Alcohol consumption is a leading modifiable risk factor for global morbidity and mortality, traditionally associated with hepatic, cardiovascular, and neuropsychiatric disease. Its effects on renal physiology and chronic kidney disease (CKD), however, have received less attention. Evidence implicating alcohol in the development or progression of CKD has been mixed, with conflicting conclusions about whether moderate consumption is harmful, neutral, or even potentially protective.

Several factors likely contribute to this inconsistency. Epidemiologic studies often examine different types of alcoholic beverages, which can produce differing results, and reliance on self-reported intake raises the possibility of underestimation.

Despite these limitations, a growing body of research suggests that in patients with cardiovascular-kidney-metabolic (CKM) syndrome and other conditions, even moderate alcohol consumption may pose a risk to kidney health. In a recent analysis of 112,207 participants in the UK Biobank and 10,904 from the National Health and Nutrition Examination Survey, moderate alcohol intake (defined as 1-2 drinks per day) was associated with higher all-cause mortality among men and women with stage II CKM and among men with stage IV CKM.

The authors interpreted these findings as evidence of alcohol’s deleterious effects in individuals with metabolic risk factors, while noting conflicting findings in some subgroups.

Suzanne Watnick, MD, professor of medicine at the University of Washington, Seattle, cautioned that this and other studies cannot establish causality. Multiple confounders may influence these associations, and some observational studies have suggested a lower risk for kidney disease among regular alcohol consumers or binge drinkers than alcohol abstainers.

“But no nephrologist would suggest to their patient to drink more alcohol to improve kidney health, or engage in binge drinking,” Watnick emphasized.

What is clear, she told Medscape Medical News, is that “alcohol has a great deal of adverse impact on overall health that can subsequently impact kidney health.”

Multiple Intersecting Pathways

Questions about alcohol’s renal impact have taken on renewed significance following the release of the 2025-2030 Dietary Guidelines for Americans, which removed specific numerical limits on daily alcohol intake. Instead of recommending no more than one drink per day for women and two for men, the guidelines now advise adults to “consume less alcohol for better overall health.”

To counsel patients effectively, nephrologists need to understand how alcohol affects the kidneys. From a pathophysiologic perspective, alcohol influences renal function through multiple intersecting and primarily indirect pathways, said Watnick, who is also an American Society of Nephrology (ASN) Health Policy Scholar and chair of the ASN Policy and Advocacy Committee.

The kidneys play an integral role in filtering ethanol and its metabolites, which are excreted into the urine; in fact, ethanol concentrations in urine exceeds those in the blood or in the liver. Chronic ethanol exposure decreases renal tubular reabsorption and reduces renal function, which may cause ethanol-induced changes in membrane composition and lipid peroxidation.

Proposed mechanisms linking chronic or excessive alcohol consumption to kidney injury include sustained alcohol-induced hypertension, oxidative stress, activation of the renin-angiotensin-aldosterone system, and increased systemic inflammation. Alcohol-related liver disease, cardiomyopathy, and rhabdomyolysis can also indirectly precipitate or worsen renal dysfunction.

Heavy alcohol use has been linked to increased risk for albuminuria, accelerated decline in estimated glomerular filtration rate (eGFR), and acute kidney injury — particularly in patients with hypertension, diabetes, or exposure to nephrotoxic agents.

“Alcohol raises blood pressure, and we know that hypertension isn’t good for the kidneys,” Watnick remarked. “That can worsen kidney disease and hasten disease progression.”

Much of alcohol’s renal impact occurs through secondary mechanisms, she added. Alcohol can impair medication adherence, cause inflammation and disrupt fluid balance, and interact with drugs commonly used in patients with CKD and coexisting conditions.

David Shusterman, MD, chief physician and founder of Modern Urologist in New York City and Forest Hills, noted that “alcohol ramps up insulin demand by impairing sensitivity in the liver and muscles, forcing compensatory hyperinsulinemia to manage those glucose fluctuations.” The resulting chronic hyperglycemia promotes potentially damaging glomerular hyperfiltration.

Alcohol’s diuretic effects can further concentrate urine and dehydrating tissues, increasing risks for urinary tract infections and kidney stones, particularly in patients with recurrent infections or early CKD markers, Shusterman said.

Counseling Patients

Both experts emphasized the importance of routinely screening patients for alcohol use during kidney evaluations. Shusterman recommends using the Alcohol Use Disorders Identification Test, alongside standard laboratory tests such as urine albumin and eGFR.

“We counsel people about potassium and sodium content and watching their blood pressure,” Watnick said. “We should also ask how much alcohol they drink because we want their overall health to positively impact their kidney health.”

“There’s no science we know of which says there’s any minimum amount without effect on the body,” she added.

Watnick encourages patients who consume alcohol to discuss their intake with primary care providers, noting that even one or two drinks daily can raise blood pressure. She stresses moderation and sometimes suggests a “damp January” approach in which patients reduce rather than eliminate it altogether to help them reflect on longer-term habits and potential health benefits.

“This can get them thinking about permanent changes,” she said.

Shusterman regards the new dietary guidance as too ambiguous for many patients.

“Patients need quantifiable targets to self-monitor,” he said, adding the guidelines avoid defining what constitutes as “safe” levels of alcohol and does little to educate on risks related to cancer or kidney health.

That said, “for healthy kidneys, occasional minimal use — under one drink per day — might not overload [the kidneys], but factors like age, medications, or comorbidities lower the threshold.”

For patients with a history of kidney stones, urinary tract infections, or early CKD, Shusterman advises complete abstinence.

“It’s better to err on the side of abstinence for optimal filtration and longevity,” he said. He also raises concerns about alcohol-related testosterone dips in men aged older than 50 years.

Ultimately, both experts agreed that the best approach is nuanced and patient specific. Shusterman advocates for incorporating digital tools and “tech-integrated guidelines with personalized risk calculators to make the concept of ‘less alcohol’ more actionable.”

Watnick and Shusterman reported having no relevant financial relationships.

Batya Swift Yasgur, MA, LSW, is a freelance writer with a counseling practice in Teaneck, New Jersey. She is a regular contributor to numerous medical publications, including Medscape and WebMD, and is the author of several consumer-oriented health books as well as Behind the Burqa: Our Lives in Afghanistan and How We Escaped to Freedom (the memoir of two brave Afghan sisters who told her their story).