**4. Treatment recommendations**

It has been seen in general terms that the inhibition of the production of uremic toxins derived from the production of intestinal bacteria may have a potential use. There are certain bacteria that assist the small intestine; however, if its population is depleted or otherwise overstimulated and grows, then an increase in population may also cause a problem. There are some potential therapeutic effects on using decreasing the amount of protein in the diet and the use of some substances (**Table 2**) [34].

#### **4.1 Low-protein diets**

Low-protein diets could be helpful, since by decreasing the intake of amino acids, the production of uremic substances can be reduced. Diets with animal protein (meat) increase the production of nitrogenous waste products, increase the risk of constipation, and worsen uremia. Strategies to reduce the amount of animal protein and increase the intake of vegetable protein may have an impact on decreasing glomerular hyperfiltration [35].

It has been evaluated that low-protein diets can slow the progression of chronic kidney disease. However, patients do not reach the goal stipulated in the recommendations of low-protein diets of 0.6–0.8 g/kg/day. One strategy would be to supplement diets with essential amino acids or ketoanalogs [36]. It is important that diets for patients must be modulated, since a very strict diet could lead the patient to a state of malnutrition [37].

#### **4.2 Probiotics**

Probiotics are a group of living species of known bacteria (*Lactobacillus acidophilus*, *bifidobacterium longum*, and *streptococci*) that administered orally and have shown to decrease some levels of potentially toxic substances such as homocysteine, indoxyl sulfate, cytokines (TNF-α, IL-5, IL-6), and pro-inflammatory endotoxins in patients with chronic kidney disease [38–40].


#### **4.3 Prebiotics**

Prebiotics are a non-digestible food ingredient that promotes the growth of beneficial microorganisms in the intestines. The majority of them are a subset of carbohydrate groups and oligosaccharide carbohydrates (OSCs), like fructo-oligosaccharides and galacto-oligosaccharides. By providing energy sources for the gut microbiota, prebiotics can modulate the composition and function of these microorganisms and can modify the gut environment [41]. The fermentation products of prebiotics are mostly acidic, thus lowering the intestinal pH. This can contribute to a change in the composition and population of the intestinal microbiota, and in some cases, the fermentation of a prebiotic complex is a substrate for another microorganism [42]. Prebiotics are found in fruits, vegetables, and whole grains like apples, artichokes, asparagus, bananas, barley, wheat, oat, onions, and green vegetables but are also added to some foods. The use of prebiotics decreases the production of indoles and p-cresyl sulfate due to the production of short-chain fatty acids (SCFAs), which provides energy to the intestine, and allows the amino acids that reach the colon to be incorporated into the bacteria and therefore excreted, instead of being used to generate uremic solutes [43].
