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Soft drink consumption shows adverse effects on bone mineral density (BMD). It is believed that the caffeine and phosphoric acid (H3PO4) present in cola may affect bone remodeling processes.
The Framington Osteoporosis Study studied the influence of cola consumption on bone mineral density. BMD was measured in the spine and 3 hip sites in 1413 women and 1125 men. Methods included using a dual-energy X-ray absorptiometry and a questionnaire to assessed dietary intake. Variables analyzed included body mass index, height, age, energy intake, physical activity score, smoking, alcohol use, total calcium intake, total vitamin D intake, caffeine from non-cola sources, season of measurement, and, for women, menopausal status and estrogen use.
Cola intake was associated with significantly lower BMD at each hip site in women but not in men. There was no evidence of decreased BMD in the spine.
The lower BMD was found in participants with a daily cola intake (at least 3 colas per day) compared with subjects who consumed <1 serving cola/month. Use of diet cola and decaffeinated cola also showed an association with BMD, however the relationship was less significant with decaffeinated cola use. There was no significant relationship between non-cola carbonated beverage consumption and BMD.
The study also showed that women who regularly drank colas had an overall lower calcium intake, possibly due to changes in dietary intake. Colas are known to contain phosphorus and the researchers believe that a diet low in calcium and high in phosphorus may promote bone loss by impacting the process of bone remodeling.
In the past thirty years, carbonated beverage consumption has increased significantly. Cola use in the current study represented greater than 70% of carbonated beverages consumed. All the colas contained phosphoric acid (H3PO4) and a majority consumed also contained caffeine. Caffeine has been shown to be associated with bone loss in older women but the relationship between phosphoric acid and bone loss is not well established. However, is believed that diets high in phosphorus and low in calcium can lead to reduced serum calcium levels. The lower calcium levels are hypothesized to increase parathyroid hormone levels which subsequently cause increased bone resorption.
Implications of the study indicate frequent cola use may be associated with a lowered BMD in the hip joints of women.
About the Author:
Jeanne Bohm, Ph.D. is a cancer biologist by training, a medical writer and an experienced science educator.
The author has no financial relationship to any of the companies listed in the article.