Coumarin (Deer Tongue)

Coumarin, which imparts a vanilla-like flavor and is a flavor fixative, was used as a food and tobacco additive for many decades. It was especially valued by tobacco product designers as a flavor booster in low-tar brands. Most commercial use was abandoned when it was discovered that coumarin caused liver damage in both rats and dogs and was suspected of being carcinogenic.

Some background on the B&W attitude toward coumarin is reflected in the January 1978 minutes of an internal BAT Additives Guidance Panel meeting on November 15, 1977 {1310.02}. The minutes indicate that numerous additives were approved for use, and that coumarin received special consideration:

The Hunter Committee [an independent committee in the UK which advised the government on smoking and health] have now considered the Final Report from BIBRA [British Industry Biological Research Association, a report apparently sponsored by BAT (see below)] but were unable to approve levels as high as those recommended by the panel at their last meeting. The reason for this was that the Hunter Committee took into account not only the intake of coumarin from tobacco smoking but also that likely to be ingested from foods in normal diets having a content of natural coumarin. Accordingly,

for the United Kingdom: THE PANEL RECOMMENDS THAT WHERE COUMARIN IS USED AS A TOBACCO ADDITIVE THE RATES OF APPLICATION SHOULD NOT EXCEED

While the limits by the Hunter Committee must be observed in the U.K. the Panel saw no reason to modify their general recommendation of revised limits (740ppm for cigarette tobacco and 1500ppm for pipe tobacco) for other countries, where no legal restriction is imposed. {1310.02, pp. 1–2}

In other words, BAT would observe the UK's prescribed limit on coumarin for products sold in the United Kingdom but not for products sold elsewhere.

On June 6, 1984, E. E. Kohnhorst, sent Thomas Sandefur a memo on coumarin in response to an inquiry from Sandefur {1320.02}. In this memo Kohnhorst indicates that R. J. Reynolds's Now and Vantage cigarettes had coumarin in them in 1982 and 1983, respectively, but the 1984 products no longer did, and efforts were under way to remove coumarin from the "RALEIGH/FIESTA flavor package."

Coumarin is specifically rejected by FDA for use on foods. This rejection was based on very questionable animal studies; but, the FDA has not lifted the ban.

BAT sponsored a study by B ritish I ndustry B iological R esearch A ssociation [BIBRA] on coumarin. The BIBRA study, which is published, showed that coumarin is of no health risk in long-term feeding to baboons.

Presented with the BIBRA results, the UK Independent Committee on Smoking and Health (Hunter, Frogget) lifted this past refusal to allow use of coumarin on tobacco products. This was published in the London Gazette. So, coumarin can be used in the UK and other areas under English influence. BAT (Germany) presented the BIBRA finding to their government decision-makers and were subsequently granted limited approval to use coumarin. This was with low delivery cigarettes (need flavor to induce good smoking quality). There was the requirement to repeat the early studies on coumarin to show they were in error. This accounts for cautious, limited use.

The BAT Additives Guidance Panel (AGP), since the BIBRA findings, has opened [opined?] that coumarin can be used.

BARCLAY originally had coumarin (12 ppm), but it was removed from the flavor formula in November, 1982 . Export cigarettes produced by B&W have not contained coumarin since June, 1983 . We do not sell licensees/associates coumarin or coumarin-containing botanicals [emphasis in original]. {1320.02, pp. 1–2}

Two weeks later, C. J. Rosene wrote General Counsel Ernest Pepples (with a copy to Kohnhorst) about coumarin substitutes {1320.01}:

There are no compounds or formulated flavors available to us that can accurately replace coumarin as a flavor on tobacco. Coumarin itself and natural substances containing coumarin are prohibited from direct addition to food as cited under 21 CFR [Code of Federal Regulations ] 189.130.

Two homologs, 6-methylcoumarin and dihydrocoumarin, exhibit coumarin-like qualities on tobacco but neither can be used as a direct replacement. Both compounds are FEMA-GRAS but are not listed as approved direct food additives by FDA.

We currently use an IFF [International Flavorings and Fragrances, Inc.]-formulated coumarin substitute on BARCLAY . It does not match coumarin very well either.

Attached is a list of domestic brands containing vanillin, mace oil, and glycerin, added either as pure compounds or as part of proprietary flavors. {1320.01}

While FEMA regarded the listed coumarin substitutes as "Generally Recognized as Safe," the FDA did not.

The following month, on July 19, Dr. Sam R. Evelyn from BAT's research laboratory in Southampton sent Kohnhorst a packet of material from his files on coumarin. The material includes reports and site visits to labs conducting animal studies on coumarin as well as a letter from a pathologist at the FDA who had re-reviewed slides from a supposedly positive animal study of carcinogenesis; he had not confirmed the initial report of cancer but had confirmed that coumarin caused liver damage. While the background material Evelyn provided his colleague at B&W is generally negative or noncommittal, his letter indicates that current work with coumarin-feeding experiments was showing some instances of metastatic cancer in the animals. He speculated that such results would likely lead some countries to ban coumarin from tobacco products {1323.02}. Even though the United States had not eliminated coumarin from tobacco as of 1994, it did not appear on a list of cigarette additives released by the six major cigarette manufacturers (2).