Natural wine is metabolized better than conventional wine. On breathalyzer measurement, it shows lower blood alcohol concentrations and slower absorption. The evidence emerges from the study-the first on the subject-conducted by a team of researchers from Turin and published in Nutrients. (1)
Natural vs. conventional wine. The study
The researchers gave 55 healthy male subjects the equivalent of 2 units of alcohol (24g total alcohol) of a white, natural or conventional wine. In two separate sessions, 3 minutes per intake, one week apart.
The wines used in the test are made with the same type of blend (same production area and variety, similar alcohol content and low residual sugar), but with different farming and winemaking techniques.
Natural wine, in fact, is distinguished by the use of grapes grown without pesticides and other agrotoxics, fermentation with wild yeasts (instead of selected commercial ones), the absence of filtration, and the minimization of technical intervention, as we have written. Characteristics that drive consumer preferences.
Natural wine, less alcohol in the blood
After ‘tasting’ the two types of wine, the volunteers were subjected to Blood Alcohol Concentration (BAC) measurements by breathalyzer. Measurements were taken every 20 minutes, within 2 hours after consumption.
Analyses have shown that-under the same amounts and conditions of intake-natural wine has lower pharmacokinetic and metabolic effects than conventional wine.
In fact, BAC, or blood alcohol concentration, was consistently lower following natural wine intake. Average:
– 0.40 mg versus 0.46 of conventional, 20 minutes after consumption,
– 0.49 versus 0.53, after 40 minutes,
– 0.52 versus 0.56 at the peak.
‘It is interesting to note that except for the peak, the median BAC measured in response to natural wine is consistently below 0.5 g/l, the maximum legal limit for driving in many countries. In contrast, BAC in response to conventional wine not only exceeds the legal limit at its peak, but also approaches the limit at T20 (after 20 minutes, ed.) and exceeds it at T40 (after 40 minutes, ed.)’.
Overall, at the peak stage of blood alcohol concentration, among those who drank 2 units of natural wine only 56 percent exceeded the 0.5 g/l limit, compared with 67 percent of those who drank the same amount of conventional wine.
Analysis of the ‘lightness’ of natural wine
The possible reasons for the different metabolization of natural wine are neither unambiguous nor proven. Overall, researchers attribute them to the different agronomic and oenological practices by which it is produced. And they analyze every aspect of it.
The dry extract of the two wines used-that is, all the nonvolatile substances in the wine, such as sugars, polyphenols, fibers and minerals-were found to be very different on physical-chemical analysis. Indeed, that of natural wine (25 g/l) exceeded the dry extract of conventional wine (18 g/l) by 1.67g. ‘This may affect the gastric emptying time and, consequently, the rate of ethanol absorption, ‘ the researchers note.
Sulfur dioxide-added in winemaking as an antioxidant and antiseptic-is another element of diversity. In natural wine, it was found to a minimal extent, 0.02 g/l, much lower than conventional (0.11 g/l). However, there is no scientific evidence of additive involvement in alcohol absorption or metabolism.
Yeasts, however, may play a role. As we have seen, natural wine is made from the spontaneous fermentation of indigenous yeasts naturally present on grapes, while conventional wines use mixtures of microorganisms (often GMOs) selected in laboratories. This results in a different wine profile in terms of amino acids and polyphenols. And the possible generation of‘other molecules that interact with absorption or with specific isoforms of alcohol dehydrogenase (ADH), the enzyme involved in the breakdown of alcohol.’ With effects therefore on wine/ethanol metabolism.
Finally, pesticides are considered as possible interferents with the absorption, metabolism and pharmacokinetics of alcohol in conventional wines. Unlike natural wine (free of agrotoxins), the conventional wine used in the study revealed the presence of two fungicides:
– iprovalicarb (45 μg/kg),
– fenhexamid (120 μg/kg).
Natural wine, doesn’t mean healthy
Although it is hypothesized that ‘natural wine consumption may have a different impact on human health than conventional wine consumption,’ the researchers do not fail to mention the toxicity of alcohol.
In one respect, wine is even considered healthy. Modest and regular consumption has been correlated by the scientific community with reduced risk for several chronic diseases, such as cardiovascular disease, osteoporosis, and diabetes. It’s all thanks to polyphenols (most present in red wine), natural antioxidants that help fight inflammation and improve plasma lipid profiles.
At the same time, international cancer prevention guidelines emphasize the direct correlation between alcohol intake and cancer risk. As well as neurological and hepatic.
The recommendation-for the generality of the healthy population-is to never exceed 2-3 units of alcohol for men, 1-2 units for women, within a day. Where one unit is 12g of ethanol, equal to about 125 ml of wine. (2) This at least is the benchmark of ‘moderate alcohol consumption‘ given by Crea-Nut (formerly Inran, National Institute for Food and Nutrition Research).
Short-term neurotoxic effects of elevated BAC include a state of euphoria or intoxication, slowed reflexes and reaction times, reduced peripheral vision, and cognitive impairment. It is no coincidence that an estimated 35 percent of road fatalities are related to alcohol consumption.
Notes
(1) Federico Francesco Ferrero, Maurizio Fadda, Luca De Carli, Marco Barbetta, Rajandrea Sethi and Andrea Pezzana. Vive la Difference! The Effects of Natural and Conventional Wines on Blood Alcohol Concentrations: A Randomized, Triple-Blind, Controlled Study. Nutrients 2019, 11, 986; doi:10.3390/nu11050986
Professional journalist since January 1995, he has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and periodicals (NumeroUno, Il Salvagente). She is the author of journalistic surveys on food, she has published the book "Reading labels to know what we eat".
