Caffeine: A positive addition to a healthy lifestyle? Ross Grant PhD Australasian Research Institute

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  • Caffeine: A positive addition to a healthy lifestyle? Ross Grant PhD Australasian Research Institute
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  • Coffee-drinking is used for social engagement, leisure, enhancement of work performance and well-being. Unlike other [functional foods].the wide use of coffee-drinking impacts a broad demographic (from children to elderly), with a wide spectrum of health benefits. Dorea J.G. etal. Br J Nutr (2005), 93:773-782
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  • Tea acts as a stimulant and, to a certain extent, produces intoxication. The action of coffee and many other popular drinks is similar. The first effect is exhilarating. The nerves of the stomach are excited; these convey irritation to the brain, and this in turn is aroused to impart increased action to the heart and short-lived energy to the entire system. Fatigue is forgotten; the strength seems to be increased. The intellect is aroused, the imagination becomes more vivid. Because of these results, many suppose that their tea or coffee is doing them great good. But this is a mistake. Tea and coffee do not nourish the system. The continued use of these nerve irritants is followed by headache, wakefulness, palpitation of the heart, indigestion, trembling, and many other evils; for they wear away the life forces. Tired nerves need rest and quiet instead of stimulation. Ministry of Healing p326
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  • Caffeine Use by Age and Sex Australia & New Zealand SDA 2001
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  • The issue: In recent times the ingestion of tea and coffee has become a topic of debate within the Adventist community.
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  • The issue: Is the introduction of caffeine into the SDA diet a beneficial adjunct to an already well-balanced lifestyle?
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  • Background: origins and sources of caffeine Molecular structure of caffeine identified by German chemist Runge in 1918
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  • Background: origins and sources of caffeine Coffee drinking in the middle east is traceable to the 15 th century Sufi monks drank coffee to stay awake during prayers (Yemen, Arabia) By 1510 coffee was widely used in all levels of Arab society from Cairo to Mecca
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  • Background: origins and sources of caffeine Tea was consumed in China from at least the 6 th century AD Olmecs (ancient American civilization) may have used cacao pods for making chocolate drinks from 400BC Carbonated beverages containing caffeine were introduced by Coco-Cola in 1866 in Atlanta Georgia, USA.
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  • Common dietary sources of caffeine Food/BeverageCaffeine content Instant coffee (1 tsp)60-80 mg/250 mL Percolated coffee60-120 mg/250 mL Instant decaffeinated2 mg/250 mL cup Tea10-50 mg/250 mL Tea decaffeinated1 mg/250 mL cup Coca-Cola36-50 mg/375 mL Milk Chocolate20 mg/100g* bar Energy Drinks (R.Bull) 80 mg/250mL can Table 1: Caffeine content of selected foods (source: ANZFA caffeine report, 2001 and Choice Magazine online (Sept, 2001)). *An average sized Mars bar weighs 80g
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  • Common dietary sources of caffeine Guarana Guarana is a woody climbing plant that is native to the Amazon basin Guarana seeds contain more than 4% caffeine by weight, in comparison with coffee beans which may contain up to 2.2% by weight depending on the variety
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  • Absorption of Caffeine into the body Caffeine is metabolized in the liver by CYP1A2 and is converted into the three products paraxanthine, theobromine and theophylline each of these have physiological effects on the body. Peak caffeine blood levels reached in 30-40 minutes typical half-life of between 4-6 hours Once caffeine is absorbed, it is able to enter all body tissues and easily crosses the blood-brain, placental and blood-testicular barriers
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  • Action of Caffeine on the body PHARMACOLOGICAL REVIEWS Vol. 51, No. 1. 1999
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  • Action of Caffeine on the body Principle action of caffeine is thought to be through blocking adenosine receptors on nerve tissue. Serotonin Caffeine
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  • Function of Adenosine receptors Adenosine levels are raised whenever there is an increase in the amount of energy (ATP) consumption compared to energy (ATP) synthesis. Activation of adenosine receptors in various tissues allow the body to modulate cellular activity in response to decreasing energy (ATP) levels.
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  • Distribution of Adenosine receptors in the body Brain Fat tissue Pancreas MuscleHeart Lung Stomach Liver human-body.jpg Lymphocytes
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  • Action of Caffeine on the body Receptor subtype HEARTCNSKIDNEYOTHER A1 Heart rhythm Decrease heart rate & force of atrial contraction & responsiveness to adrenaline Wakefulness- decrease in electrical excitability and inhibition of excitatory amino acid (EAA) release AntidiuresisAnti-lipolytic insulin enhancer Anti hypertensive Wound healing Hair growth A2A Regulates blood vessel tone- dilation of the coronary arteries supplying blood to heart and muscle Anti-inflammatory increases cerebral blood flow Wound healing Anti aggregation of platelets Increases gastric mucosal blood flow (ethanol)
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  • The widespread prevalence of caffeine- sensitive (adenosine) receptors in the body suggests the likelihood of multi- organ involvement following caffeine consumption. Action of Caffeine on the body
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  • Immediate effects of Caffeine Positive: Caffeine can increase serotonin and dopamine release in the brain; somewhat mimicking the effect caused by antidepressants. (Casas, 2004) Elevated Mood; including increased; Feeling of wellbeing Alertness Energy Sociability
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  • Immediate effects of Caffeine Positive: Studies indicate that: Caffeine decreases reaction times and improves vigilance, sustained attention and selective attention (Smith, 2004). Tasks requiring speed are more sensitive to caffeines benefits than tasks involving intellectual power (Snel, 2004). NOTE: Caffeine seems to have either no effect or a negative effect on memory (Smith, 2004).
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  • Immediate effects of Caffeine Negative: Studies indicate that: Higher doses of caffeine produce: Anxiety Jitteriness Upset stomach (Juliano and Griffiths, 2004)
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  • Immediate effects of Caffeine Negative: Studies indicate that: caffeine can exaggerate the bodys response to stress by increasing heart rate and blood pressure (Lane et al., 2002) It is possible that caffeine alone may induce an adrenocortical stress response during rest and in the absence of explicit stressful challenge (al'Absi and Lovallo, 2004)
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  • Longer-term effects of Caffeine Negative: cardiovascular James (2004) suggests that population studies of BP indicate that caffeine use could account for: 14% of premature deaths due to coronary heart disease, and 20% due to stroke.
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  • Longer-term effects of Caffeine Negative: cardiovascular A prospective study of 1971 middle-aged men, showed that heavy coffee consumption (814 mL or more/day), increased the risk of acute myocardial infarction or coronary death by up to 75% compared to non- coffee drinkers (Happonen et al., 2004). Caffeine has been shown to, dose dependently, increase serum homocysteine levels (Verhof et al., 2002, Panagiotakos et al., 2004) Increased serum cholesterol and urinary excretion of 8-hydroxy-2-deoxguanosine in rats (Sakamoto et al., 2005)
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  • Longer-term effects of Caffeine Negative: osteoporosis Basic science experiments show that caffeine increases calcium excretion in the urine In a prospective study of ~ 35 000 women followed for 6.5 years a weak association of highest caffeine intake (>6 cups daily) was observed with osteoporosis (Hansen et al., 2000).
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  • Longer-term effects of Caffeine Negative: Urinary A high caffeine intake (>400 mg/d) was associated with urinary urge incontinence in a study of almost 260 women (overall risk, 2.4%; 95% CI, 1.1-6.5), Note: This is similar to the likelihood of urinary stress incontinence of a vaginal delivery compared with caesarean delivery (2.4%; 95% CI, 1.7-3.2) (Arya et al., 2000; Rortveit et al., 2003; Holroyd- Leduc and Straus, 2004).
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  • Longer-term effects of Caffeine Negative: Brain Headache Caffeine is considered a modest risk factor in chronic daily headache, (Gadoth and Hering- Hanit, 2005). Caffeine withdrawal headache, (beginning 1 to 2 days following cessation of regular caffeine use), can last up to a week (van Dusseldorp and Katan, 1990). Caffeine may disrupt sleep or aggravate mood, both of which may exacerbate headache (van Dusseldorp and Katan, 1990).
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  • Longer-term effects of Caffeine Negative: Behavioural Dependence Caffeine exhibits physical dependence in up to 30% of consumers (Griffiths and Chausmer, 2000) Some caffeine users may also demonstrate clinical dependence (Strain et al., 1994). Withdrawal symptoms (start 12-24hrlast 2-9 days) Headache, fatigue, depressed mood, irritability, nausea, vomiting muscle pain/stiffness
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  • Longer-term effects of Caffeine Negative: Behavioural Sleep Sleep is one of the physiological functions most sensitive to the effect of caffeine in humans 200mg caffeine