Metabolism 2 Exam 2 1 Iron 1 Terminology Iron is an essential mineral that is mainly involved in oxygen transport There are many terms you ll need to know o Ferritin is the storage form of iron It can hold up to 4500 iron molecules This amount can be used to assess the body s pool o Hemosiderin is another storage form but no one cares about it o Heme iron is the form found in meats o Non Heme is in everything else and this is the form that goes through all the oxidizing and reduction soluble as this form o Ferric or Iron 3 is after non heme is oxidized electron taken away and it is poorly o Ferrous or Iron 2 is after ferric is reduced by the acidic environment and is how non heme is absorbed So if the person can t make acid for some reason absorption will be lowered o Apotransferrin is a transfer protein of iron and this is how it is made in the liver o Ceruloplasmin is another protein that oxidizes the Iron to its ferric form o Transferrin is formed once ferric attaches to the apotransferrin It has 2 binding sites and in normally 1 3 saturated and delivers the iron to the various tissues and bone marrow where RBC are formed 2 Main properties Iron is used for oxygen transport in hemoglobin and myoglobin o A hemoglobin molecule is formed when four heme groups with Fe in the middle attaches then it can hold four oxygen molecules o Myoglobin is the form that is found in muscles and only has one heme Myoglobin can only supply oxygen to the muscle that it is in o Some enzymes also use iron Enzymes in the Krebb Cycle use iron some in photosynthesis for plants and used in plants to make nitrogen Tony Berardi 2 3 Interactions 4 Absorption The DRI is 8mg for men old women and 18mg for child bearing women increased for two reason One is if they have a child they need more oxygen for the child Two is that they lose a lot in their menstrual bleeding The cool thing about Fe is that it doesn t just have to be exogenous some could come from cooking in an iron skillet drinking from an iron cup ect 5 Factors that affect absorption I already talked about this but to review Fe is either consumed as heme or non heme Fe Heme is from meat sources and non heme is from all other sources The heme Fe is good as it is but the non heme must be released from the food by HCl and then it is oxidized to ferric This form is poorly absorbed as such so it is then reduced to ferrous by the acid Certain factors can either increase of decrease how much Fe is absorbed Normally only 10 15 is absorbed All these factors are for that non heme Fe heme is fine how it is To increase Vitamin C is the strongest factor Acids These help reduce that ferric to ferrous the form it is better absorbed as ferrous To decrease Meat fish poultry factor MFP and cystein Vit C acid and MFP keep Fe as An enhanced erthryopoesis greater RBC formation This can be from blood loss hypoxia hemorrhage prolonged vessel damage resulting in blood loss So your body would need more RBC formed so it absorbs more Fe A rapid transit time will decrease the time for possible Fe absorption Achlorydria or a person that does not have sufficient acid can t from ferrous from the ferric form This will result in a higher pH or a less acidic environment Phytate and oxalate Clay tea from tannins and coffee from polyphenols Iron overload Infections inflammation Calcium Tony Berardi 3 6 Deficiency and anemia 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 This 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 storage of Fe up to 4500 atoms They still have a normal hemoglobin amount though The deficiency is not low enough to affect it Once bad enough it is termed anemia 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 7 More on anemia The RBC number is decreased and the hemoglobin amount also Hematocrit is the percentages of RBC present in the blood and it normally 40 52 in men and 37 46 in women So it will be below these numbers Also the RBC will have a altered look and be microcytic and hypochromatic less color and paler because they are carrying less oxygen Hemoglobin will be below 13mg dL and 11mg dL for men and women An anemic person will have lightheadenness can t get enough oxygen to the brain amenorrhea lack of menstrual cycle glossitis inflammation of the tongue spooned nails lowered performance 8 Causes of anemia It means lack of RBC so it can happen in multiple ways A severe blood loss can cause it an impaired production of RBC or some condition that destroys the RBCs Blood loss accounts for 25 of all cases and is easy to see when you know that 5mg of Fe is lost when 1ml of blood is lost So if you donate blood typically 500ml you lose 250mg of Fe An impaired production can be caused by renal disease an inherited condition called thalessemia impaired globin production chronic diseases and lead poisoning Conditions that cause erthropoesis also can cause anemia RBC s are normally destroyed but something enhances the destruction Some autoimmune disorders infection vitamin E deficiency remember free radicals Some inherited problems with Fe Sickle cell anemia is an inherited condition where a certain amino acid is not made and these results in an abnormal sickle shape of the RBC They need a lot Tony Berardi 4 of blood transfusion to make up for their fucked up RBC and therefore have an increased Fe amount because of all the transfusion 9 Iron overload Just as a deficiency is bad so is an excess of Fe An overload can damage the liver heart pancreas and the skin The overload can be acute or chronic An acute overload is when an individual consumes around 250 mg kg d a lot of iron usually only possible with supplements Chronic can be either hemosiderosis not affecting the person or hemochromatosis affecting them now o Hemochromatosis can be inherited and this slowly raises the amount of iron an individual absorbs They only absorb about 2 mg d more than others so it manifests when they are around 50 years old o It can also be acquired which means they caused it themselves this can be from too many blood transfusion remember 500ml is about 250mg Fe excessive prolonged intake excess vitamin C increases absorption First you get
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