Guest Columnist: Janet M. Caputo
Soft drink consumption has increased rapidly in the general population in recent years. Since carbonated beverages are now the preferred beverage, calcium intakes in North America fall short of current recommendations. Intake of carbonated beverages was associated with reduced bone mass and increased fracture risk both later in life and in children and adolescents. Colas were more strongly associated than other carbonated beverages.
Colas in particular may be associated with lower bone density for several reasons. First, individuals who prefer to drink colas substitute these beverages for more nutrient-rich sources such as milk and juices. Also, the caffeine in colas has been identified as a possible risk factor for osteoporosis. Moreover, colas contain phosphoric acid which has been shown to interfere with calcium absorption and contribute to other imbalances that lead to additional losses of calcium. Furthermore, the high fructose corn syrup used to sweeten carbonated beverages may negatively affect bone.
Consuming colas and other soft drinks from an early age can increase the risk of osteoporosis. Athletes and adolescent girls who consumed carbonated beverages had a greater risk for fractures because they were more likely to substitute soft drinks for milk and juices. The amount of bone mass obtained during youth determines skeletal health as an adult. Developing strong bones during adolescence protects against osteoporosis later in life. Normal bone growth requires proper nutrition including adequate intake of calcium, vitamin D, and protein as well as fruits and vegetables. Calcium is important because it is the main component of bone. Vitamin D and protein help the body absorb calcium. Fruits and vegetables limit the body’s excretion of calcium and provide other nutrients that contribute to greater bone density.
Colas that contain caffeine may contribute to osteoporosis. Bone loss was accelerated in elderly postmenopausal women who consumed more than 300 mg of caffeine daily (approximately 18 oz of brewed coffee). Caffeine interferes with the body’s ability to form bone cells, depresses the intestinal absorption of calcium and increases the urinary excretion of calcium. The deleterious effects of caffeine are more pronounced when the dietary intake of calcium is inadequate (less than 1000 mg per day) and less harmful when dietary intake of calcium is higher.
Although phosphorus is an essential nutrient, excessive amounts may be detrimental to bone. Increasing dietary intake of phosphorus stimulates the secretion of parathyroid hormone. Excessive parathyroid hormone increases the concentration of calcium in the blood by leeching it from the bones. Diets high in phosphorus and low in calcium are attributed to osteoporosis. Phosphorus intakes have risen 10% to 15% over the past twenty years because of the use of phosphate salts in food additives and cola beverages. Daily intakes of phosphorus in adults range between 1000 mg and 1500 mg, levels well above current recommendations of 700 mg/day.
Diets high in fructose and low in magnesium reduce calcium retention and produce greater losses of phosphorus. These dietary changes are of concern because the intake of magnesium has decreased appreciably over the last century while fructose consumption has been increasing rapidly since the introduction of high fructose corn syrup in 1970. This trend seems to be the most dramatic in children in the U.S. who are consuming large amounts of soft drinks containing high fructose corn syrup at the expense of foods containing adequate amounts of magnesium (whole grains, vegetables, nuts, and seeds) and calcium (milk and other dairy products). Magnesium deficiency decreases bone strength and volume, results in poor bone development, reduces bone formation, and increases bone loss.
Prevention of osteoporosis begins during childhood. Children need diets that focus on calcium, vitamins C, D & K, and protein. Adults may require supplements for these nutrients. Regular exercise using resistance training and weight bearing activities will maximize bone development and health. Consuming alcohol and soft drinks in small amounts is recommended. Avoid smoking and a lower than average body weight (Body Mass Index of < 18.5).
If you missed it, read Part I of this two-part series on osteoporosis, which defines osteoporosis and its causes.
Guest Columnist: Janet Caputo, PT, OCS, is associate at Mackarey & Mackarey Physical Therapy Consultants, LLC in downtown Scranton where she specializes in the practice of orthopedic and neurological physical therapy. She is currently a doctor of physical therapy student at the University of Scranton.