How does cola affect bones

We also examined associations with BMD by cola subtype, ie, sweetened, diet, caffeinated, and decaffeinated colas. Data from participants in the Framingham Osteoporosis Study, which drew from the Framingham Offspring Cohort, was used for the present study. The original population-based Framingham Heart Study began in to examine risk factors for heart disease and included a two-thirds systematic sample of the households in Framingham, MA The Offspring Cohort, established in , consists of the adult offspring and their spouses of the original cohort members.

At the first examination to , participants were enrolled. Offspring participants return every 4 y for an extensive physical examination, comprehensive questionnaires, anthropometric measurements, blood chemistries, and assessment of cardiovascular disease and other risk factors, which are all conducted by trained clinical personnel. At the 6th examination cycle to , there were participants men and women aged 30—87 y. BMD measurements were conducted from to during the end of the 6th and beginning of the 7th examination cycles.

A total of men and women completed food-frequency questionnaires during the 6th examination cycle and also had BMD measurements taken.

Of these, 84 participants were excluded because they were using bisphosphonates, selective estrogen receptor modulators, or calcitonin, which left men and women for the final analysis. Written, informed consent was obtained from all participants. The precision CV was 1. Usual dietary intakes of foods and nutrients were assessed with a semiquantitative item food-frequency questionnaire 16 , The questionnaires were mailed to the participants before each examination, and the participants were asked to complete them and bring them to the exam.

A serving was defined on the questionnaire as one glass, bottle, or can. For consistency, these responses were converted to number of servings per week. Among these items were the following: sugared caffeinated cola beverages, sugared decaffeinated cola beverages, diet caffeinated cola beverages, diet decaffeinated cola beverages, other sugared carbonated soft drinks, and other diet soft drinks.

For this analysis, we grouped drinks to obtain variables for total noncola and cola soft drinks. Colas were further divided into subgroups of sugared cola, decaffeinated cola, and diet cola. This food-frequency questionnaire has been validated for many foods and nutrients and against multiple diet records or blood measures in several populations 16 — Variables that could potentially confound the relation between carbonated beverage consumption and BMD were obtained from information collected at the 6th examination.

These included the following: age; body mass index BMI ; height; smoking; average daily intakes of alcohol, calcium, caffeine; total energy intake; physical activity; season of measurement; and, in women, estrogen use and menopause status. Height was measured to the nearest 0.

Weight was measured in pounds with the use of a standard balance-beam scale. Usual dietary intakes of calcium, vitamin D, caffeine, and total energy were assessed with the food-frequency questionnaire described above. The questionnaire included use of vitamin and mineral supplements, which allowed for the calculation of total nutrient intakes. The participants also quantified their usual intake of liquor, wine, and beer in the food-frequency questionnaire.

From this information, the total grams of alcohol consumed per week were estimated. Smoking status was defined as current smoker, past smoker, or nonsmoker and was based on questionnaire responses.

Because previous research has shown that there are seasonal changes in BMD in New England, we created a categorical variable for season of BMD measurement 22 , For the women, estrogen use was defined as either current use or never and past users; these categories were based on evidence that past use does not sustain bone benefits Postmenopausal status was defined as women who reported no menstrual period during the preceding year with no pregnancy.

We included 2 indicator variables—women who were menopausal but were not using estrogen, and women who were menopausal and were using estrogen. Both of these were then compared with premenopausal women. These beverage variables included total noncola carbonated beverage intake, total cola intake, sugared cola intake, decaffeinated cola intake, and diet cola intake. Confounders, which were described above, included age, BMI, physical activity score, alcohol use, smoking status, total calcium intake, total vitamin D intake, energy intake, caffeine intake from sources other than cola, season of bone measurement, and, for women, menopausal status and current estrogen use.

These analyses were repeated to include fruit juice consumption and any soft drink consumption other than that being analyzed. Additional models were run adding, one at a time, the calcium-to-phosphorus intake ratio, total fruit and vegetable intake, and the protein-to-potassium intake ratio. The interaction between menopausal status and cola intake on each BMD measure was also tested.

Because none of these interactions were significant, all women were included in the same models after adjustment for menopausal status, as described above. Bone measures were each regressed on these intake categories, along with the set of confounding variables, by using the general linear models procedure in SAS to obtain least-squares means by cola intake category. Categories were compared for significant differences with post-hoc comparisons and Tukey-Kramer adjustment for multiple comparisons.

For the categorical variables, percentages are presented by category. This group of men and women tended to be overweight, to be former smokers, and to consume alcohol moderately.

Women were equally likely to consume caffeinated and noncaffeinated cola but more likely to consume diet than sugared cola 2. No significant negative associations of BMD with noncola carbonated beverage intake were observed for either men or women Table 3. In the men, no significant associations were observed between BMD and cola intake. No significant associations with spine BMD were observed for either men or women data not shown. Additional analysis of cola subgroups for the women showed that the trends were not unique to the sugared, caffeinated colas, but were evident for all cola subgroups tested, with the exception of sugared decaffeinated cola Table 4.

Sugared decaffeinated soda intake was not significant at any site, but it should be noted that this was the least commonly used form of cola by the women Table 2. Carbonated beverage consumption 1. Consumption was measured in mean servings per week; one serving was defined as one glass, can, or bottle. Sugared cola includes caffeinated 1. Diet cola includes caffeinated 1. Caffeinated and decaffeinated cola categories each contain both sugared and diet colas, as combined from the above figures.

Linear associations between carbonated beverage intake and bone mineral density 1. All values are regression coefficients. Adjusted for BMI, height, smoking, alcohol use, age, physical activity score, season of bone mineral density measurement, and for intakes of total energy, calcium, vitamin D, and caffeine from sources other than carbonated beverages.

Also adjusted for menopausal status and estrogen use in the women. Additionally adjusted for consumption of remaining carbonated beverages if any and fruit juice. Further adjustment for the calcium-to-phosphorus ratio, total fruit and vegetable intake, or the protein-to-potassium intake ratio did not change the significance level or materially change the coefficient of any association between cola intake and bone mineral density.

Linear associations between carbonated beverage intake and bone mineral density in the women 1. Adjusted for BMI, height, smoking, alcohol use, age, physical activity score, season of bone mineral density measurement, and for intakes of total energy, calcium, vitamin D, and caffeine from sources other than cola. Also adjusted for menopausal status and estrogen use.

All associations were additionally adjusted for consumption of fruit juice and any carbonated beverages other than that being analyzed. In the women, a greater intake of cola was not associated with significantly lower intake of milk, but regular cola consumers did consume less fruit juice than did noncola consumers Table 5.

Regular cola consumers also had significantly lower intakes of calcium and lower calcium-to-phosphorus intake ratios for both total and dietary calcium than did nonconsumers. We repeated all models with the addition, one at a time, of milk intake, fruit juice intake, the calcium-to-phosphorus intake ratio, total fruit and vegetable intake, and the protein-to-potassium intake ratio.

None of these additions had meaningful effects on the results presented. Dietary intake of women by category of cola consumption, adjusted for age and total energy intake 1. More evidence on the distribution and size of these effects is evident in Figure 1.

A clear dose response is evident with significantly lower BMD observed at greater cola intakes. The difference in mean femoral neck BMD between those consuming cola daily or more frequently and noncola consumers was 3. For other sites not shown , differences ranged from 2.

The analysis was adjusted for age, height, BMI, smoking status, alcohol use, physical activity score, season of measurement, menopausal status, estrogen use, and intakes of total energy, calcium, vitamin D, caffeine from noncarbonated beverages, and noncola carbonated beverages. In this large population-based cohort, we saw consistent robust associations between cola consumption and low BMD in women. The consistency of pattern across cola types and after adjustment for potential confounding variables, including calcium intake, supports the likelihood that this is not due to displacement of milk or other healthy beverages in the diet.

The major differences between cola and other carbonated beverages are caffeine, phosphoric acid, and cola extract. Although caffeine likely contributes to lower BMD, the result also observed for decaffeinated cola, the lack of difference in total caffeine intake across cola intake groups, and the lack of attenuation after adjustment for caffeine content suggest that caffeine does not explain these results.

A deleterious effect of phosphoric acid has been proposed Cola beverages contain phosphoric acid, whereas other carbonated soft drinks with some exceptions do not. Although cola drinkers did have lower calcium-to-phosphorus intake ratios than did noncola drinkers, adjustment for this variable did not significantly attenuate the results and the ratio itself was not significant.

Much less is known about the possible effects of cola extract, which contains catechins, theobromine, and tannins, on BMD Catechins, which are also found in tea, may have a positive effect on bone However, it remains possible that another component in cola extract could have a deleterious effect.

If confirmed, a negative effect of cola intake on bone is of considerable importance. From to , carbonated beverage consumption increased more than three-fold Caffeine has been associated with bone loss in older women 8 — 10 , whereas the association between phosphoric acid and bone loss remains controversial 7.

Theoretically, diets high in phosphorus and low in calcium lead to complexes that reduce serum calcium, stimulating parathyroid hormone PTH , which, in turn, causes bone resorption and returns serum calcium to homeostatic concentrations.

Although it was suggested that the amount of phosphoric acid in cola is insufficient to cause this imbalance 7 , it remains unclear whether regular exposure to phosphoric acid without exposure to calcium or other beneficial nutrients slowly affects bone remodeling and causes bone loss over time.

High dietary phosphorus was shown to cause bone loss in animals In one study, cola was given to immature and adult rats and found that both developed significant hypercalciuria and hyperphosphaturia; the older animals also developed hyperparathyroidism In another study, cola was given to ovariectomized rats; subsequent hypocalcemia and loss of femoral BMD was observed in the rats relative to a control group Several studies have examined the association between carbonated beverages and fracture 4 , 32 , 33 , hypocalcemia 26 , 34 , or BMD 5 , 6 in children.

Wyshak et al 32 found a 1. Few studies have examined this in adults. The scientists compared how much cola and other sodas people drank to bone mineral density measurements taken from the spine and from three different spots on the hips. Women who drank more cola had reduced bone mineral density at all three hip sites but not at the spine. The link between cola consumption and women's bone loss was unaffected by age, menopausal status, cigarettes, alcohol, or total calcium and vitamin D intake.

Cola consumption did not affect men in the same way. Also, other carbonated drinks were not associated with bone loss. Previous studies suggested that women who drank more cola had reduced bone density because the cola replaced milk in their diets, meaning the women got less calcium. But in this study, the women who drank the most cola still drank enough milk. The authors of the cola study suggested that the caffeine in the colas may account for the cola-drinkers' lower BMD.

Other studies have also reported an association between caffeine and lower BMD. In some cases, soft drinks displace calcium-rich beverages, such as milk, and experts think that this, rather than any direct effect of soft drinks on bone, may explain the effect on BMD in adolescent girls. So feel free to enjoy seltzer water without worrying, but don't overdo the caffeinated beverages, whether carbonated or not. And if you suspect that by drinking seltzer water, coffee, colas, or other soft drinks you may be reducing your intake of healthy beverages — such as calcium and vitamin D fortified juices and milk.

So make sure you get enough calcium through other dietary sources and consider a daily vitamin D supplement. As a service to our readers, Harvard Health Publishing provides access to our library of archived content.

Please note the date of last review or update on all articles. Thanks for visiting. Don't miss your FREE gift. Sign up to get tips for living a healthy lifestyle, with ways to fight inflammation and improve cognitive health , plus the latest advances in preventative medicine, diet and exercise , pain relief, blood pressure and cholesterol management, and more.

Get helpful tips and guidance for everything from fighting inflammation to finding the best diets for weight loss Stay on top of latest health news from Harvard Medical School. Recent Blog Articles. Health news headlines can be deceiving. Why is topical vitamin C important for skin health? Preventing preeclampsia may be as simple as taking an aspirin.