Bad to the Bone! - Cola and bone density

Zahra Hassanali
23 January 2012

May 29, 2009

Lately it seems like all the foods we love are bad for our health. So it does not come as a surprise that cola beverages can have adverse effects on our bone mineral density.

Did You Know?
Bone mineral density is a measure of minerals (i.e. calcium) in your bones determined by x-ray, CT-scan or ultrasound.

Say it isn't so? For many of us colas not only quench our thirst but we have come to rely on them for the jolt of energy that we need to keep us going. The truth is that 55% of Americans, mainly women, are at risk of developing brittle bone disease (osteoporosis),which leaves bones dry, weak and more likely to fracture. Cola drinks,whether they are diet, regular or decaffeinated, all affect bone density and increase the risk of developing osteoporosis. As a matter of fact, cola consumption affects women more than men, perhaps because women's bones are smaller. As if girls don't have enough to worry about already!

Although women are more sensitive, the effect of cola isn't isolated to women. Carbonated beverages are reported to increase fracture risk in children. Although some children sustain at least one fracture during growth, the majority do not, suggesting that it is not normal for children to break bones. Poor nutrition, including inadequate intake of dietary calcium, milk avoidance and excessive consumption of carbonated beverages all impact bone health in growing children.

Logically, the reason behind bone weakening would be that if we are consuming more cola then we must be consuming less milk and therefore getting less calcium. With depleted dietary calcium the body can not maintain bone health. Well...that's not a problem you think, I'll just compensate for cola drinking by eating more calcium and vitamin D enriched foods. However, adequate dietary intake of calcium and vitamin D does not seem to be able to counteract the effects of cola on bone loss.

Did You Know?
Calcium and Vitamin D maintain bone health and growth. Food sources of calcium include milk,yogurt, cheese, spinach and almonds. But you will probably be surprised to know that the best source for vitamin D is time out in the sun.

So, if bone loss isn't because of reduced dietary calcium than there must be another factor reducing bone mineralization?Scientists discovered that the main cause is phosphoric acid,which is a compound in cola beverages that gives them their tart taste. Phosphoric acid interferes with calcium absorption by the bone.This process impedes the mineralization of bones throughout the body,weakening the skeletal structure.

The question than becomes, why don't other foods containing phosphoric acid have the same effect on our bones? Scientists have suggested that when phosphoric acid is packaged with other nutrients, it is absorbed normally and every thing is in balance. The problem with cola is that you are getting doses of phosphoric acid without calcium. Therefore in order to neutralize the acid in the body, phosphoric acid will begin taking calcium from the blood and when that source is depleted, calcium will be stripped from the bones.

Caffeine, our best friend when it comes to pulling all nighters, is also found in cola beverages. And sad but true,caffeine has also been associated with decreased bone density, but the exact mechanism of action is still not clear.

Did You Know?
Did you know that Health Canada's maximum recommended intake of caffeine in youth is equivalent to 2 cans of cola a day, while studies have shown that in adults 3 cans of cola or more a week can deteriorate your bones!

The next time you think of reaching over for Pepsi or Coke, think about your bones and think...Got Milk? Or consider juices enriched in vitamins and minerals like V8.

Learn more! Caffeine and Your Health (Health Canada) Osteoporosis Health Centre References: TuckerKL, Morita K, Qiao N, Hannan MT, Cupples LA, Kiel DP. Colas, but not other carbonated beverages, are associated with low bone mineral density in older women: The Framingham Osteoporosis Study. Am J ClinNutr. 2006 Oct;84(4):936-42. Goulding A. Risk factors for fractures in normally active children and adolescents. Med Sport Sci. 2007;51:102-20. Review.

Zahra is an MSc student in Nutrition at the University of Alberta. Her love for stories and storytelling is one of her escapes from the everyday.

Zahra Hassanali

I have my MSc in Nutritional Sciences and am currently working towards becoming a registered dietitian. Aside from the world of science, another passion of mine is painting. 

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