Natural wine is metabolized better than conventional wine. Breathalyzer measurements show lower blood alcohol concentrations and slower absorption. The evidence emerges from the study – the first of its kind – conducted by a team of Turin researchers and published in Nutrients. (1)
Natural wine vs conventional. The study
The researchers administered to 55 healthy male subjects the equivalent of 2 units of alcohol (24g total alcohol) of a white wine, natural or conventional. In two separate sessions, 3 minutes for consumption, one week apart.
The wines used in the test are made with the same type of grape blend (same production area and variety, similar alcohol content and low residual sugar), but with different agricultural and winemaking techniques.
Natural wine, in fact, is distinguished by the use of grapes grown without pesticides and other agrotoxins, fermentation with wild yeasts (instead of selected commercial ones), absence of filtration, and minimal technical intervention, as we have written. Characteristics that drive consumer preferences.
Natural wine, less alcohol in the blood
After the ‘tasting’ of the two types of wine, volunteers were subjected to measurements of blood alcohol concentration (BAC, Blood Alcohol Concentration) using a breathalyzer. Measurements were taken every 20 minutes during the 2 hours after consumption.
The analyses showed that – with equal amounts and conditions of intake – natural wine has lower pharmacokinetic and metabolic effects compared to conventional wine.
The BAC, or concentration of alcohol in the blood, was in fact always found to be lower following the intake of natural wine. On average:
– 0.40 mg versus 0.46 of conventional, after 20 minutes from consumption,
– 0.49 versus 0.53, after 40 minutes,
– 0.52 versus 0.56 at the maximum 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, the BAC in response to conventional wine not only exceeds the legal limit at its peak but approaches the limit at T20 (after 20 minutes) and exceeds it at T40 (after 40 minutes)’.
Overall, at the peak phase of blood alcohol concentration, among those who drank 2 units of natural wine only 56% exceeded the limit of 0.5 g/l, compared to 67% of those who drank the same amount of conventional wine.
Analysis of the ‘lightness’ of natural wine
Possible reasons for the different metabolism of natural wine are neither univocal nor proven. Researchers generally attribute them to the different agronomic and enological practices with which it is produced. And they analyze every aspect.
The dry extract of the two wines used – that is all the non-volatile substances of the wine, such as sugars, polyphenols, fibers and minerals – was found to be very different, in chemical-physical analysis. That of the natural wine (25 g/l) indeed exceeded by 1.67g the dry extract of conventional wine (18 g/l). ‘This may affect gastric emptying time and, consequently, the rate of ethanol absorption’, note the researchers.
Sulfur dioxide – added in winemaking as an antioxidant and antiseptic – is another element of diversity. In natural wine it was found in minimal amounts, 0.02 g/l, much lower than conventional (0.11 g/l). Moreover, there is no scientific evidence of additive involvement in the absorption or metabolism of alcohol.
Yeasts, instead, they could play a role. As we have seen, natural wine is obtained from the spontaneous fermentation of indigenous yeasts naturally present on the grape, whereas conventional wines use mixtures of microorganisms (often GMOs) selected in the laboratory. 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 the metabolism of wine/ethanol.
Pesticides, finally, 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 does not mean healthy
Although it is hypothesized that ‘the consumption of natural wine may have a different impact on human health compared to conventional wine’, researchers do not fail to remind the toxicity of alcohol.
On one hand, wine is even considered healthy. Moderate and regular consumption has been correlated by the scientific community to a reduced risk for several chronic diseases, such as cardiovascular diseases, osteoporosis, and diabetes. All thanks to polyphenols (more 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 risks.
The recommendation – for the general healthy population – is not to exceed 2-3 units of alcohol for men, 1-2 units for women, within a day. Where one unit consists of 12g of ethanol, equal to about 125 ml of wine. (2) This at least is the parameter of ‘moderate alcohol consumption’ indicated by Crea-Nut (formerly Inran, National Institute for Research on Food and Nutrition).
The neurotoxic effects short-term effects of a high BAC include a state of euphoria or intoxication, slowed reflexes and reaction times, reduced peripheral vision, and cognitive impairment. It is estimated that 35% of road accident victims are related to alcohol consumption.
Note
(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, has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and magazines (NumeroUno, Il Salvagente). Author of journalistic investigations on food, she published the book 'Reading labels to know what we eat'.
