Can nutritious diet increase glomerular filtration rate

First of all, let me make it clear that there is currently no evidence-based medical evidence that relying on nutritious diet can directly increase the glomerular filtration rate that has suffered irreversible damage. However, scientific nutritional management is the core method to delay the decline of filtration rate and even help some people with kidney damage return their filtration rate to their baseline level.

我在肾内科营养门诊待了快五年，碰上太多一坐下来就问“大夫我吃啥能把滤过率补上去”的患者，有个32岁的肾炎早期患者我印象特别深，刚查出来的时候肾小球滤过率只有72，尿蛋白也有1+，他之前做互联网运营，天天加班顿顿外卖配冰可乐，周末还爱跟朋友撸串到半夜，后来按我们给的饮食方案调整，每天盐控制在一啤酒盖以内，蛋白质选鸡蛋、牛奶、瘦肉这类优质的，量按他的体重算每天刚好50g左右，加工肉、甜饮料全戒了，半年后复查滤过率回到了88，他当时特别开心，说果然吃对了能提滤过率，我赶紧给他泼了点冷水——这哪里是“提高”，明明是之前的坏习惯把肾脏压得喘不过气，本来能正常干活的肾单位被迫降了功率，现在减负了，肾功能回到了它本来的水平而已。

Think about it, the nephron is like the filter element in our water purifier, it is non-renewable. If it has been completely fibrotic and necrotic due to long-term damage, no matter how you adjust your diet, you cannot revive the dead nephron. Naturally, it is impossible to bring the irreversibly reduced filtration rate back to normal. However, there are exceptions, such as patients with acute kidney injury, such as taking cold medicine that damages the kidneys, or transient renal failure caused by severe dehydration. The nephrons are only temporarily "on strike" without necrosis. At this time, precise nutritional support can indeed help the kidney function recover faster, and the filtration rate can return to the baseline before the illness. This is a special situation.

There are many opinions on the Internet now, for example, a low-protein diet plus keto acids, or a ketogenic diet can increase the filtration rate. In the past two years, there were indeed small-sample studies on patients with obesity-related kidney disease. After losing weight and combining a low-GI diet for half a year, the filtration rate of some patients increased slightly. However, the academic community generally believes that this is because after weight loss, the high filtration state of the kidneys that was forced to work overload was corrected. In essence, it is a callback after offloading, and it does not really repair the damaged nephrons. As for the claim that taking Cordyceps sinensis, Astragalus membranaceus or various Internet celebrity kidney-protecting supplements can improve the filtration rate through dietary therapy, there is currently no large-scale clinical evidence to support it. Instead, many random supplements of unknown ingredients have been encountered, and the originally stable filtration rate has been reduced by more than a dozen patients. It is a pity.

If your physical examination shows that your filtration rate is slightly lower than normal, don’t rush to buy kidney protection products. First, recall whether you stayed up late, ate anything too oily or salty, or exercised strenuously before the examination? Adjust your diet for two to three months. Eat less processed foods that are high in salt, sugar, and oil. Don’t overdo it in protein. Drink more water and don’t hold your urine. Then go for a reexamination. If the filtration rate picks up, it’s not that you ate some magical food. It’s just that your kidneys finally don’t have to do the extra work.

After all, don’t always think about eating shortcuts to increase the filtration rate. Eat well without putting extra burden on the kidneys, so that the remaining good nephrons can be used for decades longer. This is the most practical way to protect the kidneys.