Kidney Problems and Alcohol
Evidence is clear that AUD causes severe liver damage and convincing data exists that links AUD to cardiovascular diseases. However, data linking any amount of alcohol use to kidney damage has major discrepancies. Although the data on a direct link is unclear, it is likely that chronic AUD’s negative effects on the liver function through indirect means.
Alcohol and Kidney Stones
The most often cited reason that alcohol could cause kidney stones is the fact that alcohol consumption leads to dehydration, but empirical data that supports this claim is scarce. Similarly, alcohol-induced pH changes could potentially affect kidney stone development, but again, data is lacking. Moderate alcohol consumption has been shown to be protective against kidney stones.
Alcohol and Kidney Disease
Whether alcohol directly contributes to kidney disease is controversial. However, the link between AUD and liver and cardiovascular diseases is well established, as are links between the liver, cardiovascular diseases and reduced kidney function.
In addition, chronic AUD causes substantial injury to several other organ systems that affect kidney function, including the gastrointestinal tract and even muscle tissue. When organs are injured, they release molecules that promote inflammation and damaging oxidation (which is why antioxidants became such a hit as a diet supplement). The net result is that input to the kidneys from injured organ systems delivers damaging molecules and proteins that accumulate in the kidneys. Over time, the aggregation of harmful products can lead to kidney disease.
It should be noted that a number of well-designed studies have found that alcohol may be protective against kidney disease and that more alcohol offered more protection. However, the mechanism of this protection remains unclear and in light of substantial literature documenting the negative effects of chronic AUD on kidney function, the most appropriate route of action is to drink only in moderation.
Alcohol and Kidney Failure
Whether there is a conclusive link between alcohol and kidney failure remains to be determined. Much of the data that has been published is in disagreement, even within the same study. For example, a 2009 study determined that three or more drinks per day was significantly linked to increased urinary levels of a protein called albuminuria, which is indicative of kidney failure. However, the same study found that moderate to heavy alcohol consumption was protective against liver failure as measured by eGFR.
A 2013 study also found that kidney function as measured by eGFR was worse in non-drinkers compared to drinkers. The authors of the papers urge caution in interpreting the results as an indication that alcohol use can protect against kidney failure, especially considering that other reports indicate that alcohol use is associated with kidney failure. For example, a 1999 study found that consumption of more than two drinks per day was associated with end-stage renal disease (the last stage of chronic kidney disease).
Alcohol and Kidney Infection
Very little data exists on the role of alcohol in kidney infections. A 1994 study evaluated whether chronic AUD was associated with a kidney infection called acute postinfectious glomerulonephritis (APIGN) and found that AUD was a risk factor. However, their conclusion was complicated by the fact that 47% of the people they evaluated had cirrhosis, which is a sign of late-stage liver failure and indicates overall poor health. A 2008 study evaluated 86 patients with APIGN and found a history of AUD in only 2%, although the study cites statistics from research conducted in Germany and France between 1976 and 1993 that reported a history of AUD in 57% and 30% of patients, respectively. Taken together, the data does not provide a convincing link between alcohol use and kidney infection.