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Soda habit bad for your kidneys, heart and more

Editor’s note: This column will appear in the Healthy Living section on Sunday, April 22.


If you’re a faithful reader of my column, you know I think sodas are bad for your health.

While diet sodas may be marginally healthier than sugary ones, they still may be linked to kidney problems and other health issues.

Drinking regular soda may increase the risk of obesity, diabetes and gout, according to several studies. And the phosphate in both regular and diet colas may be linked to kidney failure, although more studies are needed.

Even children can be negatively affected by drinking soda—researchers link it to the rising rate of childhood obesity. Some studies link sodas to infertility as well, but  this is controversial. And some sodas may even contain cancer-causing coloring and flame-retardant chemicals!

The bottom line: Consider drinking more water and less soda. Soda is not evil, but habitual soda drinkers seem to have a lot of health problems.


While scientists can’t directly prove that soda causes disease, soda is associated with many ailments. For example:

– Drinking just a small, 12-ounce can of a sugary beverage such as soda each day was linked to a 20 percent higher rate of heart attacks. That’s according to research at Winthrop University Hospital in New York released last month.

The research didn’t prove whether  soda actually caused the heart attacks. Still, the American Heart Association recommends limiting soda consumption.

– Soda also slams the kidneys. New evidence suggests that consuming too much phosphorus may strain the kidneys. Japanese researchers have gone so far as to recommend that even healthy people avoid colas.

We know that severe high blood pressure or diabetes can cause kidney failure. And folks who already have kidney failure have long been warned to avoid high-phosphorus foods such as colas. 

And diet sodas, cola or not, may also be a factor. Drinking two or more diet sodas daily was associated with a 200 percent increase in kidney problems, according to researchers at Harvard Medical School.


Regular sodas can increase the risk of gout. This condition causes painful swelling in the toes and other joints in the body. Women who drank two sodas a day had more than double the risk of gout compared with soda avoiders, according to data from the Nurses Health Study of 79,000 American women.

Another area of concern: sleep. Cravings for caffeinated soda may signal sleep apnea or other silent sleep problems that make people feel fatigued. Folks with severe sleep problems consumed nearly twice as much caffeinated soda as folks with normal sleep patterns, according to researchers at the Johns Hopkins University in Baltimore.


For younger women, soda may be linked to reduced fertility. The more soda a woman drank, the lower her chances of conceiving a child, according to one study. Women who drank three sodas daily were half as likely to get pregnant as women who avoided soda, according to American and Danish researchers.

And caffeine from soda and other beverages may be linked to birth defects such as spina bifida, according to the National Birth Defects Prevention Study. More research is needed.

Beyond effects on fertility, the heart, kidneys and joints, drinking sugary sodas has been linked to fatty liver disease, tooth decay and weakened bones.


American kids are officially consuming too much sugar, according to the Centers for Disease Control and Prevention. The organization says kids are taking in an extra 280 to 360 calories daily from sugar. That’s far beyond government guidelines to limit both added sugars and fats to 15 percent of calories.

The top sources of calories for kids, from toddlers to teens, were “grain desserts” such as cookies and cakes, along with pizza and soda, according to nationwide surveys.

Eating habits started in kindergarten persist into the teen years. One study found that 5-year-olds who drank the most soda ate poorly overall even at age 15. Compared with soda avoiders, soda drinkers consumed more sugar and fewer nutrients such as protein, fiber, vitamin D, calcium, magnesium and potassium.

We know drinking soda is linked to obesity. Some schools have banned sales of soda; but it’s controversial whether this helps, as some kids just buy soda outside school. Policymakers debate whether taxing sodas might help.


Many parents have been up in arms about BPA, a chemical found in plastic baby bottles and the lining of canned foods that may cause health problems. Soda may be a source of BPA.

People who drank more soda had higher levels of BPA in their urine, according to the National Health and Nutrition Examination Survey. The survey did not ask about soda containers (plastic bottles, aluminum cans or fountain beverages).


The caramel coloring in Coca–Cola and Pepsi has been linked to cancer, so the soda makers agreed in March to switch to a different version of the caramel color that doesn’t contain the chemical 4–methylimidazole.

And Mountain Dew and Fanta orange sodas contain another chemical, called BVO, that is considered toxic and banned throughout Europe and Japan, according to a report in

All in all, soda is not a source of nutrients and  has a lot of calories and some potential links to diseases. While an occasional soda is not likely to cause problems, it may be worth cultivating a taste for unsweetened beverages.

Jennifer Motl is a registered  dietitian. Formerly of Fredericksburg, she now  lives in Wisconsin. She welcomes reader questions via her website,, or by email at