Lecture 15 - Iron deficiency in athletes Flashcards
What is iron deficiency?
depletion of iron rtores and restriction of iron supply
What gets reduced with iron deficiency?
- oxygen transport capacity
- oxidative capacity at the cellular level
What are the 4 iron containing proteins?
- ferritin
- transferrin
- hemoglobin
- myoglobin
What is the purpose of ferritin?
iron storage protein
What is the purpose of transferrin
iron binding protein
What are is the iron containing protein in RBCs?
hemoglobin
What is the iron containing protein in muscles?
myoglobin
Where is ferritin found?
liver, spleen, bone marrow
Where is transferrin produced?
liver, brain, testes
What does transferrin do?
transport iron in blood
What does hemoglobin do?
carries oxygen from lung to tissues and return carbon dioxide
What does myoglobin do?
transports oxygen to mitochondria of muscle cells
What does serum ferritin levels reflect?
amount of iron stored in the liver, spleen and bone marrow
What is the iron stores in male and females?
males: 55 mg/kg
females: 45 mg/kg
What are the 3 iron deficiency stores?
- pre-latent - iron storage depletion
- latent - iron deficiency erythropoiesis
- anemia
What characaterizes each iron deficiency stage?
depletion - low serum ferritin, normal HB
- iron stores of liver, spleen and bone marrow are depleted
erythropoiesis -** low serum ferritin, normal HB**
- erythropoiesis is impaired
- iron supply to cells is reduced
anemia - low serum ferritin, low HB
- HB synthesis falls
What is the most sensitive and specific test for estimation of total iron body stores?
serum ferritin
What is sensitivity?
correctly identify individuals who have a specific disease ( high sensitivity means few false negatives)
What is specificty?
corrrectly identify individuals who do not have a specific disease (high specificty meanse few false positives)
What is considered anemia for males and females?
low ferritin AND HB
males: <130 g/L (HB)
females: <120 g/L (HB)
What ferritin level warrants investigation?
< 35 ug/L
What are the signs and symptoms?
- low energy/fatigue
- dizziness
- shortness of breath
- poor athletic performance
- weakness
- plae skin
- lightheaded
- cold hands and feet
Who is at risk?
- females
- endurance athletes
- low energy availability/REDs
- athletes with disordered eating
- vegan and vegetarian diet
- medical conditions
What are the exercise-induced mechanisms for iron loss?
- hemolysis (destruction of RBC)
- hematuria (blood in urine)
- sweating
- gastrointestinal bleeding
- injuries
What are the 3 treatament options?
- supplements
- iron rich diet (lena meats, green leafy vegetables, fortified cereals)
- intravenous iron (if cann tolerate or don’t respond to oral iron)
Do athletes need more iron than non-athletes?
Yes, 30-70% more
How much iron do pre-menopausal women need?
15 - 18 mg/day
How much iron do vegan/vegetarian women need?
33 mg/day
How much iron do pregnant women need?
27 mg/day
How much iron do men need?
8-11 mg/day
How much iron do vegan/vegetarian men need?
14 mg/day
