Biogaii

Proceedings of the Nutrition Society (2010), 69, 434–441 g The Authors 2010 First published online 14 June 2010

doi:10.1017/S0029665110001813

The 3rd International Immunonutrition Workshop was held at Platja D’Aro, Girona, Spain on 21–24 October 2009

3rd International Immunonutrition Workshop

Session 8: Probiotics in the defence and metabolic balance of the organism Gut microbiota inobesity and metabolic disorders
Yolanda Sanz*, Arlette Santacruz and Paola Gauffin
Microbial Ecophysiology and Nutrition Group, Institute of Agrochemistry and Food Technology (IATA), Spanish National Research Council (CSIC), Valencia, Spain

Proceedings of the Nutrition Society

Obesity is a major public health issue as it is causally related to several chronic disorders, including type-2diabetes, CVD and cancer. Novel research shows that the gut microbiota is involved in obesity and metabolic disorders, revealing that obese animal and human subjects have alterations in the composition of the gut microbiota compared to their lean counterparts. Moreover, transplantation of the microbiota of either obese or lean mice influences body weight in the germ-free recipient mice, suggestingthat the gut ecosystem is a relevant target for weight management. Indigenous gut microbes may regulate body weight by influencing the host’s metabolic, neuroendocrine and immune functions. The intestinal microbiota, as a whole, provides additional metabolic functions and regulates the host’s gene expression, improving the ability to extract and store energy from the diet and contributing tobody-weight gain. Imbalances in the gut microbiota and increases in plasma lipopolysaccharide may also act as inflammatory factors related to the development of atherosclerosis, insulin resistance and body-weight gain. In contrast, specific probiotics, prebiotics and related metabolites might exert beneficial effects on lipid and glucose metabolism, the production of satiety peptides and the inflammatory tonerelated to obesity and associated metabolic disorders. This knowledge is contributing to our understanding of how environmental factors influence obesity and associated diseases, providing new opportunities to design improved dietary intervention strategies to manage these disorders. Gut microbiota: Obesity: Chronic inflammation: Type-2 diabetes: Probiotics: Prebiotics

Obesity is one of the majorcurrent public health problems because of its increasing prevalence and association with important chronic disorders(1). These include type-2 diabetes mellitus, atherosclerosis, CVD, non-alcoholic fatty liver disease and cancer. Obesity is the result of a longterm positive imbalance between energy intake and expenditure, which is regulated by multiple pathways involving metabolites, hormones andneuropeptides. Highfat diet-induced obesity and metabolic disorders are also associated with a state of chronic low-grade inflammation and increased susceptibility to infection, due to malfunction of the immune system. Obese individuals have increased macrophage infiltration in the adipose tissue along with the production of inflammatory adipokines,

cytokines and associated immune factors.Inflammatory immune mediators (e.g. C-reactive protein, TNFa, IL-6 and monocyte chemotactic protein 1) and some adipokines (e.g. leptin) are usually elevated in obese mice and human subjects, whereas the production of the anti-inflammatory and insulin-sensitizing adipokine adiponectin is reduced(2). In fact, chronic activation of the innate immune system is regarded as a risk factor for the development ofobesity and associated disorders; this activation might partly depend on the immunomodulatory effects exerted by dietary compounds in the gut and beyond(2). The human intestinal tract is populated by a vast number of bacterial species that reach concentrations ranging from 107 to 1012 cells/g intestinal content, from the small

Abbreviation:LPS, lipopolysaccharide. *Corresponding author:...