Fasting-Mimicking Diets Improved Kidney Function in Patients With Chronic Kidney Disease

A recent study, building upon previous research in animals, shows that the low-salt, fasting-mimicking diet may slow later-stage kidney disease progression.

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Researchers have discovered that a low-salt, fasting-mimicking diet (FMD) may slow kidney deterioration in patients with Stage 3 chronic kidney disease, with supporting evidence from animal studies.

A recent study included 13 participants who followed the diet over three months and found significant improvements in kidney function and inflammation markers. Animal models on the diet showed reduced kidney damage and slowed deterioration of kidney function.

The FMD is a plant-based diet that aims to mimic the effects of fasting while still allowing some food intake.

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The diet is nutrient-rich and high in fat (70 percent to 75 percent of calories) but low in calories (about 700 per day) and low in carbohydrates (less than 50 grams). It is typically followed for five-day cycles under medical supervision, especially for those with health conditions or who are on medications.

Studying the FMD in Kidney Disease

In the study published in Science Translational Medicine, researchers observed the 13 participants for three months. They ate specially designed plant-based foods for five days each month. The menu included vegetable soups, energy bars, drinks, chips, tea, and a supplement packed with minerals, vitamins, and essential fatty acids.

The researchers also tested a variation of the FMD called the low-salt, fasting-mimicking diet (LS-FMD) in rats with nephropathy, a kidney disease caused by a kidney-damaging drug called puromycin. Scientists often use this rat model to understand kidney diseases and test new treatments, as it mimics some of the damage seen in real-life kidney problems.

The team tracked various health markers throughout the study and up to a year after it ended. They looked at everything from body composition and kidney function to inflammation levels and cognitive performance. They even measured regeneration markers by looking at stem cells in the blood.

People on the diet showed better kidney function, less protein in their urine (a sign of kidney health), and reduced inflammation.

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The researchers also found that following six cycles of the LS-FMD improved glomerular function and promoted signs of podocyte (specialized kidney cells) renewal over time in the rats. Glomerular function is how well the glomeruli, small networks of blood vessels in the kidneys, are working. When functioning correctly, these tiny structures filter blood and help remove waste products and excess fluid, which then gets turned into urine.

The researchers found that the LS-FMD diet helped restore normal protein levels and improved the structure and function of kidney cells in the rats with drug-induced kidney disease, suggesting this may be because the diet changes the way specific genes work in the kidneys, supporting and encouraging the stability and health of kidney cells in the damaged rat kidneys.

FMD’s Potential for Overall Health

Previous research has shown that this type of diet may have other long-term health benefits.

A study published in February in Nature Communications found that people who followed the FMD reduced their biological age, a measure of how well our cells and tissues function, by an average of 2 1/2 years compared with their chronological age.

“This is the first study to show that a food-based intervention that does not require chronic dietary or other lifestyle changes can make people biologically younger, based on both changes in risk factors for aging and disease and on a validated method developed ... to assess biological age,” study senior author Valter Longo, a professor at the University of Southern California Leonard Davis School, said in a statement.