Iron & egg yolks

About specific vitamines, minerals or fiber, for example
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djkvan
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Iron & egg yolks

Post by djkvan »

According to the Iron Disorders Institute, calcium, an essential nutrient, is the only substance known to inhibit both heme and nonheme iron. It can be found in dairy products, tofu, canned salmon, broccoli, rhubarb, figs, almonds and turnip greens. Calcium amounts from 300 to 600 mg inhibit iron absorption, but 50 mg or less has little to no effect.

Eggs also contain an essential compound that inhibits iron: phosvitin. Phosvitin is a protein that binds to iron and inhibits its absorption. One boiled egg can reduce iron absorption in a meal by up to 28 percent, as noted by the Iron Disorders Institute.

Read more: Foods to Avoid When Low on Iron | eHow.com http://www.ehow.com/list_7252222_foods- ... z13ylVooRD

The two studies I read on phosvitin seem to have conflicting info, so I dunno.
I do so like green eggs and ham. Thank you, thank you. Sam I am.
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RRM
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Re: djkvan

Post by RRM »

It seems that what is important, is not so much the level of iron / its bioavailability in one,
but the interaction of all enhancers and inhibitors in your digestive tract.
Vitamin C (and meat) are enhancers.
Bran, polyphenols, egg yolk protein, soy, calcium and phytic acid are inhibitors http://www.ncbi.nlm.nih.gov/pubmed/10466161
as are excess zinc and magnesium.
"Eggs also contain an essential compound that inhibits iron: phosvitin.
Phosvitin is a protein that binds to iron and inhibits its absorption.
One boiled egg can reduce iron absorption in a meal by up to 28 percent
"
Vitellin (=phosvitin) and lipovitellin are known to function as yolk nutrient proteins.
Vitellogenin precursors provide the major egg yolk proteins that are a source of nutrients (including iron)
during early development of the chick.
Vitellogenin (a nutrient transport protein) will be cleaved into several egg yolk proteins, including vitellin.
They are produced in the liver of egg-laying (female) animals (including fish and crustaceans), under the control of estrogens.
The more an egg is bolied, the harder its proteins are to be digested properly.
Normally, the gastric fluid strongly diminishes the binding capacity of proteins such as vitellin.
Thus, it depends on how well your food is digested whether the iron will be released eventually.
With raw food that is readily digested, your chances are much better.

iron in mg / 100 g. food
7.2 egg yolk
5.8 oyster
5.1 ox heart
4.9 anchovy
2.7 krill
2.7 abalone
2.4 sardine
2.3 beef, shoulder / fillet
2.2 beef, muscles only / rump
2.0 crayfish
1.8 scallop
1.8 chicken leg
1.8 brownshrimp
1.5 turkey, young animal
1.5 mullet
1.1 herring
1.0 mackerel
1.0 tuna
1.0 salmon

Of all the iron in the human body (4 - 5 grams), about half is contained in hemoglobin (for oxygen transport).
About 2 grams are contained in compounds in all cells, and particularly in liver cells ('spare iron'), and bone marrow and spleen.
Iron uptake is basically the only way to regulate serum iron levels, as virtually the only way to get rid of iron,
is by sweating, shedding skin and mucosal cells (1 to 2 mg / day), since we have no means of excreting iron.
Hence on average only 15 to 35% of dietary iron (from animal food) is absorbed.
The more iron in the blood, the more susceptible to bacterial infection (bacteria need iron).
The higher the level of iron, the greater its pro-oxidative effect, causing damage to DNA, proteins, fats and all kinds of cellular components.
(in Alzheimers and Parkinsons, iron accumulates in the brain,
and if the body cannot adequately lower the iron absorption rate, it leads to disease, or even death.)
Supplementary iron may therefore be dangerous.
Vitamin C increases iron uptake. So that if (on this diet) your iron intake is substantial,
a relatively low level of iron in the blood is highly likely to be intentional, regulated by the iron uptake ratio.
Lowering iron levels even below that level is for example crucial in fighting bacterial infections (and malaria, for example).

'Normal' reference ranges for serum iron are:
Men: 65 to 176 μg/dL
Women: 50 to 170 μg/dL
Newborns: 100 to 250 μg/dL
Children: 50 to 120 μg/dL

Serum values may be very confusing, as one may be iron deficient while having perfectly normal iron levels in the case of inflammations, for example.
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