Previous studies have shown an association between consumption of cola beverages containing phosphoric acid and bone fractures in adult women (Wyshak et al Orthop Res 1989;7;91-9). We hypothesized that ingestion of a cola beverage (Diet Coca-Cola™) but not of a non-phosphoric acid-containing one (Diet 7-UP™) would result in an acute decrease in capillary blood ionized calcium (CBiCa) concentration. Subjects consisted of 15 healthy Caucasian students(14 females & 1 male, mean age 19.7±1.4) years. In each subject CBiCa concentrations were measured using a Radiometer iCa 1 lonized Calcium Analyzer before, and 30 mins. after ingestion of 500 ml(≈1½ can) of Diet Coca-Cola™, and on the following day after ingestion of Diet 7-UP™.

As shown, there was a significant (p<0.001, paired t test) decrease in CBiCa concentration 30 mins. after ingestion of Diet Coca-Colaâ„¢ but not after Diet 7-UPâ„¢. Similar falls in CBiCa were observed after ingestion of sugar containing & caffeine free cola beverages (data not shown). Figure

figure 1

Figure 1

As chronic consumption of cola beverages also lowers blood calcium levels(Mazariegos-Ramos, J Pediatr;1995;126:940-2) this might in tum lead to secondary hyperparathyrodism and skeletal demineralization. We speculate that such ingestion during childhood & adolescence could lead to inadequate achievement of peak bone mass with increased risk of osteoporotic fractures in adulthood.