W8 - Micronutrients - Minerals Flashcards
Macro mineral requirements
> 100mg/day
What minerals come under Macro minerals
Ca, Cl, Mg, K, P, Na, S
Micro mineral requirements
<100mg/day
What minerals come under Micro minerals
Fe, Zn, Cu, Cr, Co, Mn, I, F, Mo, Se
Can minerals be found in processed foods?
NO
Which minerals have a limited absorption by the body?
Calcium
Iron
What % of the iron that we eat do we absorb?
~30%
Depending on whether its heam or non-haem
Which type of iron are humans better at absorbing?
Heam
Which minerals can excess absorption impair absorption of other nutrients?
Calcium - can impair Fe + Zn absorption
Zinc - can impair copper absorption
Which minerals can be excreted by the kidneys if there’s a moderate excess amount?
Na, K, Ca, Cl + PO4
Which minerals are the most commonly supplemented?
Calcium + Iron
What are the 3 main functions of Iron in the body?
O2 transport + utilisation
Helping in energy production
Immune system support
In which foods can heam iron be found?
ONLY animal foods
In which foods can non-heam iron be found?
Plants
Not as well absorbed by the body as heam iron
What can help one absorb more non-haem iron?
Vitamin C or Calcium
Between what % can the absorption of non-haem be between?
1-20%
RDA for iron
M: 8-10mg
F: 18mg
What % of body iron is in Hb?
74%
With what protein is iron stored in the body?
Ferritin
Who has higher levels of ferritin? Males or females?
Males
Where is ferritin mostly stored?
Liver
Spleen
Bone
What happens to soluble ferritin?
Released from cells to plasma in direct proportion to cellular ferritin content.
What transports iron from ingested food to the bodys tissues?
Transferrin
Iron depletion
Normal hematocrit + Hb
Serum ferritin is less than 30
Normal transferrin saturation
To who is iron depletion common to?
Athletes but has no performance effect
Consequences to Iron deficiency
Fatigue + lethargy
⬆️ frequency of infections
⬇️ resistance to cold
Impaired learning
Hypoferrimia
What is one of the big ways to lose iron?
Through sweat
What can exercise in the heat lead to a sweat rate of?
2L / hr
How is the salt value calculated?
Sodium value x 2.5
RDA for sodium
2.4g
RDA for salt
6g
Importance of sodium in the body
Maintain fluid balance, osmotic pressure + bp
Consequences to high intake of sodium
⬆️ ECF vol
Hypertension
Zinc importance
Energy production
Macronutrient metabolism
Cell replication
Wound healing
Hormones
Enzymes
Appetite regulation
Where is zinc stored in the body?
60% muscle
30% bone
Total amount of zinc in body
2g
Which muscle fibres have high concentrations of zinc?
Slow twitch
What does prolonged exercise mean in regards to zinc?
Big losses through sweat + urine
What is oral zinc supplementation effective in?
Restoring normal eating behaviour + body weight in those suffering from anorexia nervosa.
What can inadequate zinc intake result in?
⬇️ appetite = eating disorder
RDA for magnesium
M: 400-420mg/day
F: 310-320mg/day
What can impair magnesium absorption?
Too much fibre
What can help with magnesium absorption?
Vitamin D
What can magnesium deficiency result in?
NM abnormalities
Muscle weakness
Cramps
Structural damage to muscle fibres
Low calcium + potassium
Mood
What can too much magnesium result in?
Loose stools
What hormones regulate bone turnover?
Calcitonin
Parathyroid
What does the parathyroid hormone stimulate?
Demineralisation
What amount of calcium is recommended to protect against osteoporosis?
1000-1200mg/day
What can the development of osteoporosis be from?
Low oestrogen levels
Alcohol
Caffeine intake
Family history
If female
Amount + type of PA
What is most responsive to changes in zinc?
Bone
Why is the assessment of mineral status of an athlete difficult?
Differences in bioavailability of trace element foods
Not all foods have been analysed for mineral composition
Plasma mineral conc doesn’t always give accurate reflection of total body stores of mineral
In what minerals is there likely to be an increased requirement after heavy training?
Iron
Zinc
Magnesium
Sodium
Which athletes are at risk of inadequate iron + calcium intakes?
Young
Female
Those w. low energy intakes
Weight category sports
Vegetarians
Those in hot climates
