Stimulants, caffeine cancer

Geen tea Camellia sinensis Reduces cancer, lowers lipid levels, helps prevent dental caries, antimicrobial and anti oxidative effects Contains caffeine (may cause mild stimulant effects such as anxiety, nervousness, heart irregularities, restlessness, insomnia, and digestive irritation) Contains caffeine and should be avoided during pregnancy, by individuals with hypertension, anxiety, eating disorders, insomnia, diabetes, and ulcers. 

Thea assamica Mast T. bohea L. T. cantoniensis Lour. T. chinensis Sims. T. cochinchinensis Lour. T. sinensis L. T. viridis Link. Cha (Tea) (leaf) Caffeine, theophylline, tannic acid, theobromine, xanthine, polyphenols. 33-47.405,406,409 Diuretic effect, increase renal blood flow, stimulate central nervous system, antitumor, prevent lung cancer. 

Nicotine [NIC o teen] is the active ingredient in tobacco. Although this drug is not currently used therapeutically (except in smoking cessation therapy, see p. 101), nicotine remains important because it is second only to caffeine as the most widely used CNS stimulant and is second to alcohol as the most abused drug. In combination with the tars and carbon monoxide found in cigarette smoke, nicotine represents a serious risk factor for lung and cardiovascular disease, various cancers, as well as other illnesses. 

Caffeine is one of the most studied substances in science. It stimulates the central nervous system it counteracts adenosine in the brain, thereby inhibiting its effect causing a feeling sleepiness. Caffeine also increases the level of adrenaline (a hormone) and dopamine (a neurotransmitter). Caffeine, contrary to some beliefs, does not wake people up, it only inhibits the effects of adenosine, increases the rate of heartbeat, dilates certain blood vessels and narrows some others, and makes it easier for muscles to contract. Caffeine also boosts pattern separation memory in humans. In addition to this general stimulating action, side effects may include irritability, nervousness, headache or insomnia, especially if unreasonably high amounts are consumed. Caffeine has been linked to a number of negative effects as well (heart, liver and kidney disease, cancer, osteoporosis, ulcers. 

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