Pepsi and the Carcinogen 4-MEI

Pepsi CansIn yet another reason to avoid all soft drinks like the plague it appears that Pepsi’ caramel colouring contains a trace amount of carcinogen.

But is ok – it apparently only affects rats.

The chemical is 4-methylimidazole, or 4-MEI, which can form during the cooking process and, as a result, may be found in trace amounts in many foods.

In March, Pepsi and Coca-Cola both said they would adjust their formulas in the US after California passed a law mandating drinks containing a certain level of carcinogens come with a cancer warning label.

The changes were made for drinks sold in California when the law passed.

It appears that while Coke products no longer test positive for the chemical, Pepsi products sold outside of California still do.

Pepsi said its caramel colouring suppliers are changing their manufacturing process to cut the amount of 4-MEI in its caramel. That process is complete in California and will be finished in February 2014 in the rest of the country. Pepsi said it will also be taken out globally, but did not indicate a timeline.

According to News the FDA and other regulatory agencies around the world consider Pepsi’s caramel colouring safe.

Coca-Cola said it has transitioned to using a modified caramel in US markets beyond California that does not contain MEI-4, so it wouldn’t have to have separate inventory of products for different locations. It also said all of its products, whether they have the modified caramel or not, are safe.

Trace amounts of 4-MEI have not been linked to cancer in humans. The American Beverage Association said that California added the colouring to its list of carcinogens with no studies showing that it causes cancer in humans. It noted that the listing was based on a single study in lab mice and rats.

The Food and Drug Administration has also said that a consumer would have to drink more than 1000 cans of soda a day to reach the doses administered that have shown links to cancer in rodents.


Concern has arisen about the presence of 4-MEI in caramel colour (which is the most-used food and beverage coloring), typically at a concentration between 50 and 700 ppm.

Dark beers and common brands of cola drinks may contain more than 100 μg of this compound per 600 ml serving.

At very high doses (360 mg/kg of body weight), 4-methylimidazole is a convulsant for rabbits, mice and chicks, and was the likely cause of acute intoxication observed in cattle fed with ammoniated, sugar-containing cattle feed supplements in the 1960s.

A 2007 study by the National Toxicology Program (NTP) found that high doses of 4-MEI were carcinogenic in mice and in female rats. 4-MEI was associated with a 25-fold decrease in the incidence of mammary tumors among high-dose females.

In response to high 4-MEI levels used in studies, US FDA spokesperson Doug Karas famously stated, “[a] person would have to drink more than a thousand cans of soda in a day to match the doses administered in studies that showed links to cancer in rodents.”


Based on these studies, caramel colouring of all types are considered ‘safe’ and are approved by many leading regulatory agencies around the world. However, the European Union requires class III caramels to contain <200 mg/kg 4-MEI and class IV caramels to contain <250 mg/kg 4-MEI (colour adjusted).

The food industry has strongly opposed that decision, as it implies the need for additional warning labels on many products, and it disputes the validity of the NTP study.


However, notwithstanding the conjecture on 4-MEI,  the concern is how does it interact with other chemicals in the cola. While we may have data on individual chemicals and they are carcinogenic at ‘high’ levels, does the interaction of a number of chemicals have a synergistic effect in the causation of other health issues in the unwary drinker. On this point we have no data.

I can’t talk about soft drinks and not mention the two ‘elephants in the room’. The first is the devastating effect soft drink has on calorie consumption, overloading the body with sugar and propels you toward enjoying diabesity. According to current research, it is a great way to knock 12 years off your life span while significantly increasing your rate of heat attack and stroke. And as an added bonus diabesity massively increases your chance of having a leg or foot amputated.

The second is the damaging effects of Aspartame (Nutra-sweet) the artificial sweetener has on the nervous system. Aspartame is in all diet, pepsi max and coke zero products. It is not safe. It makes you put on weight even though it is in a ‘diet’ drink. And it acts as a neurotoxin – destroys nerve cells within the brain.

Finally and as basic principle or core value, we should be looking to reduce a chemical load – not increase it.

Our bodies get hammered with so many chemicals each day. Some external and others internal.

We wash in chemicals, we are exposed to them through our daily activities at work and home.

Our food is radiated (such as tomatoes) and ‘harmless’ chemicals are sprayed on produce so they look shiny when we pick them up in the supermarket.

You cannot medicate your way out of an illness you eat yourself into.

Food for thought.


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