Iron Fe

Learn about minerals, vitamins, proteins, fats and other essential nutrients. Discuss the health benefits of each nutrient, share your experience, discuss different natural sources of nutrients in vegan diet. Educate yourself to a healthier nutrition.
Nutrients
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Iron Fe

Postby Nutrients » Jan 27, 2007 8:50 pm

Iron, Fe

Iron is an essential element for most life on Earth, including human beings. The control of this necessary but potentially toxic substance is an important part of many aspects of human health and disease. Hematologists have been especially interested in the system of iron metabolism because iron is essential to red blood cells. In fact, most of the human body's iron is contained in red blood cells' hemoglobin, and iron-deficiency is the most common cause of anemia.

Understanding this system is also important for understanding diseases of iron overload.

Importance of iron regulation
Iron is essential to life, because of its unique ability to serve as both an electron donor and acceptor.
But iron can also be potentially toxic. Iron's ability to donate and accept electrons means that if iron is free within the cell, it can catalyze the conversion of hydrogen peroxide into free radicals. And free radicals can cause damage to a wide variety of cellular structures, and ultimately kill the cell. To prevent that kind of damage, all life forms that use iron bind the iron atoms to proteins. That allows the cells to use the benefits of iron, but also limit its ability to do harm.

The most important group of iron-binding proteins are the heme molecules, all of which contain iron at their centers. Humans and most bacteria use variants of heme to carry out redox reactions and electron transport processes. These reactions and processes are required for oxidative phosphorylation. That process is the principal source of energy for human cells; without it, our cells would die.

Humans also use iron in the hemoglobin of red blood cells, in order to transport oxygen from the lungs to the tissues and to export carbon dioxide back to the lungs. And iron is an essential component of myoglobin to store oxygen in muscle cells.

Precautions

Excessive iron is toxic to humans, because excess ferrous iron reacts with peroxides in the body, producing free radicals. Iron becomes toxic when it exceeds the amount of transferrin needed to bind free iron. In excess, uncontrollable quantities of free radicals are produced.

Iron uptake is tightly regulated by the human body, which has no physiologic means of excreting iron and regulates iron solely by regulating uptake. However, too much ingested iron can damage the cells of the gastrointestinal tract directly, and may enter the bloodstream by damaging the cells that would otherwise regulate its entry. Once there, it causes damage to cells in the heart, liver and elsewhere. This can cause serious problems, including the potential of death from overdose, and long-term organ damage in survivors.

Iron Absorption
Up to 22% of the iron in meat is absorbed, while only 1-8% is absorbed from plant foods. Plant iron tends to be ‘bound’ to other nutrients in food and needs to be broken down in the body before it can be absorbed. This not only slows down the process of absorption but enables the body to limit its overall intake. As a consequence, stores of non-haem iron are low in comparison to haem iron as the body takes only what it needs, absorption decreasing as iron stores increase

Iron absorption can also be reduced by tannins (e.g. in tea) and phytates (found in nuts, grain and seeds). At this point one tends to wonder whether the rumours of vegans suffering from anaemia have substance, research has shown that iron deficiency in vegans is no more common than in the rest of the population.

The absorption of iron from plant foods is improved by the presence in a meal of vitamin C (ascorbic acid), other organic acids such as malic acid (e.g. in pumpkins, plums and apples) and citric acid (in citrus fruits). Laboratory research in which experimental meals were given to 299 volunteers has shown that the inclusion of foods (such as fresh salad, orange juice or cauliflower) providing 70-105mg of vitamin C in each meal increased the absorption of iron. A particularly pronounced effect was seen when 4.5oz cauliflower containing 60mg of vitamin C was added to vegetarian meals, causing more than three-fold increase in iron absorption.

Recommended Adequate Intake by the IOM for Iron:

Code: Select all

Age           Iron (mg/day)
0 to 6 months    0.27
7 - 12 months   11
1 to 3 years     7
4 to 8 years    10

Males
9 to 13 years     8
14 to 18 years   11
19 to 50 years    8
51+ years         8

Females
9 to 13 years     8
14 to 18 years   15
19 to 50 years   18
51+ years         8

pregnancy        27


Low Iron Stores: Not Necessarily Unhealthy

Anemia is a possible downside to lower iron absorption, but there are a few potential upsides:

1. Low iron stores are associated with higher glucose tolerance and therefore could prevent diabetes.

2. High iron stores have been linked to heart disease. Based on an early study, this was believed to be a strong link for a number of years. Now that more evidence has come in, the link appears to be only in cases of very high iron storage levels, such as greater than 200 mcg/l (vegans' ferritin levels are rarely above 100 mcg/l). For now, the Food and Nutrition Board of the Institute of Medicine says, "This body of evidence does not provide convincing support for a causal relationship between the level of dietary iron intake and the risk for coronary heart disease."

3. High iron stores have been linked to cancer.

Human Iron metabolism on wikipedia

Iron on veganhealth.org

Iron on NIH
Last edited by Nutrients on Jan 27, 2007 9:25 pm, edited 2 times in total.

BigBecka
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Postby BigBecka » Jan 27, 2007 9:11 pm

Wow :o I used to take iron supplements, on top of my steady diet of offal, because my mother was convinced I was anaemic (I wasn't!) Looks like you can have too much of a good thing!

People seem to worry about anaemia a lot, especially with teenage girls. Does anyone know how much Iron a person needs? And is it true that us ladies need more?

Nutrients
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Postby Nutrients » Jan 27, 2007 9:22 pm

Yes women need more Iron because they lose more blood.
And taking supplements isn't always a good idea. I have read a lot on this and the best way is to balance your diet so that you get enough from natural foods.
I have just posted the recommended adequate intake.
Here it is again

Code: Select all

Age           Iron (mg/day)
0 to 6 months    0.27
7 - 12 months   11
1 to 3 years     7
4 to 8 years    10

Males
9 to 13 years     8
14 to 18 years   11
19 to 50 years    8
51+ years         8

Females
9 to 13 years     8
14 to 18 years   15
19 to 50 years   18
51+ years         8

pregnancy        27


But vegans when looking for Iron in vegan foods can safely double the amount since it will not absorb if the body doesn't need it.
From what I understood an overdose can happen if one eats iron tablets.
Also products rich in vitamin C will help absorb Iron.
I can tell one sure thing I'm vegan for some time and I've passed a medical exam recently, they said I have ideal blood composition.

BigBecka
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Postby BigBecka » Jan 27, 2007 10:16 pm

Cool! Thanks! 8) (Must have scrolled past by accident...)

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Backwood
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Postby Backwood » Feb 1, 2007 11:50 am

And taking supplements isn't always a good idea.

What about Vitamin B12?

BigBecka
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Postby BigBecka » Feb 1, 2007 11:59 am

:D There's quite a few threads on B12 lurking on here :D I think the official line is that vegans are encouraged to take supplements. Though you can get it from yeast extracts (marmite/vegimite) and quinoa.

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Backwood
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Postby Backwood » Mar 4, 2007 12:53 pm

Yeast extracts?
Do they have the proper B12 vitamin?
I've read once that there is a false B12 that is very similar but it doesn't work as a normal b12 and it's bad for the body...

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AndyBa
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Vegan Products Rich in Iron, Fe

Postby AndyBa » Jan 14, 2010 11:42 am

Bigbecka quinoa does not have B12.

Here you can find a list of Vegan Products Rich in Iron

As well as lists containing:
Raw Vegetables with high Iron content
Raw Legumes with high Iron content
Raw Fruits with high Iron content


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