New Approaches to Coping with the Damage to Kidneys Caused by Excessive Intake of Processed Foods

A huge population consume large amounts of ready-to-eat foods such as bread, biscuits, and various snacks every day, which have been highly or overly heat-processed. During the processing, the chemical structure of the food is changed, thereby prolonging their shelf life, palatability, and sensory characteristics. It may also stimulate the reward center of the brain and cause excessive intake. Many studies showed that processed foods rich in fat, sugar, and salt are harmful to health, which associate with the risk of all-cause mortality, diabetes, non-alcoholic fatty liver disease, hypertension, obesity, cancer, and gastrointestinal diseases. The poor understanding of the specific mechanisms of how processed foods affect health currently urges the research to determine the molecular mechanism between long-term intake of processed foods and the occurrence and development of non-communicable diseases. Recently, a research team from Monash University published a research paper entitled "Processed foods drive intestinal barrier permeability and microvascular diseases" in Science Advances. The study shows that certain compounds in processed foods can lead to the risk of chronic kidney disease, and that foods containing highly resistant starch fibers can alleviate their negative effects, thereby restoring intestinal health and improving kidney health. Multiple studies showed that the potentially pathogenic components of processed foods are harmful compounds called advanced glycosylation end products (AGEs) that are triggered by a mixture of amino acids and reducing sugars through the Maillard reaction process to stimulate the human body's inflammatory response and chronic kidney disease. Maillard reaction (also called non-enzymatic browning reaction, or carbonyl amine reaction) is common in the heat treatment and processing of food, such as frying, frying, baking, and roasting, which will happen quickly when the temperature reaches a certain level. It elevates the flavor and aroma of food. Those compounds are widely added to processed foods, such as potato chips, bread, biscuits, and chocolate and candy because they can make the food attractive in terms of color, fragrance, and flavor. In this study, researchers fed a group of rats with hot processed food for 24 weeks. As heat treatment can increase the content of AGEs in the food, the rodent food heated for 60 minutes had increased Nε-carboxymethyl lysine (CML), Nε-carboxyethyl lysine (CEL), and fructosamine without destroying heat-resistant vitamins. It was found that heat-processed food induced albumin to penetrate into the urine, which was 5 times higher than that of the control diet, which was consistent with kidney damage. The intake of heat-processed food also leads to other characteristics of early chronic kidney disease, including increased creatinine clearance caused by renal overfiltration and morphological changes in the kidney glomeruli. It is known that tubulointerstitial fibrosis is a prominent feature of progressive chronic kidney disease, and heat-processed food leads to an increase in the expansion of the tubular interstitium, resulting in the deposition of extracellular matrix components in the tubular spaces. Transforming growth factor-β1 (TGF-β1: https://www.creative-biolabs.com/target-tgfb1-271.htm) plays a major part in renal fibrosis in chronic kidney disease, which, after long-term consumption of hot processed foods, in the renal cortex is activated, and vascular endothelial growth factor increases. This is consistent with the destruction of the microvascular structure. Researchers also found that heat-processed food induces innate immune complement activation and causes local kidney inflammation and damage through the pro-inflammatory effector molecule complement 5a (C5a). Moreover, intaking processed foods will increase the permeability of the intestinal barrier, thereby increasing the risk of microvascular disease. In diabetic mouse models, a highly resistant starch fiber diet maintains the integrity of the intestinal barrier and reduces the severity of kidney damage by inhibiting complement. These results prove the mechanism by which processed foods cause inflammation and chronic diseases. The foods rich in highly resistant starch fibers include oats, rice, barley, beans (such as black beans and peas), potatoes that are cooked and cooled, and high corn resistant starch supplements. The study represents an important progress in understanding and coping with the harmful effects of modern diets. Like most behavioral changes, dietary changes may be difficult in the long term, but by adding more highly resistant starch-fiber foods, and cooking methods such as steaming and stewing, the harmful effects can be mitigated.