minerals Flashcards
are minerals an essential element?
yes
what are the 2 different classes of minerals?
and examples?
macro/major e.g Ca (can be separated into electrolytes and pure minerals)
and micro/trace or ultra trace (really small) e.g Fe
where is sulphur found?
protein, skin and nails
2 of the most common mineral supplements?
who typically takes them?
calcium and iron
usually taken by females
what classifies a mineral as macro or micro?
macro - >100mg a day
micro - <100mg a day
where are minerals found and not found?
found in: nuts milk seeds meat
not found in:
takeaways
which minerals have a limited absorption?
calcium - absorb about 30%
iron - absorption helped by taking in vitamin C
what are the 2 types of iron?
haem iron - absorb 10-30% - meat
non haem iron - absorb 2-10% - plant
so average absorption 25%
result of excess minerals?
too much Ca affects absorption of iron and zinc
too much Zn affects absorption of copper
how do we excrete minerals in moderate excess?
through the kidneys
what are the 3 roles of iron in the body?
- oxygen transport from lungs to rest of body and utilisation
- maintaining healthy immune system
- helps with energy production - in some of the enzymes which are crucial in energy production
components of iron?
75% as haemoglobin
myoglobin
cytochromes
how is iron stored in the body?
why is it the best indicator of iron status in the body?
stored as ferritin in liver, spleen and marrow
soluble ferritin released from cells into plasma in direct proportion to how much ferritin in the cells
(large amount in cells=large amount in blood)
indicator of iron status as how much iron being released from body stores
how is iron transported?
transferrin transports iron from food to tissues
indicator of how much iron you’ve just eaten
normal haemoglobin status in the body?
120 g/L in females
140 g/L in males
most popular micronutrient deficiency and symptoms?
iron deficiency
leads to fatigue and impaired cognition
what is iron depletion?
effects?
when you don’t have enough of serum ferritin so fewer iron stores (normal haemoglobin and transferrin)
common in athletes
difference between iron deficiency and depletion?
depletion - no effect on performance or symptoms
deficiency - impairs performance and symptomatic
why is iron depletion common in athletes?
iron losses with exercise:
iron loss through sweat (2L of sweat in 1 hour and 0.4mg per L of sweat)
emphasised by low amount of iron absorbed
when feet hit ground red blood cells destroyed (loss of iron)
what is the role of sodium in the body?
maintain normal body fluid balance, osmotic and blood pressure
too much sodium effects?
symptoms?
what is the RDA?
pulling water out of cells to maintain plasma homeostasis
- associated with hypertension and handling of nitric oxide
- issues with endothelial elasticity
RDA is 2.4g (6g of salt)
how is sodium lost?
through sweat
5 roles of zinc in the body?
- cofactor in energy production
- cell replication
- macronutrient metabolism
- important for LDH and ADH (alcohol dehydrogenase allows you to consume alcohol)
- protein synthesis
where is zinc in the body?
95% stored in tissues
60% present in muscle
30% present in bone (very responsive to change in diet)
issue with monitoring zinc levels?
majority stored in tissues so blood test won’t reveal anything
relationship between zinc and appetite?
role in appetite regulation
zinc supplementation to eating disorder can help restore normal eating behaviour and body weight
which athletes are most likely to be deficient in zinc and why?
what may this lead to?
endurance athletes:
focus on carbs not protein with zinc in
lots of sweat
likely to get an eating disorder as lack of appetite
food with highest zinc levels?
oysters
protein
2 main roles of magnesium in the body?
1) cofactor of many enzymes important for energy metabolism
2) maintainance of electrical potentials
when is an increased amount of magnesium needed?
when pregnat or lactating
what is bad and good for magnesium absorption?
bad - too much fibre as food travelling too quickly
good - vitamin C
effects of magnesium deficiency?
neuromuscular abnormalities due to involvement in electrical potentials
low calcium and potassium amounts
effects of too much magnesium?
diarrhoea
role of calcium in the body?
- osteoblasts and clasts responsible for bone modelling
what happens with high and low calcium levels?
high calcium levels - calcitonin building up proteins - stimulate osteoblasts
low calcium levels - parathyroid breaking down proteins - stimulate osteoclasts which demineralise bones
factors which increase likely of osteoporosis development?
alchol and caffeine
low resistance exercise
low oestrogen levels
which groups are likely to hav calcium deficiencies?
low body fat
low energy intake
high physical activity
why may dietary intake not indicate exactly what is in an athelete’s body?
differences in bioavailability of trace element food
not all foods have been analysed for mineral composition
plasma mineral conc doesn’t give accurate representation of total body stores (e.g zinc mainly stored in bones and muscle)
what is heavy training increasing requirement for?
when in particular?
iron, zinc, magnesium and sodium as lost in sweat so reduced plasma concentrations
especially if performed in heat
who is at risk of inadequate mineral intake?
young athletes female athletes low energy intake of macros so micros also suffer weight category sport vegetarians athletes in hot climates
what should mineral supplements not exceed?
1-2x the RDA
what are the effects of excessive mineral intake?
can be toxic
can impair absorption of other essential trace elements
possible essay question?
how to have a healthy diet with minerals and their effect on performance
