In previous articles I’ve written about advanced glycation end-products and acrylamide, molecules that are formed by cooking foods at a high temperature (greater than 250ºF), which have been shown to shorten lifespan and to cause cancer, respectively. In this article I will discuss a third molecule, furan, that is also formed during cooking foods at a high temperature, and, has also been shown to cause cancer.
Furan at a dose of 2 mg/kg body weight (bw) and 4 mg/kg bw has been shown to cause bile duct cancer in rats and liver cancer in mice (National Toxicology Program, 1993; Moser et al. 2009). In addition, rats given a dose of 4 mg/kg bw furan were found to have a significant increase in liver cancer and leukemia. Furthermore, although a dose of 0.5 mg/kg bw did not cause cancer in mice, this amount was found to be toxic to the liver (Moser et al. 2009). Unfortunately, long term studies on the toxicity and carcinogenicity of furan in humans have yet to be conducted.
Using the lowest dose of 2 mg/kg/bw for carcinogenicity, how does this translate into human consumption? For a 120 lb woman (54.5 kg) and a 160 lb. man (72.7 kg), 109 and 145.4 mg, respectively, can be considered as a safe upper limit. So, in which foods is furan found?
Tables 1-3 lists the concentration of furan in various foods and beverages. The full furan list can be found at http://www.fda.gov/Food/FoodSafety/FoodContaminantsAdulteration/ChemicalContaminants/Furan/ucm078439.htm.
In Table 1 we find that furan is found in both coffee and expresso. In fact, of the four coffee products on this list, expresso has the highest concentration of furan. An average value of 52 µg/kg furan was reported to be found in brewed coffee by Morehouse et al. (2008). Relative to the other foods and beverages on the furan list, it is likely that coffee consumption is the greatest contributor to one’s daily furan load. For example, using the average furan value of 52 µg, consuming 16 oz. (2 cups; 0.45 kg) of coffee per day results in 24 µg total furan. In addition, Folgers French Roast coffee also has the carcinogen acrylamide in it, at a concentration of 240 µg/kg. That’s a double whammy of carcinogen-laden coffee!
However, the safe daily limit for furan is between 109-145 mg, an amount that differs from the furan amount found in coffee by a factor of more than 4000. In other words, there is 4000-fold less furan found in coffee than would be necessary for an increased risk of furan-related toxicity. Interestingly, coffee consumption has been linked to improved liver health (Klatsky et al. 2006), evidence that argues against the furan found in coffee as a potential health threat.
Table 2 shows that furan is also found in conventional baby/toddler foods. An average value of 25 µg/kg of furan in baby food was determined by the European Food Safety Authority in 2009.Considering a baby/toddler body weight of 10-15 kilograms, the upper limit for furan toxicity for this population would be less than 30 mg. Consumption of ~6 ounces/day of the highest furan containing Gerber foods found on this list would result in a furan exposure of ~20 µg, an amount that is still 1500-fold less than the safe upper limit.
Table 3 shows that furan is found in canned/jarred foods, including soup, baked beans, soy sauce, prune juice (which also contains 239 µg/kg acrylamide), pasta sauce, jam/jelly, and, canned vegetables and fruit. Similar to coffee and baby food, although consumption these foods won’t result in the adult’s diet coming within ~1000-fold of the safe upper limit for furan exposure, it’s important to know that it’s there.
Furan is also found in pretzels, commercially prepared cereals (Kellog’s All Bran, Cheerios), Cheetos, Pringles and Fritos. Considering the carcinogen acrylamide is also found in Cheerios (266 µg/kg), pretzels (386 µg/kg) and Pringles (693µg/kg) it would be wise to stay away from these double-carcinogen containing foods.
Although the amount of furan that’s found in these foods are far less than the amount that causes cancer in rodents, it’s important to know that it’s there, so that as an educated consumer you can choose to eat it or not. Because of the data regarding the carcinogen-creating effect of heating foods at a high temperature, I now eat as close to raw (and organic, non GMO) as possible. There is no furan, acrylamide or advanced glycation end product risk there!
EFSA. Technical report of EFSA prepared by Data Collection and Exposure Unit (DATEX) on “Monitoring of furan levels in food”. EFSA J 304:1-23.
Klatsky AL, Morton C, Udaltsova N, Friedman GD. Coffee, cirrhosis, and transaminase enzymes. Arch Intern Med. 2006 Jun 12;166(11):1190-5.
Kuballa T, Stier S, Strichow N (2005). Furan in Kaffee and Kaffeegetranken. Deutsche Lebensmittel-Rundschau 101:229-235.
Morehouse KM, Nyman PJ, McNeal TP, Dinovi MJ, Perfetti GA. Survey of furan in heat processed foods by headspace gas chromatography/mass spectrometry and estimated adult exposure. Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2008 Mar;25(3):259-64.
Moser GJ, Foley J, Burnett M, Goldsworthy TL, Maronpot R. Furan-induced dose-response relationships for liver cytotoxicity, cell proliferation, and tumorigenicity (furan-induced liver tumorigenicity). Exp Toxicol Pathol. 2009 Mar;61(2):101-11.
National Toxicology Program (1993) Toxicology and carcinogenesis studies of furan (CAS No.110-00-9) in F344 rats and B6C3F1 mice (gavage studies). Natl Toxicol Program Tech Rep Ser 402:1-286.