*Functional Foods and Antioxidant Effects: Emphasizing the Role of Probiotics DOI: http://dx.doi.org/10.5772/intechopen.104322*

stimulating the immune system (cellular and humoral) are other beneficial effects of probiotics to improve the gastrointestinal status and prevent colorectal cancer [2].

In the pharmaceutical and food industries, lactic acid bacteria (LAB) strains are widely used probiotics [24]. One of the beneficial effects of these probiotics on the body of patients is the improvement of the condition in metabolic diseases [22, 25] and ulcerative colitis (UC) [26–28]. Also, based on research on fish, improvement of oxidative status and promotion of immunity with probiotics, such as *Lactobacillus lactis* and *Lactobacillus rhamnosus*, are observed [29, 30].

*Bifidobacteria* are an example of another common bacterial probiotic. The beneficial effects of these probiotics include improving women with irritable bowel syndrome [31] and strengthening the immune system against tumors [32]. The presence of characteristics in *Bacillus* species has made them one of the most widely used probiotics in the food industry. One of these characteristics is the ability to produce protease, amylase, and lipase enzymes [33].

Based on the evidence, LAB strains are resistant to various types of ROS, such as superoxide anions, peroxide radicals, and hydroxyl radicals [34, 35]. Studies in recent decades show the antioxidant potential of probiotics; for example, the probiotic *Bifidobacterium animalis 01* eliminates free radicals (such as hydroxyl and anion peroxide) *in vitro* and increases antioxidant activity in mice [6]. In addition, improving the state of oxidative stress by multivitamin probiotics in people with type 2 diabetes [36] and increasing the level of antioxidants and neutralizing the effects of ROS by *Lactobacillus rhamnosus* in athletes who expose their bodies to oxidative stress [37]. Some of the studies on the relationship between probiotics and various diseases are listed in **Table 1**.


#### **Table 1.**

*Relationship between probiotic consumption and treatment of various diseases.*
