Effect of red wine on the intestinal absorption of thiamine and folate in the rat: comparison with the effect of ethanol alone.
BACKGROUND
This work aimed to investigate, in the rat, the acute in vitro effect of red wine and the effect of chronic red wine ingestion on the intestinal absorption of thiamine and folate and to compare them with the effects of ethanol alone.


METHODS
The effects of red wine and of an ethanol solution (same ethanol concentration as that in the red wine, i.e., 12% [v/v]) on rat jejunal apparent permeability (Papp) to H-thiamine and H-folate in the mucosal-to-serosal direction were investigated. Red wine and ethanol were tested both chronically (21-day consumption) and acutely in vitro.


RESULTS
Acutely, both red wine and ethanol 12% (v/v) (both diluted 1:5) reduced (to 65 and 60% of control, respectively) the mucosal-to-serosal Papp to H-thiamine across rat jejunum. Chronic (21-day) ethanol (12% [v/v]) consumption also decreased the Papp to H-thiamine (to 33% of control), but red wine consumption for the same period did not change it. Mucosal-to-serosal Papp to H-folate across rat jejunum was not changed by chronic ingestion of red wine or ethanol. Similarly, it was not affected by acute exposition of the tissue to red wine or ethanol. Acute ethanol (0.05% [v/v]) did not affect the Papp to H-thiamine or H-folate in jejunal tissues obtained from control and red wine-treated rats, but it significantly increased the Papp to both H-thiamine and H-folate (to 183 and 197% of control, respectively) in tissues from chronically ethanol-treated rats.


CONCLUSIONS
Acute and chronic red wine or ethanol had no effect on the intestinal absorption of folate. However, ethanol, both acutely and chronically, decreased the jejunal absorption of thiamine, and red wine reduced the jejunal absorption of thiamine, but only when tested acutely. These findings show that it is not correct to extrapolate from results obtained with ethanol alone on intestinal permeability to the effect of alcoholic beverage consumption.