**5. Role of prebiotics and probiotics in maintaining nutritional status**

Probiotics have been defined by the United Nations' Food and Agriculture Organization (FAO) and the WHO as 'living microorganisms that provide their host with health benefits when consumed in appropriate quantities' [4].

Prebiotics were defined by Gibson and colleagues in 2004 as 'ingredients that when selectively fermented, give rise to specific changes in gut microbiota composition and/or activity, which leads to many health benefits with regard to, for example, the wellbeing of individuals' [24].

According to the preceding analysis, it has been recently established that the microbiotics that colonise the human intestine can play an important role in causing obesity and developing other metabolic and immunological illnesses within their host. This statement is based on recent metagenomic studies that have determined that there are differences between obese individuals and those of a normal weight in terms of gut microbiota. These differences are associated with the presence of a microbial population in obese individuals, which has a greater capacity to recuperate dietary energy and/or favour the onset of chronic low-grade inflammation [25].

Some studies conducted on obese individuals in relation to their prebiotic consumption—capable of selectively stimulating a limited number of gut microbiota genres/species which results in health benefits—have demonstrated results that can be categorised by an increasing trend in satiation. This effect has been observed with inulin fibre [24].

The mechanisms implicated in satiation following the consumption of oligofructose and inulin have been associated with intestinal fermentation-induced hydrogen formation, which in turn has been correlated with a postprandial increase in plasma levels of peptides GLP-1 and PYY, which are involved in energy homeostasis through supressing the sensation of hunger (**Figure 2**) [24].

Studies carried out involving the use of probiotics to control body fat accumulation show promising results, but it is also necessary to carry out further, well-designed studies which incorporate randomised, double-blind trials with a placebo control, in order to demonstrate the efficacy of specific probiotic strains when preventing or treating the overweight and obese. In this sense, it is important to highlight that the results obtained in the trials would be specific to the strains analysed, meaning it is not possible to extrapolate the results or action mechanisms to a species or genre as a whole [4, 24].

Consequently, much remains to be done in this field. However, when putting everything in perspective, modulating the composition of gut microbiota using probiotics could be considered as a new avenue through which we can treat the overweight and obese [24].

**99**

*Gut Microbiota and Obesity: Prebiotic and Probiotic Effects*

On the other hand, prebiotics promote the absorption of minerals such as calcium, magnesium, zinc and iron due to their ability to bind to them. This thereby prevents their absorption into the small intestine to reach the colon, where they are released and subsequently absorbed. Better calcium absorption is linked to prebiotic fermentation caused by gut microbiota, which produces short-chain fatty acids and lowers luminal pH, increasing the bioavailability and passive absorption of calcium through colonocytes. It has also been proven that calcium bioavailability is improved when released through hydrolysis of a compound called 'calcium phytate', which occurs due to action of bacterial phytases present in the beneficial microbiota. It is also improved when calcium becomes more soluble as a result of an increase in the volume of water in the colon, caused by the osmotic effect of prebiotics. This increase in calcium absorption is beneficial for bone health as it increases bone mass and delays the onset of osteoporosis. This is important when considering growth periods, during which peak bone mass is reached in postmenopausal women

*Mechanisms implicated in the satiety of obese individuals related to inulin consumption.*

Prebiotics stimulate iron absorption into the colon, by increasing the soluble fraction in the cells. Zinc is necessary for the development and maturation of the skeleton, and prebiotics stimulate zinc bioavailability. Therefore, mineral is supplemented through the diet. Furthermore, prebiotics are attributed to another set of properties related to particular systemic disorders. Prebiotic carbohydrates (GOS, FOS, inulin) reduce blood pressure, as well as blood levels of glucose, cholesterol, triglycerides and phospholipids, as well as triglyceride and fatty acid synthesis in the liver, minimising

The development of obesity is not caused by one specific factor. On the contrary, it is the result of an interaction of genetic, environmental, social, lifestyle factors, etc., which transforms it into a multifactorial disorder, which explains how quickly it has become more prevalent throughout all age groups in developed countries and shows that traditional theories are not adequate to explain the complex phenom-

In recent decades and as a result of advances in science, research for 'nontraditional' etiological factors involved in an individual's excessive weight gain has begun [28]. One of these new factors is highlighted in a study on the role of probiotics and their influence on gut microbiota. It should be noted that even now few studies have been carried out on humans to elucidate the effect of these microorganisms on body

the risk of developing diabetes, obesity and atherosclerosis [25, 26].

**6. Influence of probiotics in the development of obesity**

*DOI: http://dx.doi.org/10.5772/intechopen.86672*

and in elderly people [25].

**Figure 2.**

enon of gaining body weight [27].

*Gut Microbiota and Obesity: Prebiotic and Probiotic Effects DOI: http://dx.doi.org/10.5772/intechopen.86672*

**Figure 2.**

*Oral Health by Using Probiotic Products*

ing GM as a predisposing factor for obesity [17].

example, the wellbeing of individuals' [24].

with inulin fibre [24].

include increased lipoprotein lipase (LPL) activity, increased intestinal permeability and lipogenesis [20]. Faecal microbiota transplantation studies in both healthy individuals and rats to obese receptors have shown the favourable action of the GM of the emitters towards the obese individuals, reducing the levels of glycemia, preventing the expansion of fat and regulating inflammatory processes. Studies also suggest that the reverse mechanism, that is, transplantation of intestinal microbiota from obese to healthy individuals, can transmit the development of obesity, assign-

Thanks to many randomised studies that have been carried out, it will be possible to identify the microbiota properties that are contributing to the obesity epidemic, diabetes and metabolic diseases. This will in turn allow scientists to extract information and characterise diseases with the aim to prevent or cure them [21].

**5. Role of prebiotics and probiotics in maintaining nutritional status**

with health benefits when consumed in appropriate quantities' [4].

Probiotics have been defined by the United Nations' Food and Agriculture Organization (FAO) and the WHO as 'living microorganisms that provide their host

Prebiotics were defined by Gibson and colleagues in 2004 as 'ingredients that when selectively fermented, give rise to specific changes in gut microbiota composition and/or activity, which leads to many health benefits with regard to, for

According to the preceding analysis, it has been recently established that the microbiotics that colonise the human intestine can play an important role in causing obesity and developing other metabolic and immunological illnesses within their host. This statement is based on recent metagenomic studies that have determined that there are differences between obese individuals and those of a normal weight in terms of gut microbiota. These differences are associated with the presence of a microbial population in obese individuals, which has a greater capacity to recuperate dietary energy and/or favour the onset of chronic low-grade inflammation [25]. Some studies conducted on obese individuals in relation to their prebiotic consumption—capable of selectively stimulating a limited number of gut microbiota genres/species which results in health benefits—have demonstrated results that can be categorised by an increasing trend in satiation. This effect has been observed

The mechanisms implicated in satiation following the consumption of oligofructose and inulin have been associated with intestinal fermentation-induced hydrogen

plasma levels of peptides GLP-1 and PYY, which are involved in energy homeostasis

Studies carried out involving the use of probiotics to control body fat accumulation show promising results, but it is also necessary to carry out further, well-designed studies which incorporate randomised, double-blind trials with a placebo control, in order to demonstrate the efficacy of specific probiotic strains when preventing or treating the overweight and obese. In this sense, it is important to highlight that the results obtained in the trials would be specific to the strains analysed, meaning it is not possible to extrapolate the results or action mechanisms

Consequently, much remains to be done in this field. However, when putting everything in perspective, modulating the composition of gut microbiota using probiotics could be considered as a new avenue through which we can treat the

formation, which in turn has been correlated with a postprandial increase in

through supressing the sensation of hunger (**Figure 2**) [24].

to a species or genre as a whole [4, 24].

overweight and obese [24].

**98**

*Mechanisms implicated in the satiety of obese individuals related to inulin consumption.*

On the other hand, prebiotics promote the absorption of minerals such as calcium, magnesium, zinc and iron due to their ability to bind to them. This thereby prevents their absorption into the small intestine to reach the colon, where they are released and subsequently absorbed. Better calcium absorption is linked to prebiotic fermentation caused by gut microbiota, which produces short-chain fatty acids and lowers luminal pH, increasing the bioavailability and passive absorption of calcium through colonocytes. It has also been proven that calcium bioavailability is improved when released through hydrolysis of a compound called 'calcium phytate', which occurs due to action of bacterial phytases present in the beneficial microbiota. It is also improved when calcium becomes more soluble as a result of an increase in the volume of water in the colon, caused by the osmotic effect of prebiotics. This increase in calcium absorption is beneficial for bone health as it increases bone mass and delays the onset of osteoporosis. This is important when considering growth periods, during which peak bone mass is reached in postmenopausal women and in elderly people [25].

Prebiotics stimulate iron absorption into the colon, by increasing the soluble fraction in the cells. Zinc is necessary for the development and maturation of the skeleton, and prebiotics stimulate zinc bioavailability. Therefore, mineral is supplemented through the diet. Furthermore, prebiotics are attributed to another set of properties related to particular systemic disorders. Prebiotic carbohydrates (GOS, FOS, inulin) reduce blood pressure, as well as blood levels of glucose, cholesterol, triglycerides and phospholipids, as well as triglyceride and fatty acid synthesis in the liver, minimising the risk of developing diabetes, obesity and atherosclerosis [25, 26].
