Some soda contains a potential carcinogen, and a new Consumer Reports' study shows many Americans drink enough to put their health at risk
The culprit? A chemical called 4-methylimidazole (4-MeI). This potential carcinogen is found in some types of caramel color, the artificial ingredient used to turn colas and other soft drinks brown. Every day, more than half of Americans between the ages of 6 and 64 typically drink soda in amounts that could expose them to enough 4-MeI to increase their cancer risk, according to a new analysis of national soda consumption conducted by scientists at Consumer Reports and the Center for a Livable Future at the Johns Hopkins Bloomberg School of Public Health. The study was published today in the scientific online journal PLOS ONE.
The risks of 4-MeIThis analysis was a follow-up to testing we did in 2013 to measure 4-MeI content in soft drinks. We looked at 110 samples of colas and other soft drinks purchased in California and the New York metropolitan region. Excluding a clear soda used as a control, we found that average 4-MeI levels in the samples we tested ranged from 3.4 to 352.5 micrograms (mcg) per 12-ounce bottle or can. There’s no federal limit for the amount of 4-MeI permitted in foods and beverages currently, but California requires manufacturers to label a product sold in the state with a cancer warning if it exposes consumers to more than 29 mcg of 4-MeI per day. We submitted our test findings to the California State Attorney General’s office, and we’ve also petitioned the federal government to set limits for 4-MeI in food.
How big a threat is soda?We conducted this new study in response to debate surrounding the amount of soda Americans actually drink on a daily basis. We estimated soda consumption in a typical 24-hour period by analyzing seven years of data (2003 to 2010) from the National Health and Nutrition Examination Survey (NHANES). Then we used that data to estimate the potential cancer risk at different levels of consumption.
Among the more than half of Americans age 6 to 64 who drink soda on a typical day, it turns out that the average intake ranges from a little more than one 12-ounce can to nearly 2.5 cans a day. About a third of very young children (age 3 to 5) drink soda on a typical day; the average intake is approximately two-thirds of a can. The biggest soda consumers are in the 16 to 44 year-old age group. Those who drink the most average about three cans a day. "The findings of this comprehensive study have scientific, policy, and legal implications for calculating cancer risk and establishing limits for 4-MeI in food,” says Urvashi Rangan, Ph.D., toxicologist and executive director of Consumer Reports’ Food Safety & Sustainability Center.
Our analysis shows that at this level of consumption, we would expect to see between 76 and 5,000 cases of cancer in the U.S. over the next 70 years from 4-MeI exposure alone. “We don’t think any food additive, particularly one that’s only purpose is to color food brown, should elevate people’s cancer risk,” says Rangan. “Ideally, 4-MeI should not be added to food.”
Soda is not the only source of 4-MeIAccording to the Food and Drug Administration, caramel-color-containing carbonated drinks contribute about 25 percent of the amount of 4-MeI in the diets of people over age 2. That’s more than any other source, but caramel color is found in a wide variety of foods, including bread and other baked goods, dark sauces such as soy or barbecue, pancake syrup, and soups. While we don’t know what type of caramel color or how much 4-MeI is in those foods, it’s clear that many people are already getting concerning amounts of 4-MeI in their diets just from the soda they drink.