Polycyclic aromatic hydrocarbons in whiskies

A State-of-the-Science Review of Alcoholic Beverages and Polycyclic Aromatic Hydrocarbons

BACKGROUND

The association between alcohol and certain cancers is well established, yet beyond ethanol and its metabolite acetaldehyde, little is known about the presence of other carcinogenic compounds in alcoholic beverages, including polycyclic aromatic hydrocarbons (PAHs), such as benzo[a]pyrene (a Group I carcinogen).

OBJECTIVES

We summarized the published literature on PAH levels in alcoholic beverages to identify potential gaps in knowledge to inform future research.

METHODS

Medline and Scopus were searched for primary research published from January 1966 to November 2023 that quantified PAH levels among various types of alcoholic beverages, including whisky, rum, brandy, gin, vodka, wine, and beer. Studies that were not primary literature were excluded; only studies that quantified PAH content in the specified alcoholic beverages were included.

RESULTS

Ten studies published from 1966 to 2019 met the criteria for review. Other than beverage type, no publication reported selection criteria for their samples of tested alcohol products. Studies used a variety of analytical methods to detect PAHs. Of the 10 studies, 7 were published after 2000, and 6 assessed < 20 products. Of the studies, 7 examined spirits; 3, beer; and 4, wines. Benzo[a]pyrene was most prevalent among spirit products, particularly whisky, with values generally exceeding acceptable levels for drinking water. Some beer and wine products also contained PAHs, albeit at lower levels and less frequently than spirit products.

DISCUSSION

PAHs are found in some alcohol products and appear to vary by beverage type. However, there is an incomplete understanding of their presence and levels among large, representative samples from the range of currently available alcohol products. Addressing this gap could improve understanding of alcohol-cancer relationships and may have important implications for public health and the regulation of alcohol products. In addition, novel methods, such as direct mass spectroscopy, may facilitate more thorough testing of samples to further investigate this relationship. https://doi.org/10.1289/EHP13506.

Effect of Temperature Range and Kilning Time on the Occurrence of Polycyclic Aromatic Hydrocarbons in Malt

Kilning is an integral part of malt production; it ensures grain and enzyme preservation. Kilning temperatures can range between 80 and 220 °C, depending on the type of malt that is being produced. Polycyclic aromatic hydrocarbons (PAHs) are prone to appear at higher temperatures and are generally designated as undesirable in food and beverages. Sixteen PAHs are framed in legislation, but there is a lack of scientific data related to PAHs in malt, malt-related foods (bread, cookies) and beverages (whisky, malted non-alcoholic beverages). The aim of this paper was to assess and quantify the occurrence of different PAHs in malts exposed to different kilning temperatures (50-210°) over a variable time frame. The results indicate that some of the PAHs detected at lower temperatures disappear when malt is exposed to high temperatures (>100 °C). Phenanthrene was no longer detected at 100 °C and indeno [1,2,3-cd] pyrene at 130 °C, while fluorene, anthracene and benzo (a) anthracene were not quantified at 170 °C. The results of this research can be implemented in food safety legislation since foods available to children utilize malted flour (bread, cookies, bakery goods, etc.) due to its enzymatic activity or as a colour additive.

Polycyclic Aromatic Hydrocarbons in Malt

The kilning of malt occurs at different temperatures, depending on the desired color and aromas. Higher temperatures applied during kilning can be involved in polycyclic aromatic hydrocarbons (PAHs) formation in malt. PAHs are undesirable and designated as health hazards, it is important to quantify and qualify them in different malts. Since the European Food Safety Authority (EFSA) gave strict recommendations about PAHs in different foods, but omitted malt as a potential hazardous raw material that can cause health damage to beer consumers, the aim of this investigation was to assess the presence of 16 PAHs (naphthalene (Nap), acenaphthylene (Anl), acenaphthene (Ane), fluorene (Flu), anthracene (Ant), phenanthrene (Phen), fluoranthene (Flt), benz[a]anthracene (BaA), pyrene (Pyr), chrysene (Chry), benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), dibenz[a,h]anthracene (DahA), benzo[ghi]perylene (BghiP), and indeno[1,2,3-cd]pyrene (InP)) in different, commercially available malts (amber, black, pilsner, and cara-120). The results showed that PAHs are present in different malts, with some in high amounts (BaA in black malt was 737 µg/kg). Minimal levels of BaA were detected in the amber malt, 60.53 µg/kg. The PAH4 (BaP, BaA, BbF, and Chry) sums are identical to the BaA concentrations in all malts and greatly exceed the EFSA prescribed levels for PAH4 in processed cereal-based foods (1 µg/kg).

A gradient of mercury concentrations in Scottish single malt whiskies

Mercury (Hg) concentrations were measured in 26 Scottish single malt whiskies, and all found to be very low (<10 ng L(-1)), posing no threat to human health through reasonable levels of consumption. However, a significant south-to-north declining gradient in Hg concentrations was observed reflecting that reported for atmospheric deposition. We speculate that this gradient could be due to a combination of contemporary deposition and the legacy of industrial mercury emissions and deposition over the last 200 years affecting concentrations in local waters used in whisky production. As UK atmospheric emissions of mercury have declined by 90 % since the 1970s, we suggest that whisky being produced today should have even lower Hg concentrations when consumed in 10- to 15-years time. This reduction may be compromised by the remobilisation of contaminants stored in catchment soils being transferred to source waters, but is very unlikely to raise the negligible health risk due to Hg from Scottish single malt whisky consumption.

Interaction of alcohol use and specific types of smoking on the development of oral cancer

BACKGROUND

Oral cancer is one of the most common life threatening diseases all over the world, in particular in Asian countries, and tobacco and alcohol are considered to be the most potent risk factors for oral cancer.

OBJECTIVES

The aim of this study was to examine the combined effect of smoking types and alcohol consumption on the development of oral cancer.

PATIENTS AND METHODS

A case-control study of 350 cases and 350 controls over a period of 19 months in the time period between February 2005 and September 2006 was carried out in Pune, India. The self-reported information about their consumption of alcohol and smoking behaviors was collected by structured questionnaires. The data was analyzed by SPSS software package. Risk analysis was performed using conditional logistic regression, which provides results in the form of crude odd ratios.

RESULTS

The smoking as well as alcohol drinking rates in the subjects of the case group were significantly higher than the controls. Of smoking types, bidi (a hand rolled cigarette) (OR = 4.1, 95% CI = 2.4-6.9), and among alcohol types, hard liquor (OR = 2.6, 95% CI = 1. 4-6.4), country liquor (OR = 2.5, 95% CI = 1.3-3.6) and beer (OR = 2.2, 95% CI = 1.2-5.0), showed a strong association with oral cancer. A significant interaction effect was found between alcohol consumption and bidi smoking (OR = 19.6, 95% CI = 4.6-83.5) followed by alcohol and non-filtered cigarette (OR = 4.2, 95% CI = 1.8-12.0) as well as filtered-cigarette (OR = 2.3, 95% CI = 1.1-5.0).

CONCLUSIONS

We conclude that oral cancer is etiologically related to the interaction between smoking and drinking.

Comparison of polycyclic aromatic hydrocarbons (PAHs) between smoked marc spirits and whiskies

The presence of polycyclic aromatic hydrocarbons (PAHs) in three brands of smoked marc spirits, the only actually on the market, was studied and compared with literature PAHs concentrations reported for whiskies. In two brands of smoked marc spirit the higher-molecular-weight PAHs concentrations (5 and 6 rings PAHs) resulted higher (0.09-0.3 microg L (-1)) than in whiskies (0.00-0.02 microg L(-1)) and consequently higher resulted the carcinogenic potential expressed using the toxicity equivalent factor (TEF).

Determination of polycyclic aromatic hydrocarbons in alcoholic drinks and the identification of their potential sources

Some polycyclic aromatic hydrocarbons (PAHs), particularly those with a high molecular mass, have been classified as probably being carcinogenic to humans by the International Agency for Research on Cancer (IARC). The significance of the determination of PAHs is reflected by the special attention the European Union is paying to regulating their maximum allowed levels in various types of foodstuffs. Like tobacco and smoked meats, alcoholic drinks can also contain these carcinogenic chemicals, as the latter have been detected in the charred insides of barrels, some ingredients such as caramel or the smoke released during the drying of germinated barley in beer or whisky. This paper determined the contents of seven PAHs in alcoholic beverages of variable alcoholic strength that had been aged in charred barrels for different times (months, years). The aim was to elucidate the dependence of the formation of seven PAHs on the type of charring (traditional or convective) used and the charring intensity (light, medium or heavy). Based on the results, the way the tree raw material is toasted strongly influences PAH levels in alcoholic drinks; thus, traditional charring produces increased amounts of PAHs from the wood relative to convective toasting. The sum of the analysed PAH concentrations in the aged alcoholic beverages studied ranged from zero for a white wine to 172 ng l(-1) for a 'brandy de jerez solera'. The carcinogenic indicator benzo[a]pyrene was found at concentrations below 10 ng l(-1). These PAH concentrations in alcoholic beverages are very low relative to those in smoked and char-broiled foodstuffs. Any health hazards, however, can be minimized by using convective toasting to manufacture the barrels where the drinks are to be aged.

Alcohol-related diseases of the mouth and throat

Chronic consumption of alcoholic beverages is an accepted social custom worldwide. In the upper aerodigestive tract, local morphologic, metabolic and functional alterations are present due to alcohol consumption. A clinical link between the chronic consumption of alcohol and head and neck cancer has been observed for decades. While alcohol was described initially as a risk enhancer only in smokers, a number of epidemiological studies have now provided sufficient evidence that chronic alcohol consumption increases the risk of head and neck cancer independent of exposure to tobacco smoke. The systemic effects of alcohol interact with local changes in the morphology and function of the salivary glands. In addition, alcohol leads to accumulation of pathologic microbes within the mucosa, leading to chronic infection. Susceptibility to carcinogens and cell proliferation in the mucosa are increased, resulting in genetic changes with the development of dysplasia, leukoplacia and carcinoma. Chronic alcohol consumption is correlated with an increased risk of cancer and an increased mortality in a dose-effect relationship. A number of biologically plausible mechanisms exist by which alcohol may cause cancer. These mechanisms are discussed in this article.

[Alcohol related diseases of the head and neck]

Chronic consumption of alcohol is an accepted social custom worldwide. In the upper aerodigestive tract, local morphologic, metabolic and functional alterations can be present due such consumption. Gastroesophageal reflux or alterations in sleep structure are typical examples of functional disorders. While alcohol was initially described as a risk enhancer only in smokers, a number of epidemiological studies have now shown that chronic alcohol consumption increases the risk of head and neck cancer independently of exposure to tobacco smoke. In addition, alcohol leads to an accumulation of pathologic microbes within the mucosa, leading to chronic infection. Susceptibility to carcinogens and cell proliferation in the mucosa are increased, resulting in genetic changes with the development of dysplasia, leucoplakia and carcinoma. Chronic alcohol consumption is correlated with an increased risk of cancer and increased mortality in a dose-dependent relationship. A number of biologically plausible mechanisms exist by which alcohol may cause cancer.

Alcohol-related diseases of the mouth and throat

Chronic consumption of alcoholic beverages is an accepted social custom worldwide. In the upper aerodigestive tract, local morphological, metabolic and functional alterations can be present as a result of alcohol consumption. A clinical link between the chronic consumption of alcohol and head and neck cancer has been observed for decades. While alcohol was described initially as a risk enhancer only in smokers, a number of epidemiological studies have now provided sufficient evidence that chronic alcohol consumption increases the risk of head and neck cancer independent of exposure to tobacco smoke. Systemic effects of alcohol interact with local changes in the morphology and function of the salivary glands. In addition, alcohol leads to the accumulation of pathological microbes within the mucosa, leading to chronic infection. Susceptibility to carcinogens and cell proliferation in the mucosa are increased, resulting in genetic changes with the development of dysplasia, leucoplakia and carcinoma. Chronic alcohol consumption has been correlated with an increased risk of cancer and increased mortality in a dose-effect relationship. A number of biologically plausible mechanisms exist by which alcohol may cause cancer. These mechanisms are discussed in this chapter.

Possible mechanisms by which alcohol may influence the development of oral cancer--a review

Although pure ethanol has never been shown to be carcinogenic in laboratory experiments, alcoholic beverages are now recognised as being important aetiological factors in the development of oral cancer. Despite this, the exact mechanism by which alcohol may exert an influence upon the oral mucosa has received less attention. An overview of the association of alcohol and oral cancer, both in combination with tobacco and without, is provided and consideration given to some of the pathways by which alcohol exerts its effect upon the oral mucosa.

Aetiology of oral cancer: alcohol

The effect of alcohol alone on the oral mucosa and its association with the development of oral cancer is difficult to establish, principally because alcohol consumption histories are difficult to verify, alter over time, both with respect to beverage type and quantity, and are frequently confounded by tobacco use. This review considers the various pathways by which alcohol may exert such an influence. Namely, due to topical exposure (e.g. direct effect on cell membranes, altered cell permeability, variation in enzymes that metabolise alcohol) and/or systemic effects (e.g. nutritional deficiency, immunological deficiency, disturbed liver function). Finally, the numerous papers that have sought to establish the relative risk for oral cancer in association with alcohol intake are reviewed.