Iron(Fe)

Iron is the part of haemoglobine, mioglobine, citochrome etc. Approximately 70% of iron reserves in organism is located is essential, and 85% of this amount is located as a part of haemoglobine. Non-essential iron is found as a reserve in liver, bone marrow and spleen. By regular nutrition 10-20mg of iron is intaked, from which 10% is absorbed. Normal daily iron loss is 1mg, and it is result of loss through urine and feces and intestine epitels peeling.

Physiological iron needs are increased during the period of intensive growth(adolescence), while at female it is needed to recharge the loss created by menstrual bleeding.

Physiological iron needs are increased during period of intensive growth, while at women menstrual bleeding loss has to be compensated.

Showers of insufficient iron amounts in organism are: low feritine level, increased erythrocytes protoporfirine, reduced transferine saturation and reduced haemoglobine level. When insufficient intake is present, firstly existing reserves are dropping. If missing is becoming higher and higher, haemoglobine concentration is decreased, which is manifested by anemia signs. One of anemia signs is endurance level decrease during physical work, as a consequence of decreased capacity for oxygen transportation.

Training influence to iron condition in organism

In significant percent of athletes haemoglobine concentration that is classified as “suboptimal” is spotted.

Clinical criteria for anemia is concentration of haemoglobine under 120g/l  at women and 140g/l at men. At “athletes’ anemia” only this type of criteria cannot be considered alone. It was recently thought that top hematocrit limit is 45%, which suits concentration of 160g/l. This opinion is today questioned. Use of “blood doping and some other researches about hematocrit and viscosity blood connection leads to thinking that optimal hematocrit for good tissue oxygenation during training can be higher than previously said(maybe even 50-60%). Anemia at the athletes could be defined as any concentration of haemoglobine that doesn’t enable normal tissue oxygenation.

There are two basic causes of anemia at the athletes:

1. Non-adequate iron intake

It is well known that iron intake is connected to total energy intake; due to that athletes with low energy intake are under the risk of iron insufficiency. This is primarily related to female athletes(gymnastics) and athletes that are included into sports cathegorized according to the weight. Food intake at previously described cathegories, is often not responsive by quantity and quality of high physically active athletes needs, so iron intake is compromised too. There are data that some athletes enter iron in non-hem shape(weaker absorption). Very often misses intake of food factors(ascorbic acid, proteins) that optimize non-hem iron absorption.

2. Increased iron losses

Iron losses can be increased by intensive sweating, haemoglobineuria and mioglobineuria: they are consequence of erythrocyte destruction(hemolysis) and muscle cells(miolysis) and they are present during hard training(especially at runners).

Blood plasma expansion, that lead to relative decrease in haemoglobine concentration, is seen in many athletes that were exposed to long term trainings. In these cases, training leads to bigger increase in plasma volume relatede to total haemoglobine(pseudoanemia).

At females, normal loses can be increased through abundant menstruations, and insufficient nutritive iron intake. It is thought that normal nutrition with 1000kcal will enter 6mg of iron.

Intake of iron and zync in food
Groceries	Amount	Iron(mg)		Zync(mg)
Animal origin
Liver, chicken	120g, cooked	9		5
Beef meat	120g	3		6
Turkey meat	120g, red	2		5
Pork meat	120g	1		3
Oysters	6 middle, fresh	6		75
Chicken breast	120g	1		1
Cod	120g	1		1
Tuna	90g, white meat	1		1
Egg	1 big	1		0,5
Fruit and juices
Apricot	5 dried halves	3		1
Date	10 dried	1		1
Raisins	1/3 cup	1		0,3
Vegetables and legumes
Spinach	1 cup, cooked	3		1
Peas	1 cup	1		1
Broccoli	1 cup	1		0,3
Milk and products
Milk, skimed	1 cup	0,1		1,0
Cheese, cedar	30g	0,2		1,0
Cereals and products
Cereals	1 cup		18	0,7
Pasta	1 cup, cooked enriched		2	1
Bread	1 piece, enriched		1	0,2
Rice, unglazed	1 cup, cooked		1	1,2
Wheat germs	1 cup		2	3,5
Iron and zync are the best absorbed from the animal origin groceries
Iron and zync are the very weak absorbed from plant origin groceries

Iron intake

Iron that is entered through food is found in 2 shapes: hem and non-hem(elementary iron). Hem iron is found connected in the shape of porfirine and represents 40% of  iron content in meat. In this shape iron is the easiest to be absorbed from food. In this shape iron is the easiest absorbed from food. The biggest part of diet iron is found in non-hem iron in plant food, and in the other groceries of plant origin. Absorption of non-hem shape is under influence of numerous diet factors. Amount of fish and meat influences non-hem iron absorption, or increase of that type of food intake leads to non-hem iron absopiton. Ascorbic acid also increases the absoption, by leading to forming helats that are easier for absorption. Reverse, tea, coffee, food rich with diet fibers, calcium and phosphates decreases absorption of this mineral.

In anemia therapy due to iron deficit oral use of iron rimifons is widespread(gluconate, sulfate, fumarat) that enables 100-200mg of elementary iron per day. Recommendation is that prevention of iron deficit at athletes “under risk” is done through intake of 18mg of elementary iron per day.

Judge of other minerals, like zync and cooper, can be compromised by non-adequate iron intake. Intake of iron rimifons that do not contain some vitamins and minerals is not recommended, cause it is thought that use of this rimifons can distract good absorption of this mineral. 

“Athletes’ nutrition”, Marina Djordjevic Nikic