Minerals Flashcards
What sports are at risk for mineral deficiencies and what is the cause?
Gymnast,jockey,ballet,dancing: low BW, low EI
Weight-class sports (rowing, judo, wrestling): competition weight
Body building: low-fat, drastic weight loss
(female) endurance athletes: vegetarian diets
Endurance events: Training in hot/humid conditions
Iron is a very toxic element (ROS) true/false
true
In what sources does iron come?
Haem-iron vs non-haem-iron
What type of charged state does iron have and when can the body directly use it?
Fe2 used, like incorporated in membranes
Fe3 will have to be changed first
Absorption of iron in the intesine is..
poor (10%). Increases when deficient.
Learn the scheme on p. 93. Ferritin = ?
Ferroportin = ?
Transferrin = ?
Hepcidin = ?
- Ferritin = cellular protein that stores iron, important marker. Bit of spillover in the blood
- Ferroportin (Fpn) = transporter in cellular membranes (inside cell -> outside)
- Transferrin = transport protein in blood
- Hepcidin = important for exrcise, can block activity of ferroportin
What happens when there is too long activity of hepcidin?
Hepcidin activity for too long: may become aenemic, even though you ingest enough iron
When is hepcidin upregulated?
in response to inflammation, infection. Will keep iron in cells so it is not available for bacteria. Also upregulated by exercise (exercise -> inflammation).
What is assessed as iron status with haemoglobin, ferritin, transferrin?
▪ Haemoglobin: ‘functional’ iron
▪ Ferritin: iron storage
▪ Transferrin: iron transport
How are stages of iron deficiency defined?
Early stage: decrease ferritin
Intermediate stage: transferrin decrease
Late stage: haemoglobin decrease, altered RBC volume parameters
Iron deficiency is common/uncommon
uncommon
Symptoms of iron deficiency?
▪ Weakness, breathlessness, impaired aerobic capacity
▪ Non-specific symptoms
Effect of iron on aerobic capacity / performance:
● Iron depletion: no effect on aerobic capacity (VO2max)
● Iron deficiency anaemia: clear impairment
Recall some reasons why there is an increased iron requirement in athletes
- Increased requirement: red cell mass
- Sweat loss
- loss due to haemolysis
(urine, GI-bleeding, mechanical forces)
Iron is highly toxic, what are some side-effects?
constipation, black stools, abdominal cramping
Calcium status in blood: reliable measure?
No, does not say much
Vit D is needed for calcium uptake. Without it: risk for..
Stress fractures . History of one or more stress fractures = significant.
- Calcium ‘not a significant risk factor’, apparently. However supplementing vit D and calcium reduced incidence of stress fractures.
How can you get enough calcium from the diet, even on a restricted diet?
▪ Include three servings per day low-fat dairy
▪ Include these dairy foods in high-CHO meals
▪ Eat fish with bones
▪ Include Ca-enriched soy products
▪ Eat leafy green vegetables
Magnesium is needed for about …. processes in the human body
> 600
Magnesium is important for these processes (4): (among others)
- Energy metabolism
- DNA replication
- Formation bone tissue
- Nerve conduction & muscle function
What are deficiency symptoms for magnesium?
▪ Muscle spasms
▪ Cardiovascular disease
▪ Osteoporosis
▪ Caused by poor intake, disturbed digestion (e.g. polypharmacy: taking medicine), or excessive excretion (e.g. kidney disease)
What is good to take into account when measuring magnesium status?
All kinds of exercise have different effects on magnesium concentrations. Temporary metabolic response due to exercise-induced stress: low magnesium. But after exercise, the values increase again. But also when doing the same exercise on day 1, 2, 3, 4. There will be decrease on day 1, then it is stable again: your body adapts.
There are no sports-specific recommendations for iron or magnesium
true!
Zinc: what is it?
Component of enzymes involved in muscle energy production and protein synthesis
What decreases plasma zink and what is the risk with increased intake?
- stress
- CVD
Why is there an increased requirement for athletes for selenium/copper?
▪ Increased requirement through free radical formation during exercise
▪ Increased loss via sweat and urine
Are there sports-specific recommendations for selenium/copper?
No. Main message: general recommendations for micronutrients are working well for athletes
