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NFS302 > Lecture 7: Non-nutritive Supplements > Flashcards

Lecture 7: Non-nutritive Supplements Flashcards

1
Q

How does the US army get caffeine and why?

A

Gum, since caffeine is best absorbed via the mouth

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2
Q

Which groups should limit their caffeine intake?

A
  • Children (
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3
Q

Paradox of caffeine & coffee

A

Although caffeine decreases insulin sensitivity, long-term coffee drinking decreases risk of T2DM. This is because there are many other compounds in coffee; complex food interactions.

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4
Q

Mechanisms: how caffeine increase sport performance

A

1) Increase fat metabolism (carnitine) to spare glycogen (this glycogen can be used for sprint at the end)
2) Directly affect skeletal muscle – increase excitation-contraction
3) CNS effect; makes you feel good

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5
Q

Caffeine increases ENDURANCE performance by…

A

3% (on average)

Another study found ~14% (not likely)

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6
Q

Supplementation protocols for caffeine

A
  • ~6 mL/kg 1 h before exercise (300-500 mg)
  • New evidence shows less is also effective
  • Doesn’t matter how or when it’s taken, many times have shown to be effective
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7
Q

Individual differences in response to caffeine is likely due to…

A

genetics

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8
Q

Detrimental effects of coffee (perhaps)?

A

Health

  • CVD
  • Certain cancers
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9
Q

Dose of caffeine per day (for no health consequences)

A
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10
Q

Long-term effects of drinking coffee (good for health)

A

Decreased risk of liver cancer & T2DM

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11
Q

Caffeine increases STRENGTH performance by…

A

~ 4%

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12
Q

Supplementation aim

A

Develop a personalized protocol that is effective for them using the least possible dose

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13
Q

Buffers work to prevent…

A

Acidosis & alkalosis

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14
Q

What do buffers do?

A

Inhibit negative consequences of lactic acid formation

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15
Q

How is lactic acid formed? What happens after it’s formed?

A

Pyruvate + NADH -> Lactic acid + NAD+

Lactic acid -> lactate + H+

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16
Q

Is lactic acid bad?

A

No, the H+ from breakdown is bad. The lactate is not.

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17
Q

Why is acid bad for exercise?

A

1) Inhibits actin-myosin crossbridge formation
2) Inhibits various enzymes
3) Feels uncomfortable, burns

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18
Q

Factors affecting lactic acid formation

A

1) Anaerobic respiration
2) More reliance on glycolysis (untrained person)
3) More use of type 2 fibres (fast-twitch)
4) Clearance of lactate from blood

(efficiency of oxygen use, how circulation distributes oxygen)

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19
Q

Two buffer systems we studied

A

1) Sodium bicarb (oldest)

2) Beta-alanine

20
Q

Where does bicarb naturally exist?

A

extracellular space

21
Q

How does bicarb works as a buffer?

A
  • increase pH extracellularly

- increase buffering capacity

22
Q

define: buffering capacity

A

the body’s ability to handle increasing acidic load

23
Q

When is bicarb most effective?

A
  • sports lasing 1-7 min (best evidence)
  • sprinting to finish after 30-60 min effort (maybe)
  • intermittent-type sports (maybe)
24
Q

AIS: class for bicarb

A

class A

25
Q

Negative effects of bicarb

A

GI distress

26
Q

Dose for bicarb

A

0.3 g/kg taken 2-2.5 h before start of exercise. GI distress may decrease if taken with a meal.

27
Q

Where does B-alaine work?

A

intracellular

28
Q

Carnosine =

A

L-histidine + B-alanine

protein found inside muscle cells (natural buffer)

29
Q

Why don’t we take carnosine? Why take B-alanine instead?

A

Body can’t absorb carnosine. Since B-alanine is the rate-limiting precursor, supplementing with B-alanine will increase carnosine levels.

30
Q

Supplementation of B-alanine / guidelines / how to take it

A

Need loading phase followed by maintenance phase:

  • 4 - 6.4 g/day increases carnosine by 60% after 4 weeks (take for at least 4 weeks)
  • 80% increase after 10 weeks
  • Divide dose over 0.8 - 1 g servings
  • Lower doses over longer time have also been effective
31
Q

Which sports is most beneficial if taking B-alanine?

A

high intensity anaerobic exercise

32
Q

AIS classification of B-alanine

A

Class A (used to be class B)

33
Q

How does B-alanine make one feel?

A

Paresthesia: tingly, i-feel-ready feeling

34
Q

Negative effects of B-alanine

A

Not many studies have been conducted

  • Does not always work for everyone
  • No side effects discovered as of yet
35
Q

Once B-alanine is “loaded”, how long does buffering capacity last?

A

6 - 15 weeks (so make sure you take it in advance of most intensive training period)

36
Q

What’s special about beetroot juice?

A

nitric oxide (NO)

37
Q

What is NO?

A

physiological signalling molecule

38
Q

Functions of NO

A
  • vasodilation*
  • angiogenesis (blood vessel formation)
  • regulation of blood pressure
  • mitochondrial respiration
  • mitochondrial biogenesis
  • glucose uptake
39
Q

Synthesis of NO in humans

A

L-arginine + O2 (in the presence of synthases) -> NO

Reduction of nitrate (NO3-) and nitrite (NO2-). These can come from diet!

40
Q

Study outcome: effect of dietary nitrate on oxygen cost during exercise (also, what type of nitrate source was used?)

A

Took supplemental form of NO3-

  • 82% increase in plasma nitrite concentration
  • Reduction of BP
  • **Need less oxygen to do sub-maximal exercise (changed VO2Max)!!!
41
Q

What control was used for beetroot juice? What’s a better control?

A

blackcurrant cordial ;

nitrate-free beetroot juice

42
Q

Supplement for nitrate?

A

beetroot juice

43
Q

Why is beetroot juice > beets?

A
  • more convenient
  • nitrate content changes depending on how you cook it
  • need to eat A LOT to get desirable dose
44
Q

How to supplement with nitrate?

A
  • 5-9 mmol of nitrate/day for 1-15 days improves physiological response to exercise
  • also 2-3 h before exercise
45
Q

Duration of benefit after taking beetroot juice?

A

5-30 min of continuous max effort exercise

NFS302 (11 decks)

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