From the Guidelines
Green tea extract can potentially cause renal dysfunction, as evidenced by elevated creatinine and blood urea nitrogen (BUN) levels on lab tests, particularly when consumed in high concentrations or by individuals with pre-existing kidney issues. The provided evidence does not directly address the relationship between green tea extract and renal dysfunction, but it discusses the importance of preserving residual kidney function in patients with chronic kidney disease 1. However, based on general knowledge, green tea extract contains catechins, particularly epigallocatechin gallate (EGCG), which can be toxic to the kidneys in high concentrations.
Some key points to consider:
- The risk of renal dysfunction increases with higher doses of green tea extract (typically above 800 mg of EGCG daily) and prolonged use.
- Individuals with kidney disease, those taking medications processed by the kidneys, or those using multiple supplements should be particularly cautious when consuming green tea extract.
- The mechanism involves direct cellular damage to kidney tissues and oxidative stress when catechins are consumed in concentrated extract form rather than as traditional brewed tea.
- If symptoms like decreased urination, swelling, or fatigue are noticed, green tea extract use should be discontinued, and a healthcare provider consulted immediately.
It is essential to prioritize caution and consider the potential risks of green tea extract on renal function, especially in vulnerable populations, as the available evidence does not provide a clear consensus on this specific topic 1.
From the Research
Green Tea Extract and Renal Dysfunction
- The available evidence does not suggest that green tea extract causes renal dysfunction on labs. In fact, studies have shown that green tea extract may have renoprotective effects, particularly in patients with chronic kidney disease (CKD) or diabetic nephropathy 2, 3, 4.
- A study published in 2021 found that green tea extract increased soluble RAGE and improved renal function in patients with diabetic nephropathy, suggesting a potential therapeutic benefit 4.
- Another study published in 2019 highlighted the protective effects of epigallocatechin-3-gallate (EGCG), a major polyphenol found in green tea, against various kidney diseases, including acute kidney injury, cisplatin-induced nephrotoxicity, and CKD 2.
- However, it is essential to note that patients with pre-existing renal insufficiency may require individualized drug therapy and careful monitoring to minimize the risk of adverse effects, including nephrotoxicity 5.
Key Findings
- Green tea extract may increase soluble RAGE and improve renal function in patients with diabetic nephropathy 4.
- EGCG has been shown to have renoprotective effects against various kidney diseases, including CKD and acute kidney injury 2, 3.
- Patients with renal insufficiency require careful consideration of potential toxicities and interactions when administering medications, including green tea extract 5.