Daily cola 'raises cancer risk' due to caramel coloring

He chemical process during the manufacture of the caramel coloring used in soft drinks such as cola produces a carcinogen that could be raising the risk of cancer to above the accepted threshold of one extra case in every 100,000 people consuming the drinks, suggests an analysis.

Matching laboratory tests conducted by Consumer Reports on 11 different soft drinks, first reported last year, with an analysis of average consumption by Americans, the researchers found that one can a day could be enough to expose them to potentially cancer-causing levels of the chemical known as 4-MEI (short for 4-methylimidazole).

The potential carcinogen is formed during the manufacture of the familiar caramel color that is added to many widely-consumed beverages.

A law in California requires that drinks must carry warning labels if they contain enough 4-MEI to pose an excesscancer risk of more than 1 case in every 100,000 exposed people (an exposure of 29 mcg of 4-MEI every day).

Testing on 110 samples of soda brands carried out by the Consumer Reports researchers, led by a team at the Johns Hopkins Center for a Livable Future in Baltimore, MD, found that drinks contained levels ranging from 9.5 mcg per liter (mcg/L) to 963 mcg/L.

Concentrations of 4-MEI varied considerably by soda brand and state of purchase, the researchers concluded, "but were generally consistent across lots of the same beverage purchased in the same state/area."

They add: "Routine consumption of certain beverages can result in 4-MEI exposures greater than 29 mcg a day" - the level that triggers a new case of cancer in every 100,000 people consuming the drink, toxicity that was established by previous studies in mice and rats conducted by the US National Toxicology Program.

The researchers say there was not enough data from individual drinks samples to recommend one brand over another in terms of carcinogen exposure, but suggest: "State regulatory standards appear to have been effective in reducing exposure to carcinogens in some beverages."

Lead author of the study Tyler Smith, a program officer with the Johns Hopkins Center for a Livable Future, says 4-MEI levels can "vary substantially across samples, even for the same type of beverage." Smith explains:

"For example, for diet colas, certain samples had higher or more variable levels of the compound, while other samples had very low concentrations."

In the lab sampling, Malta Goya had the highest 4-MEI concentration while Coca-Cola produced the lowest value.

California listed 4-MEI as a carcinogen in 2011, under the Safe Drinking Water and Toxic Enforcement Act of 1986 - better known as Proposition 65. The authors say their results suggest that "federal regulation of 4-MEI in caramel color may be appropriate."

Variety of cola-drinking habits

To estimate consumers' exposure to the potential carcinogen, the researchers took the laboratory readings and analyzed soft drink consumption using data from the National Health and Nutrition Examination Survey (NHANES).

The data from this survey covered overall health and nutrition patterns between 2003 and 2010 for tens of thousands of US children and adults aged between 3 and 70 years.

The authors say: "We analyzed consumption of all sodas, and further categorized soda into five mutually exclusive categories: 1) cola, 2) diet-cola, 3) root beer, 4) pepper cola and 5) other (non-diet) cola."

They found the proportion of the population consuming each type of soft drink varied, with "colas being the most popular and root beer and pepper colas being the least popular."

Adolescents and young adults consumed the most of any soft drink compared with young children and older adults. Average consumptions of any soda were:

• Between 550 and 1,070 milliliters drunk each day by 16- to 20-year-olds
• Between 457 and 864 milliliters drunk each day by 45- to 64-year-olds.

Lifetime cancer risks

"This study sought to answer a critical question," says Urvashi Rangan, PhD, executive director of the food safety and sustainability center of Consumer Reports: "How much soda do American consumers drink on average?"

"This new analysis underscores our belief that people consume significant amounts of soda that unnecessarily elevate their risk of cancer over the course of a lifetime," Dr. Rangan says.

She adds: "We believe beverage makers and the government should take the steps needed to protect public health."

"California has already taken an important step by setting a threshold," Dr. Rangan says.

Keeve Nachman, PhD, is a senior author of the study and director of the food production and public health program at the Johns Hopkins Center for a Livable Future.

Also an assistant professor at the Johns Hopkins Bloomberg School of Public Health, Dr. Nachman says:

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'Bionic' eye allows man to see wife for first time in a decade

A Blind man is now able to see objects and people again, including his wife and family, for the first time in a decade. How? With the help of a bionic eye implant.

Affected by a degenerative condition known as retinitis pigmentosa, Allen Zderad was effectively blind, unable to see anything but a bright light. As the condition has no cure, Zderad, from Minneapolis-Saint Paul, MN, was forced to quit his professional career.

He made adjustments to his lifestyle and was able to continue woodworking through his sense of touch and spatial awareness. However, with the help of his new retinal prosthesis, Zderad is now able to make out the outlines of objects and people, and could even register his reflection in a window.

"I would like to say I think he's a remarkable man, when you consider what he's overcome in dealing with his visual disability," says Dr. Raymond Iezzi Jr., an ophthalmologist from the Mayo Clinic. "To be able to have offered him the retinal prosthesis to enhance what he can already do was a great honor for me."

Retinitis pigmentosa is an inherited condition that causes the degeneration of specific cells in the retina called photoreceptors. The disease can cause some people to lose their entire vision. Mr. Zderad's grandson has the disease in its early stages and, after seeing him, Dr. Iezzi asked if he could meet his grandfather.

The eye implant that Zderad now has works by bypassing the damaged retina and sending light wave signals directly to the optic nerve. A small chip was attached to the back of the eye with multiple electrodes offering 60 points of stimulation.

'Not like any form of vision that he's had before'

Wires from the device on the retinal surface connect to a pair of glasses worn by Mr. Zderad. The glasses have a camera at the bridge of the nose that relay images to a small computer worn in a belt pack. These images are then processed and transmitted as visual information to the implant which in turn interprets them, passing them on to the retina and eventually the brain.

"Mr. Zderad is experiencing what we call artificial vision," explains Dr. Iezzi. "It's not like any form of vision that he's had before. He's receiving pulses of electrical signal that are going on to his retina and those are producing small flashes of light called electro-phosphenes. These small flashes of light are sort of like the points of light on a scoreboard at a baseball game."

There are only 60 of these flashes of light, but it is enough for Zderad to reconstruct scenes and objects. Although he will not be able to see the details of faces or read, Mr. Zderad will now be able to navigate through crowded environments without the use of a cane, significantly improving his quality of life.

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