Placeholder Image

字幕列表 影片播放

  • - HELLO, AND WELCOME TO OUR FIFTH SECTION

  • IN THE SERIES ON WATER AND MINERALS.

  • IN THIS SECTION, WE'LL BE COVERING IRON.

  • I'M GOING TO START BY REVIEWING THE TRACE MINERALS.

  • REMEMBER, WE REVIEWED THE MAJOR MINERALS INITIALLY.

  • THOSE ARE MINERALS THAT ARE REQUIRED IN FAIRLY HIGH AMOUNTS.

  • THE TRACE MINERALS ARE NEEDED IN OR

  • REQUIRED IN VERY SMALL AMOUNTS.

  • IT DOESN'T MEAN THEY'RE LESS IMPORTANT,

  • IT JUST MEANS THAT WE REQUIRE LESS OF THEM.

  • WE'RE GOING TO BE COVERING THE FIRST FIVE.

  • AND IT'S NOT THAT THESE ARE NOT IMPORTANT,

  • IT'S JUST THIS IS WHERE OUR FOCUS WILL BE.

  • I'D ALSO LIKE TO POINT OUT,

  • THIS IS NOT AN ALL-INCLUSIVE LIST.

  • WE'RE GOING TO BE STARTING WITH IRON.

  • I THINK THIS IS A WELL-KNOWN MINERAL,

  • ESPECIALLY IN ITS IMPORTANCE.

  • THE MAIN FUNCTION OF IRON IS IN OXYGEN TRANSPORT,

  • SO DELIVERING OXYGEN TO THE TISSUES.

  • NOW IT DOES THIS BY BEING PART OF WHAT'S CALLED HEME.

  • NOW HEME IS PART OF BOTH HEMOGLOBIN,

  • THAT'S IN OUR RED BLOOD CELLS, AND MYOGLOBIN,

  • THIS IS IN OUR MUSCLE,

  • SO THESE ARE COMPOUNDS THAT WILL CARRY IRON.

  • NOW OVER HERE, I WANT YOU TO SEE,

  • THIS IS ACTUALLY A PICTURE OF HEMOGLOBIN.

  • REMEMBER, HEMOGLOBIN IS A PROTEIN.

  • WHAT DO PROTEINS DO?

  • THEY'RE A STRING OF AMINO ACIDS, AND THEY END UP COILING

  • AND THEN THEY FOLD AND THEN THEY JOIN TOGETHER.

  • WELL, PART OF THIS COMPLEX IS HEME,

  • WHICH YOU CAN SEE HERE, AND PART OF THAT HEME IS IRON.

  • SO IRON IS NECESSARY TO FORM THIS COMPLEX,

  • IT'S NECESSARY TO CARRY OXYGEN.

  • WE KNOW THAT IRON DEFICIENCY CAN

  • RESULT WHEN IT'S SEVERE IN ANEMIA.

  • MOST PEOPLE HAVE HEARD OF IRON DEFICIENCY ANEMIA,

  • AND ONE OF THE SYMPTOMS WITH THAT,

  • THEY'RE USUALLY FATIGUE, A LOSS OF ENERGY.

  • WELL, IF YOU DON'T HAVE OXYGEN GOING TO YOUR TISSUES,

  • YOU'RE DEFINITELY GOING TO FEEL FATIGUE,

  • YOU'RE DEFINITELY GOING TO FEEL WEAK,

  • YOU'RE DEFINITELY GOING TO FEEL LIKE YOU HAVE A LOSS OF ENERGY.

  • YOU CAN HAVE IRON DEFICIENCY WITHOUT ANEMIA, AS WELL,

  • AND THESE ARE SYMPTOMS THAT AREN'T QUITE AS SEVERE.

  • NOW THERE ARE TWO TYPES OF IRON SOURCES,

  • ONE IS A HEME IRON SOURCE AND ONE IS A NON-HEME.

  • REMEMBER, HEME IS PART OF HEMOGLOBIN,

  • HEMOGLOBIN IS GOING TO CARRY OXYGEN IN THE BLOOD,

  • SO THIS IS ONLY GOING TO OCCUR IN ANIMALS.

  • NOW THE ABSORPTION BETWEEN THESE TWO IS VERY DIFFERENT.

  • THE ABSORPTION RATE IS GOING TO RANGE ABOUT 15 TO 35%,

  • AND YOU'LL SEE THOSE RANGES VARY.

  • IN YOUR BOOK, IT SAYS ABOUT 23%.

  • NON-HEME IRON MEANS THAT IT DOES NOT HAVE HEMOGLOBIN.

  • SO WHAT DOESN'T HAVE HEMOGLOBIN?

  • WELL, PLANTS, PLANTS DON'T HAVE RED BLOOD CELLS

  • THAT ARE CARRYING OXYGEN AROUND TO THEIR TISSUES,

  • SO WE CALL THIS A NON-HEME IRON.

  • YOU WILL ALSO FIND SOME NON-HEME SOURCES IN ANIMALS, AS WELL.

  • BUT I'D LIKE YOU TO THINK OF NON-HEME AS

  • PLANT SOURCES AND HEME IRON FROM ANIMALS.

  • THE NON-HEME SOURCES ARE NOT ABSORBED AS WELL.

  • ALMOST ALL OF THEM ARE NOT

  • ABSORBED AS WELL AS HEME SOURCES.

  • AND WE'RE GOING TO GO OVER THIS IN JUST A MINUTE,

  • WHY THIS OCCURS.

  • SO FOR MOST OF YOUR SOURCES THAT ARE NON-HEME,

  • THEY'RE NOT GOING TO BE BIOAVAILABLE.

  • THAT MEANS THAT EVEN THOUGH THEY MIGHT CONTAIN

  • A LOT OF IRON WHEN YOU CONSUME THEM THAT IRON

  • IS NOT GETTING INTO THE BLOODSTREAM,

  • AND THEREFORE IT CAN'T BECOME PART OF YOUR RED BLOOD CELL.

  • SO WHAT ARE FOODS WITH HEME IRON?

  • REMEMBER, THESE ARE ANIMAL SOURCES,

  • ANIMALS HAVE HEMOGLOBIN, THEY HAVE RED BLOOD CELLS THAT

  • CARRY OXYGEN TO ALL THE TISSUES, HEME IRON.

  • BEEF, YOU ARE MOSTLY GOING TO FIND

  • THE HIGHEST SOURCES OF HEME IRON,

  • WHICH IS MORE ABSORBABLE IN BEEF.

  • THERE IS ALSO SOME IRON IN BOTH POULTRY AND FISH,

  • NOT IN AS GREAT OF AMOUNTS AS IN BEEF.

  • YOU ALSO FIND IT IN OYSTERS,

  • BUT THAT'S NOT A COMMON FOOD THAT PEOPLE EAT.

  • AND THEN EGGS, EVEN THOUGH WE THINK OF THIS

  • AS AN ANIMAL SOURCE IS ACTUALLY A POOR SOURCE,

  • NOT ONLY IS THERE NOT A LOT OF IRON,

  • IT'S NOT WELL-ABSORBED, WHICH I'LL TALK ABOUT NEXT.

  • FOODS WITH NON-HEME IRON--

  • SO SOME OF THESE ANIMAL FOODS HERE WILL HAVE NON-HEME IRON.

  • THE REMAINING FOODS ARE GOING TO BE PLANTS,

  • NON-HEME IRON GENERALLY FROM PLANTS.

  • SPINACH, LEGUMES, PRUNES, POTATOES,

  • TOFU, THESE ARE ALL GOOD SOURCES OF NON-HEME IRON.

  • SOY BEANS ACTUALLY HAVE A FAIRLY

  • GREATER ABSORBABILITY OF THE IRON,

  • BUT A LOT OF THESE SOURCES ARE FAIRLY POORLY ABSORBED.

  • REMEMBER, I SAID IT'S 2 TO 20%

  • ABSORPTION RATE FOR NON-HEME IRON.

  • SO WHAT DOES THIS MEAN?

  • THIS MEANS IF YOU ARE CONSUMING MOSTLY PLANT

  • FOODS AND THAT'S WHERE YOU'RE GETTING YOUR IRON SOURCES,

  • YOU ARE LIKELY NOT ABSORBING VERY MUCH,

  • EVEN IF YOU ARE MEETING THE DAILY RECOMMENDED AMOUNT.

  • SO FACTORS THAT ACTUALLY INCREASE

  • OR ENHANCE IRON ABSORPTION,

  • THERE ARE TWO MAIN FACTORS, ONE IS CALLED MFP FACTOR,

  • AND THIS IS FOUND IN MEAT, FISH, AND POULTRY.

  • VERY EASY TO REMEMBER, RIGHT?

  • SO THESE ANIMAL SOURCES ACTUALLY HAVE

  • A NATURAL SOURCE OCCURRING IN THEM,

  • THIS FACTOR THAT ENHANCES NON-HEME IRON,

  • MOSTLY NON-HEME IRON.

  • AND REMEMBER, ANIMAL SOURCES HAVE BOTH HEME AND NON-HEME,

  • SO THEY HAVE A HIGHLY ABSORBABLE SOURCE OF IRON.

  • I SAY, "HIGHLY," BUT IT'S STILL NOT REALLY HIGH,

  • BUT A HIGHLY ABSORBABLE SOURCE OF IRON, THAT HEME IRON.

  • AND THEN THEY HAVE A NON-HEME IRON,

  • BUT IT'S ACTUALLY BOOSTED BY THE MFP

  • FACTOR THAT NATURALLY OCCURS THERE.

  • VITAMIN C AND THIS OCCURS IN ORANGES,

  • STRAWBERRIES, BELL PEPPERS,

  • WATERMELON, KIWI, AND A LOT OF SOURCES,

  • BUT IT'S A REALLY POWERFUL ENHANCER OF NON-HEME IRON.

  • A GREAT EXAMPLE OF HOW THIS WORKS OR OCCURS IN NATURE IS

  • THAT SPINACH IS A VERY GOOD SOURCE OF NON-HEME IRON.

  • SPINACH HAS NATURALLY OCCURRING VITAMIN C.

  • SO THAT NATURALLY OCCURRING VITAMIN C ACTUALLY BOOST THE

  • NON-HEME IRON ABSORPTION WITHIN THAT SPINACH.

  • NOW WHAT ABOUT INHIBITORS?

  • THIS IS WHY A LOT OF PLANT FOODS ARE POORLY ABSORBED,

  • AND I'LL GET DOWN TO THIS ON OUR THIRD ON OUR LIST HERE,

  • BUT LET'S START WITH THE TANNINS.

  • TANNINS ARE FOUND IN TEA, COFFEE, WINE,

  • THEY'RE GOING TO INHIBIT NON-HEME IRON ABSORPTION,

  • CALCIUM AND PHOSPHORUS IN MILK AND DAIRY PRODUCTS,

  • PHYTATES IN LEGUMES, WHOLE GRAIN CEREALS, BREADS.

  • THIS IS ONE OF THE MAIN REASONS WHY A LOT OF THE IRON FROM PLANT

  • FOODS OR THE GRAIN-BASED FOODS IS POORLY ABSORBED.

  • AND I ALSO WANT YOU TO THINK ABOUT

  • WHERE YOU'RE GETTING YOUR IRON.

  • IF YOU'RE GETTING A FORTIFIED SOURCE OF

  • IRON IN YOUR CEREAL THAT'S A NON-HEME IRON,

  • AND THEN ANY NATURALLY OCCURRING IRON THAT'S NON-HEME IRON,

  • AND YOU ARE CONSUMING THAT WITH MILK, AN INHIBITOR,

  • AND OF COURSE IS A GRAIN SO YOU HAVE THE PHYTATES

  • WITHIN THE FIBER, YOU HAVE A LOT OF

  • INHIBITORS AND A POORLY ABSORBABLE SOURCE OF IRON.

  • SO YOU HAVE KIND OF A TRIPLE WHAMMY,

  • AND YOU'RE NOT GOING TO GET A LOT OF IRON.

  • SO YOU DON'T WANT TO RELY ON THAT

  • FORTIFIED PRODUCT FROM YOUR CEREAL.

  • EVEN THOUGH IT'S STILL HEALTHFUL,

  • IT'S NOT AS POWERFUL AS YOU THINK.

  • THE PHOSVITIN

  • IS FROM THE EGGS.

  • THIS IS A PHOSPHOPROTEIN THAT'S FOUND IN EGGS,

  • AND EGGS ARE NOT A VERY GOOD SOURCE ANYWAY.

  • THEY DO HAVE A HEME IRON,

  • BUT THIS ENDS UP INHIBITING THE ABSORPTION,

  • SO EGGS END UP HAVING A VERY LOW BIOAVAILABILITY.

  • THEIR IRON HAS VERY LOW I.O. AVAILABILITY.

  • THAT TERM SOUNDS COMPLEX.

  • IT JUST MEANS THAT THAT IRON IS NOT GETTING FROM THE FOOD,

  • FROM YOUR INTESTINES INTO YOUR BLOODSTREAM,

  • SO IT'S NOT AS HELPFUL.

  • SO I WANT TO FINISH WITH GOING THROUGH HOW

  • YOU THINK ABOUT THE INHIBITORS AND THE

  • ENHANCERS IMPACTING THE BIOAVAILABILITY OF IRON,

  • BECAUSE YOU'RE GOING TO NEED TO DO THIS IN THE DISCUSSION FORM.

  • AND LET'S START WITH THIS CHILI WITH GROUND BEEF,

  • BEANS, PEPPERS, AND TOMATOES, JUST LIKE THIS PICTURE SHOWS.

  • SO WHAT'S GROUND BEEF?

  • GROUND BEEF IS AN ANIMAL SOURCE.

  • THAT MEANS IT'S A HEME IRON.

  • HEME IRON IS MORE HIGHLY

  • ABSORBABLE THAN THE NON-HEME IRON.

  • IT DOES HAVE A LITTLE BIT OF NON-HEME IRON,

  • SO IT HAS BOTH SOURCES.

  • BEANS ARE GOING TO HAVE A NON-HEME SOURCE.

  • IT'S NOT AS WELL ABSORBED.

  • BUT WE HAVE BOTH PEPPERS AND TOMATOES,

  • BOTH GOOD SOURCES OF VITAMIN C. VITAMIN C

  • ISN'T GOING TO BOOST THE NON-HEME IRON SOURCE OF

  • THE BEANS AND ANY NON-HEME IRON IN THE GROUND BEEF.

  • THE GROUND BEEF ALSO HAS MFP FACTOR AS ANOTHER

  • ENHANCER OF NON-HEME IRON, SO THAT'S GOING TO BOOST

  • THE ABSORPTION RATE OF THE IRON IN BEANS.

  • SO THIS MEAL IS GOING TO ACTUALLY HAVE IRON

  • WITH ACTUALLY A FAIRLY HIGH BIOAVAILABILITY.

  • THIS IS A VERY GOOD SOURCE OF IRON.

  • ROAST BEEF SANDWICH ON WHOLE GRAIN BREAD--

  • OKAY, SO WE HAVE ANOTHER BEEF SOURCE.

  • WE KNOW THIS IS A GOOD SOURCE OF HEME IRON.

  • IT'S GOING TO BE MORE ABSORBABLE.

  • THERE'S A LITTLE BIT OF NON-HEME IRON IN THERE.

  • WE HAVE IT ON A WHOLE GRAIN BREAD.

  • THAT'LL HAVE A LITTLE BIT OF IRON IN IT, A NON-HEME IRON,

  • BUT IT'S ALSO GOT THE FIBER WITH PHYTATES.

  • THAT'S GOING TO INHIBIT THE NON-HEME

  • IRON HERE AND ANY NON-HEME IRON HERE.

  • IT'S NOT GOING TO HAVE TOO MUCH OF AN IMPACT ON THE HEME IRON,

  • SO THIS IS GOING TO BE A MODERATE SOURCE.

  • WE HAVE MORE INHIBITORS, AND WE DON'T HAVE ANY ENHANCERS

  • EXCEPT FOR THE MFP FACTOR WHICH NATURALLY OCCURS IN THE BEEF.

  • SO THERE'S STILL A MODERATELY GOOD SOURCE

  • OF IRON IN THIS WHICH IS MODERATELY BIOAVAILABLE.

  • SPINACH SALAD WITH A GLASS OR ORANGE JUICE--

  • OKAY, SO THE FIRST THING WE LOOK AT IS

  • THERE'S NO GOOD HEME SOURCES.

  • WE ONLY HAVE NON-HEME IRON IN THE SPINACH.

  • THE NON-HEME IRON IN THE SPINACH IS GOING TO BE BOOSTED

  • BY THE NATURALLY OCCURRING VITAMIN C IN THE SPINACH,

  • AS WELL AS VITAMIN C IN THE ORANGE JUICE.

  • AND REMEMBER, VITAMIN C IS A VERY POWERFUL ENHANCER

  • OF IRON ABSORPTION, NON-HEME IRON ABSORPTION.

  • SO ALTHOUGH THIS IS CERTAINLY NOT

  • GOING TO BE AS HIGH AS THE CHILI,

  • IT MAY NOT EVEN BE AS HIGH AS THE ROAST BEEF,

  • IT'S GOING TO BE MODERATELY HIGH.

  • IT'S GOING TO BE MODERATELY GOOD BIOAVAILABILITY.

  • AND LASTLY IS THE IRON FORTIFIED

  • WHOLE GRAIN CEREAL WITH LOW FAT MILK.

  • OKAY, SO WE LOOK THROUGH THESE,

  • AND THERE REALLY AREN'T ANY GOOD HEME SOURCES.

  • MILK ISN'T REALLY A GOOD SOURCE OF IRON.

  • WE DO HAVE IRON FORTIFICATION, THAT'S NON-HEME,

  • BUT IT'S IN THE WHOLE GRAIN CEREAL,

  • FIBERS, GOT THE PHYTATES,

  • WHICH ARE GOING TO INHIBIT THE NON-HEME IRON.

  • THEN WE HAVE CALCIUM AND PHOSPHATE IN THE MILK,

  • AND THAT'S GOING TO INHIBIT THE IRON.

  • SO WE DON'T HAVE A VERY GOOD SOURCE TO START WITH,

  • IT'S NOT VERY ABSORBABLE,

  • AND THEN WE HAVE A COUPLE FACTORS,

  • THREE OF THEM THAT ACTUALLY INHIBIT THE ABSORPTION,

  • SO THIS IS POOR BIOAVAILABILITY OF ITS IRON.

  • IT'LL END UP BEING A POOR SOURCE.

  • NOW I'M NOT GOING TO ASK YOU, YOU KNOW,

  • EXACTLY ON THE EXAM, YOU KNOW,

  • GIVE YOU THESE EXAMPLES, BUT WHAT I WILL WANT YOU

  • TO DO IS BE ABLE TO THINK THROUGH THAT PROCESS,

  • HOW THE INHIBITORS AND THE ENHANCERS

  • IMPACT IRON BIOAVAILABILITY,

  • AND YOU'LL HAVE TO DO THIS IN YOUR DISCUSSION, AS WELL.

  • AND THIS IS THE END OUR SECTION ON IRON.

  •  

- HELLO, AND WELCOME TO OUR FIFTH SECTION

字幕與單字

單字即點即查 點擊單字可以查詢單字解釋

B1 中級 美國腔

10.5 礦物。鐵 (10.5 Minerals: Iron)

  • 19 7
    wenwen 發佈於 2021 年 01 月 14 日
影片單字