Can nutritious diet increase glomerular filtration rate

There is currently insufficient clinical evidence to prove that nutritious diet can directly increase glomerular filtration rate, but the specific effect will vary greatly depending on the individual's renal function status and cannot be generalized.

I worked in the follow-up position in the Department of Nephrology for three years, and I met many people who asked this question with their physical examination reports. The one who impressed me most was a 28-year-old Internet operator who usually only eats takeaways that are heavy in oil and salt, drinks functional drinks as water, and stays up late to catch up. During the project, he always ate barbecue as a late-night snack. The physical examination showed that the glomerular filtration rate was 89ml/(min·1.73m²), which was just 1 unit worse than the lower reference limit for normal adults. He was so scared that he thought he was going to have uremia. The doctor gave him no other advice at the time. He did not need to take medicine first, but first adjusted his diet. Do not exceed 5g of salt every day, replace all drinks with warm water, stop processed meats and desserts, and make sure to eat one pound of fresh vegetables every day. For high-quality protein, choose eggs, freshwater fish, milk and other things that are easy to digest. Don’t eat big fat meat and ribs every day. He went back and persisted for 3 months before checking again, and the filtration rate returned directly to 98. At that time, he even brought milk tea to share with us, saying that eating the right food can really "improve" the filtration rate. But we also made it clear to him at that time that his condition was not that his kidney function was really damaged at all, but that long-term eating of Haisei put too much extra burden on the kidneys. The glomerulus is like a small sieve in the kidney. You pour "garbage" of heavy oil and salt on it every day to block the holes, which naturally filters slowly. If these extra burdens are removed, the sieve itself is not broken, and the work efficiency will naturally return to what it should be. It is not that diet really supplements your kidney function.

Of course, not everyone will see an increase in filtration rate when they adjust their diet. If there is clear chronic kidney damage, the effect will be completely different. I previously followed up a 42-year-old patient with stage 2 hypertension and chronic kidney disease. When he was found, his filtration rate had dropped to 62. He strictly followed the doctor's instructions to eat a low-protein diet, supplemented with ketoacid supplements, and controlled salt and sugar very strictly. After a review almost a year later, the filtration rate was stable between 63 and 66 at most, and never rose above 70. The director in charge also said that for patients whose kidney parenchyma has been damaged, a nutritious diet can at best slow down the decline of the filtration rate. If it can stabilize it and prevent it from falling, it is already a very good effect. It is impossible to "repair" the damaged kidney by eating and return the filtration rate to normal levels.

There are now a few small-sample studies in the academic community that indicate that for patients with early-stage diabetic nephropathy, accurately adjusting the intake ratio of Omega-3 and dietary fiber may lead to a small rebound in filtration rate. However, there is no large-sample evidence to support this conclusion. Most scholars in the industry still prefer that this is a reduction in the metabolic burden on the kidneys, rather than a nutritional diet that directly improves glomerular function.

To be honest, you really don’t need to blindly look for dietary supplements with the mentality of “relying on eating to increase filtration rate”. Even taking kidney-tonifying supplements may put extra burden on the kidneys. If you really find out that the filtration rate is abnormal, you should first consult a doctor to evaluate whether it is a transient burden or real kidney damage, and then adjust your diet accordingly.