pat05
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Which of the following factors increases iron absorption from a diet?
A)ascorbic acid
B)high altitude
C)transfusion
D)all of the above
E)A & B
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| harpist88
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Becuse the ascorbic acid increase the of the Rateof the iron absorption Significantely in the upper region of the small intestine, While Exposure to high altitude environment increase the absorption of the iron but only in the First few Days and reach maximum rate at the rend of the first week,so that the answer is C (Ascorbic Acid and High Altitude)
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| SILVER
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to harpist88, what's the source of your answer, could you plz tell me?
thanks
I think it should be D.
Ascorbic acid does help in absorption of iron and any condition which leads to iron deficiency anemia, along with conditions such as high altitudes because people living in high altitudes have polycethemia and their iron saturation is increased due to the excess erythropoiesis. Transfusion also increases it by increasing uptake from iron stores and diet
Edited by silver on 06/13/07 - 03:27 PM
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| RayBerg
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I disagree w/ harpist because my understanding is that you have polycythemia at high altitude for a long period of time. So, in that case the answer should be D.
EDIT: I'm sorry! I think the answer should be E. D was a typo.
Edited by RayBerg on 06/13/07 - 04:32 PM
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| doc179
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why not E? I dont know how transfusion would increase iron absorption but ascorbic acid does and high altitude, cos there is high production of RBCs I assume there is increased absorption of iron.
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| new_n_lost
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Ascorbic Acid Will not Form Soluble complexes with Iron Without Gastric Acid Secretion. Its presence does indicate the formation of soluble complexes which reduce Dietary Iron to its Ferrous form. But will the extra amount increase the absorption. No I dont think so.
High Altitude will increase the production of heme which will increase the uptake of Iron form its Stores such as Ferritin whether the Diet Factor is involved or not dont know abt tht.
Transfusion increases the uptake of Iron from the body stores and the diet as well.
So i will go with C .
Edited by new_n_lost on 06/13/07 - 03:05 PM
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| new_n_lost
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silver wrote:
Ascorbic acid does help in absorption of iron and any condition which leads to iron deficiency anemia, along with conditions such as high altitudes because people living in high altitudes have polycethemia and their iron saturation is increased due to the excess erythropoiesis. Transfusion also increases it by increasing uptake from iron stores and diet
The Link Plz to the Ascorbic Acid part plz the rest of it I agree with u
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| ssrpk
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wel yeah ascorbic acid does make nonavailable form of iron into avaliable form (by reducing it) but yeah probably not controlling the rate of iron absorption ...
as for high altitude because it cause tissue hypoxia therefore erythropoeitin secretion is increased which tends to increase the RBC mass, and any cause of increase eryhtropoeisis will increase iron absorption from the gut. Its true that it is said that any cause of anemia will increase iron absorption from the diet but there is no receptor in the body that detects hemoglobin conc. only hypoxia is detected which results in increase erythropoeitn.
Finally transfusing someone blood is like indirectly giving that person loads of iron or transfusing the blood from someone will be like taking away that poor fellows iron so this misunderstading probably has a linguistic basis.
if i were given this question I would go with B
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| new_n_lost
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Ok This Might seem silly but i understood Tranfusion here in the question as in tranfuse the blood out ( bleeding the pt.) did not definitely think the other way around. If thats the case then the options get a different view. As the Ascorbic Acid Link hasnt been provided till then the Answers Remains B.
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| drduck
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i feel the answer...is E.....
high altitude was clear.....i think problem is with vitamin C,
Citrus fruit doesn't have much iron itself. But, vitamin C does help the body absorb iron, especially one form of iron called "non-heme" iron.
Heme iron is the type of iron found in meat that originally comes from hemoglobin (the iron-containing part of the red blood cell) and myoglobin (a compound in muscle tissue). Close to half of the iron in red meat is heme iron. Usually, about 20 percent to 25 percent of heme iron in food is absorbed by the body.
Non-heme iron is much more common in the diet, making up about 85 percent to 90 percent of the iron we consume. It's found in egg yolks and all sorts of plant-based foods, including fortified breakfast cereals, bran, prune juice, spinach, kidney and lima beans, whole wheat bread and soybean nuts. Unfortunately, only 2 percent to 20 percent of non-heme iron is usually absorbed -- with most people absorbing closer to 2 percent.
Citrus fruits can help the body absorb non-heme iron through a chemical reaction that actually adds an electron to the ferric form of iron. That allows a series of changes to take place, making the iron more absorbable by the body.
Non-heme iron also is more absorbable when it is consumed together with heme iron. Also, a protein factor in meat, fish and poultry help the body absorb non-heme iron. Even higher amounts of acid in your stomach can increase the amount of iron the body absorbs.
On the other hand, some foods decrease iron absorption. Tannins in tea, phytic acid in fiber, oxalic acid in spinach and some other vegetables, and high doses of calcium -- especially the kind found in calcium supplements -- all reduce the amount of iron your body absorbs. So, if you drink calcium-fortified orange juice, don't take your iron supplement at the same time.
hope this helps........
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| doc179
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I think the ans is E, cos Ascorbic acid does increase iron absorption and in High altitude you make more RBC and hence I guess iron absorption should be increased cos of increased need for it.
NNL its in pharmacology text book that vit.C increases iron absorption.Pls go thru the link and about iron is in rare side effects!!!
http://en.wikipedia.org/wiki/Vitamin_C
Edited by doc179 on 06/15/07 - 11:24 AM. Reason: wanted to post the link
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| SILVER
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http://sickle.bwh.harvard.edu/iron_absorption.htm...
here's the link NNL...sorry took me a while to get back.
you're right doc179, now that i think about it, it doesn't make sense for transfusion to increase absorption. i agree, ans. is E!
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| SILVER
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http://sickle.bwh.harvard.edu/iron_absorption.htm...
here it is again in case it wasn't opening previously
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| peraspera
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E
Ascorbic acid & high altitude
Corporeal factors. Two major “corporeal” factors related to the regulation of iron absorption are the status of body iron stores and the rate of erythropoiesis. Decreased body iron stores are associated with increased intestinal absorption of iron, and vice versa. This means that iron absorption will be increased in some pathological conditions like anemia and hemorrhage, and in the physiological conditions of menstruation, pregnancy and lactation. Increased erythropoiesis (stimulated, for example, by high altitude hypoxia, hemolysis or following hemorrhage) is also accompanied by increased absorption of iron.
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| paganini
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Guys you are overthinking, Ans is A. Only Ascorbic acid or any other reducing agent will increase iron ABSORPTION. Certainly not a change in pH. The question directly asks about absorption not about requirements.
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| tompat
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no way the ans will include C.
i dont know any one else but a famous star from bollywood called DHARMENDRA who wud drink blood.
tranfusion aint a part of diet.
much has been munched on vit.c, and i think hypoxia is a factor that wud definately influence iron absorption.
so i wud say E as ans.let me know if i m wrong
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| paganini
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yes, you're wrong
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| tompat
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hi paganini,
as peraspera said, hypoxia will lead to increased iron absorption.why it is not true.
i hope here we are considering a normal person at high altitude without any respiratory aid.
i dint get ur second last post , cud u please elaborate for me.
thanks
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| paganini
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The problem with the question is that is not specific, what is clear is that ascorbic acid increases iron absorption. Although an increased erythropoiesis would increase iron absortion, to say that high altitude would increase iron absortion is difficult, I would say that during acclimatization iron absortion would increase but, would iron absorption increase in people who are already living at high altitude? I mean that they are at an STEADY STATE, but if is compared with others(people living at sea level) they would show higher iron absorption, now maybe I am reading or understanding the question in a wrong way, if you ask me which of the following would increase iron absorption? and letter B says GOING to high altitude, well that's a possibility and I would agree that A and B are correct, but if the question is asking about living at high altitude, uhmm is difficult for me to say yes. Maybe we need explanation from the person who wrote the question.
I have two links that maybe you would like to see:
http://sickle.bwh.harvard.edu/iron_absorption.htm...
http://stinet.dtic.mil/oai/oai?&verb=getRecor...
Good luck, thanks for your observation, I had to read about iron absorption again after your reply.
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| drhouse
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thanks paganini for ur time, explanation
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| tompat
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thanks
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