A soft drink (also called pop, soda, coke,[1] soda pop, fizzy drink, tonic, or carbonated beverage) is a non-alcoholic beverage that typically contains water (often, but not always carbonated water), a sweetener, and a flavoring agent. The sweetener may be sugar, high-fructose corn syrup, or a sugar substitute (in the case of diet drinks).
A soft drink may also contain caffeine, fruit juice, or both.
Examples of beverages not considered to be soft drinks are: pure juice, hot chocolate, tea, coffee, milk, and milkshakes. Beverages like Gatorade and Powerade may meet the definition of a soft drink but are usually called sports drinks.
Soft drinks are called "soft" in contrast to "hard drinks" (alcoholic beverages). Small amounts of alcohol may be present in a soft drink, but the alcohol content must be less than 0.5% of the total volume[2][3] if the drink is to be considered non-alcoholic.[4]
Widely sold soft drink flavors are cola, cherry, lemon-lime, root beer, orange, grape, vanilla, ginger ale, fruit punch, and sparkling lemonade.
Soft drinks may be served chilled or at room temperature. They are rarely heated.
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The first marketed soft drinks (non-carbonated) in the Western world appeared in the 17th century. They were made from water and lemon juice sweetened with honey. In 1676, the Compagnie des Limonadiers of Paris was granted a monopoly for the sale of lemonade soft drinks. Vendors carried tanks of lemonade on their backs and dispensed cups of the soft drink to thirsty Parisians.
In the late 18th century, scientists made important progress in replicating naturally carbonated mineral waters. In 1767, Englishman Joseph Priestley first discovered a method of infusing water with carbon dioxide to make carbonated water which has 3.4 mg in the drink[5] when he suspended a bowl of distilled water above a beer vat at a local brewery in Leeds, England. His invention of carbonated water (also known as soda water) is the major and defining component of most soft drinks.[6]
Priestley found that water treated in this manner had a pleasant taste, and he offered it to friends as a refreshing drink. In 1772, Priestley published a paper entitled Impregnating Water with Fixed Air in which he describes dripping oil of vitriol (or sulfuric acid as it is now called) onto chalk to produce carbon dioxide gas, and encouraging the gas to dissolve into an agitated bowl of water.[7]
Another Englishman, John Mervin Nooth, improved Priestley's design and sold his apparatus for commercial use in pharmacies. Swedish chemist Torbern Bergman invented a generating apparatus that made carbonated water from chalk by the use of sulfuric acid. Bergman's apparatus allowed imitation mineral water to be produced in large amounts. Swedish chemist Jöns Jacob Berzelius started to add flavors (spices, juices, and wine) to carbonated water in the late 18th century.
A variant of soda in the United States called "phosphate soda" appeared in the late 1870s. It became one of the most popular soda fountain drinks from 1900 through the 1930s, with the lemon or orange phosphate being the most basic. The drink consists of 1 US fl oz (30 ml) fruit syrup, 1/2 teaspoon of phosphoric acid, and enough carbonated water and ice to fill a glass. This drink was commonly served in pharmacies.[8]
Artificial mineral waters, usually called "soda water", and the soda fountain made the biggest splash in the United States. Beginning in 1806, Yale chemistry professor Benjamin Silliman sold soda waters in New Haven, Connecticut. He used a Nooth apparatus to produce his waters. Businessmen in Philadelphia and New York City also began selling soda water in the early 19th century. In the 1830s, John Matthews of New York City and John Lippincott of Philadelphia began manufacturing soda fountains. Both men were successful and built large factories for fabricating fountains.
The drinking of either natural or artificial mineral water was considered a healthy practice. The American pharmacists selling mineral waters began to add herbs and chemicals to unflavored mineral water. They used birch bark (see birch beer), dandelion, sarsaparilla, fruit extracts, and other substances. Flavorings were also added to improve the taste. Pharmacies with soda fountains became a popular part of American culture. Many Americans frequented the soda fountain on a daily basis. Due to problems in the U.S. glass industry, bottled drinks were a small portion of the market in the 19th century. (However, they were known in England. In The Tenant of Wildfell Hall, published in 1848, the caddish Huntingdon, recovering from months of debauchery, wakes at noon and gulps a bottle of soda-water.[9]) In America, most soft drinks were dispensed and consumed at a soda fountain, usually in a drugstore or ice cream parlor. In the early 20th century, sales of bottled soda increased exponentially. In the second half of the 20th century, canned soft drinks became an important share of the market.
Over 1,500 U.S. patents were filed for either a cork, cap, or lid for the carbonated drink bottle tops during the early days of the bottling industry. Carbonated drink bottles are under great pressure from the gas. Inventors were trying to find the best way to prevent the carbon dioxide or bubbles from escaping. In 1892, the "Crown Cork Bottle Seal" was patented by William Painter, a Baltimore, Maryland machine shop operator. It was the first very successful method of keeping the bubbles in the bottle.
In 1899, the first patent was issued for a glass-blowing machine for the automatic production of glass bottles. Earlier glass bottles had all been hand-blown. Four years later, the new bottle-blowing machine was in operation. It was first operated by the inventor, Michael Owens, an employee of Libby Glass Company. Within a few years, glass bottle production increased from 1,400 bottles a day to about 58,000 bottles a day.
During the 1920s, "Home-Paks" were invented. "Home-Paks" are the familiar six-pack cartons made from cardboard. Vending machines also began to appear in the 1920s. Since then, soft drink vending machines have become increasingly popular. Both hot and cold drinks are sold in these self-service machines throughout the world.
Soft drinks are made by mixing dry ingredients and/or fresh ingredients (for example, lemons, oranges, etc.) with water. Production of soft drinks can be done at factories or at home.
Soft drinks can be made at home by mixing either a syrup or dry ingredients with carbonated water. Carbonated water is made using a home carbonation system or by dropping dry ice into water. Syrups are commercially sold by companies such as Soda-Club.
Drinks like ginger ale and root beer are often brewed using yeast to cause carbonation.
Of most importance is that the ingredient meets the agreed specification on all major parameters. This is not only the functional parameter (in other words, the level of the major constituent), but the level of impurities, the microbiological status, and physical parameters such as color, particle size, etc.[10]
A report in October 2006 demonstrated that some soft drinks contain measurable amounts of alcohol. In some older preparations, this resulted from natural fermentation used to build the carbonation. In the United States, soft drinks (as well as other beverages such as non-alcoholic beer) are allowed by law to contain up to 0.5% alcohol by volume. Modern drinks introduce carbon dioxide for carbonation, but there is some speculation that alcohol might result from fermentation of sugars in an unsterile environment. A small amount of alcohol is introduced in some soft drinks where alcohol is used in the preparation of the flavoring extracts.[11]
The consumption of sugar-sweetened soft drinks is associated with obesity,[12][13] type 2 diabetes, dental cavities, and low nutrient levels.[13] Experimental studies tend to support a causal role for sugar-sweetened soft drinks in these ailments,[12][13] though this is challenged by other researchers.[14][15] "Sugar-sweetened" includes drinks that use high-fructose corn syrup, as well as those using sucrose.
Many soft drinks contain ingredients that are themselves sources of concern: caffeine is linked to anxiety and sleep disruption when consumed in excess,[16] and some critics question the health effects of added sugars and artificial sweeteners. Sodium benzoate has been investigated by researchers at University of Sheffield[17] as a possible cause of DNA damage and hyperactivity. Other substances have negative health effects, but are present in such small quantities that they are unlikely to pose any substantial health risk.
In 1998, the Center for Science in the Public Interest published a report titled Liquid Candy: How Soft Drinks are Harming Americans' Health. The report examined statistics relating to the increase in soft drink consumption and claimed that consumption is "likely contributing to health problems." It also criticized marketing efforts by soft drink companies.[18]
From 1977 to 2001, Americans doubled their consumption of sweetened beverages[19]—a trend that was paralleled by doubling the prevalence of obesity.[20] The consumption of sugar-sweetened beverages is associated with weight and obesity, and changes in consumption can help predict changes in weight.[12][13] One study followed 548 schoolchildren over 19 months and found that changes in soft drink consumption were associated with changes in body mass index (BMI).[21] Each soft drink that a child added to his or her daily consumption was accompanied by an increase in BMI of 0.24 kg/m2. Similarly, an 8-year study of 50,000 female nurses compared women who went from drinking almost no soft drinks to drinking more than one a day to women who went from drinking more than one soft drink a day to drinking almost no soft drinks.[22] The women who increased their consumption of soft drinks gained 8.0 kg over the course of the study while the women who decreased their consumption gained only 2.8 kg. In each of these studies, the absolute number of soft drinks consumed per day was also positively associated with weight gain.
It remains possible that the correlation is due to a third factor: people who lead unhealthy lifestyles might consume more soft drinks. If so, then the association between soft drink consumption and weight gain could reflect the consequences of an unhealthy lifestyle rather than the consequences of consuming soft drinks. Experimental evidence is needed to definitively establish the causal role of soft drink consumption. Reviews of the experimental evidence suggest that soft drink consumption does cause weight gain,[12][13] but the effect is often small except for overweight individuals.[14]
Many of these experiments examined the influence of sugar-sweetened soft drinks on weight gain in children and adolescents. In one experiment, adolescents replaced sugar-sweetened soft drinks in their diet with artificially sweetened soft drinks that were sent to their homes over 25 weeks.[23] Compared with children in a control group, children who received the artificially sweetened drinks saw a smaller increase in their BMI (by −.14 kg/m2), but this effect was only statistically significant among the heaviest children (who saw a benefit of −.75 kg/m2). In another study, an educational program encouraged schoolchildren to consume fewer soft drinks.[24] During the school year, the prevalence of obesity decreased among children in the program by 0.2%, compared to a 7.5% increase among children in the control group.
Sugar-sweetened drinks have also been speculated to cause weight gain in adults. In one study, overweight individuals consumed a daily supplement of sucrose-sweetened or artificially sweetened drinks or foods for a 10 week period.[25] Most of the supplement was in the form of soft drinks. Individuals in the sucrose group gained 1.6 kg, and individuals in the artificial-sweetener group lost 1.0 kg. A two week study had participants supplement their diet with sugar-sweetened soft drinks, artificially sweetened soft drinks, or neither.[26] Although the participants gained the most weight when consuming the sugar-sweetened drinks, some of the differences were unreliable: the differences between men who consumed sugar-sweetened drinks or no drinks was not statistically significant.
Other research suggests that soft drinks could play a special role in weight gain. One four-week experiment compared a 450 calorie/day supplement of sugar-sweetened soft drinks to a 450 calorie/day supplement of jelly beans.[27] The jelly bean supplement did not lead to weight gain, but the soft drink supplement did. The likely reason for the difference in weight gain is that people who consumed the jelly beans lowered their caloric intake at subsequent meals, while people who consumed soft drinks did not. Thus, the low levels of satiety provided by sugar-sweetened soft drinks may explain their association with obesity. That is, people who consume calories in sugar-sweetened beverages may fail to adequately reduce their intake of calories from other sources. Indeed, people consume more total calories in meals and on days when they are given sugar-sweetened beverages than when they are given artificially sweetened beverages[26][28][29] or water.[29]
A study by Purdue University reported that no-calorie sweeteners were linked to an increase in body weight. The experiment compared rats who were fed saccharin-sweetened yogurt and glucose-sweetened yogurt. The saccharin group eventually consumed more calories, gained more weight and more body fat, and did not compensate later by cutting back.[30]
The consumption of sugar-sweetened soft drinks can also be associated with many weight-related diseases, including diabetes,[22] metabolic syndrome and cardiovascular risk factors,[31] and elevated blood pressure.[25]
In a meta-analysis of 88 studies, drinking soda correlates with a decrease in milk consumption along with the vitamin D, vitamin B6, vitamin B12, calcium, protein and other micronutrients. [32] Phosphorus, a micronutrient, can be found in cola-type beverages, but there may be a risk in consuming too much [33]. Phosphorus and calcium are used in the body to create calcium-phosphate, which is the main component of bone. However, the combination of too much phosphorus with too little calcium in the body can lead to a degeneration of bone mass [34].
Most soft drinks contain high concentration of simple carbohydrates: glucose, fructose, sucrose and other simple sugars. Oral bacteria ferment carbohydrates and produce acid, which dissolves tooth enamel during the dental decay process; thus, sweetened drinks are likely to increase risk of dental caries. The risk is greater if the frequency of consumption is high.[35]
A large number of soft drinks are acidic, and some may have a pH of 3.0 or even lower.[36] Drinking acidic drinks over a long period of time and continuous sipping can therefore erode the tooth enamel. However, under normal conditions, scientific evidence indicates Coca-Cola's acidity causes no immediate harm.[37]
Using a drinking straw is often advised by dentists as the drink does not come into as much contact with the teeth. It has also been suggested that brushing teeth right after drinking soft drinks should be avoided as this can result in additional erosion to the teeth due to the presence of acid.[38][39]
There have been a handful of published reports describing individuals with severe hypokalemia (low potassium levels) related to chronic extreme consumption (4-10 L/day) of colas.[40]
Research suggests a statistically significant inverse relationship between consumption of carbonated beverages and bone mineral density in young girls, which places them at increased risk of suffering fractures in the future.[41]
One hypothesis to explain this relationship is that the phosphoric acid contained in some soft drinks (colas) displaces calcium from the bones, lowering bone density of the skeleton and leading to weakened bones, or osteoporosis.[42] However, calcium metabolism studies by Dr. Robert Heaney suggested that the net effect of carbonated soft drinks, (including colas, which use phosphoric acid as the acidulent) on calcium excretion in urine was negligible. Heaney concluded that carbonated soft drinks, which do not contain the nutrients needed for bone health, may displace other foods which do, and that the real issue is that people who drink a lot of soft drinks also tend to have an overall diet that is low in calcium.[42] In the 1950s and 1960s there were attempts in France and Japan to ban the sale of Coca-Cola as dangerous since phosphates can block calcium absorption. However, these were unsuccessful as the amounts of phosphate were shown to be too small to have a significant effect.[8]
The USDA's recommended daily intake (RDI) of added sugars is less than 10 teaspoons per day for a 2,000-calorie diet. High caloric intake contributes to obesity if not balanced with exercise, with a large amount of exercise being required to offset even small but calorie-rich food and drinks.
Until 1985, most of the calories in soft drinks came from sugar or corn syrup. As of 2010, in the United States high-fructose corn syrup (HFCS) is used nearly exclusively as a sweetener because of its lower cost, while in Europe, sucrose dominates, because EU agricultural policies favor production of sugar beets in Europe proper and sugarcane in the former colonies over the production of corn. HFCS has been criticized as having a number of detrimental effects on human health, such as promoting diabetes, hyperactivity, hypertension, and a host of other problems.[43] Although anecdotal evidence has been presented to support such claims, it is well known that the human body breaks sucrose down into glucose and fructose before it is absorbed by the intestines. Simple sugars such as fructose are converted into the same intermediates as in glucose metabolism.[44] However, metabolism of fructose is extremely rapid and is initiated by fructokinase. Fructokinase activity is not regulated by metabolism or hormones and proceeds rapidly after intake of fructose. While the intermediates of fructose metabolism are similar to those of glucose, the rates of formation are excessive. This fact promotes fatty acid and triglyceride synthesis in the liver, leading to accumulation of fat throughout the body and possibly non-alcoholic fatty liver disease. Increased blood lipid levels also seem to follow fructose ingestion over time.
In 2006, the United Kingdom Food Standards Agency published the results of its survey of benzene levels in soft drinks,[45] which tested 150 products and found that four contained benzene levels above the World Health Organization (WHO) guidelines for drinking water.
The United States Food and Drug Administration released its own test results of several soft drinks containing benzoates and ascorbic or erythorbic acid. Five tested drinks contained benzene levels above the Environmental Protection Agency's recommended standard of 5 ppb. The Environmental Working Group[46] has uncovered additional FDA test results that showed the following results: Of 24 samples of diet soda tested between 1995 and 2001 for the presence of benzene, 19 (79%) had amounts of benzene in excess of the federal tap water standard of 5 ppb. Average benzene levels were 19 ppb, about four times tap water standard. One sample contained 55 ppb of benzene, 11 fold tap water standards. Despite these findings, as of 2006, the FDA stated its belief that "the levels of benzene found in soft drinks and other beverages to date do not pose a safety concern for consumers".[47]
In 2003, the Delhi non-profit Centre for Science and Environment published[48][49] a disputed report finding pesticide levels in Coke and Pepsi soft drinks sold in India at levels 30 times that considered safe by the European Economic Commission.[50][51] The Indian Health Minister said the CSE tests were inaccurate, and said that the government's tests found pesticide levels within India's standards but above EU standards.[52][53]
A similar CSE report in August 2006 prompted many state governments to have issued a ban of the sale of soft drinks in schools. Kerala issued a complete ban on the sale or manufacture of soft drinks altogether. (These were later struck down in court.) In return, the soft drink companies like Coca Cola and Pepsi have issued ads in the media regarding the safety of consumption of the drinks.[54]
The UK-based Central Science Laboratory, commissioned by Coke, found its products met EU standards in 2006.[55] Coke and the University of Michigan commissioned an independent study of its bottling plants by The Energy and Resources Institute (TERI), which reported in 2008 no unsafe chemicals in the water supply used.[56]
In recent years, debate on whether high-calorie soft drink vending machines should be allowed in schools has been on the rise. Opponents of the (soft drink) vending machines believe that soft drinks are a significant contributor to childhood obesity and tooth decay, and that allowing soft drink sales in schools encourages children to believe they are safe to consume in moderate to large quantities.[57] Opponents argue that schools have a responsibility to look after the health of the children in their care, and that allowing children easy access to soft drinks violates that responsibility. Vending machine proponents believe that obesity is a complex issue and soft drinks are not the only cause. They also note the immense amount of funding that soft drink sales bring to schools. Some people take a more moderate stance, saying that soft drink machines should be allowed in schools, but that they should not be the only option available. They propose that when soft drink vending machines are made available on school grounds, the schools should be required to provide children with a choice of alternative drinks (such as fruit juice, flavored water and milk) at a comparable price. Some lawmakers debating the issue in different states have argued that parents--not the government--should be responsible for children's beverage choices.[58]
On May 3, 2006, the Alliance for a Healthier Generation, Cadbury Schweppes, Coca-Cola, PepsiCo, and the American Beverage Association announced new School Beverage Guidelines that will voluntarily remove high-calorie soft drinks from all U.S. schools.
On 19 May 2006, the British Education Secretary, Alan Johnson, announced new minimum nutrition standards for school food. Amongst a wide range of measures, from September 2006, school lunches will be free from carbonated drinks. Schools will also end the sale of junk food (including carbonated drinks) in vending machines and tuck shops.
In the United States and elsewhere, legislators, health experts and consumer advocates are considering levying higher taxes on the sale of soft drinks and other sweetened beverages to help curb the epidemic of obesity among Americans, and its harmful impact on overall health. Some speculate that higher taxes could help reduce soda consumption.[59] Others say that taxes could help fund education to increase consumer awareness of the unhealthy effects of excessive soft drink consumption, and also help cover costs of caring for conditions resulting from overconsumption.[60] The food and beverage industry holds considerable clout in Washington, DC, as it has contributed more than $50 million to legislators since 2000.[61]
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