Jun 092012
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Lets review the scientific evidence linking alcohol consumption with leaky gut syndrome.

Increased intestinal permeability to macromolecules and endotoxemia in patients with chronic alcohol abuse in different stages of alcohol-induced liver disease looked at couple alcoholics with Alcoholic Liver Disease (ALD) as well as healthy controls.  Found leaky gut in alcoholics drawing a conclusion that the bacterial toxins crossing the gut barrier contribute to the inflammatory process of the ALD. Endotoxins were five times higher in the blood of alcoholics compared to healthy folks which is a potential sign of leaky gut.  We have to be careful on the causation as the study results could be interpreted also in a way that it is the inflammatory process that causes leaky gut not the other way round.

„The results of this study indicate that alcohol abuse impairs the function of the intestinal barrier, which might enhance the translocation of bacterial toxins, thereby contributing to inflammatory processes in alcoholic liver disease.”

"alcohol abuse impairs the function of the intestinal barrier, which might enhance the translocation of bacterial toxins, thereby contributing to inflammatory processes in alcoholic liver disease"

Recent Advances in Alcoholic Liver Disease I. Role of intestinal permeability and endotoxemia in alcoholic liver disease considers ethanol and acetaldehyde (ethanol’s metabolic derivate) as factors disrupting epithelial tight junctions thus causing leaky gut.

This study Alcohol, burn injury, and the intestine claims that alcohol intoxication at the time of burn injury suppresses intestinal immunity and impairs barrier function possibly by altering bacterial growth.

The differing effects of acute and chronic alcohol on gastric and intestinal permeability

„Chronic ethanol reversibly affects the integrity of small intestinal villi without significantly affecting gastrointestinal permeability. In contrast, a single oral dose of ethanol increases gastroduodenal permeability but has no effect on the lactulose or mannitol permeability of the small intestine. These regional changes in gut permeabilities may contribute to alcohol-induced GI symptoms.“

Effects of ethanol and acetaldehyde on tight junction integrity: in vitro study in a three dimensional intestinal epithelial cell culture model

„These results indicate that ethanol at concentrations found in the blood after moderate drinking and acetaldehyde, alone and in combination, can increase the intestinal epithelial permeability.“

Alcohol, intestinal bacterial growth, intestinal permeability to endotoxin, and medical consequences: Summary of a symposium
"Alcohol exposure can promote the growth of Gram-negative bacteria in the intestine, which may result in accumulation of endotoxin. In addition, alcohol metabolism by Gram-negative bacteria and intestinal epithelial cells can result in accumulation of acetaldehyde, which in turn can increase intestinal permeability to endotoxin by increasing tyrosine phosphorylation of tight junction and adherens junction proteins. Alcohol-induced generation of nitric oxide may also contribute to increased permeability to endotoxin by reacting with tubulin, which may cause damage to microtubule cytoskeleton and subsequent disruption of intestinal barrier function. Increased intestinal permeability can lead to increased transfer of endotoxin from the intestine to the liver and general circulation where endotoxin may trigger inflammatory changes in the liver and other organs. Alcohol may also increase intestinal permeability to peptidoglycan, which can initiate inflammatory response in liver and other organs. "

Effect of daily ethanol ingestion on intestinal permeability to macromolecules
"regular ingestion of sizable amounts of alcohol alters morphological characteristics of the gut and increase the permeability of the mucosa to undigested macromolecules"

The leaky gut of alcoholism: Possible route of entry for toxic compounds

"Patients abstaining from alcohol for less than 4 days almost invariably had higher intestinal permeability than controls, and in many the abnormality persisted for up to 2 weeks after cessation of drinking"

Effect of acute ethanol administration on the intestinal absorption of endotoxin in rats

Acute ethanol administration increases intestinal permeability before pathological changes are revealed by light microscopy. Acute ethanol ingestion, especially at high concentrations, facilitates the absorption of endotoxin from rats' small intestine via an increase in intestinal permeability, which may play an important role in endotoxemia observed in alcoholic liver injury
Long-term ethanol feeding enhances susceptibility of the liver to orally administered lipopolysaccharides in rats.

„Long-term ethanol feeding increases intestinal permeability to and absorption of endotoxin, which can sequentially enhance hepatic susceptibility to orally administered endotoxin.“

Differential effects of T-cell activation on gastric and small bowel permeability in alcohol-consuming mice.

„Overall, these data suggest that alcohol potentiates the effects of T-cell activation on gastric permeability, at the same time blunting effects on small bowel permeability.“

Endotoxin and Kupffer Cell Activation in Alcoholic Liver Disease describes mechanisms that may be contributing to leaky gut following alcohol consumption:

“Several mechanisms may underlie the significant increase in endotoxin levels in the bloodstream following chronic alcohol use.

"In addition, increased absorption of endotoxin from the intestine may play a role in alcohol–induced liver disease"

"Researchers found that, in rats, acute ingestion of high alcohol concentrations facilitated the absorption of endotoxin from the animals’ small intestine by increasing intestinal permeability—that is, the degree to which the cell wall allows the passage of various molecules, including endotoxin, into the blood"

"Other studies have shown that high alcohol concentrations can directly damage the cells lining the interior of the intestine (i.e., the intestinal epithelium), thereby impairing the ability of the epithelium to serve as a barrier preventing access of unwanted substances from the intestine to the bloodstream."

"Interestingly, females have higher levels of endotoxin in the blood after chronic alcohol exposure than do males (Kono et al. 2000a), suggesting that females may be more susceptible than males to alcohol–induced increases in gut permeability to endotoxin. These variations may be related to differences between male and female hormone systems, because researchers have demonstrated that gut permeability is significantly increased in animals treated with the female hormones estradiol and progesterone (Konno et al. 2002). Whether this mechanism explains the long–standing observation that women are more susceptible than men to alcohol–induced liver damage, however, has yet to be determined. "

Acetaldehyde-induced Barrier Disruption and Paracellular Permeability in Caco-2 Cell Monolayer found acetaldehyde (which is a result of alcohol metabolism) causing leaky gut.

To sum up any amount of alcohol causes intestinal damage however not all studies made the link to leaky gut a clear cut. As the short term effects of alcohol on intestinal permeability seem to last 4-14 days it could be advisable to stay away from foods that can cross the epithelial barrier like gluten, lactose, fructose for that period of time.

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