Sports anemia is often caused by a lack of iron. This deficiency occurs mainly in endurance athletes and may depend on inadequate intake, poor absorption and increased losses.
INCREASE OF GASTROINTESTINAL IRON LOSSES:
Gastrointestinal iron losses in the sedentary subject represent about 60% of the losses (excluding menstrual ones) and are mainly represented by small blood losses (about 1 ml / day) and the breakdown of red blood cells (hemolysis).
After long run races such as the marathon in more than 80% of the subjects there are gastrointestinal bleeding phenomena. It is hypothesized that this phenomenon is linked to the numerous traumas suffered by the intestinal walls during running action and by the reduced supply of blood to the intestine. Despite being modest, this bleeding causes iron losses of between 0.7 and 0.9 mg.
INCREASE OF URINARY IRON LOSSES
The small urinary iron losses of the sedentary subject (0.1mg / day) can increase considerably in the cross-country skier.
INCREASE OF CUTANEOUS IRON LOSSES
Due to increased desquamation of epithelial cells caused by sweating. However, this aspect has a marginal contribution to the total iron losses in the basic athlete.
INCREASE OF MESTRUAL IRON LOSSES
The amount of blood that a woman of childbearing age loses every month with her period is between 30 and 60 ml of blood. A woman who loses 60 ml of blood per cycle loses an average of 1.0 mg of iron a day, or 30 mg of iron a month. To these physiological losses in the female athlete must be added the urinary and gastrointestinal losses and eventually the dietary restrictions that can decrease the iron intake with the diet
WHY IRON IS IMPORTANT IN PERFORMANCE
Iron deficiencies lead to reductions in the concentration of hemoglobin in the blood and consequently to the athlete's ability to perform.
These deficits initially manifest themselves with general reductions in strength and continue with progressive reductions in power and aerobic endurance, particularly evident in middle-distance and bottom athletes.
Iron is an essential constituent of hemoglobin and myoglobin and is therefore linked to the transport of oxygen in the blood; has an important role in energy production and is a constituent of many enzymes.
Iron is absorbed intestinal and more precisely in the duodenum and in the jejunum. Iron absorption depends on many factors including stomach acid production and intestinal mucosal integrity.
In a bottom athlete this intake should increase up to 17-23 mg / day.
It is considered that a balanced diet brings about 6-7 mg of iron every 1000 Kcal.
However, there are some factors that can increase or reduce iron absorption.
EME IRON (Fe 2+) and NON EME IRON (Fe 3+): more than 20% of the EME iron introduced with the diet is absorbed in the intestine, while less than 5% of the non-EME iron is assimilated.
EME iron is found in meat and fish, while non-EME iron is contained in vegetables, fruit, cereals and eggs.
Theina, caffeine, and fibers reduce intestinal absorption of iron while vitamin C increases assimilation and function.
ARE THERE IRON STOCKS?
Yes, iron is stored mainly in the liver as ferritin, the total amount of iron in the body is about 4-5 grams.
INTEGRATION: If the serum iron, ferritin and transferrin values are within normal values, it is useless to take iron to correct an even mild anemic picture.
A reduction in hemoglobin and hematocrit occurs normally in athletes who practice endurance sports (cycling, marathon etc.).
The explanation to this phenomenon has not yet been fully clarified.
What is certain is that if the decrease of hemoglobin and consequently of the hematocrit on one hand penalizes the performance as it limits the availability of oxygen, on the other hand increasing the fluidity of the blood ensures a greater flow of oxygen to the tissues improving performance .
Furthermore, the increase in plasma volume, typical of endurance athletes, is a positive phenomenon because it makes the blood more fluid and consequently increases stroke volume and blood flow to the tissues.
In the presence of hypervolemia the hematocrit decreases because the blood is more diluted but in reality the quantities of red blood cells and hemoglobin remain unchanged.
