The Real Pumpkin Spice Latte: Cancer-in-a-Cup?

It’s fall! And you know what that means…pumpkin spice latte season! (Or just PSL for everyone on social media.)

Pumpkin spice is all the rave. And it seems to be getting better (or worse) each year (depending on your point of view). I’ll spare you from the gluttonous lists of pumpkin spice flavored products and just say that taking a stroll through a supermarket (or perusing down your Pinterest page) is all you need to do to notice the trend. (Deep-fried pumpkin spice, anyone?)

I will leave it to your discretion to decide if the pumpkin spice burrito is indeed a real thing or not...but beware falling into the pumpkin spice rabbit hole of the internet.
I will leave it to your discretion to decide if the pumpkin spice burrito is indeed a real thing or not…but beware falling into the pumpkin spice rabbit hole of the internet.

Let’s cut to the real question that’s on every pumpkin spice latte drinker’s mind: Will drinking pumpkin spice lattes give you cancer?


It comes as no surprise that you may be at risk for diabetes if you habitually drink three sugar-laden lattes a day…but cancer?

As preposterous as it sounds, this is a claim that blogger Vani Hari, better known as “Food Babe,” made last fall. And the carcinogenic culprit?…caramel food coloring.

Starbucks has been under pressure for the past year to change their pumpkin spice latte recipe to include real pumpkin (which it didn’t before, but not without good reason) and also to get rid of the caramel food coloring. In August 2015, Peter Dukes, the man who led the creation of the pumpkin spice latte back in 2003, recently released a statement saying that the beloved beverage would now include real pumpkin puree and no longer use caramel food coloring.

So what’s the big deal with caramel food coloring?

Caramel food coloring is used in all kinds of products, including whiskey, beer, condiments, soft drinks, and before this fall, the pumpkin spice latte. There are four classes of caramel food coloring categorized by the reactants used during manufacturing. Class IV caramel food coloring, which is used in soft drinks and the old pumpkin spice latte, contains a chemical called 4-methylimidazole, or just 4-MEI for short.

The organic structure of 4-methylimidazole, from Wikipedia Commons.
The organic structure of 4-methylimidazole, from Wikipedia Commons.

A study published in 2007 and funded by the National Toxicology Program determined that 4-MEI was actually carcinogenic and toxic in mice and rats:

“Under the condition of the present studies 4MI induced alveolar/bronchiolar adenoma and carcinoma in male and female mice. 4MI also induced clonic seizures and mononuclear cell leukemia in female rats…”

Basically, when the mice were fed 4-MEI in their drinking water, they were more likely to develop lung cancer, and females in particular were more likely to develop leukemia. This study was published back in 2007 though, so why is 4-MEI still in allowed food?

Well, 4-MEI is indeed in many foods, but it is not added directly. Rather, it occurs as a byproduct during the cooking process through a chemical reaction called the Maillard reaction (which I briefly mentioned in a previous post about the science of sugar). For example, 4-MEI forms when coffee beans are roasted and when meats are grilled, so you’ve probably been exposed to it regardless of whether you indulge in pumpkin spice lattes or not. Furthermore, it is important to note that 4-MEI is found as a trace impurity in class III and IV caramel food coloring, meaning in minuscule amounts.

In regards to the National Toxicology Program (NTP) study, the FDA says:

FDA 4MEI safe
From the FDA webpage on the safety of caramel food coloring.

“These NTP studies were conducted in rodents at levels of 4-MEI that far exceed current estimates of human exposure to 4-MEI from the consumption of Class III and Class IV caramel coloring in food products such as colas.”

The Center for Food Safety in Hong Kong put it this way:

“Based on the highest detected level of 4-MI in cola drinks (i.e. 153 micrograms per 12 fl. oz. or about 360 mL) as reported by a U.S. policy advocacy organisation, a 60-kg individual would have to consume over 300 cans of that cola drink a day to reach the doses causing cancer in rodents after applying an uncertainty factor of 100.”

So at the moment, the risks from 4-MEI in caramel food coloring, if indeed there are any, seem minimal. None of this was news in 2014, and yet Starbucks decided to do away with the caramel food coloring in their pumpkin spice latte likely due to pressure from consumers. From a health perspective, this change was probably unnecessary.

In fact, Starbucks may have been doing us a favor by leaving caramel food coloring in our favorite fall beverage.

Be not disheartened my friend, after all this talk of cancer, the pumpkin spice latte still loves you.
Be not disheartened my friend, after all this talk of cancer, the pumpkin spice latte still loves you.

A brief study published in 2011 re-examined the 4-MEI cancer study. They found that:

“…dose-related, statistically significant decreases in multiple tumors were observed in both male and female rats exposed to 4-MEI in the NTP bioassay. For example, 4-MEI was associated with a 25-fold decrease in the incidence of mammary tumors among high dose females.”

In other words, while 4-MEI increased the likelihood of some cancers, namely lung cancer and leukemia, it decreased the likelihood of other cancers including breast and pituitary gland cancers. The author claims that the cancer preventative properties of 4-MEI were overshadowed in the report since the funding for the study was focused on toxicology. Of course, no one is advocating that Starbucks purposefully put 4-MEI in their beverages, because it still does seem to carry some toxicity. The point is that these issues are never as straightforward as they seem.

This is evident from another short paper published in 2012 which re-examined the original NTP study and concluded that the authors should have said there was “some evidence” as opposed to “clear evidence” of carcinogenicity from 4-MEI based on the NTP’s interpretation of other studies involving lung cancer.

I guess it turns out that a simple interest in pumpkin spice lattes can lead to discussions on much bigger issues in the interpretation and dissemination of medical information, especially where toxicology and carcinogenicity are involved.

The lesson learned here? Cancer is complicated, and it is easy to just look at the data that supports your opinions. All that aside, your “fall-in-a-cup” is probably not any more likely to be “cancer-in-a-cup” than most other foods we consume. As for the amount of sugar our beloved pumpkin spice lattes contain…well, let’s just not go there…So until next time, keep on enjoying that pumpkin spice, because peppermint mocha season will be here before you know it!

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