Soft drink consumption is higher now than ever before. This is even truer during the hot summer months. Kids are heavy consumers of soft drinks. But just how healthful are these beverages, which provide a lot calories, sugars and caffeine but no significant nutritional value? And what happens if you drink a lot of them at a very young age?
Nearly everyone by now has heard the litany on the presumed health effects of soft drinks: Obesity. Tooth decay. Caffeine dependence. Weakened bones. But does drinking soda pop really cause those things?
One very recent, independent, peer-reviewed study demonstrates a strong link between soda consumption and childhood obesity. One previous industry-supported, unpublished study showed no link. Explanations of the mechanism by which soda may lead to obesity have not yet been proved, though the evidence for them is strong.
Many people have long assumed that soda -- high in calories and sugar, low in nutrients -- can make kids fat. A recent British study found that 12-year-olds who drank soft drinks regularly were more likely to be overweight than those who didn't. For each additional daily serving of sugar-sweetened soft drink consumed during the nearly two-year study, the risk of obesity increased 1.6 times.
Could it be that the soda pop drinkers were simply living extremely sedentary lives? Or that they ate more than the kids who didn't drink soft drinks regularly? Researchers aren't sure and say that drinking soda proved to be "an independent risk factor for obesity.
If soft drinks do prove to contribute to obesity, how might this happen? Is it simply a matter of drinking in too many calories?
A Harvard team conducting a meta-analysis -- a number-crunching examination of similar research conducted over the past 25 years -- concluded that drinking sugary calories doesn't register with the brain the same way that eating calories does. In other words, the brain seems to get confused by these sugary liquid calories that pass quickly through the stomach; they do not seem to trigger feelings of satiety in the same way calories from foods do. Because there is no signal that calories have been consumed via soft drinks or sweetened fruit juices, the stomach does not tell the brain to quit eating at the current meal or to eat less at the next meal. In this way, the thinking goes, excess pounds are added.
The British study found that schoolchildren who drank soft drinks consumed almost 200 more calories per day than their counterparts who didn't down soft drinks. That finding helps support the notion, he says, that "we don't compensate well for calories in liquid form."
The soft drink industry however argues that childhood obesity is the result of many factors. Blaming it on a single factor, including soft drinks, is nutritional nonsense. On this point, the obesity experts tend to agree. It's unlikely that the obesity epidemic can be linked to any single change in the way we live. It is much more complex than that.
Though the soft drink industry admits that soda contributes to tooth decay, most data suggest it is just one of several contributors, and a less important one in developed countries than elsewhere in the world. Neither are soft drinks the sole cause of tooth decay.
In fact, a lot of sugary foods, from fruit juices to candy and even raisins and other dried fruit, have what dentists refer to as "cariogenic properties," which is to say they can cause tooth decay.
An illustrative British study in 1994 of tooth decay among 12-year-olds in 90 countries found that through out the world, dental decay rises proportionally with sugar consumption. But when researchers examined data from 29 industrialised nations, there was no evidence of a link between sugar and tooth decay.
"These results suggest," the researchers reported in the British Dental Journal, "that in addition to sugar, other factors" -- including improved diet, fluoridated water and even genetics -- play an important role in reducing tooth decay.
But sugar isn't the only ingredient in soft drinks that causes tooth problems. The acids in soda pop are also notorious for etching tooth enamel in ways that can lead to cavities. "Acid begins to dissolve tooth enamel in only 20 minutes," notes the Ohio Dental Association in a release issued earlier this month.
The stimulant properties and dependence potential of caffeine in soda are well-documented, as are their effects on children. While health advocates argue that childhood use of caffeine can lead to dependence later in life -- and that regular doses of caffeine can have negative effects on brain development -- there is no conclusive science to demonstrate this.
Ever tried going without your usual cup of java on the weekend? If so, you may have experienced a splitting headache, a slight rise in blood pressure, irritability and maybe even some stomach problems. These well-documented symptoms describe the typical withdrawal process suffered by about half of regular caffeine consumers who go without their usual dose.
The soft drink industry agrees that caffeine causes the same effects in children as adults, but officials also note that there is wide variation in how people respond to caffeine. The simple solution, the industry says, is to choose a soda pop that is caffeine-free. All big soda makers offer products with either low or no caffeine.
Okay, so most enlightened consumers already know that colas contain a fair amount of caffeine. It turns out to be 35 to 38 milligrams per 12-ounce can, or roughly 28 percent of the amount found in an 8-ounce cup of coffee. But few know that diet colas -- usually chosen by those who are trying to dodge calories and/or sugar -- often pack a lot more caffeine.
Confused? You're not alone. There is no way for a parent to know how much caffeine their kids are getting. Caffeine occurs naturally in kola nuts, an ingredient of cola soft drinks. But why is this drug, which is known to create physical dependence, added to other soft drinks?
The industry line is that small amounts are added for taste, not for the drug's power to sustain demand for the products that contain it. Caffeine's bitter taste, they say, enhances other flavours.
The unknown could be especially troublesome for the developing brains of children and adolescents. As a Stanford researcher sees it, logic dictates that "when you are dependent on a drug, you are really upsetting the normal balances of neurochemistry in the brain. The fact that kids have withdrawal signs and symptoms when the caffeine is stopped is a good indication that something has been profoundly disturbed in the brain."
Exactly where that leads is anybody's guess -- which is to say there is little good research on the effects of caffeine on kids' developing brains.
Animal studies demonstrate that phosphorus, a common ingredient in soda, can deplete bones of calcium. And two recent human studies suggest that girls who drink more soda are more prone to broken bones. The industry denies that soda plays a role in bone weakening.
The scientific literature is scant on this topic, and the soft drink industry says the few studies that have been done are flawed. But the studies seem to consistently link soft drink use with the kind of bone weakening that can raise the risk of fractures. Most troubling is that the studies suggest the increased risk of fractures occurs as early as adolescence.
Exactly how soft drinks may contribute to bone weakening is not yet known. But research has found that soft drinks often displace more nutritious beverages, including milk. It's that combination of increased consumption of soda, decreased consumption of milk and other beverages, and the possible link between phosphorus and bone health that researchers believe is enough to justify a "national concern and alarm about the health impact of carbonated beverage consumption on teenage girls."
Besides, to many researchers, the combination of rising obesity and bone weakening has the potential to synergistically undermine future health. "Adolescents and kids don't think long-term," says Jamie Stang, professor of epidemiology at the University of Minnesota. "But what happens when these soft-drinking people become young or middle-aged adults and they have osteoporosis, sedentary living and obesity?"
By that time, switching to water, milk or fruit juice may be too little, too late.
Source: Chet Day's Health and Beyond, Online
(R) thedailystar.net 2005