From the Research
Reduced water intake can cause a reduced estimated glomerular filtration rate (eGFR), as evidenced by the body's response to dehydration, which decreases blood volume and blood pressure, temporarily lowering the glomerular filtration rate. When you don't drink enough water, your body becomes dehydrated, triggering hormonal changes that affect kidney filtration rates. The kidneys respond to dehydration by conserving water and producing more concentrated urine. This is why patients are typically advised to be well-hydrated before blood tests that measure kidney function. For accurate eGFR results, it's recommended to maintain normal hydration by drinking about 1.5-2 liters of water daily, with particular attention to hydration in the 24 hours before kidney function testing.
According to a study published in 2022 1, the relation between plain water intake and progression to kidney failure appears to be U-shaped, with both low and high intake potentially being harmful in patients with chronic kidney disease (CKD). The study found that high plain water intake was significantly associated with faster eGFR decline.
Key points to consider:
- Dehydration can lead to a temporary reduction in eGFR, which is usually reversible once proper hydration is restored.
- The physiological mechanism involves the body's attempt to maintain blood pressure and conserve water when intake is insufficient.
- Maintaining normal hydration is essential for accurate eGFR results, and patients should drink about 1.5-2 liters of water daily.
- The relationship between water intake and kidney function is complex, and both low and high intake may have negative effects on kidney health in certain populations, as suggested by the study published in 2022 1.
In terms of morbidity, mortality, and quality of life, it is essential to prioritize proper hydration to prevent dehydration-related kidney damage and to maintain optimal kidney function. While the evidence suggests that reduced water intake can cause a reduced eGFR, it is crucial to consider the individual's overall health status, kidney function, and other factors that may influence the relationship between hydration and kidney health.