字幕列表 影片播放 列印英文字幕 - 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.