论文快览！植物性饮食：慢性肾脏病儿童医学营养治疗的“时尚”还是未来？

Plant-based diets: a fad or the future of medical nutrition therapy for children with chronic kidney disease?

植物性饮食：慢性肾脏病儿童医学营养治疗的“时尚”还是未来？

Pediatric Nephrology, 2023

儿科肾病学，2023

    Plant-based diets are growing in popularity worldwide due to the importance of reducing the population’s ecological footprint as well as an emerging role in the prevention and treatment of chronic human diseases. In adults, plant-based diets have been shown to be beneficial for preventing and controlling conditions that are common  in patients with chronic kidney disease (CKD), such as obesity, hypertension, type 2 diabetes, dyslipidemia, and metabolic acidosis. Emerging evidence suggests that the higher fiber content of plant-based diets may help to modulate production of uremic toxins through beneficial shifts in the gut microbiome. The effects of the plant-based diet on progression of CKD remain controversial, and there are no data to support this in children. However, knowledge that the bioavailability of potassium and phosphorus from plant-based foods is reduced has led to recent changes in international kidney-friendly diet recommendations for children with CKD. The new guidelines advise that high potassium fruits and vegetables should no longer be automatically excluded from the kidney-friendly diet. In fact, a plant-based diet can be safely implemented in children with CKD through building the diet around whole, high fiber foods, avoiding processed foods and using recommended cooking methods to control potassium. The health benefits of the plant-based diet compared to omnivorous diets in children with CKD need investigation.

    由于减少人口对生态影响的重要性以及在预防和治疗人类慢性疾病方面的新作用，植物性饮食在世界范围内越来越受欢迎。在成年人中，植物性饮食已被证明有利于预防和控制慢性肾脏疾病（CKD）以及常见的疾病，如肥胖、高血压、2型糖尿病、血脂异常和代谢性酸中毒。新出现的证据表明，植物性饮食中较高的纤维含量可能有助于通过肠道微生物的变化来调节尿毒症毒素的产生。植物性饮食对CKD的影响仍然存在争议，没有数据支持儿童疾病的这一观点。然而，由于植物性食物中钾和磷的生物利用度降低，最近国际上对儿童CKD友好的饮食建议发生了变化。新指南建议，高钾水果和蔬菜不应再被自动排除在肾脏友好型饮食之外。事实上，植物性饮食可以安全地在儿童CKD中实施，方法是使用全高纤维食物构建饮食，避免加工食品，并使用推荐的烹饪方法来控制钾摄入。与杂食性饮食相比，植物性饮食对儿童CKD的健康益处需要进一步调查。

 

    A plant-based diet is defined as a diet that predominantly contains nutrients from plant-based sources such as fruits, vegetables, nuts, seeds, whole grains, legumes, and plant oils, with limited animal-based products such as low-fat dairy, poultry, and fish.

    植物性饮食是指主要含有来自植物性来源的营养素的饮食，如水果、蔬菜、坚果、种子、全谷物、豆类和植物油，以及有限的动物性产品，如低脂乳制品、家禽和鱼类。

 

    Plant-based diets include proteins derived from plant sources, as well as complex carbohydrates and a higher proportion of unsaturated fats compared to traditional non-plant-based diets. Additionally, plant-based diets typically contain lower amounts of total, saturated, and trans fats. Plant-based diet also contain modest amounts of phytosterols (plant sterols and stanols structurally related to cholesterol) which form the structural components of plant membranes. The plant-based diet also contains bioactive plant-derived compounds called phytonutrients and is rich in dietary fiber, both of which are associated with positive health effects. Plant-based diets are growing in popularity due to their role in preventing several chronic diseases in adults. Their role in children with chronic diseases is less well defined. Almost no data exist on the role of plant-based diets in children with CKD, and therefore, benefits have been extrapolated from adult studies.

    与传统的非植物性饮食相比，植物性饮食包括来源于植物的蛋白质，以及复杂的碳水化合物和更高比例的不饱和脂肪。此外，植物性饮食通常含有较低量的总脂肪、饱和脂肪和反式脂肪。植物性饮食还含有适量的植物甾醇，它们形成了植物膜的结构成分。植物性饮食还含有一种名为植物营养素的生物活性衍生化合物，并富含膳食纤维，这两种物质都对健康有积极影响。植物性饮食因其在预防成人几种慢性疾病方面的作用而越来越受欢迎。他们在患有慢性病的儿童中的作用还不太明确。几乎没有关于植物性饮食在儿童CKD中的作用的数据，因此，从成人研究中推断其益处。

 

    In the general population, scientific data support the use of plant-based diets to improve cardiovascular disease (CVD), obesity, type 2 diabetes (T2D), hypertension, dyslipidemia, and osteoporosis. Many of these chronic diseases are interrelated.

    在普通人群中，科学数据支持使用植物性饮食来改善心血管疾病（CVD）、肥胖、2型糖尿病（T2D）、高血压、血脂异常和骨质疏松症。这些慢性病中有许多是相互关联的。

 

    Plant-based diets can help with lowering blood pressure via promotion of weight loss due to the close relationship between adiposity and blood pressure. A large meta-analysis showed that a decrease of approximately 4 mmHg in both systolic and diastolic blood pressure was achieved by losing 5kg of weight in adults, and additional reductions in systolic and diastolic blood pressures were observed in those with more than 5-kg weight loss. Furthermore, a diet rich in fruits and vegetables and low in saturated fats has been shown to effectively lower blood pressure, even in the absence of weight loss. A lower urine sodium to potassium ratio observed in those consuming plant-based proteins may be responsible for the lower blood pressure in these individuals.

    由于肥胖和血压之间的密切关系，植物性饮食可以通过促进减肥来帮助降低血压。一项大型荟萃分析显示，成年人体重减轻5公斤可使收缩压和舒张压降低约4毫米汞柱，体重减轻5千克以上的人可观察到收缩压和舒张压进一步降低。此外，富含水果和蔬菜、低饱和脂肪的饮食已被证明可以有效降低血压，即使在没有减肥的情况下也是如此。在食用植物蛋白的人中观察到的尿钠钾比较低可能是这些人血压较低的原因。

 

    The gut microbiome, a microcosm composed of trillions of highly complex communities of microorganisms, is known to affect human health and well-being and can be manipulated to attenuate the risk of obesity, T2D, cancer, and CVD. Diet has a significant impact upon the gut microbiota composition and function, and plant-based diets rich in fiber can help to promote a more favorable profile, as gut microbes help with fermentation of nondigestible carbohydrates and dietary fiber to increase production of butyrate and other short-chain fatty acids. Plant foods also contain polyphenols, flavanols, and phytochemicals, including carotenoids and phytosterols, which undergo microbial metabolization. The resulting bioactive compounds have anti-inflammatory and antioxidant activity, as do the short-chain fatty acids. Phytochemicals also increase beneficial bacteria in the gut such as Lactobacilli and Bifidobacterium. In those consuming a typical Western diet low in fiber, increased penetration of the intestinal barrier and a shift from fiber-degrading to mucus-degrading bacteria with the production of pro-inflammatory metabolites was observed. However, more studies are needed to elucidate the relationship between plant-based diets, the gut microbiome, and associated metabolic responses.

    肠道微生物组是由数万亿高度复杂的微生物群落组成的微观世界，已知会影响人类健康，并可利用以降低肥胖、T2D、癌症和心血管疾病的风险。饮食对肠道微生物群的组成和功能有重大影响，富含纤维的植物性饮食有助于促进更有利的状况，因为肠道微生物有助于发酵不易消化的碳水化合物和膳食纤维，以增加丁酸和其他短链脂肪酸的产生。植物性食品还含有多酚、黄烷醇和植物化学物质，包括类胡萝卜素和植物甾醇，它们经过微生物代谢产生的生物活性化合物具有抗炎和抗氧化活性，短链脂肪酸也是如此。植物化学物质还会增加肠道中的有益细菌，如乳酸杆菌和双歧杆菌。在那些食用典型的低纤维西方饮食的人中，观察到肠道屏障的渗透增加，并且随着促炎代谢产物的产生，细菌从纤维降解转变为粘液降解。然而，还需要更多的研究来阐明植物性饮食、肠道微生物组和相关代谢反应之间的关系。

 

    Dietary fiber can increase gastric motility by increasing the consistency and volume of the stool. The water-soluble dietary fiber contains pectin, beta-glu-cans, gums, and psyllium. These water soluble fibers form viscous gels in the gut and hence reduce the adsorption of carbohydrates, fats, and cholesterol from the diet. Soluble fiber is present in vegetables, legumes, fruits, and cereals, and insoluble fiber is present in vegetables, nuts, and whole grains.

    膳食纤维可以通过增加粪便的稠度和体积来增加胃动力。水溶性膳食纤维含有果胶、β-葡聚糖和树胶。这些水溶性纤维在肠道中形成粘性凝胶，从而减少对饮食中碳水化合物、脂肪和胆固醇的吸收。可溶性纤维存在于蔬菜、豆类、水果和谷物中，不溶性纤维存在于植物、坚果和全谷物中。

 

    There is some evidence in the literature that higher dietary fiber intake is associated with lower risk of CVD, T2DM, and obesity since they decrease the caloric and fat absorption form the diet. An intake of 25~30gm dietary fiber intake is recommended in adults to have a beneficial effect on bowel health, and reduce risk of T2DM and coronary heart disease and obesity.

    文献中有一些证据表明，较高的膳食纤维摄入量与较低的CVD、T2DM和肥胖风险有关，因为它们会减少饮食中的热量和脂肪吸收。建议成年人每天摄入25~30克的膳食纤维，对肠道健康有有益影响，并降低患T2DM、冠心病和肥胖的风险。

 

    Observational studies such as the Atherosclerosis Risk in Communities Study indicated a significant increase in incidence of CKD in individuals who consumed more red and processed meat whereas there was decreased incidence of CKD in those with higher intake of legumes, nuts, and low-fat dairy products. This is in line with a meta-analysis of 7 studies of over 15000 adults with CKD, which similarly reported an association of increased red meat consumption with increased risk of developing kidney failure. High-quality data showing clear benefits of plant-based diet in adults are lacking, and low-protein diets are not recommended for children with CKD due to the adverse effects on their growth and development.

    社区动脉粥样硬化风险研究等观察性研究表明，摄入更多红肉和加工肉的人CKD的发病率显著增加，而摄入更多豆类、坚果和低脂乳制品的人则CKD的发生率降低。这与一项针对15000多名CKD成年人的7项研究的荟萃分析一致，该研究同样报告了红肉消费量增加与肾衰竭风险增加之间的关系。目前缺乏显示植物性饮食对成人有明显益处的高质量数据，并且由于对CKD儿童的生长发育有不利影响，因而不建议对他们使用低蛋白饮食。

 

    As kidney function declines, uremia can lead to modification of the gut microbiome, denoted as “uremic dysbiosis”. This imbalance favors pathobiont overgrowth over symbiont growth. Uremic dysbiosis can be caused increased urea levels or by medications such as antibiotics, phosphate binders, and chemotherapy agents. This dysbiosis of gut microbiome can lead to detrimental effects in production of microbiota-derived metabolites and therefore could contribute to accumulation in uremic retention solutes observed in CKD.

    随着肾功能的下降，尿毒症会导致肠道微生物组的改变，称为“尿毒症微生态失调”。这种不平衡倾向于病理生物的过度生长而不是共生体的生长。尿素水平升高或抗生素、磷酸盐结合剂和化疗药物等药物可导致尿毒症生态失调。肠道微生物组的这种微生态失调会对微生物群衍生代谢产物的合成产生不利影响，因此可能导致CKD中观察到的尿毒症滞留溶质的积累。

 

    A meta-analysis of multiple studies including a total of 630108 adult participants revealed that healthy diets focused on fruits, vegetables, fish, legumes, whole grains, and fiber may lower mortality in CKD patients. Those who consumed the highest quartile of vegetable proteins had decreased risk of CKD.

    一项对包括630108名成年参与者在内的多项研究的荟萃分析显示，以水果、蔬菜、鱼类、豆类、全谷物和纤维为重点的健康饮食可以降低CKD患者的死亡率。

 

    Prebiotics are indigestible food additives that support growth of beneficial gut bacteria and limit growth of deleterious bacteria. In pre-dialysis patients, multiple studies report that supplementation of Arabic gum and fermentable carbohydrates had the ability to decrease serum urea concentrations and increase nitrogen in stool. Studies for investigating this novel therapy in CKD are limited and largely remain inconclusive. Studies are needed to further characterize the intestinal microbiome profile in CKD to identify beneficial and deleterious bacteria.

    益生元是不易消化的食物，支持有益肠道细菌的生长，限制有害细菌的生长。在透析前患者中，多项研究报告称，补充阿拉伯树胶和可发酵碳水化合物能够降低血清尿素浓度并增加粪便中的氮。研究这种新型CKD治疗方法的研究是有限的，并且在很大程度上仍然没有结论。需要进一步研究CKD的肠道微生物组特征，以确定有益和有害细菌。

 

    Beans (such as black, pinto, red, garbanzo), lentils, peas, tofu, tempeh, unsalted nuts, and natural nut butters are not only excellent sources of protein, but also contain potassium and phosphorus. To lower the potassium content in legumes, one cup of dried legumes can be soaked in six cups of water for 12h, then cooked in fresh water for 30 min on the stovetop or 15 min in a pressure cooker. Canned legumes are inherently lower in phosphorus and potassium than cooked dried beans, so using the canned product is a good strategy to reduce preparation time. However, it should be noted that canned legumes often contain added sodium, so it is recommended to look for products canned with “no added salt” and/or check the nutrition facts label for the sodium content. Canned products with added sodium should be rinsed and drained prior to use to reduce sodium content.

    豆类（如黑、花、红、鹰嘴豆）、扁豆、豌豆、豆腐、豆豉、无盐坚果和天然坚果黄油不仅是蛋白质的极好来源，而且含有钾和磷。为了降低豆类中的钾含量，一杯干豆类可以在六杯水中浸泡12小时，然后在炉灶上在淡水中煮30分钟或在高压锅中煮15分钟。罐装豆类的磷和钾含量天生低于煮熟的干豆，因此使用罐装产品是节约准备时间的好方法。然而，需要注意的是，罐装豆类通常含有额外添加的钠，因此建议使用“不添加盐”的罐装产品和/或查看营养标签中的钠含量。添加了钠的罐头产品在使用前应冲洗并沥干水分，以减少钠含量。

 

    Brown or wild rice, whole grain pasta and breads, oats, quinoa, couscous, or farro are examples of whole grain starches that can provide a healthy source of carbohydrates as part of a plant-based diet. Whole grain products are now preferred over those made with white refined flour, which are more highly processed and contain fewer nutrients, less fiber, and more preservatives.

    糙米或野生大米、全谷物意大利面和面包、燕麦、藜麦、蒸粗麦粉或二粒小麦都是全谷物的食物，它们可以作为植物性饮食的一部分，提供健康的碳水化合物。全谷物产品现在比用白色精制面粉制成的产品更受欢迎，后者经过高度加工，营养成分更少，纤维更少，防腐剂更多。

 

    Potatoes are known to be one of the richest sources of natural dietary potassium. One medium baked potato contains 926 mg of potassium. Subsequently showed that the “double boiling method” is more effective, reducing the potassium content of various types of potato by approximately 50%. As suggested by the name, the “double boiling” method involves first boiling peeled, diced potato in a pot of fresh water for 10-15 min, draining, then adding the potatoes to a new pot of fresh water and boiling for an additional 10-15 min. Alternatively, cauliflower is a vegetable that is significantly lower in potassium and can be used as a substitute for mashed potato in recipes.

    众所周知，土豆是天然膳食钾最丰富的来源之一。一个中等大小的烤土豆含有926毫克的钾。随后表明，“双煮法”可使各种类型马铃薯的钾含量降低约50%。正如名字所暗示的，“双煮”方法包括首先将去皮的土豆丁放在一壶淡水中煮10-15分钟，沥干水分，然后将土豆加入一壶新的淡水中，再煮10-15分钟。或者，花椰菜是一种钾含量明显较低的蔬菜，可以在食谱中用作土豆泥的替代品。

 

    Some of the most challenging aspects in the care of children with kidney disease include controlling hyperphosphatemia and hyperkalemia. In the past, it was thought that many of the plant-based foods that are traditionally regarded as “healthy” should be avoided by patients with kidney disease due to their objectively higher potassium and phosphate contents. However, according to the recent Pediatric Renal Nutrition Taskforce (PRNT) guidelines, plant-based foods can now be included in the kidney-friendly diet, given the lower bioavailability of potassium and phosphorus from plant sources. Because the potassium in plant foods is mostly intracellular, a significant proportion of dietary potassium is not absorbed and is excreted in feces. Similarly, naturally occurring phosphorus in plant-based foods is bound to phytate, which is not easily absorbed, since humans lack the enzyme (phytase) required to digest this compound. As such, the bioavailability of phosphorus and potassium from whole plant foods is reduced, and these foods contain other nutrients and fiber that provide additional nutritional benefits.

    肾病儿童护理中一些最具挑战性的方面包括控制高磷血症和高钾血症。过去，人们认为，许多传统上被视为“健康”的植物性食物，由于其客观上钾和磷酸盐含量较高，肾病患者应该避免食用。然而，根据最近的儿科肾脏营养工作组（PRNT）指南，鉴于植物来源的钾和磷的生物利用度较低，植物性食物现在可以被纳入肾脏友好型饮食。因为植物性食物中的钾主要是细胞内的，所以饮食中很大一部分钾没有被吸收，而是通过粪便排出。同样，植物性食物中天然存在的磷与不易吸收的植酸酶结合，因为人类缺乏消化这种化合物所需的酶，因此，全植物食品中磷和钾的生物利用度降低，这些食品含有其他营养素和纤维，可提供额外的营养益处。

 

    Overall, the bioavailability of potassium and phosphorus is lowest from plant-based sources (40-60%), higher from animal sources (70%), and highest from inorganic additives to processed foods (100%). Processed foods, whether plant-based or not, are often laced with such inorganic sodium, potassium, and phosphorus preservatives. The used of additives and preservatives are continuing to increase with the creation of ultraprocessed foods, and this phenomenon presents a hidden danger to patients with kidney disease. Added potassium may be disguised within products that are promoted as “healthy” and “low in sodium” because the sodium has been replaced with potassium chloride. The key is to choose a plant-based diet that is focused on whole, high-fiber foods, avoid processed foods, and use recommended cooking methods.

    总的来说，植物来源的钾和磷的生物利用度最低（40-60%），动物来源的磷和钾的生物利用率较高（70%），加工食品的无机添加剂的生物利用性最高（100%）。加工食品，无论是否以植物为基础，通常都含有无机钠、钾和磷防腐剂。随着过度加工食品的出现，添加剂和防腐剂的使用量不断增加，这一现象对肾病患者构成了隐患。添加的钾可能被伪装在被宣传为“健康”和“低钠”的产品中，因为钠被氯化钾取代。关键是要选择以植物为基础的饮食，重点是完整的高纤维食物，避免加工食品，并使用推荐的烹饪方法。