Diet soda depletes the body's calcium stores

Soda drinking has previously been associated with lower bone mineral density in women and children1,2, and other studies focus specifically on the effects of diet soda on bone health. The authors commented that this research was sparked by the observation that diet soda drinking behaviors are often different than regular soda drinking behaviors – women often use diet sodas in an effort to avoid weight gain – either to stave off hunger between meals or as a replacement for calorie-containing beverages. Many women drink over 20 diet sodas per week.3

The average American drinks 216 liters of soda each year.4

Pouring soda

These researchers discovered that parathyroid hormone (PTH) concentrations rise strongly following diet soda consumption. PTH functions to increase blood calcium concentrations by stimulating bone breakdown, and as a result release  calcium from bone.

In the study, women aged 18-40 were given 24 ounces of either diet cola or water on two consecutive days, and urinary calcium content was measured for three hours. Women who drank diet cola did indeed excrete more calcium in their urine  compared to  women who drank water. The authors concluded that this calcium loss may underlie the observed connection between soda drinking and low bone mineral density.5

Although caffeine is known to increase calcium excretion and promote bone loss6, caffeine is likely not the only bone-harming ingredient in sodas. A 2006 study in the American Journal of Clinical Nutrition found consistent associations between low bone mineral density and caffeinated and non-caffeinated cola (both regular and diet), but not other carbonated beverages.7 One major difference between the two is the  phosphoric acid in  colas, absent from most other carbonated beverages. 

In the Western diet, phosphorus is commonly consumed in excess – at about 3 times the recommended levels, whereas dietary calcium is often low.  Although phosphorus is an important component of bone mineral, a high dietary ratio of phosphorus to calcium can increase parathyroid hormone secretion, which is known to increase bone breakdown.   Studies in which women were given increasing quantities of dietary phosphorus found increases in markers of bone breakdown and decreases in markers of bone formation.8,9 Therefore it is likely that the phosphorus content of colas,  triggers calcium loss.

There is nothing healthy about diet soda. It is simply water with artificial sweeteners and other chemical additives, such as phosphoric acid. The safety of artificial sweeteners is questionable, and their intense sweetness disrupts the body’s natural connection between taste and nourishment,  promoting weight gain.10 Diet sodas don’t just weaken our bones, they are linked to kidney dysfunction and promote obesity and other common medical problems.



1. McGartland C, Robson PJ, Murray L, et al. Carbonated soft drink consumption and bone mineral density in adolescence: the Northern Ireland Young Hearts project. J Bone Miner Res. 2003 Sep;18(9):1563-9.

Mahmood M, Saleh A, Al-Alawi F, Ahmed F. Health effects of soda drinking in adolescent girls in the United Arab Emirates. J Crit Care. 2008 Sep;23(3):434-40.

2. Tucker KL, 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 Clin Nutr. 2006 Oct;84(4):936-42

3. Frieden J. ENDO: Diet Soft Drinks Deplete Urinary Calcium. Medpage Today.

5. NS Larson, et al "Effect of Diet Cola on urine calcium excretion" ENDO 2010; Abstract P2-198.

6. Vondracek SF, Hansen LB, McDermott MT. Osteoporosis risk in premenopausal women. Pharmacotherapy. 2009 Mar;29(3):305-17.

Massey LK, Whiting SJ. Caffeine, urinary calcium, calcium metabolism and bone. J. Nutr. 19923 Sep;123 (9): 1611-14

7. Tucker KL, Morita K, Qiao N, et al. Colas, but not other carbonated beverages, are associated with low bone mineral density in older women: The Framingham Osteoporosis Study. Am J Clin Nutr. 2006 Oct;84(4):936-42.

8. Kemi VE, Kärkkäinen MU, Karp HJ, et al. Increased calcium intake does not completely counteract the effects of increased phosphorus intake on bone: an acute dose-response study in healthy females. Br J Nutr. 2008 Apr;99(4):832-9.

9. Kemi VE, Kärkkäinen MU, Lamberg-Allardt CJ. High phosphorus intakes acutely and negatively affect Ca and bone metabolism in a dose-dependent manner in healthy young females. Br J Nutr. 2006 Sep;96(3):545-52.

10. Swithers SE, Martin AA, Davidson TL. High-intensity sweeteners and energy balance. Physiol Behav. 2010 Apr 26;100(1):55-62. 

Dangers associated with food dyes

Synthetic food dyes are used in many processed foods, such as colored breakfast cereals, candy, and “fruit-flavored” beverages and snacks. A total of 15 million pounds of dyes are added to the U.S. food supply each year. Our consumption of food dyes has increased 5-fold since 1955 as our nation has consumed more and more packaged foods.1

These synthetic dyes have been linked to a wide variety of health concerns including behavioral problems, hyperactivity, allergic reactions, and even cancers. The Center for Science in the Public Interest (CSPI), an organization that advocates for nutrition and food safety, called for a ban on these synthetic dyes. Food-based dyes such as beet juice and turmeric are readily available, but are more expensive and often less bright, making synthetic dyes more attractive to food manufacturers.

Food dyes and allergic reactions:

Blue 1, Red 40, Yellow 5, and Yellow 6 have been reported to cause allergic reactions in some people.

Food dyes and hyperactivity:

Food dyes are of particular concern for children, since many colored foods are marketed to children, and their smaller body size makes them more susceptible to potential toxins. Hyperactivity in children following ingestion of food dyes is well-documented in placebo-controlled studies. Furthermore, a 2004 meta-analysis of 16 studies in children who were already hyperactive showed that their hyperactive behavior increased in response to food colorings.2 In a study published in Lancet in 2007, researchers tested two different mixtures of food dyes vs. placebo in children of two age groups – one mixture increased hyperactivity in 3 year old children, and both mixtures increased hyperactivity in the 8-9 year-olds.3 This study sparked a reaction by the British government. They instructed food manufacturers to eliminate all of these synthetic dyes by the end of 2009. In fact, a warning notice is now required on dyed foods in Europe stating that these foods “may have an adverse effect on activity and attention in children.”4  As a result, several international food companies now produce products with food-based dyes or no dyes in the U.K., but continue to include synthetic dyes in their U.S. products.

Food dyes and cancer:

There are eight commonly used synthetic dyes in the U.S., and all have undergone toxicity and tumorigenicity testing in animals. CSPI summarized the results of cancer-related studies in a report1:

  • Red 3 was acknowledged by the FDA to be a carcinogen in 1985 and was banned in cosmetics and externally applied drugs. However Red 3 is still used in ingested drugs and foods.
  • The three most widely used dyes (Red 40, Yellow 5, Yellow 6) which account for 90% of dyes in the U.S. are contaminated with low levels of chemical carcinogens, as byproducts of the manufacturing process. Although the FDA places limits on the concentrations of these contaminants in the final dye products, they still may pose risks.
  • Citrus Red 2 added to the diet resulted in bladder tumors.
  • Red 3 resulted in thyroid tumors and caused DNA damage.

In their report, CSPI noted flaws in many of the animal cancer studies on Yellow 6, Yellow 5, Red 40, Green 3, and Blue 2, including bias – most studies were either commissioned or conducted by dye manufacturers, short duration, and lack of exposure to dyes during fetal development. Additional studies are likely needed to determine whether these dyes are safe.

The simplest and most effective way to avoid the potential harmful effects of synthetic dyes is to avoid processed foods.   Unrefined plant foods contain health promoting phytochemicals, not empty calories and synthetic additives of questionable safety. When buying the occasional packaged food, check the ingredient list to avoid synthetic dyes.


1. Center for Science in the Public Interest. Food Dyes: A Rainbow of Risks.

2. Artificial food colouring and hyperactivity symptoms in children. Prescrire Int. 2009 Oct;18(103):215.

Schab DW, Trinh NH. Do artificial food colors promote hyperactivity in children with hyperactive syndromes? A meta-analysis of double-blind placebo-controlled trials. J Dev Behav Pediatr. 2004 Dec;25(6):423-34.

3. McCann D, Barrett A, Cooper A, et al. Food additives and hyperactive behaviour in 3-year-old and 8/9-year-old children in the community: a randomised, double-blinded, placebo-controlled trial. Lancet. 2007 Nov 3;370(9598):1560-7.

4. CSPI Says Food Dyes Pose Rainbow of Risks.

That's cool, because I am into healthy eating, too!

I’ve come to realize over the past three years of my college experience that the phrase “I am a healthy eater,” is used liberally and with conviction among my peers. Amazingly, in spite of eating almost no produce they believe that they eat healthful diets. Telling them otherwise would result in defensiveness and rationalizations. I have friends who are athletes, environmental activists, pre-meds, you name it, and are intelligent, forward-thinking people. Yet, when it comes to what they put in their mouths, they are clueless. For example, I just moved into an apartment with two new roommates (one female, one male) and the refrigerator and cabinets were already stocked with food (well, if you could call it that) when I arrived. After living at home for a while with its endless supply of fresh fruits and vegetables, I was taken aback by what I saw: oreos, chips, weight watchers bars, and other convenient, imperishable foods were in the cabinets, frozen pizzas, macaroni dishes, and fake meats with unpronounceable, artificial ingredients, in the freezer. Other than a few carrots and a melon, no fresh vegetables and fresh fruits, no mushrooms, no beans and no raw nuts or seeds were in the kitchen. 


I began chatting with my new roommate about my upbringing and how important eating healthfully is to me. As a competitive runner, he heartily agreed with me about the importance of fueling your body with nutritious foods and he explained that healthy eating is very important to him too. There was a clear discrepancy between his nutritional philosophy and the foods he had stocked in our kitchen. This has been a frequent occurrence for me over the years and shows how nutritionally uneducated people are. Little is done to educate the American populace about one of the most important topics of their lives: how to eat a disease- preventing diet.   I do my best to educate my friends when they ask me for advice, but I’ve learned from experience not to push my eating philosophy on others. Their chosen eating habits are like a religion to some people, and not open to debate. I hope my friends are curious about what I eat and ask me questions, and in many instances they do. I also have friends who could care less about what I put in my mouth, convinced that their mediocre diet is just as healthy, if not more so. I accept this, but I do wish that all my friends and others were blessed with the nutritional knowledge that I am fortunate to possess. 

Have you found those around you to be curious about your diet and the nutritarian lifestyle? How do you handle conflicting nutritional beliefs?