Minerals Flashcards

1
Q

what are minerals?

A

Dietary element essential to life process

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2
Q

what diseases are associated with inadequate intake?

A

Cancer

Anaemia

Diabetes

Hypertension

Osteoporosis

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3
Q

mineral requirements - macro

A

Macro mineral

> 100mg / day

Ca, Cl, Mg, K, P, Na, S

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4
Q

mineral absorption

A

Some minerals = limited absorption

Calcium, Iron (Haem and non Haem)

Excess can be harmful / impair absorption of other nutrients

Ca - Fe and Zn

Zn - Cu

Moderate excess - kidneys - excrete

Na, K, Ca, CL, PO4

Haem - 10-30% - absorbed better

Non haem - 2-10% - vegetarians -

Calcium - 30% absorbed

Help absorption of iron if taken with vitamin C

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5
Q

what is the role of iron in the body?

A

Oxygen transport and utilisation

Component

Others

RDA

Physical health and mental wellbeing

Carry oxygen from lungs to rest of body

Important to maintain healthy immune system

Energy production - in several enzymes imp for energy production - cytochromes

Haem = meat, non = plants

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6
Q

iron stores

A

Ferritin

Liver, spleen and bone marrow

  • Soluble ferritin
  • transferrin

Stored with ferritin

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7
Q

iron depletion

A

Normal Ht and Hb

Serum ferritin <30

Normal transferrin sat

Common in athletes

No performance effect

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8
Q

iron losses with ex

A

Exercise in heat can lead to sweat rate of 2 L per h

Thus, 2 h of exercise results in 4 L sweat loss (0.3-0.4 mg Fe per litre of sweat)

1.2 mg Fe loss

Not all dietary iron can be absorbed in the gut (25%?)

Need more?

Large proportion lost

RBCs break when running

Increased demand in form of myoglobin as well for athletes

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9
Q

sodium

A

Maintain normal body fluid balance, osmotic pressure and blood pressure

Sodium lost in sweat can vary between 500 to 1800 mg/L

Take in too much salt - pull water out of cells - maintain homeostasis

Amount lost varies depends on indv

Issues with endothelial elasticity - how well vessels expand and contract, abnormal ion handling - pumps skewed, issues with hypertension due to nitric oxide

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10
Q

what happens if you have too much sodium

A

increase in extracellular fluid volume as water is pulled from cells to maintain normal sodium concentrations.

related to hypertension

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11
Q

RDA sodium

A

2.4g (6g salt)

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12
Q

zinc

A

Energy production

Macronutrient metabolism

Enzymes - LDH ADH

Nucleic acid

Hormones

Protein synthesis

Wound healing

Co factor in energy metabolism

Required for normal cell replication, immune function, wound healing and in some hormones

Alcohol dehydrogenase - need zinc to help break down alcohol - fat before - keep ADH in contact with alcohol - less quickly in bloodstream

Growth, thyroid hormones and insulin

Higher in slow twitch fibres than in fast

Changes in zinc in diet will most likely affect bonze zinc
95% stored in tissues - 5% blood

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13
Q

zinc and appetite

A

Zn intake within some groups of athletes is considerably less than rda (11 and 8 mg/day for m and f)

Prolonged exercise may result in significant losses of Zn in sweat (and urine)!

Role in appetite regulation.

Oral zinc supplementation is effective in restoring normal eating behaviour and body weight in patients suffering from anorexia
nervosa

High incidence of eating disorders in gymnasts

Involved in anorexia nervosa - effective in restoring normal appetite behaviour

Endurance runners - weight category sports

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14
Q

magnesium

A

Essential cofactor of enzymes involved in energy metabolism.

Mg is also required for maintenance of electrical potentials in
muscles and nerves

Dietary sources

Too much fibre

Vitamin D

Over 300 enzymes

Needed for protein synthesis, ox carbs, glycolytic pathways

Increased mg for pregnant/lactating

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15
Q

magnesium too high/low?

A

RDA magnesium

Mild Mg deficiency - period of heavy training, particularly in warm environment

Mg deficiency

  • Neuromuscular abnormalities, muscle weakness, cramps and structural damage of muscle fibres
  • Low calcium and potassium
  • Mood

Too high = poss diahorrea

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16
Q

calcium intake and osteoporosis

A

Osteoblasts and osteoclasts are responsible for bone modelling

Turnover – calcitonin and parathyroid hormones

Inadequate Ca - Osteoporosis

Ca intake of 1000-1200 mg/day is recommended to protect against osteoporosis

Dietary sources

Vitamin D is important for healthy bones

Vitamin C imp in bone formation

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17
Q

development of osteoporosis

A

(low) estrogen levels
Alcohol

Caffeine intake

Family history

Gender (female)

Amount and type of physical activity

Resistance type exercise

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18
Q

calcium intake for athletes: Cause for concern?

A

Amenorrhea / oligomenorrhea

Contributing factors:

low body fat

low energy intakes

high physical activity

19
Q

mineral status of an athlete

A

Caution - dietary intakes

Assessment is difficult

Plasma mineral concentration does not always give accurate reflection of total body stores of mineral (e.g. zinc)

20
Q

mineral status and ex

A

Exercise can decrease plasma concentrations of minerals

Heavy training likely to increase requirement

Iron

Zinc

Magnesium

Sodium

21
Q

athletes at risk of inadequate iron and calcium intake

A

Young athletes

Female athletes

Low energy intakes (<10 MJ/day)

Weight category sports

Vegetarians

Athletes training in hot climates

22
Q

iron deficiency

A

Most widespread deficiency

Tiredness, feel cold, more infections, impaired cognition

Impact on performance

Depletion - not enough stores for what you’re doing

23
Q

zinc and eating disorders

A

Zinc in protein rich foods - oysters - nuts and legumes

24
Q

how much of the body mass consists of 22 minerals?

A

4%

25
Q

women and minerals

A

women who train intensely but cannot match energy intake to energy output reduce body weight and fat to point that may adversely affect menstruation

often show advanced bone loss at early age

restoration of normal menstruation doesn’t totally restore bone mass

26
Q

association between muscular strength and bone density

A

raises likelihood of using strength testing of postmenopausal women as clinically useful tool to screen for osteoporosis

27
Q

how many American women of child-bearing age suffer from dietary iron deficiency

A

40%

neg affects aerobic ex perf and ability to perf intense training

28
Q

the DASH eating plan

A

lowers blood pressure in some indvs to same extent as pharmacologic therapy and often more than other lifestyle changes

29
Q

micromineral requirements

A

<100mg / day

Fe, Zn, Cu, Cr, Co, Mn, I, F, Mo, Se

30
Q

ultra trace requirements

A

<1mg day - very small amount

Nuts, milk, fruit, seeds

Not in processed food

31
Q

what is iron a component of?

A

Haemoglobin - 75% of iron in form of Hb

Myoglobin

Cytochromes

32
Q

iron stored

A

Stored (25%)

1000mg - males

300-500mg - females

33
Q

RDA of iron

A

8-10mg (M) and 18mg (F)

Females need more due to menstrual cycle

34
Q

sodium intake in USA

A

4.5 g per day!

35
Q

total amount of zinc in body

A

2g and most of this is present in muscle (60%) and bone (30%).

36
Q

dietary sources of magnesium

A

seafood, nuts, fruits, milk, etc

37
Q

RDA magnesium

A

400-420 mg (m) and 310-320 mg (f)

38
Q

dietary sources of calcium

A

dairy products, beans, canned salmon, dark green leafy vegetables and peas

39
Q

soluble ferritin role

A

released from cells into plasma in direct proportion to how much ferritin in cells - indicative of iron status - amount stored

40
Q

transferrin role

A

transports from food to tissues - how much iron just eaten - amount released

41
Q

why is assessment of mineral status difficult?

A

differences in bioavailability of trace element in various foods

not all foods have been analysed for mineral composition

42
Q

osteoblasts

A

Calcitonin with high calcium

43
Q

osteoclasts

A

breakdown of bones - demineralisation –> osteoporosis