL'S GOING TO DECONSTRUCT IT.

HE STARTS BY PUTTING AROUND 7 FLUID OUNCES, A FEW FEEDS FOR A NEWBORN, INTO A CENTRIFUGE.

A QUICK STRAIN, AND THE FIRST CHEMICAL IN THE MILK IS VISIBLE.

NOW, THIS CONTAINS AROUND 8 GRAMS OF FAT, ABOUT THE SAME AMOUNT AS YOU'D FIND IN A BAG OF CRISPS, NARRATOR: FAT THAT'S ESSENTIAL FOR BUILDING A BABY'S NERVE TISSUES AND THE SMOOTH RUNNING OF THEIR BRAIN.

AND WHAT'S LEFT IS THIS SKIMMED MILK, WHICH IS MAINLY WATER BUT WHICH ALSO INCLUDES ANOTHER VITAL INGREDIENT.

NARRATOR: MICHAEL WILL MAKE IT APPEAR BY ADDING A FEW DROPS OF VINEGAR.

NOW I NEED TO FILTER IT.

NARRATOR: THIS IS PROTEIN, ESSENTIAL FOR BUILDING A BABY'S BODY.

HE'S LEFT WITH A SOLUTION OF VITAMINS, MINERALS, AND ONE LAST MAJOR COMPONENT.

NOW I'M GOING TO DO SOMETHING SLIGHTLY WEIRD BECAUSE I HAVEN'T TASTED BREAST MILK SINCE I WAS A BABY.

SURPRISINGLY SWEET.

NO.

I GUESS IT SHOULDN'T BE SURPRISING BECAUSE ABOUT 7% OF THAT IS MADE UP OF LACTOSE, WHICH IS A SUGAR, A FORM OF CARBOHYDRATE.

AND BABIES NEED CARBOHYDRATE BECAUSE THEY NEED AN INSTANT SOURCE OF ACCESSIBLE ENERGY.

NARRATOR: SO THIS MIX OF CARBS, PROTEINS, FATS, VITAMINS, AND MINERALS IN BREAST MILK IS ALL A BABY NEEDS TO SURVIVE.

AND THE FUNNY THING IS THAT AS WE GET OLDER, IT DOESN'T REALLY CHANGE.

THEY JUST TO COME TO US IN DIFFERENT FORMS OF FOOD.

NARRATOR: AS ADULTS, WE'RE PRESENTED WITH A HUGE RANGE OF DIFFERENT FOODS TO CHOOSE FROM... [SIZZLING] SO HOW DO WE GO ABOUT GETTING THE RIGHT BALANCE OF FAT, PROTEIN, CARBS, VITAMINS, AND MINERALS... AND WHICH ARE ABSOLUTELY ESSENTIAL FOR OUR SURVIVAL?

[INSECTS CHIRPING] EVERY MORNING ALL OVER THE GLOBE, WE WAKE UP READY FOR FOOD.

[ROOSTER CROWS] OHH... NARRATOR: WE RISE WITH OUR BLOOD SUGAR LOW AND THE SAME NEED-- QUICK ENERGY.

BE IT TOAST, CEREAL, OR RICE, MOST OF US TURN TO THE SAME TYPE OF FOOD FOR THAT FIRST MEAL OF THE DAY--CARBOHYDRATES.

WONG: DID I SNORE?

[SNORTS] NO.

IT'S ALL RIGHT.

OK. HA HA HA!

WONG: CARBOHYDRATES ARE FANTASTICALLY DIVERSE.

IT'S REALLY SORT OF A CATCH-ALL TERMINOLOGY FOR A GROUP OF CHEMICALS THAT ARE MADE UP OF BUILDING BLOCKS OF SUGAR.

NARRATOR: THERE ARE MANY DIFFERENT TYPES-- GLUCOSE, LACTOSE, AND, PROBABLY THE MOST EXCITING ONE TO US--STARCH.

IT'S WHAT PLANTS USE TO STORE AWAY THEIR ENERGIES IN A CONCENTRATED FORMAT, AND AROUND HERE, IT'S USUALLY FOUND IN THE FORM OF A SEED STOLEN FROM A GRASS.

NARRATOR: ORYZA SATIVA, BETTER KNOWN AS THE RICE PLANT.

EACH SEED IS A GRAIN OF RICE, A MARVEL OF NATURE, BUT RICE DOESN'T GIVE UP ITS ENERGY EASILY.

THESE TERRACES HERE IN BANAUE ARE CALLED BY SOME THE EIGHTH WONDER OF THE WORLD.

THE PEOPLE WHO LIVE IN THESE MOUNTAINS HAVE BEEN CULTIVATING RICE FOR OVER 2,000 YEARS.

CHILD: HELLO.

HELLO.

NARRATOR: ALTHOUGH JAMES' FAMILY ORIGINALLY CAME FROM THIS REGION, HE'S NEVER FARMED RICE BEFORE.

FEEL LIKE SUPERMAN TO BE ABLE TO DO THIS.

NARRATOR: AS THE FARMERS WORK THE TERRACES, THEY'RE BURNING CALORIES, A MEASUREMENT OF ENERGY.

EVEN AT REST, OUR BODIES NEEDS FUEL TO KEEP GOING.

JUST STANDING STILL, WE BURN ABOUT 100 CALORIES AN HOUR, BUT WHILE WORKING THE FIELDS, THAT NUMBER JUMPS UP TO AROUND 350.

YOU OK?

I'M WAITING FOR MY ASIAN RICE FARMER GENES TO KICK IN.

I DON'T--I DON'T THINK THEY WORK.

NARRATOR: OUR BODIES GET ENERGY FROM FOOD, AND CARBOHYDRATE-RICH ONES LIKE RICE GIVE US FUEL MORE QUICKLY THAN ANY OTHER TYPE.

THE BODY BREAKS DOWN LONG CARBOHYDRATE CHAINS INTO A SIMPLE SUGAR--GLUCOSE.

IT'S QUICKLY AND EASILY ABSORBED IN THE BLOOD AND TRANSPORTED AROUND THE BODY, FEEDING OUR MUSCLES AND OUR ORGANS.

CARBS ARE THE ROCKET FUEL IN OUR DIETS.

[ROOSTER CROWS] GROWING RICE BY HAND REQUIRES LOTS OF ENERGY.

HARVESTING THE STUFF IS LABOR-INTENSIVE.

WE CAN BURN OVER 400 CALORIES AN HOUR...

SO WE HAVE TO BE SURE WE'RE GETTING A LOT MORE ENERGY FROM EATING IT THAN IT TAKES TO PRODUCE IT.

WONG: SO AFTER 6 MONTHS OF LOVING CARE AND HUNDREDS OF LABOR HOURS, YOU END UP WITH THIS BEAUTIFUL STUFF-- RAW RICE.

I STILL WOULDN'T CALL IT A FOOD, THOUGH.

NARRATOR: ALL THIS EFFORT BEGS THE QUESTION, WHY DO WE BOTHER WITH RICE AT ALL?

WONG: THE REASON WHY RICE IS SUCH A PHENOMENALLY IMPORTANT FOOD IS THE SHEER AMOUNT OF ENERGY THAT IS PACKED INTO EACH ONE OF THESE TINY GRAINS, AND I CAN ACTUALLY SHOW YOU HOW MUCH ENERGY THEY HAVE VISUALLY, BUT FIRST, I'M GOING TO TO BREAK THEM OPEN.

[WHIRRING] NARRATOR: GRINDING THE RICE TEARS THE TIGHTLY PACKED STARCH CHAINS APART, MAKING THE ENERGY IN THE CARBOHYDRATES EASIER TO UNLEASH.

WONG: THIS STUFF MIGHT NOT LOOK VERY EXCITING, BUT IT'S PACKED FULL OF ENERGY.

YOU CAN CONVERT THE POTENTIAL ENERGY THAT'S STORED IN THE RICE GRAINS INTO HEAT AND LIGHT ENERGY JUST BY DOING THIS.

NARRATOR: EACH PUFF IS AROUND A THIRD OF AN OUNCE... LOOK AT THAT.

I COULD DO THIS ALL DAY.

NARRATOR: AND CONTAINS ABOUT 35 CALORIES OF ENERGY, ALL GOING UP IN FLAMES, AND ALMOST ALL OF IT COMES FROM CARBOHYDRATES.

WONG: NOW, OUR BODIES MIGHT NOT DO THIS IN THE EXACTLY SAME WAY BECAUSE WE USE COMPLEX BIOCHEMISTRY TO DO IT.

NARRATOR: AND RICE DOESN'T GIVE UP ITS ENERGY WITHOUT A FIGHT...

BUT WE HAVE DISCOVERED ANOTHER WAY TO HARNESS ITS POWER.

WONG: EVEN ONCE FULLY PROCESSED, RICE IS ESSENTIALLY INDIGESTIBLE BECAUSE STARCH REALLY STUBBORNLY HOLDS ON TO ITS ENERGY UNTIL YOU DO THIS.

NARRATOR: COOKING IS THE GAME CHANGER.

THE STARCH IN THE RICE IS MADE UP OF TWO ENERGY-GIVING CARBOHYDRATE MOLECULES-- AMYLOSE AND AMYLOPECTIN...

BUT THEIR LONG CHAINS ARE PACKED TOGETHER, MAKING THEM MOSTLY INDIGESTIBLE.

THE COMBINATION OF HEAT AND WATER HAS THE POWER TO BREAK THE TANGLED CHAINS APART.

THIS CHEMISTRY IS GOING ON INSIDE EVERY GRAIN... AND MAGNIFIED 600 TIMES, WE CAN SEE THE EFFECT ON THE CELLS AS THE BOILING WATER MAKES THEM SWELL, EVEN THE MOMENT WHEN THEY FIRST OPEN AND THE DIGESTIBLE CARBS ERUPT.

SO TURNING RICE INTO A FOOD IS INCREDIBLY ENERGY-INTENSIVE.

A CUPFUL TAKES ABOUT 70 CALORIES TO PRODUCE, BUT WE GOT 35 CALORIES FROM JUST A THIRD OF AN OUNCE, WHICH MEANS A CUP OF RICE GIVES BACK AROUND 700 CALORIES.

WE GET A WHOPPING 10 TIMES MORE ENERGY OUT THAN WE PUT IN... AND THAT'S WHY RICE, A CULTIVATED RIVER GRASS, HAS BECOME SUCH AN IMPORTANT STAPLE IN THE WATER-RICH TROPICS.

[INSECT BUZZES] WHERE IT'S TOO COLD OR TOO DRY TO GROW RICE, WE IN THE WESTERN WORLD HAVE TURNED TO ANOTHER CROP FOR OUR CARB HIT-- WHEAT.

[CAR HORN HONKS] [BELL RINGS] MOST OF THE WHEAT WE CONSUME COMES IN THE FORM OF BREAD, AND THIS CITY IS FAMOUS FOR ONE PARTICULAR TYPE OF BREAD--SOURDOUGH.

MAN: I'VE BEEN DOING THIS FOR 37 YEARS.

THE MINUTE I TOUCHED DOUGH, I FELL IN LOVE WITH IT.

THIS IS WHAT I WANT TO DO.

NO MATTER IF YOU'RE RICH, POOR, OR ANYTHING, YOU'RE MAKING SOMETHING WONDERFUL FOR EVERYBODY.

NARRATOR: IT BEGINS WITH UNPROCESSED WHEAT FLOUR... A BLAND, TASTELESS POWDER THAT, IF COOKED, WOULD SET LIKE CONCRETE.

TO TURN IT INTO A TASTY FOOD, FERNANDO PADILLA EMPLOYS AN ARMY OF MICROBES.

THESE MICROBES LIVE IN SOMETHING AFFECTIONATELY KNOWN AS THE MOTHER DOUGH.

SEE, THIS IS WHERE SHE LIVES, AS YOU CAN TELL.

IT SAYS, "MOTHER DOUGH LIVES HERE."

WE GOT TO PUT AN ADDRESS HERE, YOU KNOW, BUT... WOW.

I'M CARRYING A PIECE OF HISTORY HERE.

YEAH.

BLIMEY.

NARRATOR: THE MOTHER DOUGH IS A MIX OF WATER AND FLOUR MORE COMMONLY KNOWN AS A STARTER.

INSIDE IT, A COMMUNITY OF LIVE YEAST CELLS AND BACTERIA THRIVE...

BUT THIS IS NO ORDINARY STARTER.

IT'S REPORTED TO BE THE OLDEST IN THE U.S. AND THIS GOES BACK TO 1849, DOES IT?

SO IMAGINE FOR OVER 165 YEARS AGO, IT IS THE SAME DOUGH, SO A LITTLE, TINY PIECE STILL DATES BACK TO THE SAME FAMILY.

NARRATOR: THIS STARTER WAS APPARENTLY CREATED BY IMMIGRANTS TO CALIFORNIA DURING THE GREAT GOLD RUSH.

INHALE.

OH, GOD!

HA HA!

HA HA!

HA HA!

HA HA HA!

THAT'S ALL THE SWEETNESS OF THE FLOUR BEING FERMENTED.

YOU KNOW, IT CREATES ALL THIS ALCOHOL FLAVOR, BUT IT ALL EVAPORATES.

YOU SEE HOW STRONG IT IS?

I WAS EXPECTING SOMETHING NICE.

THIS LITTLE THING IS GOING TO GIVE US, LIKE, 400 LOAVES OF BREAD.

LET'S BRING IT OUT.

NARRATOR: EVERY DAY, HALF OF THE MOTHER DOUGH IS FED WITH FLOUR AND WATER.

THEN IT'S LOCKED AWAY IN A REFRIGERATOR OVERNIGHT, WHERE IT REGENERATES, DOUBLING IN SIZE.

GOOD NIGHT, MUMMY.

SEE YOU TOMORROW.

HA HA HA!

THIS IS 200 POUNDS OF FLOUR HERE.

NARRATOR: THE OTHER HALF OF THE MOTHER DOUGH WILL BE USED TO CREATE OVER 400 LOAVES OF DELICIOUS, FRESH BREAD.

WE SHOULD'VE WORN THE APRON.

NARRATOR: ADDING WATER ACTIVATES ENZYMES IN THE FLOUR.

THIS, IN TURN, STARTS A COMPLEX BIOCHEMICAL CASCADE WHICH BEGINS WITH STARCH IN THE FLOUR TURNING INTO A SUGAR CALLED MALTOSE.

MIX IT FOR 10 MINUTES.

NARRATOR: BACTERIA FROM THE MOTHER DOUGH NOW FEED GREEDILY ON THE MALTOSE, BREAKING IT DOWN INTO GLUCOSE.

THE BACTERIA HAVE BEGUN TO DIGEST THE FLOUR FOR US.

[POPPING] PADILLA: YOU HEAR THAT?

WHEN YOU HEAR THE DOUGH POPPING... YEAH.

"POP, POP, POP."

"POP, POP, POP."

TALKS BACK TO YOU.

"HEY, I'M READY.

GET ME OUT OF HERE."

NARRATOR: IF IT WAS BAKED NOW, THIS WOULD TURN OUT AS FLAT AS A PANCAKE.

WHY IS MINE NOT LOOKING LIKE YOURS?

AND WE JUST FOLD IT OVER.

YEP.

NARRATOR: FORTUNATELY, ANOTHER GROUP OF MICROBES WILL USE SOME OF THE GLUCOSE TO TRANSFORM THE DOUGH.

MOSLEY: OK.

THIS IS DRIED YEAST.

IT DOESN'T LOOK INCREDIBLY EXCITING, DOES IT, BUT EVERY SINGLE GRAM THERE CONTAINS THOUSANDS OF THESE SINGLE-CELLED ORGANISMS, AND THEY'RE HELD CURRENTLY IN A STATE OF SUSPENDED ANIMATION.

I AM ABOUT TO BRING THEM BACK TO LIFE.

TO DO THAT, THEY NEED FOOD AND WATER, SO I'M GOING TO ADD SUGAR AND THEN WATER, AND NOW I ADD THE YEAST.

NARRATOR: IF THE YEAST CELLS ARE STILL ALIVE, THEY'LL PRODUCE A GAS WHICH PASSES THROUGH THE PIPE TO THE TEST TUBE.

MOSLEY: WELL, IN THERE, THOSE YEAST CELLS ARE SPRINGING BACK TO LIFE, AND THEY'RE GOING TO GET STUCK INTO THAT SUGAR.

SO IT'S WORKING.

YOU CAN SEE THE BUBBLES BEING PRODUCED THERE.

THEY'RE BEING CREATED BY THE YEAST GOBBLING UP THE SUGAR, PRODUCING CARBON DIOXIDE GAS, WHICH YOU CAN SEE BUBBLING UP, AND IT'S THIS REACTION WHICH IS ABSOLUTELY KEY TO PRODUCING A NICE, FLUFFY LOAF.

NARRATOR: WITH CARBON DIOXIDE BUBBLING THROUGH HIS BREAD MIX, FERNANDO MUST NOW STOP THE GAS ESCAPING, AND TO DO THAT, HE ALTERS THE CHEMICAL STRUCTURE OF THE DOUGH BY A PROCESS CALLED KNEADING.

MOSLEY: NOW, I'M NOT AN EXPERT BAKER AT ALL, BUT I KNOW THE SECRET TO MAKING GOOD BREAD IS GETTING-- MAKE REALLY SURE YOU KNEED IT THOROUGHLY.

NARRATOR: WHEN WE KNEAD BREAD, WE ARE FORCING TWO PROTEINS INSIDE THE FLOUR, GLIADIN AND GLUTENIN, TO FORM BONDS, CREATING A TOUGH, NEW SUBSTANCE--GLUTEN... AND THIS IS WHERE THE ART OF BREADMAKING COMES IN.

IF YOU DON'T KNEAD ENOUGH, THEN YOU WON'T CREATE ENOUGH GLUTEN IN YOUR LOAF, SO THE GASES WILL ESCAPE, AND IT WON'T RISE, BUT GET IT JUST RIGHT, AND THE EFFECT ON THE LOAF IS MAGICAL.

AS IT RISES, THE VOLUME MORE THAN DOUBLES AS THE YEAST CONSUME THE GLUCOSE AND BLOW BUBBLES INSIDE THEIR GLUTEN HOME.

THE BACTERIA ALSO PRODUCE A SMALL AMOUNT OF LACTIC ACID, AND, WITH NO ADDED SUGAR, THE ACID GIVES THE LOAF THE DISTINCTIVE TANG OF SOURDOUGH BREAD.

BAKING THEN SEALS THE AIR POCKETS, AND, THANKS TO THE MICROBES FROM THE MOTHER DOUGH, WE END UP WITH A CARB-RICH, LIGHT, FLUFFY LOAF.

OOH!

OH, WOW.

CAKE.

EVEN-- HOW MANY LOAVES IS THAT?

THIS IS ABOUT 100 LOAVES OF BREAD.

AH, PERFECT.

AHH... MOSLEY: MM, IT'S-- THAT'S INCREDIBLE.

AHH... MM.

SOURDOUGH USED TO BE ONE OF THE MOST POPULAR FORMS OF BREAD UNTIL IT GOT DISPLACED BY CHEAP, MASS-PRODUCED STUFF, AND THAT SEEMS LIKE A SHAME BECAUSE IT'S TASTY.

IT'S ALSO HEALTHIER.

IT HASN'T GOT ADDED SUGARS, AND THE ACID IN THE BREAD MEANS THAT YOU'RE MUCH BETTER ABLE TO ABSORB THE MINERALS AND THE VITAMINS THAT ARE LOCKED UP IN THE FLOUR.

IN FACT, I THINK I'M GOING TO TRY BAKING SOME WHEN I GET HOME.

NARRATOR: FROM THE EAST TO THE WEST, BY UNLOCKING THE SECRETS OF RICE AND WHEAT, OUR ANCESTORS MADE THE INDIGESTIBLE DIGESTIBLE.

THESE DAYS, CARBS HAVE A MIXED REPUTATION, AND LOW-CARB DIETS ARE ALL THE RAGE.

MANY REDUCE OR ELIMINATE THEM ENTIRELY FROM THEIR DIET.

BUT OUR MODERN WORLD WOULD SIMPLY NOT HAVE BEEN POSSIBLE WITHOUT THESE KEY STAPLES... [SIREN] BUT UNLIKE CARBS, WE CANNOT LIVE WITHOUT PROTEIN.

OUR BODIES MAKES AT LEAST 250,000 DIFFERENT TYPES OF PROTEIN MOLECULES.

THESE BUILD EVERYTHING FROM HORMONES AND ENZYMES TO ELECTRICAL PATHWAYS IN THE BRAIN AND OUR HAIR, SKIN, AND MUSCLES.

TO DO THIS, WE NEED PLENTY OF PROTEIN FROM FOOD TO WORK WITH, REQUIRING US TO EAT AROUND 50 GRAMS A DAY.

THE BODY BREAKS DOWN THIS PROTEIN INTO ITS BASIC BUILDING BLOCKS FROM WHICH WE CAN BUILD NEW PROTEINS, AND ONE OF THE WORLD'S FAVORITE SOURCES OF HIGH-QUALITY PROTEIN IS EGGS.

MICHAEL'S GOING TO DECONSTRUCT AN EGG TO REVEAL EXACTLY WHAT IS INSIDE.

MOSLEY: RIGHT, SO I'M JUST GOING TO PRISE OFF A LITTLE BIT OF SHELL, AND THERE IT IS.

AND, AS YOU CAN SEE, IT'S HARD, CRYSTALLINE, AND MADE UP MAINLY OF CALCIUM CARBONATE.

NARRATOR: HERE MAGNIFIED OVER 2,000 TIMES, WE CAN SEE THE SURFACE OF THE SHELL IS COVERED IN LOTS OF TINY HOLES, THERE SO A DEVELOPING CHICK CAN BREATHE.

EACH HOLE IS FORMED OVER A GAP IN A LATTICE OF PROTEIN THAT THE SHELL GROWS OVER.

SURPRISINGLY, THIS MEMBRANE IS PARTLY MADE FROM A TOUGH PROTEIN CALLED KERATIN, THE SAME STUFF OUR HAIR AND NAILS ARE MADE FROM.

IT PROTECTS THE CONTENTS OF THE EGG FROM BACTERIA AND DUST.

INSIDE THE WHITE, OR ALBUMEN, IS A MIX OF WATER AND 11% PROTEIN.

MOSLEY: BUT IT'S THE EGG YOLK WHERE MOST OF THE GOODNESS RESIDES.

IT'S GOT MINERALS, VITAMINS, SOME FAT, SOME CHOLESTEROL, BUT ITS ALSO GOT 17% PROTEIN, AND THE FACT THAT YOU FIND PROTEIN IN THE MEMBRANE, THE WHITE, AND THE EGG YOLK SHOWS YOU JUST HOW IMPORTANT PROTEIN IS.

IN US, IT'S RESPONSIBLE FOR EVERYTHING FROM RUNNING YOUR IMMUNE SYSTEM TO CARRYING OXYGEN AROUND YOUR BODY, AND EGGS ARE A REALLY BEAUTIFUL SOURCE OF PROTEIN BECAUSE ALMOST ALL THE PROTEIN THERE-- APART, OBVIOUSLY, FROM THE SHELL--CAN BE READILY DIGESTED.

NARRATOR: SO HOW DOES THE PROTEIN FROM FOOD LIKE EGGS FIND ITS WAY TO WHERE IT'S NEEDED?

AS WE WORK OUR BODIES, WE'RE CAUSING WEAR AND TEAR TO OUR MUSCLES, AND THE PROTEIN IN OUR FOOD IS VITAL IN REPAIRING THE DAMAGE.

ENZYMES IN OUR STOMACHS AND INTESTINES BREAK DOWN THE PROTEIN INTO INDIVIDUAL BUILDING BLOCKS, MOLECULES CALLED AMINO ACIDS.

THEY ENTER OUR BLOODSTREAM AND TRAVEL TO AREAS SUCH AS OUR MUSCLES WHERE THEY ARE NEEDED.

THESE AMINO ACIDS THEN JOIN TOGETHER TO MAKE THE PROTEINS WE NEED TO BUILD OUR BODIES.

BUT THE WAY WE PREPARE EGGS MAKES A MASSIVE DIFFERENCE TO HOW EASILY WE CAN USE THE PROTEIN THEY CONTAIN.

CONTRARY TO POPULAR BELIEF, EAT EGGS RAW, AND WE ONLY BENEFIT FROM ABOUT HALF THE PROTEIN.

COOK THEM, AND IT'S A VERY DIFFERENT STORY.

IT FUNDAMENTALLY CHANGES THE PROTEINS, AND WE CAN SEE IT HAPPENING.

MOSLEY: THIS IS A RAW EGG, AND AS IT SLOWLY COOKS, IT CHANGES.

SO OVER HERE, YOU CAN BEGIN TO SEE SOME OF THE EGG WHITE IS SETTING.

THE PROTEIN IN IT IS DENATURING.

NARRATOR: THE LONGER EGGS COOK, THE MORE THE PROTEIN FIBERS DENATURE.

THE PROTEIN MOLECULES LITERALLY UNFOLD, AND OUR DIGESTIVE ENZYMES CAN MORE EASILY BREAK DOWN THESE UNFOLDED PROTEIN MOLECULES INTO AMINO ACIDS.

SO COOKED EGGS DON'T JUST TASTE BETTER.

THEY MORE EASILY GIVE US THE PROTEIN WE NEED.

ALTHOUGH OUR BODIES ARE BUILT FROM AROUND 250,000 DIFFERENT PROTEIN MOLECULES, ALL THESE PROTEINS ARE CONSTRUCTED FROM JUST 20 AMINO ACIDS.

THE AMAZING THING IS, OUR BODIES CAN JUST MANUFACTURE 11 OF THOSE, BUT THAT LEAVES 9, AND WE CALL THEM THE 9 ESSENTIAL AMINO ACIDS.

NARRATOR: WE HAVE EVOLVED THE CELLULAR MACHINERY TO PRODUCE ALL BUT THE 9 ESSENTIAL ONES.

THESE WE MUST GET FROM OUR DIET, BUT THIS ISN'T ALWAYS EASY.

EGGS, FISH, AND MEAT CONTAIN ALL 9 ESSENTIAL AMINO ACIDS, BUT THERE ARE PLENTY OF FOODS, INCLUDING VEGETABLES, THAT DON'T.

TO SURVIVE ON VEGETABLES ALONE, WE HAVE TO CAREFULLY MIX AND MATCH WHAT WE EAT.

OH, LOOK AT THIS.

THIS IS REAL AZTEC GOLD.

FOR MILLENNIA, CORN HAS BEEN THE STAPLE CROP THROUGHOUT PRETTY MUCH THE WHOLE OF LATIN AMERICA, AND THAT'S BECAUSE IT'S JUST PACKED FULL OF THE GOOD STUFF.

NARRATOR: CORN IS BURSTING WITH CARBS, VITAMINS, AND FIBER, BUT CRUCIALLY, IT'S MISSING TWO ESSENTIAL AMINO ACIDS-- LYSINE AND TRYPTOPHAN.

BUT IN THIS PART OF MEXICO, THEY'VE FOUND AN INGENIOUS WAY OF EATING CORN TO GET ALL THE AMINO ACIDS THEY NEED, AND IT'S A RATHER SURPRISING LOCAL DELICACY.

I'VE ALWAYS WANTED TO SEE IT IN THE FIELD.

UH!

YOU GET THESE MASSIVELY SWOLLEN EARS OF CORN, AND WHEN YOU SPLIT THEM OPEN, YOU CAN SEE THE DEFORMITY THAT LIES BENEATH.

NARRATOR: HUITLACOCHE HAS BEEN CALLED FOOD OF THE GODS.

IT LOOKS LIKE SOMETHING OUT OF A HORROR MOVIE, BUT IT CONTAINS BOTH LYSINE AND TRYPTOPHAN, SO EAT THIS WITH REGULAR CORN, AND WE GET ALL 9 ESSENTIAL AMINO ACIDS.

WONG: THIS IS CREATED BY A PATHOGENIC FUNGUS, AND IT'S A DEBILITATING DISEASE ON MAIZE PLANTS AROUND THE WORLD, BUT ONLY IN MEXICO DO FARMERS OPEN THIS UP AND GET REALLY EXCITED.

[INSECTS BUZZ] NARRATOR: THIS FUNGUS BEGINS AS NOTHING MORE THAN A MICROSCOPIC SPORE.

CARRIED ON THE WIND, JUST ONE COULD INFECT AN ENTIRE CROP.

IT GERMINATES AND SENDS OUT BRANCHES THAT PASS THROUGHOUT THE EAR OF CORN, WHERE IT AFFECTS EVERY KERNEL, CREATING THE SWOLLEN TUMORS.

OTHER COUNTRIES WOULD TORCH THESE INFECTED FIELDS, BUT NOT HERE.

[MUSIC AND CONVERSATION] WONG: WHAT TIME IS IT NOW?

OH, 6:00, 6:30 IN THE MORNING AND IN FULL SWING.

NARRATOR: HUITLACOCHE HAS BECOME A DELICACY, SERVED UP IN THE BEST RESTAURANTS IN TOWN.

IT'S CRAZY, NO?

NARRATOR: AT MARKET, INFECTED CORN IS WORTH 50% MORE THAN JUST REGULAR CORN, SO MASTER CHEF LALO GARCIA ARRIVES EARLY TO ENSURE HE GETS THE PICK OF THE BUNCH.

[SPEAKS SPANISH] THIS IS WHERE I BUY THE HUITLACOCHE.

WOW.

LOOK AT THAT.

AND THE SMELL.

THE SMELL IS AMAZING, THAT OF EARTH.

IT'S WHY I REALLY LOVE THIS PRODUCT.

IT'S AMAZING THAT EARTH STILL PRODUCES THIS, THIS TYPE OF BEAUTY.

SO WE HAVE A LITTLE OLIVE OIL HERE, ONIONS.

WE ADD OUR HUITLACOCHE.

WE'RE GOING TO MAKE A VERY, VERY BASIC SALSA TO GO WITH OUR HUITLACOCHES.

WONG: YOU'D NEVER KNOW TO LOOK AT IT, BUT HUITLACOCHE HAS THE MOST AMAZING FLAVOR.

IT'S KIND OF LIKE BLACK TRUFFLES MEETS SHITAKE MUSHROOMS BUT THAT SAVORY VOLUME JUST WHACKED UP.

SMOKY, RICH.

IT'S GOT TO BE THE WORLD'S BEST COMFORT FOOD.

NARRATOR: AND EATEN WITH CORN TORTILLAS, WE GET OUR HIT OF ALL 9 OF THOSE ESSENTIAL AMINO ACIDS...

BUT MEXICANS AREN'T THE ONLY ONES TO PULL OFF THIS CLASSIC COMBINATION.

FROM THE BRITISH FAVORITE OF BEANS ON TOAST... TO THE INDIAN HOLY GRAIL OF RICE AND DHAL... OR THE ITALIAN STAPLE OF BEANS AND PASTA, ACROSS THE GLOBE, WE'VE INVENTED COMBINATIONS OF PULSES AND BEANS MIXED WITH GRAINS TO GIVE US ALL 9 OF THE AMINO ACIDS WE DESPERATELY NEED.

INSTINCTIVELY, WE'VE BECOME EXPERT NUTRITIONISTS, HUNTING OUT WHAT WE NEED FROM OUR FOOD... [SIZZLING] AND NO NUTRITIONIST WOULD RECOMMEND A DIET THAT DIDN'T CONTAIN SOME FAT.

WHETHER WE GET IT FROM MILK, FISH, MEAT, NUTS, OR VEGETABLES, FAT IS ESSENTIAL FOR HEALTH.

SOME FATS ARE EVEN CRUCIAL FOR THE FUNCTIONING OF OUR BRAINS.

NOW, DIFFERENT FOODS HAVE DIFFERENT FORMS OF FAT.

WE'VE GOT OLIVES, WALNUT, AVOCADO.

NARRATOR: MOST OF THESE FATS ARE LIQUID AT ROOM TEMPERATURE.

MOSLEY: THE ODD ONE OUT IS THIS ONE, WHICH CAME FROM THE BEEF.

IT'S SOLID AT ROOM TEMPERATURE.

NARRATOR: AND THE REASON THERE ARE SO MANY DIFFERENT TYPES OF FAT IS BECAUSE THERE ARE SO MANY DIFFERENT TYPES OF BUILDING BLOCKS FOR FAT.

BECAUSE EACH FAT IS, IN TURN, MADE UP OF SOMETHING CALLED FATTY ACIDS.

NARRATOR: COMPLEX FAT CHAINS ARE BUILT BY ASSEMBLING THESE SMALLER UNITS OF FATTY ACIDS.

TAKING A CLOSE LOOK AT THE FAT IN A PIECE OF SALMON SHOWS JUST HOW MANY FATTY ACIDS THERE ARE.

MICHAEL'S MASHING IT UP WITH SOME ACETONE, STUFF MORE COMMONLY USED TO REMOVE NAIL POLISH.

THIS WON'T ADD TO THE FLAVOR, BUT IT WILL HELP SEPARATE OUT THE FAT.

THERE'S A LOVELY LAYER OF PINK FAT RIGHT THERE ON THE TOP.

NARRATOR: ANALYZING THIS FAT AT THE MOLECULAR LEVEL REVEALS WHAT HE'S LOOKING FOR.

YOU CAN SEE LOTS OF DIFFERENT PEAKS, AND EACH OF THESE PEAKS REPRESENTS A DIFFERENT FATTY ACID.

NARRATOR: THESE FATTY ACIDS ARE ESSENTIAL TO THE SMOOTH RUNNING OF OUR BODIES.

EATING SALMON IS A GREAT WAY OF GETTING THEM, BUT WE ARE SO DEPENDENT ON FAT, WE HAVE EVOLVED CELLULAR MACHINERY TO BUILD MOST OF THE FATTY ACIDS THAT MIGHT BE MISSING FROM OUR DIET.

MOSLEY: THERE ARE TWO TYPES, HOWEVER, WHICH YOUR BODY CANNOT MAKE.

THEY ARE OMEGA 6 AND THE RATHER MORE ELUSIVE OMEGA 3.

NARRATOR: OMEGA 6 IS EASY-- THERE'S PLENTY IN VEGETABLE OIL-- BUT WE HAVE TO WORK A LITTLE HARDER TO GET OMEGA 3.

IT'S ONLY FOUND IN FOODS LIKE BEANS, OILY FISH, AND GRASS-FED BEEF.

[GULLS SQUAWKING] IN SEARCH OF OMEGA-3-RICH MEAT, MICHAEL HAS TRAVELED TO THE HIGHLANDS OF SCOTLAND.

THESE ARE SCOTTISH HIGHLAND CATTLE.

THEY'RE REALLY WELL ADAPTED TO LIFE HERE... AND THOUGH THEY SPORT THE LONGEST HAIR OF ANY COW, THAT'S NOT WHAT MAKES THEM SPECIAL.

WHAT MAKES THESE CATTLE STAND OUT IS THAT, UNLIKE MOST CATTLE, THEIR MEAT IS RICH IN ELUSIVE OMEGA 3... AND IT'S THIS NATURAL ENVIRONMENT THAT PROVIDES THE CATTLE WITH THE OMEGA 3 THAT WE CAN'T LIVE WITHOUT.

MOSLEY: IN FACT, IT IS ABSOLUTELY VITAL FOR BUILDING AND MAINTAINING MY FAVORITE ORGAN--THE BRAIN.

SURPRISINGLY ENOUGH, A BRAIN IS HALF FAT, AND OF THAT FAT, A QUARTER IS MADE UP OF OMEGA 3.

NARRATOR: ALL THIS OMEGA 3 FORMS THE CONNECTIONS BETWEEN EVERY NERVE CELL IN THE BRAIN, CELLS WHICH SEND AND RECEIVE ELECTRICAL IMPULSES FROM THE BRAIN'S 80 BILLION OTHER CELLS.

LOW LEVELS OF OMEGA 3 HAVE BEEN LINKED WITH DEPRESSION AND ANXIETY.

FORTUNATELY, THERE'S A READY SUPPLY OF THE STUFF SCATTERED THROUGHOUT THIS PARTICULAR LANDSCAPE.

IT'S FOUND NATURALLY IN THE OILS IN THE GRASS...

BUT THE HIGHEST DOSE CAN BE DRAWN FROM A DELICIOUS MOUTHFUL OF HIGHLAND CLOVER.

MAGNIFY THE CLOVER 600 TIMES, AND SOON, MICROSCOPIC GLOBULES OF OMEGA 3 FAT BECOME VISIBLE.

IN THIS FORM, IT'S NOT THAT NUTRITIOUS FOR HUMANS, BUT LUCKILY, THE CATTLE ARE ON HAND TO HELP.

THEY FACE THE SAME CHALLENGE AS US, HAVING TO GET THEIR OMEGA 3 FROM THEIR DIET.

IT MATTERS WHAT THEY EAT.

GRAIN CONTAINS VERY LITTLE OMEGA 3, SO FACTORY-FARMED MEAT IS LACKING IN THIS VITAL FATTY ACID.

BUT THESE COWS GET THEIR FILL FROM GRASS AND CLOVER.

ONCE EATEN, THE ESSENTIAL FATTY ACIDS ENTER THE CELLS IN THEIR BODIES.

OH, LOOK AT THAT.

HOORAY!

HOORAY!

OHH... THAT LOOKS GOOD.

MM!

YEP.

NARRATOR: MAKING THIS GRASS-FED STEAK FAR HIGHER IN OMEGA 3 THAN BEEF INTENSIVELY FARMED AND FED ON GRAIN ALONE.

LOOKS GOOD.

VERY GOOD, DADDY.

WOW.

NARRATOR: BOTH OMEGA 3 AND OMEGA 6 ARE VITAL FOR LIFE, BUT IT'S A BALANCING ACT.

MOSLEY: TOO HIGH A RATIO OF OMEGA 6 TO 3 HAS BEEN LINKED TO A WHOLE RANGE OF INFLAMMATORY DISEASES, FROM TYPE 2 DIABETES TO ARTHRITIS, NARRATOR: AND A RECENT U.S. STUDY FOUND IT WASN'T UNUSUAL FOR THERE TO BE 25 TIMES MORE OMEGA 6 THAN OMEGA 3 IN PEOPLE'S DIETS, MOST OF IT COMING FROM THE VEGETABLE OIL USED TO COOK FAST FOODS LIKE BURGERS, FRIES, AND COOKIES.

AND AS OMEGA 6 IS SO EASY TO GET, IT MEANS WE REALLY DO HAVE TO CONCENTRATE ON GETTING ENOUGH OMEGA 3.

MOSLEY: IN A MACABRE SORT OF WAY, I LIKE THE FACT THAT I'VE MET THIS COW'S RELATIVES, THAT IT HAD A HAPPY LIFE AND IT DIDN'T TRAVEL VERY FAR TO GET TO MY PLATE.

I ALSO REALLY LIKE THE FACT THAT IT'S RICH IN OMEGA 3, AND IT IS INCREDIBLY SUCCULENT.

NARRATOR: MOST OF THE NUTRIENTS WE REQUIRE ARE FOUND IN THE CARBS, PROTEINS, AND FATS HIDDEN INSIDE EVERY MEAL, BUT NOT QUITE ALL.

ALTHOUGH ONLY NEEDED IN TINY AMOUNTS, WE NEED TO GET A CONSTANT SUPPLY OF VITAMINS AND MINERALS TO KEEP US HEALTHY.

THERE ARE 16 ESSENTIAL MINERALS THAT WE NEED TO GET FROM OUR FOOD, INCLUDING IRON, FOUND IN MEAT, TO BUILD RED BLOOD CELLS; SODIUM FROM SALT FOR OUR NERVOUS SYSTEM; AND MAGNESIUM, FOUND IN NUTS, FOR OUR BODY'S BIOCHEMICAL FUNCTIONS.

AND, AS WE KNOW, THERE IS ONE MINERAL-RICH FOOD WE RELY ON FROM BIRTH--MILK.

[BIRDS CHIRPING] HERE IN THE RHODOPE MOUNTAINS OF BULGARIA, PEOPLE ARE 30% MORE LIKELY TO LIVE TO 100 THAN PEOPLE FROM THE U.S. [MAN SPEAKING BULGARIAN] TRANSLATOR: "I'M 71 YEARS OLD.

"I HAVE FRIENDS OLDER THAN ME.

"THEY KEEP LIVESTOCK, PLANT POTATOES AND BEANS.

"THEY PRODUCE THEIR OWN MEAT AND MILK.

THEY KEEP HEALTHY."

NARRATOR: JAMES HAS COME TO INVESTIGATE WHETHER IT'S THEIR DIET THAT HELPS THEM LIVE SO LONG.

WHAT UNITES THEM IS THE AMOUNT OF MILK THEY CONSUME, RICH IN A MINERAL THAT OUR BODIES CAN'T MAKE-- CALCIUM.

ABSORBED FROM FOOD AND PASSED FROM OUR GUT INTO THE BLOODSTREAM, CALCIUM IS TRANSPORTED TO WHERE IT'S NEEDED MOST-- OUR BONES.

WE ARE CONSTANTLY REBUILDING OUR SKELETONS... AND TO DO THAT, WE HAVE TO KEEP EATING CALCIUM, AND THE AMOUNT WE NEED INCREASES AS WE GET OLDER BECAUSE WE DON'T REPAIR OUR BONES AS EASILY.

[WOMAN SPEAKING BULGARIAN] TRANSLATOR: "EVERYTHING COMES FROM HER-- BUTTER, CHEESE, AND COTTAGE CHEESE."

EACH MORNING, DOBRINA BAKLAREV SETS ABOUT A DAILY FOOD RITUAL THAT MIGHT HOLD THE KEY TO HER FAMILY'S LONG, HEALTHY LIVES.

[DOBRINA SPEAKING BULGARIAN] YOU MUST HAVE A MUCH BETTER TECHNIQUE THAN ME BECAUSE THERE'S NOTHING COMING OUT HERE.

I COULD BE HERE ALL DAY.

NARRATOR: MILK, BE IT HUMAN BREAST OR FROM THE COW, IS A FANTASTIC SOURCE OF VITAMINS AND MINERALS.

BACK IN THE LAB, JAMES HAS REMOVED ALL THE FAT AND PROTEIN TO SEE JUST WHAT THE OTHER CONSTITUENTS ARE.

WONG: AND WE FOUND THIS INCREDIBLY RICH CHEMICAL SOUP OF ALL SORTS OF VITAMINS AND MINERALS THAT ARE FLOATING AROUND IN HERE, AND I WANT TO GET OUT ONE THING THAT'S LEFT IN THERE.

NARRATOR: AFTER WARMING TO 100 DEGREES FAHRENHEIT, HE ADDS A SALT SOLUTION TO EXTRACT WHAT HE'S LOOKING FOR.

A SUCTION FILTRATION PROCESS THEN PRODUCED... WONG: THIS GUNGY STUFF.

THAT IS CALCIUM PHOSPHATE.

IT'S WHAT YOUR BONES ARE MADE OUT OF, SO IT'S ESSENTIAL TO HUMAN LIFE.

NARRATOR: BUT FOR SOME OF US, GETTING ENOUGH CALCIUM FROM MILK IS HARDER THAN WE MIGHT THINK.

BY THE AGE OF 5, SOME PEOPLE LOSE THE ABILITY TO DIGEST LACTOSE, THE SUGAR IN MILK.

70% OF AFRICAN AMERICANS ARE THOUGHT TO BE LACTOSE INTOLERANT AND 80% OF SOUTHERN EUROPEANS, BUT ONLY 5% OF BRITS.

THE DIFFERENCE IS BECAUSE CULTURES THAT RAISE DAIRY CATTLE ADAPTED AND DEVELOPED THE ABILITY TO DIGEST LACTOSE, WHILE CULTURES WITHOUT COWS DIDN'T.

AND THAT'S A LOT OF PEOPLE WHO CAN'T DRINK OUR MAIN SOURCE OF CALCIUM.

BUT WE HAVE LEARNED TO UNLOCK THE CHEMISTRY OF MILK.

FOR PEOPLE WHO CAN'T DIGEST LACTOSE, DRINKING MILK CAN TURN THEIR STOMACHS, AND THAT'S BECAUSE A GENE THAT TRIGGERS THE PRODUCTION OF AN ENZYME CALLED LACTASE HAS BEEN TURNED OFF.

NOW, LACTASE WOULD NORMALLY BREAK DOWN LACTOSE, AND IN ITS ABSENCE, YOUR BODY'S REACTION TO THE LACTOSE CAN IRRITATE YOUR GUT, CAN MAKE YOU FEEL REALLY SICK, AND, AS A CONSEQUENCE, IT ELIMINATES THIS RIDICULOUSLY RICH CALCIUM SOURCE FROM YOUR DIET.

NARRATOR: BUT LONG AGO, THESE MOUNTAIN PEOPLE DISCOVERED A BACTERIUM THAT THRIVES ON LACTOSE, TURNING MILK INTO YOGURT.

AND EVERY DAY, DOBRINA CARRIES ON THIS FAMILY TRADITION OF MAKING YOGURT, BEGINNING WITH BOILING THE MILK.

WONG: WHAT IT DOES IS EFFECTIVELY STERILIZES THE MILK, GIVING YOU A CLEAN SLATE UNTIL YOU'RE READY TO ADD THE BACTERIA THAT YOU WANT.

OH, YEAH.

PERFECT.

DOBRINA: HA HA HA!

JUST THE RIGHT AMOUNT.

NOW, THE CURIOUS THING IS, QUITE A LOT OF BACTERIA ACTUALLY ALSO HAVE A PROBLEM BREAKING DOWN LACTOSE EXCEPT FOR A FEW STRAINS, AND THIS IS ONE OF THEM HERE, A CULTURE OF LACTOBACILLUS BULGARICUS, OTHERWISE KNOWN AS YESTERDAY'S YOGURT, AND I THINK WHAT I DO IS, I JUST KIND OF POUR IT IN HERE.

IS THAT WHAT I DO?

OK. OH, WAIT.

NO?

TKOO TKOO TKOO.

OK. OK.

I TAKE THIS?

I PUT IT IN THERE, AND THEN I POUR IT IN?

YEAH.

NE.

NO?

MORE?

[SPEAKING BULGARIAN] OK, AND I STIR IT, AND THEN I POUR IT IN?

OK. NARRATOR: ONCE THE MICROBES ARE ADDED, THEY MULTIPLY AS THEY FEED ON THE LACTOSE IN MILK, PRODUCING LACTIC ACID, WHICH IS VITAL TO MAKING YOGURT.

[SPEAKING BULGARIAN] THIS EXACT PROCESS HAS BEEN HAPPENING OVER AND OVER AGAIN FOR POTENTIALLY THOUSANDS OF YEARS.

A LID ON TO KEEP ANY OTHER BACTERIA OUT, AND ALL WE'RE DOING NOW IS INSULATING THE MIX TO KEEP THAT HEAT IN BECAUSE THE BACTERIA HAVE QUITE A NARROW WINDOW OF WHEN THEY'RE ACTUALLY ACTIVE IN TERMS OF TEMPERATURE.

[SPEAKING BULGARIAN] 3 HOURS.

NO.

YES.

[SPEAKS BULGARIAN] 3 HOURS, AND WE'RE EATING?

OK.

I CAN DO THAT.

I CAN DO THAT.

[LAUGHTER] I THINK IT'S BACK TO BULGARIAN SCHOOL FOR ME.

HA HA HA!

NARRATOR: AS THE MIXTURE BECOMES MORE ACIDIC, THE MILK PROTEINS CLUMP TOGETHER, CREATING A SOFT, TANGY CURD--YOGURT.

WONG: LOOK AT THAT.

IS THAT WHAT WE MADE?

[SPEAKING BULGARIAN] OH, LOOK AT THAT PROUD SMILE.

LET'S OPEN THAT UP.

HA HA HA!

YOU DOUBTED MY ABILITY.

LOOK AT THAT.

IT WAS SO SIMPLE.

HA HA!

YOU CAN TELL ME WHAT BULGARIAN YOGURT TASTES LIKE MADE BY AN ENGLISH GUY.

[MAN SPEAKS BULGARIAN] THAT'S REALLY GOOD.

HA HA HA!

OH, THANK YOU.

THAT'S LOVELY.

THERE'S BEEN THIS AMAZING TRANSFORMATION IN ONLY A COUPLE OF HOURS.

THE BACTERIA HAVE BROKEN DOWN A LARGE PROPORTION OF THE LACTOSE, WHICH MEANS THE WHOLE MIX IS SO MUCH MORE DIGESTIBLE, POTENTIALLY EVEN FOR PEOPLE WITH A LACTOSE INTOLERANCE, AND THAT MEANS YOU GET MORE CALCIUM-RICH DELICIOUSNESS BACK IN YOUR DIET.

MM.

NARRATOR: JUST 10 FLUID OUNCES OF YOGURT WILL GIVE US NEARLY HALF OF OUR DAILY CALCIUM NEEDS, BUT EATING PLENTY OF THIS VITAL MINERAL WON'T AUTOMATICALLY MEAN THAT OUR BODIES CAN USE IT... BECAUSE THERE'S A FINAL BIT OF CHEMISTRY NECESSARY TO LAY DOWN AND REPLACE BONE.

AND TO DO THAT, WE NEED THE HELP OF VITAMINS.

NOW, THESE MOLECULES ARE STRANGELY HARD TO CLASSIFY.

MOSLEY: VITAMINS ARE MOLECULES THAT, IN MANY WAYS, ARE BEST DEFINED BY WHAT THEY'RE NOT.

THEY'RE NOT MINERALS, NOT FATTY ACIDS, NOT AMINO ACIDS, BUT THEY ARE ABSOLUTELY ESSENTIAL, ALBEIT IN VERY SMALL AMOUNTS.

NARRATOR: THIS IS A CRYSTAL OF VITAMIN C MAGNIFIED OVER 1,000 TIMES, THE POLARIZED MICROSCOPE PRODUCING A RAINBOW OF COLOR.

IN THE BODY, VITAMIN CRYSTALS ARE DISSOLVED IN THE BLOOD, WHERE THEY PASS TO WHERE THEY'RE NEEDED AND SUPPORT BODILY FUNCTIONS.

VITAMIN C, ABUNDANT IN CITRUS FRUITS, STRENGTHENS BLOOD VESSELS AND GIVES SKIN ITS ELASTICITY... AND THERE ARE 8 DIFFERENT TYPES OF B VITAMINS.

B6 IS FOUND IN NUTS AND DOES EVERYTHING FROM KEEPING OUR NERVOUS SYSTEMS RUNNING TO PROCESSING THOSE AMINO ACIDS INTO PROTEINS THAT WE NEED TO REPAIR MUSCLES AND ORGANS.

VITAMIN E, THAT WE GET FROM FOODS LIKE AVOCADO, ACTS AS AN ANTIOXIDANT AND PROTECTS OUR CELLS FROM DAMAGING CHEMICALS THAT ARE FORMED WHEN WE CONVERT OUR FOOD INTO ENERGY.

THE VITAMIN A WE GET FROM CARROTS KEEPS OUR EYES HEALTHY AND HELPS US FIGHT INFECTIONS, WHILE LEAFY GREENS SUPPLY US WITH VITAMIN K, HELPING OUR BLOOD TO CLOT.

AND THE ONLY WAY OUR DIGESTIVE SYSTEM IS ABLE ABSORB CALCIUM IS WITH THE HELP OF ANOTHER VITAMIN--VITAMIN D. THE KEY TO GETTING OUR DAILY DOSE OF VITAMIN D IS TO GET ENOUGH SUNLIGHT.

WHEN SUNLIGHT REACTS WITH MOLECULES IN OUR SKIN, THE RESULT IS THE VITAMIN D MOLECULE.

CALCIUM IS THE ONLY MINERAL THAT NEEDS A VITAMIN IN THIS WAY, AND IN PARTS OF THE WORLD, IT CREATES A REAL CHALLENGE BECAUSE PLACES FAR FROM THE EQUATOR, LIKE HERE HIGH UP IN THE BULGARIA MOUNTAINS, YEAR-ROUND SUNSHINE IS SCARCE.

BUT THERE IS A WAY THROUGH FOOD THAT DOICHO BAKLAREV AND HIS FAMILY CAN GET THE VITAMIN D THEY NEED ALL YEAR ROUND.

[DOICHO SPEAKING BULGARIAN] TRANSLATOR: "THIS IS A VERY GOOD MUSHROOM.

"ADD IT TO SOME BEANS, AND IT'S AS IF YOU'VE ADDED MEAT, SUCH A GREAT FLAVOR AND AROMA."

NARRATOR: SURPRISINGLY, WE'VE DISCOVERED THAT MUSHROOMS ARE A POTENTIAL SOURCE OF VITAMIN D. JUST LIKE US, THEY NEED THIS VITAMIN TO SURVIVE, AND THEY USE IT AS PROTECTION FROM THE SUN'S HARMFUL RAYS.

WONG: HOW'S THAT?

IS THAT GOOD?

YEAH?

[SPEAKS BULGARIAN] AHA.

NARRATOR: SUNLIGHT FALLING ON A MUSHROOM TURNS IT INTO A VITAMIN D FACTORY.

THEY USE A CHEMICAL SIMILAR TO CHOLESTEROL CALLED ERGOSTEROL WHICH REACTS WITH SUNLIGHT TO MAKE VITAMIN D. WONG: THERE'S SOMETHING MIRACULOUS ABOUT WHAT WE'RE DOING HERE BECAUSE THESE MUSHROOMS THAT ARE FRESHLY PICKED FROM THE DARK FOREST FLOOR DON'T REALLY CONTAIN THAT MUCH VITAMIN D. BUT PUTTING THEM OUT IN THIS INTENSE, UV LIGHT, AND THE MUSHROOMS, WHICH ARE STILL ALIVE, START TO REACT BY CHURNING OUT THAT VITAMIN D. NARRATOR: AND IF WE PUT THEM GILL SIDE UP, THE SURFACE AREA EXPOSED TO THE SUN INCREASES, AND THEY PRODUCE EVEN MORE.

[SIZZLING] JUST A FEW HOURS OUT IN THE SUN, AND A COUPLE OF PORTOBELLO MUSHROOMS WILL GIVE US OUR DAILY DOSE OF VITAMIN D. DRY THEM, AND IT STAYS LOCKED AWAY IN THE MUSHROOM FOR UP TO A YEAR, A TASTY WAY OF GETTING OUR VITAMIN D THROUGH THOSE DARK, WINTER MONTHS.

HA HA!

WONG: THIS IS AMAZING.

I LOVE THIS STUFF... [LAUGHTER] BECAUSE YOU'VE GOT BREAD WITH CHEESE, YOGURT, A YOGURT DRINK.

THERE'S NO LACK OF CALCIUM HERE.

NARRATOR: AND THE VITAMIN D IN THESE LOVELY MUSHROOMS ALLOWS OUR BODIES TO ABSORB THAT ALL-IMPORTANT CALCIUM... SENDING IT THROUGH THE BLOODSTREAM TO CELLS CALLED OSTEOBLASTS IN OUR BONES.

THESE CREEP THROUGH THE SKELETON, LAYING DOWN CALCIUM-RICH BONE.

THIS CONSTANT RENEWAL PROTECTS US AGAINST DISEASES LINKED TO AGEING, SUCH AS OSTEOPOROSIS.

IT COULD BE A KEY FACTOR NOT ONLY TO A HEALTHY LIFE, BUT ALSO LONGEVITY.

WONG: SO THERE ARE LOADS OF FACTORS AT WORK, BUT I CAN'T HELP THINKING, WITH AIR LIKE THIS, RUNNING AROUND EVERY DAY, HOMEMADE FOOD, AND TALK ABOUT A TON OF CALCIUM, IT CAN'T HURT, CAN IT?

NARRATOR: WE'VE DONE A GREAT JOB DISCOVERING THE FOODS WE ALL NEED TO KEEP US GOING.

DAY TO DAY, MEAL TO MEAL, WE GET MUCH PLEASURE FROM THE FOOD WE EAT.

THE SMELLS, TASTES, COLORS, AND TEXTURES DELIGHT US.

WE'RE ALSO BEGINNING TO UNDERSTAND THE HIDDEN BIOCHEMISTRY AT WORK.

THIS NOT ONLY HELPS US APPRECIATE OUR FOOD, BUT IT ALSO MEANS WE'RE ABLE TO MAKE THE MOST OF THE INGREDIENTS HIDDEN INSIDE EVERY DELICIOUS MOUTHFUL, INGREDIENTS WHICH NOURISH NOT JUST OUR BODIES, BUT ALSO OUR MINDS.

WONG: SO IF YOU'RE ADVENTUROUS WITH FOOD AND YOU TRY A BIT OF EVERYTHING, NOT ONLY ARE YOUR SENSES REWARDED.

YOUR BODY HAS A GREATER CHANCE OF GETTING HOLD OF ALL OF THOSE ESSENTIAL MOLECULES BECAUSE ULTIMATELY, OUR BODIES AND EVERYTHING WE ARE, COMES FROM OUR PLATES.

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