Every day, your kidneys filter almost 180 litres of blood (the same amount of fluid that fills an average bathtub), quietly removing waste, balancing fluids and electrolytes, regulating blood pressure, and even helping produce red blood cells. Most of the time, you never notice them working. They simply do their job in the background.

But for people living with diabetes, these small multitaskers are often among the first to come under strain, with around 30-40% of individuals with diabetes developing diabetic kidney disease during their lifetime. 

To understand why diabetes affects the kidneys, it helps to understand how these organs work.

Inside each kidney sits an extraordinary network of microscopic blood vessels and filtration units known as glomeruli. You can think of them as millions of tiny coffee filters, constantly cleaning the blood. Waste products and excess fluid pass through the filter into the urine, while important components such as proteins and blood cells remain in circulation.

Persistently high blood glucose places enormous stress on this delicate system.

When blood sugar levels remain elevated over time, the pressure inside these filtration units increases. The kidney begins filtering blood at a higher-than-normal rate, a process known as hyperfiltration. While this may sound helpful, the increased pressure gradually damages the filtration structures themselves.

Over time, the filters begin to thicken and scar. Inflammation develops, and the kidneys slowly lose their ability to clean the blood effectively. Proteins that should stay in the bloodstream begin leaking into the urine, and the kidneys gradually lose their capacity to remove waste and regulate fluid balance.

Diabetes and high blood pressure are now the leading causes of kidney failure worldwide, contributing to rising rates of dialysis and kidney transplantation. Beyond the personal burden for individuals and families, this trend places growing pressure on healthcare systems.

The encouraging news is that diabetic kidney disease does not develop overnight. It usually reflects years of metabolic stress, which means it is never inevitable and there are always meaningful opportunities to intervene early.

Protecting kidney health largely comes down to protecting metabolic health:

• Stabilising blood sugar levels is one of the most powerful ways to reduce pressure on the kidneys. Eating patterns that minimise rapid spikes in blood glucose, particularly by reducing refined carbohydrates and focusing on whole, nutrient-dense foods, help to improve metabolic stability and reduce long-term strain on the body’s filtration system.
• Blood pressure control is equally important. Elevated blood pressure places additional force on the kidney’s delicate blood vessels, accelerating damage to the filtration units. Monitoring and managing blood pressure, therefore, plays a critical role in protecting kidney function.
• Physical activity and weight management also contribute to improved insulin sensitivity and overall metabolic balance. Even moderate daily movement can help stabilise blood sugar levels and reduce the physiological stress that drives long-term complications.

Perhaps most importantly, kidney health should be checked regularly in people living with diabetes. Simple blood and urine tests can detect early signs of kidney stress long before symptoms appear. Early detection also allows healthcare providers to intervene early, slowing progression and helping preserve kidney function.

The tragedy of diabetic kidney disease is that it often develops quietly, hidden behind years of subtle metabolic changes. But the opportunity lies in that same silence. When metabolic health is improved early, through diet, lifestyle, and appropriate medical care, the trajectory of kidney disease can often be slowed or even altered.

This World Kidney Day is a reminder that protecting your kidneys is not only about kidney health. It is about caring for the metabolic systems that keep your body in balance.

Small organs, working tirelessly every day… and worth protecting long before they ever ask for attention

References

CDC (2024) Kidney Failure and Diabetes, Centers for Disease Control and Prevention. Available at: https://www.cdc.gov/diabetes/data-research/research/kidney-failure-diabetes.html (Accessed: 6 March 2026).

DeFronzo, R.A., Reeves, W.B. and Awad, A.S. (2021) ‘Pathophysiology of diabetic kidney disease: impact of SGLT2 inhibitors’, Nature Reviews Nephrology, 17, pp. 319–334.

Hu, H., Ding, G. and Liang, W. (2025) ‘Dietary therapy to halt the progression of diabetes to diabetic kidney disease’, Food & Function, 16, pp. 2622–2636.

International Diabetes Federation (n.d.) Diabetes & Kidneys. Available at: https://idf.org/about-diabetes/diabetes-complications/diabetes-and-the-kidneys/ (Accessed: 5 March 2026).

Jha, R. et al. (2024) ‘Diabetes and renal complications: an overview on pathophysiology, biomarkers and therapeutic interventions’, Biomedicines, 12(5), p.1098.