It may come as no surprise that most children and teens will choose soft drinks over milk when given a choice. This is unfortunate, since milk and other calcium -rich foods are especially important during the bone-building years of childhood and adolescence. Lower bone mineral density in adolescence has been associated with an increased risk of osteoporosis later in life, especially in girls. This has led many public school educators to follow the advice of school nutritionists and replace soft drinks in school vending machines with milk, water, and 100% fruit juices. Will this really help young girls build stronger bones?
There have been many research studies on dietary intake and its relation to the bone health of young girls, the results of which have been mixed. But overall, it seems reasonable to conclude that school-age girls who drink a lot of carbonated soft drinks are increasing their risk of osteoporosis.
Evidence for the Health Claim
Osteoporosis is a disease that gradually weakens bones until they break easily. Since your bones reach their peak mass and strength during your 20s, the more bone mineral density (BMD) you build when you are young, the less likely you are to develop osteoporosis later in life.
Exercise and diet are two important factors that influence children’s bone health. Performing weight-bearing activities and eating a diet that contains plenty of calcium-rich foods have been shown to build stronger bones. What’s more, some studies have suggested that certain soft drinks may directly interfere with healthy bone growth.
A study in the Journal of Bone and Mineral Research found that the more carbonated soft drinks girls (aged 12-15) drank, the lower their BMD. There was no consistent relationship, however, between BMD and soft drink consumption in boys.
Two other studies found that consuming soft drinks was associated with an increased risk of bone fractures in school-age girls. In the first study, published in the Journal of Adolescent Health , researchers found that 14-year-old girls who drank the most cola were 3.6 times more likely to have bone fractures than those who drank the least. The second study, published in the Archives of Pediatric and Adolescent Medicine , revealed that the girls who drank carbonated beverages were 3.1 times more likely to have bone fractures than those who did not .
Experts are not sure how drinking soft drinks could adversely affect bone health, but they have proposed a couple of possible explanations. First, laboratory studies have reported that high levels of phosphorus intake could lead to the breakdown of bones; soft drinks contain phosphoric acid. Second, children may drink soft drinks instead of milk and other calcium-fortified beverages. One study in the Journal of the American College of Nutrition found that children aged 1-5 years who drank soft drinks and sugary beverages tended to drink less milk.
Evidence Against the Health Claim
While most studies support the notion that soft drink consumption has a negative impact on calcium intake, others have suggested the opposite.
Researchers found that increased soft drink consumption was positively associated with calcium intake. Similarly, a study in the Journal of the American College of Nutrition found that children who drank more soft drinks and other non-dairy beverages had higher calcium intakes. As an explanation for their findings, the authors of this study suggested that milk and soft drinks don’t necessarily replace each other. In other words, children who pour themselves a glass of soda to eat with their pizza, may be just as likely to down a glass of milk with a cookie.
While the research is a bit conflicted, there is sufficient evidence to conclude that young girls who regularly consume soft drinks are placing themselves at increased risk for future osteoporosis. To help build strong bones, children and teens should participate in weight-bearing activity (eg, running, jumping rope, gymnastics, tennis, basketball) and eat a diet rich in calcium. How much calcium is enough? The National Academy of Sciences recommends that children ages 2-3 get 500 milligrams (mg) of calcium daily, children ages 4-8 get 800 mg daily, and children and teens ages 9-18 get 1,300 mg daily from calcium-rich foods, such as milk, yogurt, and cheese.
While the occasional glass of soda pop isn’t going to harm an otherwise healthy teenager, it is a good idea to limit soda’s availability. In addition to an increased risk of osteoporosis, excessive consumption of sugary soft drinks has been linked to obesity, type 2 diabetes, and tooth decay.