COLD DRINK

Health effects

The consumption of sugar-sweetened soft drinks is associated with obesity,^[17][18] type 2 diabetes, dental cavities, and low nutrient levels.^[18]Experimental studies tend to support a causal role for sugar-sweetened soft drinks in these ailments,^[17][18] though this is challenged by other researchers.^[19][20] "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^[21] when consumed in excess, and the health effects of high-fructose corn syrup and artificial sweeteners remain controversial. Sodium benzoate has been investigated 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. Benzene belongs to this category: the amount of benzene in soft drinks is small enough that it is unlikely to pose a health risk.^[22]

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 soaring consumption of soft drinks, particularly by children, and the consequent health ramifications, including tooth decay, nutritional depletion, obesity, type 2 diabetes, and heart disease. It also reviewed soft drink marketing and made various recommendations aimed at reducing soft drink consumption.^[23]

[edit]Obesity and weight-related diseases

From 1977 to 2001, Americans doubled their consumption of sweetened beverages^[24]—a trend that was paralleled by a doubling of the prevalence of obesity.^[25] The consumption of sugar-sweetened beverages is associated with weight and obesity, and changes in consumption predict changes in weight.^[17][18] 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).^[26] 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.^[27] 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.

Still, it is possible that people who lead unhealthy lifestyles 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,^[17][18] but the effect is often small except for overweight individuals.^[19]

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.^[28] 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.^[29] 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 also 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.^[30] 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.^[31] 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 might 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.^[32] 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^[31][33][34] or water.^[34]

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.^[35]

The consumption of sugar-sweetened soft drinks is also associated with many weight-related diseases, including diabetes,^[27] metabolic syndrome and cardiovascular risk factors,^[36] and elevated blood pressure.^[30]

[edit]Dental decay

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.^[37]

A large number of soft drinks are acidic, and some may have a pH of 3.0 or even lower.^[38] Drinking acidic drinks over a long period of time and continuous sipping can therefore erode the tooth enamel. Drinking through a straw is often advised by dentists as the drink is then swallowed from the back of the mouth and does not come into contact with the teeth as much. 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.^[39][40]

[edit]Hypokalemia

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.^[41]

[edit]Soft drinks and bone density

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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.^[42]

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.^[43] 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.^[43] 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.^[6]

[edit]Nutritional value

Unless fortified, they also contain little to no vitamins, minerals, fiber, protein, or other essential nutrients. Soft drinks may also displace other healthier choices in people's diets, such as water, milk, fruit juice,^[44] and vegetable juice.

[edit]Sugar content

See also: Diet soda

While the USDA recommended dietary allowance (RDA) of added sugars is less than 10 teaspoons per day for a 2,000-caloriediet^{[citation needed]}, many soft drinks contain more than this amount.^{[citation needed]} 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^{[citation needed]}, while in Europe, sucrose dominates, because EUagricultural 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.^[45] 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.^[46] 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 triglyceridesynthesis 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.