**3. Impact on lipoprotein**

444 Lipid Metabolism

**2. Antioxidant effect** 

Probiotic yoghurt containing *Lactobacillus acidophilus* La5 and *Bifidobacterium lactis* Bb12

Probiotic yoghurt containing *Lactobacillus acidophilus* LA-5 and *Bifidobacterium* BB-12

There are some reports that fermented soy milk by probiotics also showed favorable function of regulating lipids level [12]. The advantages of fermented soy milk are that undesirable soybean oligosaccharides can be hydrolysed which provide nutritional components for probiotic and a large variety of peptides and amino acids are produced as well as active aglycon form of isoflavones [13]. An improved cholesterol profile was observed with daily intake of a probiotic soy product [14]. It seems possible that living

Probiotic originated from longevity research by the well-known Eli Metchnikoff. As we all known, various published evidence suggested reduction of oxidative stress led to longevitypromoting consistent with Harman's Free Radical Theory of Aging [15]. These two

Oxidative stress induced by obesity tend to produce surplus reactive oxygen species (ROS) which may cause further damage by free radical chain reaction mechanism [16]. ROS have some deleterious effects on polyunsaturated lipids in cell membrane leading to damage of cell structure and malondialdehyde (MDA), which was also toxic to DNA and protein and formed as a marker of lipid peroxidation at the same time [17] [18]. As for the oxidative stress, human body has its own antioxidant defense system including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) , glutathione (GSH) and so on [19]. Many *Lactobacillus* strains with antioxidative effects were not only reducing MDA level, but

Strains Model Antioxidant effects Renferences

Serum MDA concentration

Increased erythrocyte glutathione reductase levels, plasma glutathione and 8-oxo-7,8-dihydroguanine levels

A decrease of MDA and increase of SOD and GSH-Px in serum and liver

Increased total antioxidant capacity, SOD and GSH-Px activity in serum as well as hepatic CAT and muscle SOD; Decreased MDA level in serum and muscle

significantly decreased [20]

[21]

[22]

[23]

probiotics and functional isoflavones cooperated in regulating lipid profile.

observations inspired the investigation of antioxidant ability of probiotics.

Type 2 diabetic patients

Pregnant Women

rat

also enhance the antioxidants production (Table1).

*Lactobacillus casei* Zhang High-fat fed

*Lactobacillus fermentum* pigs

Lipoprotein transport play an important role in accumulation of host lipopolysaccharide level (LPS) [33]. Studies by Cani et al showed that elevated LPS level was considered as a trigger factor involved in the pathogenesis of obesity and metabolic risk via innate immune mechanism [34]. LPS-binding protein (LBP) and lipoproteins exert a synergistic effect on reducing the toxic LPS level[35].

Several fermented milk containing probiotics were demonstrated to reduce low-density lipoprotein cholesterol(LDL-c) level and very-low-density lipoprotein cholesterol (VLDL-c) in animal and human [26] [36] [37].Recently, *L. casei* Shirota had been proved a plasma LBPlowering effect in obesity mice and *L. reuteri* NCIMB 30242 yoghurt could improve ApoB-100 level in hypercholesterolaemic subjects, suggesting that probiotic possess LPS-reducing function to delay the obesity risk [38] [39].
