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1. Caffeine--Not just a
stimulant
M.Prasad Naidu
MSc Medical Biochemistry,
Ph.D.Research Scholar

2.  Introduction
 Consideration of the physiological effets of caffeine
typically are limited to presumptive “stimulant effects”.
 Many of the human responces to caffeine extend
beyond”stimulant effects” and evidence of such
beneficial responces to caffeine consumption is
abundant.

3. Caffeine potentiates postsynaptic
neurotransmission in the sympathetic nervous
system
Caffeine (1,3,7-trimethylxanthine) is a
plant alkaloid that increases the excitability of the
adenosine-sensitive sympathetic nervous system.signals
originating within the sns produce transient increases in the
cAMP concentration within the postsynaptic cells through
which the signal is expressed.

4. •By acting as a competitive antagonist of
adenosine,caffeine inhibits the enzymatic
degradation of cAMP by phosphodiesterase
within the postsynaptic cell & the presence of
caffeine may increase strength of transmitted
signals.

5. Caffeine increases resting energy expenditure
 Human 24-h energy expenditure,sleeping metabolic rate,&
resting awake metabolic rate all are proportional to the rate
of sympathetic nerve activity & plasma norepinephrine
concentration.
 By potentiating sympathetic activity,caffeine stimulates
lypolysis.

6. For Ex.the ingestion of as little as 50 mg of
caffeine by normal-weight,non-
excercising,healthy men produced a significant
increase in resting energy expenditure within 30
min of caffeine ingestion.
The increase persisted for 4 h & produced a
significant 6% total increase in daily energy
expenditure.
Exercise-associated FA oxidation is also
increased.

7. Caffeine increases endurance and enhances
performance In addition to effects on energy production,caffeine increases
serotonin concentration in brainstem regions that have
excitatory projections to spinal motor neurons,increasing the
self sustained firing of the skeletal muscle motor units that
are innervated by these neurons.
 By potentiating motor unit sensitivity to stimulation,caffiene
postpones fatigue & increases human endurance

8. •In its definitive 2001 report,the
institute of medicine food & nutrition
board committee on military nutrition
research concluded that 150 mg of
caffeine enhances physical
endurance & the quality of physical
performance...

9. Caffeine increases mental energy
 In adition to benefiting physical performance &
endurance,caffeine directly supports the CNS
 MRI evidence shows that cerebral blood flow is directly
proportional to recent caffiene intake & the acute
consumption of 400mg of caffeine has been shown by pulsed
trans cranial doppler sonography to increase significantly
blood flow through the middle & anterior cerebral arteries.

10. In addition, caffeine acutely increases the
functioning efficiency of neuronal networks
in the human cerebral cortex.
Such increases in “mental energy”can
produce increases in the functional capacity
to engage in cognitively demanding tasks
that can be expressed as increased
vigilance,alertness,ability to concentrate,&
ability to choose among alternatives.

11. Caffeine enhances cognitive functioning
 In many human studies,caffeine consumption has
increased alertness,ability to concentrate,problem-
solving ability,wakefulness,& feelings of “energy”.
 The benefits of caffein consumption extend beyond
“wakefulness” to other reflections of enhaced mental
energy.

12. •Cognitive functions,including the ability to
concentrate & to solve problems requiring
reasoning,mental fatigue,&
vigor&alertness,reaction time,accuracy of
responces,ability to focus attention,working
short-term memory,sentence varification
ability.

13.  In its definitive 2001 report(caffeine for the
sustainment of mental task performance.Formulations
for Military Operations),the Institute of Medicine
Food & Nutrition Board Committee on Military
Nutrition Research concluded that the consumption of
150 mg of caffeine enhances cognitive performance &
that these effects can persist for as long as 10 h after
consumption.

14. Caffeine increases neuromuscular coordination,
 In contrast to common misconseptions,moderate
caffeine consumption contributes to enhanced
neuromuscular coordination.
 A single dose of caffeine upto 600 mg enhance
cognitive functioning capabilities & neuromuscular
coordination.

15.  Approved the inclusion of Caffeine in dietary
supplements intended to promote
alertness,wakefulness,enhanced cognitive
performance,endurance,decrease of fatigue,&enhanced
motor performance.
 The Recommended intakes of caffeine are 100 to 200
mg, every 3 to 4 h, upto five times daily.

16. Caffeine elevates mood and relieves anxiety
 Improvement in cognitive functioning capabilities are
accompanied by improved mood,self image, and
overall “happiness” and less anxiety.
 The cognitive & emotional benefits of caffeine
consumption increase in magnitude as the amount of
acutely consumed caffeine increases,persist for 6 h
after consumption.

17. Caffeine consumption is safe
 Moderate intakes of caffeine pose no health risks.
 Daily consumption of up to 400 mg of caffeine significantly
decreased(by10%)the risk of dying from any cause.
 Study demonstrated that even more than six cups of
caffeinated coffee(equivalent to about 1000 mg of caffeine)
daily had no risk for developing coronary heart disease.

18.  A Health Professionals Follow-Up Study with type-2
diabetes,there was no relation between habitual coffee
consumption & risk for developing cardiovascular disease.
 Another study indicated that the risks for dying prematurely
from any cause & specifically from cardiovascular disease &
risk of developing a stroke also were significantly inversely
proportional to chronic daily coffee consumption.

19.  Lowa Women’s Health Study on Postmenopausal women
demonstrated that any amount of habitually consumed
caffeinated coffee decreased the risk of death from
cardiovascular disease by 15% to 25%
 Consistent with these findings,the 10-y prospective
Framingham Study of men&women initially 65 to 96 y old
found that the consumption of coffee halved the risk for
heart valve disease & from death from CAD

20. Regular intake of caffeinated coffee does not increase
the risk of hypertention
 The US Food & Drug Administration has concluded that
individuals who habitually consume coffee develop
Tachyphylaxis-a dimnishment of a response after the
repetative consumption of a pharmocologically active
substance.
 Based on published scientific evidence that any acute
pressor effects of caffein consumption cease after 1 to 2
wk of daily consumption,USFDA concluded that “the
available evidence shows that cronic use of caffeine has
no effect on bloob pressure that persists beyond 2 weeks.

21.  The risk of developing GOUT,the most common
inflammatory arthtitis in men, was approx.halved by the
daily consumption of six or more cups of caffeinated coffee.
 Postmenopausal women also showed a 12% decrease in risk
of developing breast cancer.
 Study indicated that the risk for developing Diabetes
decreases as habitual caffeine intake increases in men &
women.
 The safety of caffeine during pregnancy remains
contraversial.

22.  The potential for habitual caffeine consumption to be
associated with the neurologic phenomen of
dependence,tolerence,&withdrawl might suggest the
presence of a relation between caffeine consumption &
psychiatric sequlae.
 A 21 y study of initially middle aged men & women(the
Cardiovascular Risk Factors,Aging & Dementia {CIADE}
study)found that compared with subjects routinely
consuming less than 300mg of caffeine daily,those subjects
routinely consuming 400 to 650mg daily showed a
significantly lower incidence of clinical dementia &
parkinson’s disease.

23. CONCLUSIONSThe foregoing publicly available scientific evidence
substantiates the conclusions that the consumption of
moderate amounts of caffeine
 Increases energy availability
 Increases daily energy expenditure
 Decreases fatigue
 Decreases the sense of effort associated with physical
activity
 Enhances physical performance

24.  Enhances motor performance
 Enhances cognitive performance
 Increases alertness,wakefulness,and feelings of
“energy”
 Decreases mental fatigue
 Quickens reactions
 Increases the accuracy of reactions,
 Increases the ability to concentrate & focus attention
 Enhances short-term memory

25.  Increases the ability to solve problems requiring
reasoning
 Increases the ability to make correct decisions
 Enhances cognitive functioning capabilities &
neuromuscular coordination,and
 In otherwise healthy non-pregnant adults is safe.

26. THANK YOU