Can a nutritious diet increase glomerular filtration rate?

There is currently insufficient evidence-based medical evidence to support that nutritious diet can directly increase glomerular filtration rate, but reasonable nutritional intervention is indeed one of the core means to delay the decline in glomerular filtration rate and even assist in reversing the early decline in filtration rate in some acute kidney injuries.

For people with completely normal kidney function, the glomerular filtration rate is basically stable in the range of 90-120ml/min/1.73㎡. Not to mention eating nutritious meals, no matter how many supplements claimed to be "kidney-protecting", it is impossible to raise the value out of thin air. If it is really a physical examination, If the filtration rate is found to be above the normal upper limit, you should be wary of glomerular hyperfiltration, which will deplete the kidney reserve function in the long run. Many young people who eat high-protein fitness meals and like to drink carbonated drinks occasionally find that the filtration rate is high, mostly due to this reason.

Two years ago, I followed up a 32-year-old patient with acute interstitial nephritis. When the disease first started, his filtration rate dropped to 58. The renal biopsy results showed that there was no irreversible fibrotic damage. We customized a very low-protein diet with alpha ketone for him. The sour diet plan strictly controlled salt and phosphorus, and also specifically helped him get rid of his habit of drinking Laohuo soup and eating pickled vegetables. After two and a half months, his filtration rate returned to 89, basically back to the basic level before the onset of the disease. But this was not actually a nutritional diet that “improved” his filtration rate. Rather, after removing the triggers for kidney damage, nutritional intervention helped reduce the metabolic burden on the kidneys, allowing the nephrons that had only been temporarily “on strike” to resume normal work.

There are many small studies now mentioning that supplementing antioxidant nutrients such as Omega-3 polyunsaturated fatty acids and proanthocyanidins may improve renal microcirculation and have a mild positive effect on filtration rate. However, these conclusions have not been verified with large samples and are only targeted at specific susceptible groups, and are not universal at all. I have also encountered many patients who falsely believed in the rumor that "diet therapy can increase the filtration rate". They originally had stage 3 chronic kidney disease and their filtration rate had been stable at 62 for several years. They heard that eating cordyceps and astragalus stewed chicken could make up for it. After eating it for more than three months, their filtration rate dropped to 56 during the reexamination, and they were also found to have hyperphosphatemia. To put it bluntly, they did not take the correct supplements, which put extra metabolic pressure on the kidneys, which was not worth the gain.

Many people have misunderstandings about nutrition and kidney protection. They think that they need to supplement enough nutrition to "restore" kidney function. In fact, for patients who have suffered from chronic renal damage, the key is to appropriately "reduce" the burden. It is like reducing the burden on an old car that has traveled hundreds of thousands of kilometers. Don't pull too heavy cargo and don't step on the accelerator so that you can drive longer. It is now clearly mentioned in the global kidney disease guidelines that patients with chronic kidney disease can slow down the annual decline in glomerular filtration rate by about half if they adhere to a high-quality, low-protein diet. Even if the value cannot be raised, if the value can be stabilized or reduced, it is already the best effect of nutritional intervention.

If an abnormality in filtration rate is detected, don’t rush to find dietary prescriptions. First, consult a nephrology department to determine whether the injury is acute or chronic, and then contact a clinical nutrition department to customize a personalized diet plan. Don’t blindly search for recipes to supplement the kidneys. After all, the kidneys are too delicate, and eating the wrong food is more harmful than not eating at all.