A recent case study published in The American Journal of Clinical Nutrition highlights the potential dangers of the carnivore diet, particularly its impact on kidney stone risk. The research delves into a patient's experience with recurrent kidney stones and how switching to an all-meat diet influenced his condition. The findings suggest that while the carnivore diet may offer short-term benefits, it can significantly increase the risk of kidney stones due to metabolic imbalances and gut microbiome disruption.

Understanding the Patient's Journey and Diet Impact

The case revolves around a 61-year-old man who had a long history of kidney stones, gout, hypertension, and diabetes. Initially asymptomatic after his first stone at age 45, he began experiencing more frequent and painful episodes from age 55 onwards. Despite multiple treatments, including shock wave therapy and medications, his condition worsened. His urine analysis revealed high levels of calcium, oxalate, uric acid, and supersaturation for calcium phosphate and oxalate, despite adequate fluid intake.

Intrigued by a YouTube video promoting the carnivore diet as a remedy for gout, the patient adopted a 90% meat-based diet. While some risk factors improved initially, others worsened, notably urine calcium and uric acid levels. By age 68, after discontinuing the diet, he no longer passed stones but still exhibited elevated citrate, urea nitrogen, and protein catabolic rate levels. This case underscores the importance of evidence-based dietary practices over trendy fad diets, especially concerning kidney health.

Exploring the Mechanisms Behind Increased Stone Risk

The carnivore diet's lack of fiber and plant-based nutrients can disrupt the gut microbiome, contributing to increased kidney stone formation. Urine supersaturation levels, which indicate the concentration of minerals beyond their solubility, spiked for calcium oxalate, calcium phosphate, and uric acid during the patient's time on the carnivore diet. High animal protein consumption elevates uric acid excretion and reduces protective urinary citrate levels, promoting stone growth. Conversely, adequate fluid and calcium intake can help prevent stone formation by diluting urine and binding oxalate.

Research suggests that dietary fiber plays a crucial role in reducing kidney stone risk by influencing gut microbiota and urine pH. Without fiber, the carnivore diet may lead to gut dysbiosis, further exacerbating nephrolithiasis risk. To mitigate these risks, patients should focus on lowering sodium intake, reducing red meat consumption, and increasing fruits and vegetables like citrus fruits, bell peppers, broccoli, and bananas. These foods provide essential citrate, which helps prevent calcium stone formation. Additionally, raising dairy consumption can bind oxalate in the gastrointestinal tract, reducing absorption and decreasing the likelihood of calcium oxalate stones.