Stimulant Beverages

1. Stimulant Beverages There are only a few commonly consumed beverages that have a stimulant effect. They are: coffee, tea, chocolate and certain soft drinks like Coca Cola. What do they have in common that makes them stimulants? Caffeine (and other alkaloids that differ among plants) – all are stimulants to the mammalian CNS. They are collectively called secondary chemicals. This means plants produce them as offshoots/slight modifications to normal metabolism. The most likely function for these chemicals is to act against herbivores.

2. Caffeine is rapidly absorbed from the stomach and small intestine (within 45 minutes of ingestion), and distributed throughout the body by the circulatory system. It has effects on many systems… • In the liver it is metabolized by the same enzyme system that works on organic pollutants, the P450 system. There are three metabolites produced by that metabolism: • Paraxanthine – increases glycerol and fatty acid levels in • circulation • 2. Theophylline – relaxes smooth muscles, particularly in the bronchi. In higher doses than you can get from beverages it can be used as an asthma treatment. • 3. Theobromine – same stuff as in chocolate. Dilates blood vessels and acts as a weak diuretic.

3. Caffeine also crosses the blood-brain barrier, and its structural similarity to adenosine seems to cause a number of other effects.

4. Those effects include: Blocking adenosine receptors, which in turn results in increased activity of dopamine. This is the root cause of the stimulating effect. Increases in serotonin levels that ‘improve’ mood. An increase in epinephrine, the adrenal hormone involved in flight-or-fight responses. It stimulates the sympathetic nervous system, resulting in increased heart rate, blood pressure, and blood flow to the muscles. It blocks cyclic nucleotide phosphodiesterase, resulting in increased levels of cyclic AMP. That prolongs the effects of epinephrine.

5. Caffeine is believed to lower the chances of getting Parkinson’s disease (in men; in women the result is uncertain), and may also lower the probability of becoming type II diabetic. Caffeine is a sufficient stimulant of physical performance (7% increase in work output, 19% increase in exercise endurance) that the IOC has set a urinary output threshold. The IOC limit is 12 g/ml urine; that would be the result of consuming 8 cups of coffee in 2-3 hours. The U.S. NCAA has set its limit at 15 g/ml urine.

6. All that sounds relatively positive. However, there are also negative effects: One can habituate to caffeine, but in occasional consumers (2-3 cups of coffee per day) consumption of >250 mg typically results in headaches, nervousness, irritability, anxiety, and even muscle twitching. There are even names for these ‘diseases’ – caffeinism when the caffeine comes from coffee drinking, theism when the source of caffeine is tea. Habitual users have the opposite problem – withdrawal symptoms. Abstinence for more than a day results in headache, irritability, insomnia, and dysphoria (the opposite of euphoria). Long-term overconsumption (~15 cups of coffee or more per day) can have serious consequences, including heart attack.

7. Other negatives: Caffeine consumption is associated with birth defects and with infertility in women. Caffeine can exacerbate heart problems through causing increased level and persistence of epinephrine and vaso-constriction raising blood pressure. (Note the opposite effects of some caffeine metabolites with respect to smooth muscle and blood pressure!) Caffeine is addictive, with more rapid recovery from withdrawal symptoms than with drug addiction, but many of the same problems during withdrawal.

8. How much caffeine do we get from some of our favorite beverages? BeverageCaffeine per serving (mg) Brewed coffee 135 Excedrin tablet 65 Expresso coffee 100 Chocolate (dark, 1.5oz bar) 31 Red Bull 80 Jolt Cola 150 Mountain Dew 54.5 Coca Cola 34 Tea (leaf or bag) 50

9. Now, what are the plants, the sources and current production of coffee and tea? Coffee Coffee is made by roasting, grinding, and brewing the seeds of Coffea arabica (Rubiaceae) mostly. The drink and use of the seeds can be traced back to the Ethiopian highlands in the 9th century. There are other species of Coffea, but only one, with more caffeine but inferior flavor, is grown commercially – C. robusta. Originally the coffee berries (beans) were eaten raw and whole. Later they were crushed with fat and eaten as a ‘food’.

10. Coffee was spread from Ethiopia into the Middle East by the 13th century. By then coffee beans were roasted much like today. By 1500 coffee was widely cultivated in Yemen, and had been carried to southern Asia (particularly Sri Lanka and Java). It became an important social drink in coffeehouses. The muslim Imams did not approve of coffeehouses, but their popularity prevented forcing closure. The name mocha comes from the Yemeni port from which beans were exported. The name java similarly arises from an early important source of beans. Coffee was imported to Europe by traders in 1615. By 1700 there were coffeehouses spread over Europe. They were, much like in the 1960s, centers of art, culture, political debate and discussion; Lloyd’s of London began from insurance underwriters meeting in a dockside coffeehouse.

11. There were coffee plantations in South America by 1720, and a North American coffeehouse in Boston (using beans imported from Europe) in 1669. Coffee was initially not as popular in North America as in Europe. However, as the British reduced access to and taxed tea (resulting in the Boston ‘tea party’), coffee consumption grew. Today both species of coffee are grown. Cheaper C. robusta beans caused a major global economic dislocation. C. robusta trees (really evergreen bushes) are more tolerant of (and actually ‘like’) bright light conditions, and can be grown in open plantations where machine harvesting is possible. It is more disease-resistant.

12. Less efficient hand harvesting and tree/bush management of shade-grown C. arabica led to small coffee growers abandoning their plantations; world price did not meet cost of production for them. Now you can find “Fair Trade” coffee. Growth also requires year round rain, total precipitation of 1 – 1.5 m, and a temperature not varying much from ~20°C. C. arabica accounts for about 75% of the world’s commercial coffee crop. The leading producers (2007) are: Brazil 17 million metric tons (C. arabica +) Vietnam 15.6 “ (C. robusta) Columbia 9.4 “ (C. arabica) Indonesia 2.8 “ (C. arabica +)

13. r:Coffea canephoram:Coffea canephora and Coffea arabicaa:Coffea arabica Structure of coffee berry and beans: 1: center cut 2:bean (endosperm) 3: silver skin (testa, epidermis), 4: parchment (hull, endocarp) 5: pectin layer 6: pulp (mesocarp) 7: outer skin (pericarp, exocarp) The red berry is the fruit. Each fruit contains two seeds (beans) with their ‘flat’ sides oriented towards each other. It takes about 7 years for a coffee tree to mature and produce fruit. Growth is optimum between 1,300 and 1,500 m altitude, but some coffee is grown from sea level to 2,800 m.

14. Since the flavor of coffee is very dependent on harvest at exact ripeness, most high quality (arabica) coffee is still picked by hand. Coffee production in some places (Sri Lanka, Indonesia, Africa) has been limited by a fungal rust (Hemileia vastatrix). C. robusta is resistant. Sri Lanka was so affected that it shifted from coffee to tea production. Production of arabica beans is limited to areas that have never been infested with the rust. Harvested beans are first de-pulped to extract the beans. In the Americas this is done by the ‘wet method’. Fruits are floated in tanks to remove other debris, then mechanically de-pulped. Pulp remaining is allowed to ferment for a day. Beans are washed and dried, and seed coats are mechanically removed. Beans are then roasted.

15. In the dry method used in Africa, fruits are spread in the open and allowed to dry for days. The pulp ferments, then the pulp is removed mechanically, and the beans can be roasted. Roasting The roasting process produces the flavor and aroma of coffee. The end points of roasting are: light roasts (beans look pale to chocolate brown) at 212-218°C producing a milder coffee with more caffeine – to dark roasts (French black and expresso, beans come out black) at 240 -250°C producing stronger and typically more bitter coffee. Expresso roast

16. Roasting turns starches into sugars in the beans, then, at the final roasting temperature carmelizes the sugars. At just below 240°C sugars are burned to carbon. Thus lighter roasts only carmelize the sugars, while expresso roasts carbonize them. The oils that give coffee aroma are also driven out of cells to the surface of the beans by roasting. Unroasted beans can be stored for extended periods without detriment. Roasted beans only have a shelf life of somewhat more than one month. That’s the reason quality coffee beans are vacuum packed. However, roasted beans cannot be immediately vacuum packed; they emit CO2 for a few days after roasting, and packing has to be delayed.

17. Ground coffee has a shelf life of no more than a few days. Grind it just before brewing if you can. Refrigerate (or even freeze) ground coffee to retain as much of the flavor as possible.

18. Processed coffees Instant coffee was developed in 1901 by Satori Kato, a Japanese chemist working in Chicago. During WW I the U.S. found the light shipping weight and rapid preparation a great advantage, and shipped it to the troops. However, it was not an instant hit. Nescafé finally launched commercial instant coffee in 1938. Production: usually lower quality, cheaper beans are used. After roasting and grinding, coffee is ‘brewed’ by percolation through columns at >300°F. This coffee is concentrated (15 – 30% coffee solids). It is then dried to crystals by either spraying (spray drying, evaporating the water) or freeze drying (wet coffee is frozen, then placed in a vacuum chamber; water ‘evaporates’, leaving coffee crystals).

19. This is one granule of freeze dried coffee. The large pits are what remains of air bubbles, left when the air is removed in vacuum.

20. Decaffeination Caffeine is removed from unroasted, green coffee beans. The first version of the process was developed by German chemists Ludwig Roselius and Karl Wimmer in 1903. Beans were steamed in salt water brine, then caffeine was extracted using benzene as the solvent. Decaffeinated coffee made this way was sold as Sanka brand. Benzene is now recognized as a carcinogen. It is no longer used as the solvent. Now methylene chloride (banned in hairspray as a carcinogen) and ethyl acetate are used. After steaming, beans are soaked in these solvents for 10 hours, then steamed again for 10 hours to remove any residual solvent.

21. An alternative is Swiss water decaffeination. Beans are soaked in hot water until all the coffee flavors and caffeine are released. Beans are discarded, and the water and coffee solids pass through carbon filters that absorb the caffeine. This water is then used to extract caffeine from beans without losing flavor. The soaking in ‘flavor-charged’ water can be repeated until >99% of caffeine has been removed. However [from Dr. Crosby] a comedian/musician named Bob Irwin apparently said drinking decaffeinated coffee is “like kissing your sister/brother”. Make your own decisions about caffeine…

22. Tea Tea is a beverage brewed by steeping processed leaves, twigs, and/or buds of plants. What we usually mean by tea is brewed using leaves of Camellia sinensis [Theasceae]. The various types of tea are determined by how the leaves are processed. After the leaves are picked they begin to wilt and oxidize. The leaves darken because chlorophyll breaks down and tannins are released. The tea industry calls this fermentation, though it is not biological fermentation (no microbes involved). The process is stopped at different stages to produce the varieties of tea.

23. White tea – produced from young buds with oxidation • prevented. Buds are shielded from sunlight to prevent chlorophyll formation. • 2. Green tea – oxidation is stopped very early, either with steam (Japanese method) or dry cooking in pans (Chinese method). • 3. Oolong tea – oxidation is allowed to continue for 2 – 3 days. The process is then stopped and the leaves further processed. • 4. Black (or red) tea – the oxidation process is allowed to continue for 2 weeks to one month. The leaves turn black, but the liquid tea is reddish. • 5. Kukicha (or winter) tea – made from twigs and old leaves pruned during the dormant season and dry roasted over fire.

24. The small tips of oolong tea leaves are what make up ‘Orange Pekoe’ tea. Jasmine tea is made by adding dried Jasmine flowers to the tea. Earl Grey tea has been infused with bergamot oil. Herbal teas generally have no tea leaves. Instead they have various plant parts replacing tea leaves, e.g. rose hip or chamomile. Tea bags are made with the broken leaves of the various varieties of tea.

25. About 3% of the dry weight of tea is caffeine. Tea also contains catechins (antioxidants, up to 30% of dry weight), with a much larger content in white and green teas than in oolong or black tea. It also has both theobromine and theophylline. The cradle of the tea plant is a region that encompasses eastern and southern China, northern Myanmar, and Assam in northeastern India. The variant sinensis grows naturally in eastern and southeastern regions of China. China is the first place where tea drinking was recorded, dating back to 2737 BC, when a tea leaf accidentally fell into water being boiled for drinking. Green tea was drunk in Japan at least as early as 900 AD. Tea reached Europe in the second half of the 16th century.

26. Tea had become popular in the American colonies by the mid-1700s. In the colonies much more tea was consumed than coffee. The British passes the Tea Act in 1773. It was not a new tax on tea, rather it was an act to allow the British East India Company to avoid a colonial tax on tea, and therefore undercut colonial merchants who had to pay the tax. That led to the Boston Tea Party, when the Sons of Liberty, dressed as Native Americans, dumped 342 crates of British East India tea into Boston Harbor. The tide was out, and many of the crates actually stood out above the water. Retaliatory measures the British took led to the American Rebellion.

27. Camellia sinensis is an evergreen plant and grows in tropical to sub-tropical climates. In addition to tropical climates (at least 50 inches [slightly less than 1½ m] of rainfall a year), it also prefers acidic soils. Many high quality tea plants grow at elevations up to 5,000 feet (1524 meters), as the plants grow more slowly and acquire a better flavor. Only the top 1-2 inches (tip leaves) of the mature plant are picked. Tea production China 800,000 tons India 820,000 tons Kenya 328,000 tons Sri Lanka 309,000 tons Turkey 205,500 tons Global total 3.2 million tons

28. Health effects of tea The catechins in green and white tea may have antibiotic effects, resulting from disrupting bacterial DNA replication. Green tea has been reported to reduce growth rate of breast cancer (controversially, the FDA says the evidence is insufficient). The only experimentally documented effect on cancer derives from the presence of a catechin (epigallocatechin gallate) that affects a lung cancer cell binding site and evidence that the same binding protein may be important in prion disease (Creuzfelt-Jacob/mad cow). Green tea may improve insulin sensitivity (of value in treating type II diabetes), and may even help prevent the occurrence of diabetes.

29. Theanine (from tea leaves) seems to boost immune response when fighting a disease – coffee does not have this effect. Immediately after stress the stress hormone cortisol declines back to near normal levels more rapidly in regular drinkers of black tea (no info about other types of tea). These same subjects had lower levels of blood platelet activation, which should reduce the probability of cardiac thrombosis. Drinking 3 cups or more of tea per day is apparently associated with decreased risk of stroke and cardiovascular disease. There are some negatives: remember that tea contains caffeine. Drinking enough tea to gain some of those benefits may also expose you to risks of excess caffeine consumption.

30. Tea leaves contain oxalates. If you drink a lot of tea, the oxalates (in low amounts in general) can bind calcium and can cause kidney stones.

31. Kola drinks The seeds of the Kola tree (Cola nitida) are the basic flavor source. The tree is native to West Africa (Sierra Leone and around the Niger delta), and related to the cacao tree. It is now cultivated in the West Indies, Brazil and Java, as well. The cola nut is the source of caffeine in these beverages.

32. A little history: Coca Cola was invented by John S. Pemberton in Atlanta in 1885. Originally it was a ‘cocawine’, but re-formulated into coca cola at the outset of prohibition. The first recipes used fresh coca leaves, and contained 9 mg of cocaine per glass. Later, the recipe called for “spent leaves” from which the cocaine had already been extracted. Other ingredients: Kola seed extract, caramel, high fructose corn syrup, vanilla, cinnamon, lime juice and orange oil. The U.S. Federal government allows one ‘farm’ in New Jersey to grow Coca plants for production of Coca Cola. There have been a number of legal and political ‘shenanigans’ associated with who owns and controls coke’s formula. Asa Griggs Candler, who founded what is now Coca Cola, apparently forged at least two signatures to take control of the formula – the inventor Pemberton’s and Margaret Dozier.

33. The original recipe is held in the Sun Trust bank vault in Atlanta, and is a closely guarded industrial secret. It’s held there because Sun Trust’s predecessor was the underwriter for Coca Cola’s initial public stock offering. Myth (??) has it that only two executives have access, and each to only half the formula.