Consumption of home-made spirits is one of the main source of exposure to higher alcohols and there may be a link to immunotoxicity

Reply to:

Dirk W. Lachenmeier, Jürgen Rehm. What is the main source of human exposure to higher alcohols and is there a link to immunotoxicity? June 2013, Vol. 35, No. 3, pages 451–453. doi: 10.3109/08923973.2013.794147.

Dear Editor,

We are grateful to Dr. Lachenmeier and his colleague for their interest in our article1. We were surprised by his comments but wonder whether they reflect a difference in terminology in that we included aliphatic alcohols in illegally produced spirits within the category of “contaminants”. Dr. Lachenmeier claim that 1-propanol, 1-butanol and isobutanol are considered as “flavouring agents” when spirits contain these substances at certain concentrations2. However, those manufacturing spirits seek to avoid their presence at high levels, while methanol, also a component of some spirits, is not a “flavouring agent”2. We believe that, regardless of the choice of terminology, it is important to know whether the presence of these substances in alcoholic beverages has an impact on human immune system, so justifying our investigation.

In our previous work, we found that aliphatic alcohols were more frequently present in home-made spirits than in commercial spirits3. We detected methanol in 82% (13% in commercial spirits), 2-butanol in 94% (55% in commercial spirits), 1-propanol 100% (81% in commercial spirits), isobutanol in 100% (81% in commercial spirits), 1-butanol 47% (6% in commercial spirits) and isoamyl alcohol in 100% (71% in commercial spirits) of the home-made spirit samples. Furthermore, the concentration of aliphatic alcohols was significantly higher in home-made spirits than in those of from commercial sources3. This is consistent with Dr. Lachenmeier’s own research where he also found higher alcohols more common in unrecorded products (samohon for personal use or for sale) than in commercially manufactured alcohol (vodka)4. Where we differ is our view about the relative amount of legally and illegally produced spirits being consumed, but this is not something that can be resolved definitively with the data available. If it is felt necessary, the meaning of our “critical sentence” could be easily resolved by modifying it as follows: “Consumption of contaminated unrecorded alcohols, particularly illicitly produced spirits is one of the most common forms of exposure to AAs affecting large populations worldwide”. However, we do rather feel that we are getting into semantics.

The statement that “the concentration of higher alcohols in unrecorded alcohols is significantly lower than in commercial alcohol” can be disputed for the following reasons. The average level of higher alcohols in unrecorded products shown in their Figure 1 (presented in Lachenmeier D W, Rehm J. What is the main source of human exposure to higher alcohols and is there a link to immunotoxicity? Immunopharmacol Immunotoxicol 2013;35:451--453) is derived from previous studies in which different types of unrecorded alcoholic products were analyzed. These included home-made spirits, illegally imported and untaxed alcohols, smuggled alcoholic beverages, counterfeit or relabeled alcohols, surrogate alcohols, medicinal alcohols, wines and beers from several European countries4–8. However, these studies were not representative and suffer from two important limitations. First, the collection of samples was not systematic and, except in Poland, Russia and Ukraine, only unrecorded products were obtained and examined but their commercially produced, and thus recorded, counterparts were not compared. Second, although to the World Health Organization’s definition of unrecorded alcohol encompasses all of the products tested, this is actually a very heterogeneous group, being produced from different raw materials (grain, a variety of fruits and grapes), by different technologies, including fermentation and brewing (beer), fermentation (wine), fermentation and distillation (spirits)9,10. In addition, some smuggled alcohols are industrially produced, subject to quality control and recorded in their countries of origin9. Consequently, their quality may not differ from their counterparts obtained from legal sources. As a result, their comparison, in Figure 1, may be biased by inclusion of unrecorded alcohols with low concentrations of higher alcohols, including vodka, surrogate alcohols, medicinal alcohols, smuggled alcohols, illegally imported and untaxed alcohols, analyzed by Dr. Lachenmeier in his previous studies4–8. When the concentration of higher alcohols in commercial spirits was compared with those of home-made spirits, the level of aliphatic alcohols proved to be significantly higher in home-made spirits3. Therefore, until sufficient representative samples of different types of unrecorded alcohols and their recorded and quality controlled counterparts from different European countries have been analyzed, it is premature to state that “the concentration of higher alcohols in unrecorded alcohols is significantly lower than in commercial alcohol”.

As described in our study, toxicokinetic studies have demonstrated that the concentration of higher alcohols and ethanol in the blood of alcoholics after ingestion of beverages contaminated with aliphatic alcohols are within the ranges of 0.01–0.10 mM and 10 mM, respectively11. In the presence of ethanol, aliphatic alcohols inhibited phagocytosis at a concentration of 0.05 mM, which was within the range observed in alcohol abusers11. However, the peak concentrations of methanol and 1-propanol in the blood of alcoholics have been reported to be as high as 10.0 mM and 0.22 mM, respectively11–13. Therefore, we reiterate that the key contribution of our article was to show that aliphatic alcohols of home-made spirits may inhibit phagocytosis in episodic heavy drinkers at the concentrations tested in our study, regardless of their source. We also noted that further research is needed to address this question. Until then, it is premature to make any firm recommendations for policy.

Declaration of interest

The authors report no conflict of interest. The authors alone are responsible for the content and writing of the letter.

The work commented by Dr. Lachenmeier and Dr. Jürgen Rehm was supported by the National Development Agency (Contract No.: TÁMOP 4.2.2./B-10/1-2010-0024 and TÁMOP 4.2.1./B-09/1/KONV-2010-0007), TÁMOP-4.2.2.A-11/1/KONV-2012-0031 and Ministry of National Resources (Contract No. 1EVJ 1NB0 EGPL 320). The project was co-financed by the European Union and the European Social Fund.