Metabolism 2 Exam 2 1 Iron 1 What is Iron and where is it stored When you think of iron think of hemoglobin and oxygen transport The average adult has 2 5mg 3 5mg at any moment in their body mostly in the form of hemoglobin and There is an iron pool in the body that the body always has access to in the form of ferritin myoglobin how iron is stored in the body So it is used for hemoglobin synthesis which is four heme groups and myglobin synthesis which is only one heme group Hemeglobin serves to transfer oxygen throughout the body and myoglobin transfers oxygen in a certain muscle Iron is stored in the body while not in use as ferritin Around 30 is stored as this also in the form hemosiderin This protein can hold up to 4500 iron atoms Since this is the storage form it is used to measure iron status 2 What is the function 3 What is the RDA Iron is mainly for oxygen transport and also a coenzyme in many reactions involving energy metabolism even in plants via photosynthesis Iron is set at 8mg for men and 15mg for women It is higher in women due to menstrual bleeding as iron is lost in blood It is only higher for child bearing women those past menopause are set at 8mg just like men Whenever she gives a ratio of mineral or vitamin 1000 kcal know it Iron is estimated at 5 mg per every 1000kcal in your diet This means women have to basically consume 3000kcal to get the DRDA not likely Tony Berardi 2 4 How is it classified and absorbed Depending on what source you ingest the iron from it is either heme or non heme iron Heme iron is always from animal meats as you are ingesting the animal muscles that already have myoglobin and hemoglobin So your body has no problem using this iron in the form that it is in So this iron requires no further reactions to be used Non heme iron is iron obtained in any other source All minerals have to be realized from the food via HCl in the stomach remember this from metab 1 So HCl is required in order to extract the non heme iron from the food source So acid will always increase absorption Any situation to increase the acidic environment will increase absorption Likewise any situation that decreases the acidity will decrease absorption Ok so now we have extracted the non heme iron from the food source what s the next step When bound to food the iron is in the form of iron or ferric form this form is poorly absorbed So now the ferric has to be reduced GAIN and electron to iron or the ferrous form This is what the HCl actually does it reduces it This form is much more readily absorbed thus why the acidic environment increases absorption Despite it being readily absorbed as ferrous it is still only around 15 absorbed 5 What affects the absorption So following the fact that an acidic environment will help ferric be reduced to ferrous anything that increases the acidity of the stomach will increase absorption Vitamin C greatly increases the acidity of the stomach along with all the organic acids MFP or meat fish and poultry factor always greatly increase the absorption mainly from the cysteine concentration in them A general rule in the body is that if the body is in need of something it will increase the absorption of it So since ion is used to from hemoglobin in the blood if you have a blood loss your body loses all that iron and needs to replace it Thus it will increase the iron absorption Also pregnancy and the general rule is pregnancy increases everything as you need nutrients for two people Then for factors that decrease absorption are anything that lowers the acidity of the stomach such as achlorhydira simply don t produce acid Phytate and oxalate are also Tony Berardi seen for every mineral that decreases the absorption Know the other weird ones like coffee due to polyphenols and tea due to tannins Also if you have too much iron our body won t absorb as much Just like if you are deficient in something you will absorb more 3 6 How does it travel in the blood So now the ferrous was absorbed so it has to be oxidized back to ferric So AFTER it is absorbed it has to be oxidized back to be transported Ceruloplasmin protein will oxidize it back to ferric The transporter protein is called apotransferrin and this is made in the liver Once the ferric binds to the apotransferrin it becomes transferrin This is normally 1 3 saturated and this is another way iron level is assessed Because if you are deficient in iron then the transfer protein will have less iron Then this protein will bring it to various tissues and to the bone marrow where RBC are made 7 Now all about the deficiency Deficiency is still a serious problem and results in weakness decreases performance inability to maintain body temperature less oxygen an increased lead absorption affect pregnancy If you know the function of iron in oxygen transport then all o these symptoms make since When looking at someone s blood when deficient they will presents with a lower transferring saturation remember it is normally 1 3rd saturated but now you have less Fe and a decrease in ferritin level this is that storage pool of iron They still have a normal hemoglobin amount though The deficiency is not low enough to affect it This is important to note Once bad enough it is termed anemia Now the hemoglobin amount is decreasing in the body This means without blood so your blood has less hemoglobin and therefore less oxygen to deliver to muscles Once the hemoglobin amount is affected it is termed anemia Because of Tony Berardi 4 the definition anemia is not necessarily from a severe iron deficiency it can arise from any situation that results in a loss of RBC s That chart on the next slide is showing that as one crosses the line between iron deficient and anemia their hemoglobin will fall once they are termed anemia As you can see the ferritin storage level decrease all the cross but the binding capacity to transferrin increases the more deficient one gets This is because when deficient the body tries to increase the use of what little it has so it will bind more readily and absorb more iron 8 More on anemia Now the amount of hemoglobin starts to decrease and as a result the amount of RBC s decrease As a result of the lack of hemoglobin the RBC s will be microcytic small and hypochromatic lacking color due to no oxygen Hematocrit is the of RBC in a certain volume of blood and when this falls below a certain value you are termed anemic Hemoglobin will be below 13mg dL and 11mg dL for men and women An anemic person will
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