How children s and adolescents soft drink consumption is affecting their health: A look at building peak bone mass and preventing osteoporosis

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1 Journal of the HEIA Vol 13, No. 1, 2006 Student article How children s and adolescents soft drink consumption is affecting their health: A look at building peak bone mass and preventing osteoporosis Stephanie Wheler This paper was selected as one of the winners of the 2005 Dr. Elizabeth Feniak Award for Excellence in Technical Writing (undergraduate category) presented by the Canadian Home Economics Foundation. Contact details: Stephanie Wheler Second Year Nutrition College of Pharmacy and Nutrition University of Saskatchewan Saskatoon SK S7N 5C9 smw683@mail.usask.ca Abstract Building peak bone mass during adolescence is important to reduce the risk of osteoporosis later in life. Calcium is important for building bone; however, milk consumption is declining while soft drink consumption is increasing among children and adolescents. There is disagreement regarding whether soft drink is leading to replacement of milk, reduced calcium intake, reduced bone mass and an increased risk of osteoporosis. Some research supports the idea that it is a lack of milk consumption that is leading to osteoporosis, and decreasing soft drink consumption may not necessarily lead to increased milk consumption. Research acknowledges that soft drink consumption increases with age in children and adolescents. There is agreement regarding a need to increase calcium intake among children and adolescents since they are not meeting the daily requirements. Increasing knowledge leads to higher intakes of milk and so this is an important step where parents and health professionals can play a role. Introduction Over the past few decades, soft drink consumption among children and adolescents has increased while milk consumption has decreased. Milk is a very nutrient-dense beverage, whereas carbonated or uncarbonated soft drink beverages only provide sugar and energy. A lack of milk products in the diet, or consumption below the recommended intake may lead to possible health problems in the future. Milk is an excellent source of calcium, which is required to build strong bones; there are also many non-milk sources of calcium available. Calcium is especially important during adolescence, which is the period when peak bone mass is achieved. Building optimal bone mass is important in order to reduce 34 the risk of osteoporosis later in life. Of key concern is the increased intake of soft drinks and declining intake of milk; however, many studies offer differing opinions regarding soft drinks effects on the health of both children and adolescents. There are varying attitudes concerning whether soft drink consumption is leading to replacement of milk, reduced calcium intake, reduced bone mass, and an increased risk of osteoporosis. Building peak bone mass and preventing osteoporosis One way to treat and possibly prevent osteoporosis is to build up bone mass during adolescence. Research shows that the attainment of peak bone mass during adolescence is important in the primary prevention of osteoporosis (Bachrach, 2001; Cromer & Harel, 2000; Harnack, Stang, & Story, 1999). Most research does agree that adolescence is a critical period since 40% of total bone mass is achieved during puberty (Cromer & Harel, 2000; Harel, Riggs, Vaz, White, & Menzies, 1998; Lloyd, Rollings, Kieselhorst, Eggli, & Mauger, 1998). Women will lose 30 50% of their initial bone mass throughout their lifetime, while men will only lose 20 30% (Cromer & Harel, 2000). Harnack et al. (1999) state that differences in calcium intakes of children result in 5% to 10% differences in subsequent peak bone mass. This small difference may increase risk of hip fracture by 50%. However, research does not agree on the factors that can affect bone mass accrual. Bachrach (2001) points out that 60 80% of peak bone mass variance is due to genetics, with activity level and hormonal status also playing a role. Harel et al. (1998) also point out the roles of ethnicity, body weight, and lifestyle activities such as smoking, in addition to those mentioned by Bachrach. Cromer and Harel (2000) point out that increasing calcium intake and moderate

2 Student article: How children s and adolescents soft drink consumption is affecting their health Found parental soft drink intake to be a stronger infl uencing factor than peer intake weight bearing exercise is a possible approach to optimizing peak bone mass. Obesity and activity levels There is disagreement when it comes to looking at the relationships between body weight, soft drink consumption, and risk of osteoporosis. Some researchers will not place the blame on soft drink consumption, but rather on a lack of physical activity among today s youth. Harel et al. (1998) controversially point out that being overweight actually increases bone mineral density and therefore reduces the risk of osteoporosis. Their findings support the idea that soft drink consumption is contributing to the increasing epidemic of obesity among children rather than to an increased risk of osteoporosis (Harel et al., 1998). Harnack et al. (1999) also support this concern regarding obesity. Grimm, Harnack and Story (2004) found soft drink consumption to be positively associated with energy intake, and thus they too support the idea that soft drink consumption is contributing to obesity. On the other hand, Forshee and Storey (2003) found no differences in the amount of soft drink consumed by heavier individuals as compared to lighter individuals. Harnack et al. (1999) however, found that energy intake was higher for individuals consuming the highest amount of soft drinks versus those who consumed the lowest amount of soft drinks. Johnson (2000) found that children s and adolescents increased energy intakes are due to high carbohydrate intakes, primarily due to increased soft drink consumption. There is also evidence that it is the overall health and lack of physical activity that is putting children and adolescents at a risk of osteoporosis in the future. The lifestyles of children and adolescents may contribute to poor bone health since calcium intake has decreased while television watching and computer use have increased and levels of physical activity have declined (Bachrach, 2001). Grimm et al. (2004) feel that it is soft drink advertisements rather than just time spent in front of a television that is leading to high soft drink intakes. Forshee and Storey (2003) concluded that the extra calories young children are consuming from soft drink can easily be balanced with a moderate level of physical activity, yet they also note that middle school children consuming soft drink are at increased risks of becoming overweight. Thus, it could be the lack of physical activity that prevents children and adolescents from burning off the calories that are consumed from soft drinks. Soft drink consumption versus milk consumption Many studies have identified the trend of increased soft drink consumption and declining milk consumption. These same studies have also raised concern regarding children s and adolescents calcium intakes that are below the daily recommendations (Bowman, 2002; Harel et al., 1998; Harnack et al., 1999; Johnson, 2000; Storey, Forshee, & Anderson, 2004). Most research also identified the association of increased soft drink consumption with increasing age (Rampersaud, Bailey, & Kauwell, 2003; Forshee & Storey, 2003; Harnack et al., 1999; Grimm et al., 2004). Research differs in its interpretation of the role that parents play in children s and adolescents beverage choices. Grimm et al. (2004) found parental soft drink intake to be a stronger influencing factor than peer intake. Forshee and Storey (2003) along with Bowman (2002) also support the notion that parents are important role models when it comes to beverage choices. Harnack et al. (1999) also identified the significant role of parents, but suggest that parents should limit the amount of soft drinks brought into the home while also setting healthy examples for their children. There is much disagreement regarding whether soft drink consumption is actually replacing milk consumption. Harnack et al. (1999) found that school children consuming more than 9 oz of soft drink per day were about three times more likely to consume less than 8 oz of milk per day. While this might suggest that soft drinks are replacing milk, Harnack et al. (1999) state that it might just be the fact that those children who enjoy soft drinks also dislike milk and therefore would consume less regardless of their soft drink consumption. Rampersaud et al. (2003) could not conclude whether soft drink consumption displaces 100% fruit juice and milk in the diet. Nevertheless, Bowman s (2002) research found that, among milk drinkers, those who did not drink soft drinks drank more milk than those who did. Further, those children who drank soft drinks and milk drank less soft drinks than those who did not drink milk. 35

3 Journal of the HEIA Vol. 13, No. 1, 2006 Not only have children s and adolescents intakes of milk and soft drinks changed, but so has the availability of these beverages. Grimm et al. (2004) acknowledge that milk availability has decreased since the 1950s while soft drink availability doubled from Bowman (2002) identified the problem by the fact that those who drank milk in the 1990s have decreased their intake. According to Johnson s (2000) analysis of the research, Americans drank more than four times as much milk as soft drink in 1945, and in 1997 they drank almost two and a half times more soft drink than milk. Thus it is not just a general low intake, but a decreased intake of milk. In dealing with the issue of high soft drink intakes, the research differs on how intervention should be approached. Harnack et al. (1999) feel that there is no need to recommend eliminating soft drinks, but that moderation needs to be stressed. Grimm et al. (2004) suggest that the availability of soft drinks in schools should be limited along with the introduction of public service announcements to promote healthy eating behaviours. Conversely, Forshee and Storey (2003) feel that attempts to restrict soft drink consumption are impermanent solutions that will not cause children and adolescents to reject soft drinks. Storey et al. (2004) state that milk and soft drink are not close substitutes and thus eliminating soft drinks from the diets of adolescents does not necessarily mean that milk consumption will increase. Calcium intake Although children s and adolescents milk consumption has decreased, they could obtain calcium from fortified foods, various dairy products, or possibly even supplements. Bowman (2002) points out that calcium can be obtained from a variety of sources besides dairy products and that consuming a variety of foods will increase the intakes of other essential nutrients. Bachrach (2001) states that 90% of adolescent females and 50% of adolescent males consume less than optimal levels of calcium. According to Whiting, Vatanparast, Baxter-Jones, Faulkner, Mirwald, and Bailey (2004), girls were found to consume less than 900 mg of calcium per day on average, whereas boys consumed in excess of 1000 mg which may affect vulnerability to dietary influences on bone accrual. 36 There is disagreement regarding what other nutrients are at risk of inadequacy along with low intakes of milk and therefore calcium. The only nutrient that is agreed upon is vitamin A (Bowman, 2002; Harnack et al., 1999; Johnson, 2000; Rampersaud et al., 2003). Harnack et al. (1999), Johnson (2000), and Rampersaud et al. (2003) are also concerned about riboflavin, and vitamin C. In addition, folate (Bowman, 2002; Harnack et al., 1999; Johnson, 2000), phosphorus (Bowman, 2002; Johnson, 2000), and magnesium (Bowman, 2002; Harnack et al., 1999) are listed as nutrients at risk of inadequacy. Harnack et al. (1999) also mention the importance of the calcium to phosphorous ratio, while Storey et al. (2004) point out the importance of vitamin D in building strong bones. The recent DRIs (Dietary Reference Intakes) for calcium indicate an increase in the recommended value for children and adolescents from previous values. The problem, as identified by Johnson (2000) is that, while the recommendations have increased, children and adolescents are not even meeting the old recommendations. Storey et al. (2004) found calcium intake increases with age among boys; calcium intake increased among girls up to age 13 and then decreased among year olds. According to Storey et al. (2004) children aged 2 3 years and 4 8 years were, on average, consuming calcium in excess of the recommendation, whereas boys and girls aged 9 13 years consumed 79% and 65% respectively of the recommended Adequate Intake (AI). Storey et al. (2004) found milk to have a positive relationship with calcium intake and found soft drink to have no relationship or a weakly positive one with calcium intake. Therefore, Storey et al. (2004) support the idea of encouraging calcium consumption, but do not feel it is necessary to attempt to reduce soft drink intake since they did not find soft drink consumption to be related to reduced calcium intake. They do not feel that soft drink consumption replaces milk consumption and therefore calcium intake since there are other sources of calcium available in the diet. Diet (High sugar) Rampersaud et al. (2003) found evidence suggesting that high intakes of added sugars (such as those in sugar sweetened beverages) are associated with reduced diet quality and Eliminating soft drinks from the diets of adolescents does not necessarily mean that milk consumption will increase

4 Student article: How children s and adolescents soft drink consumption is affecting their health Adolescents are unfamiliar with the calcium content of various dietary sources nutrient inadequacy. According to the USDA: 47.1% of boys and 44.8% of girls aged 6 11 years consume some form of carbonated soft drinks 69.2% and 62.2% of boys and girls, respectively, aged years consume some carbonated soft drinks (Forshee & Storey, 2003). Forshee and Storey (2003) state that soft drinks account for 8% of the total energy intake of adolescents. Harnack et al. (1999) established that 12% of preschool-aged children and more than one third of schoolaged children consumed more than 9 oz of soft drinks per day, while almost a quarter of adolescents drank more than 26 oz of soft drinks per day. Rampersaud et al. (2003) state that soft drinks provide little or no nutritional value beyond calories and represent the largest contributor of added sugars in the diets of adolescents. In comparison, Whiting et al. (2004) point out the importance of fruit and vegetable intake on bone mineral accrual of adolescent girls. Therefore, Whiting et al. (2004) are not stating that it is the high sugar intake, but perhaps a lack of other nutritious foods in the diet that is leading to osteoporosis. Knowledge Cromer and Harel (2000) and Harel et al. (1998) found evidence supporting the idea that adolescents with knowledge regarding calcium requirements, its role in the prevention of osteoporosis, and its importance in building peak bone mass were more likely to consume calcium. Harel et al. (1998) reached the conclusion that adolescents may be aware of the main health benefits of calcium, but are unfamiliar with the calcium content of various dietary sources. There is controversy surrounding where the knowledge should be coming from. Rampersaud et al. (2003) state that it is the responsibility of health professionals to encourage nutrient-dense beverage consumption. Harel et al. (1998) found health classes and parents to be the primary sources of information, while health care providers were not considered to be a good source. Harnack et al. (1999) place the responsibility on the shoulders of dietitians, parents, and other health professionals to work towards limiting access to soft drinks in day-care environments and schools. Thus, Harnack et al. (1999) feel that these individuals need to provide knowledge, but also limit access to soft drinks. Harnack et al. (1999) also support the idea of increasing children s knowledge through nutrition education messages that encourage limiting soft drink consumption. Rampersaud et al. (2003) point out the lack of knowledge and guidelines, since there are no recommendations regarding intake of beverages such as soft drinks. Gender differences Most studies support the finding that males consume more soft drinks than females (Forshee & Storey 2003; Grimm et al., 2004). However, Harnack et al. (1999) found gender differences to only affect soft drink consumption in adolescence. Although males on average consume more soft drinks compared to females, females are at a higher risk for osteoporosis. Therefore, this does not necessarily have to do with high soft drink intake, but rather low milk intake. Males also tend to consume more calories and thus are likely receiving calcium from other sources as well. Grimm et al. (2004) found that boys have a stronger taste preference for soft drinks compared to girls, and this leads to higher intakes of soft drinks. Bowman (2002) found that diet soft drink consumption increased among high school-aged girls, possibly due to increased awareness of body image. Whiting et al. (2004) state that replacing milk intake with soft drinks is detrimental to bone gain by girls, but not by boys. According to Whiting et al. (2004), males have 22% more bone mineral content than females, which may be biological, or the result of higher calcium intakes and higher activity levels among males. Whiting et al. (2004) support the idea that adolescent girls bone mineral accrual is negatively impacted by the consumption of soft drinks, whereas boys is not. This differs from the other studies, which recognized a difference in the intakes of soft drinks among males and females, but not the differing effects on health. Whiting et al. (2004) also found that boys may be more efficient in their handling of calcium. Whiting et al. (2004) identified 14.0 ± 1.0 years in boys and 12.5 ± 0.9 years in girls to be the ages for building peak bone mass. During this period, boys gained an average of 407 ± 92 g of bone mineral, while girls only gained 322 ± 66 g. Since it can not be known when an adolescent will develop peak bone mass, it is important that recommendations span the ages that are important (Whiting et al., 2004). 37

5 Journal of the HEIA Vol. 13, No. 1, 2006 Conclusion The problem is that children are not receiving adequate calcium intakes to support optimal peak bone mass. There is much discrepancy among the research to determine whether soft drink consumption is a leading cause of this low calcium intake, or whether it is just low milk intakes. Even without agreement about the causes and effects of the situation, most researchers agree that work must be done to increase calcium intakes during the critical periods of childhood and especially adolescence. Whether or not it is thought that soft drinks are replacing milk, it is widely acknowledged that milk consumption has decreased and soft drink consumption has increased. The growing epidemic of obesity and the risk of osteoporosis provide valid concerns for intervention early on in life. Providing knowledge to children and adolescents has been shown to increase milk consumption. Children and adolescents need to be informed that there are other sources of calcium in the diet and need to be encouraged to be physically active for the benefit of their health. Practical advice The declining intake of milk and rising intake of soft drinks are very important issues. Changes can be made early in life to prevent the development of osteoporosis later. Nutrition educators need to take the responsibility to encourage children and adolescents to consume milk, or at least provide them with information regarding its importance and other foods that contain calcium to help them reach their peak bone mass. They should also involve the parents, since parents are strong role models. Parents need to limit their children s access to soft drink. Children and adolescents spend a large part of their time at school and so it is important to encourage schools to remove vending machines that contain non-nutritious foods and beverages. It is also essential for children and adolescents to have physical activity in their lives, and this can also be accomplished through school programs. It is important to build these healthy eating and activity patterns in childhood so that they become habits for life. References Bachrach, L. K. (2001). Acquisition of optimal bone mass in childhood and adolescence. TRENDS in Endocrinology & Metabolism, 12 (1), Bowman, S. A. (2002). Beverage choices of young females: Changes and impact on nutrient intakes. Journal of the American Dietetic Association, 102, Cromer, B., & Harel, Z. (2000). Adolescents: At increased risk for osteoporosis? Clinical Pediatrics, 39, Forshee, R. A., & Storey, M. L. (2003). Total beverage consumption and beverage choices among children and adolescents. International Journal of Food Sciences and Nutrition, 54 (4), Grimm, G. C., Harnack, L., & Story, M. (2004). Factors associated with soft drink consumption in school-aged children. Journal of the American Dietetic Association, 104, Harel, Z., Riggs, S., Vaz, R., White, L., & Menzies, G. (1998). Adolescents and calcium: What they do and do not know and how much they consume. Journal of Adolescent Health, 22, Harnack, L., Stang, J., & Story, M. (1999). Soft drink consumption among US children and adolescents: Nutritional consequences. Journal of the American Dietetic Association, 99, Johnson, R. K. (2000). Changing eating and physical activity patterns of US children. Proceedings of the Nutrition Society, 59 (2), Lloyd, T., Rollings, N. J., Kieselhorst, K., Eggli, D. F., & Mauger, E. (1998). Dietary caffeine intake is not correlated with adolescent bone gain. Journal of the American College of Nutrition, 17 (5), Rampersaud, G. C., Bailey, L. B., & Kauwell, G. P. (2003). National survey beverage consumption data for children and adolescents indicate the need to encourage a shift toward more nutritive beverages. Journal of the American Dietetic Association, 103, Storey, M. L., Forshee, R. A., & Anderson, P. A. (2004). Associations of adequate intake of calcium with diet, beverage consumption, and demographic characteristics among children and adolescents. Journal of the American College of Nutrition, 23 (1), Whiting, S. J., Vatanparast, H., Baxter-Jones, A., Faulkner, R. A., Mirwald, R., & Bailey, D. A. (2004). Factors that affect bone mineral accrual in the adolescent growth spurt. Journal of Nutrition, 134, Boys have a stronger taste preference for soft drinks compared to girls 38