Have Probiotics and Synbiotics passed the test of time to be implemented in management of obesity and related metabolic disorders-a comprehensive review

Obesity continues to be a big public health problem, with its prevalence increasing continuously. As per the WHO it has been estimate that In last 40 years, obesity prevalence almost tripled and in 2016, over 650million people around the world, which included various million infants and children became obese.1 Increased body weight is associated with development of several severe chronic conditions like type 2 diabetes mellitus, (T2DM), cardiovascular disease (CVD), musculoskeletal disorders and different cancers.2 Every year because of overweight/obesity, there are 28million deaths worldwide.2 Further obesity leads to a big medical, social and economic burden.3 We have been trying to find simple answers for treating obesity, medically, the problem remains that gradually most of the previous approved medications for obesity have got removed from the market, in view of different side effects, along with their inability to maintain long term weight loss.4–8 Although interventions like bariatric surgery are the most effective till date for reducing increased weight in people with morbid obesity, it is a very invasive procedure, having risks of unforeseen complications along with needing marked effort in adopting a new lifestyle [reviewed in ref.9 Thus need for looking simpler approaches is there. Symbiosis has been described in nonalcoholic steatohepatitis (NASH),10,11 T2DM, metabolic syndrome,12–15 and obesity,16,17 As far as overweight/obesity, is concerned various studies have demonstrated that the gut micro bio decomposition may be significantly different from lean individuals, the faecal bacteria may exert a key role in modulating energy metabolism with modifications of gut microbiotacomposition might be associated with decreases In body mass index (BMI)16,17 Reviewed in ref. 5,18,19 In view of this manipulation of gut microbiota composition using probiotics has been considered a possible way for preventing and treating obesity. The word probiotic comes from the Greek word, which means ‘’for life’. Despite ’lot of change in definitions, currently the definition recognized by Food and Agricultural Organization of the United Nations (FAO) and world health organization (WHO) working group experts is that probiotics are live strains of strictly selected microorganisms, which once administered in adequate amounts, give a health benefit to the host.20 This definition was accepted by the International Scientific Association of Probiotics and Probiotics (ISAPP) in 2013.21 Though dead bacteria and their components can also show probiotic properties. Most commonly used bacterial strains are Bifidobacteria and Lactobacillus that exhibit probiotic properties and get included in many functional foods and dietary supplements.22 Main mechanisms of actions of probiotics are improvement of the gut barrier function ,increasing competitive adherence to the mucosa and epithelium, modification of gut microbiota, along with regulation of the gut associated lymphoid immune system .Thus probiotics communicate with the host utilizing intestinal cell pattern recognition receptors ,like toll like receptors and nucleotide binding oligomerization domain containing protein like receptors that modulate important vital signaling pathways like nuclear factor kappa B (NFκB) and mitogen activated protein kinase to increase or suppress either activation or effect downstream pathways.21,23–26 A Probiotics is a nonviable food component which gives a health benefit on the host associated with modulation of microbiota, which might be a fiber, but all fibers are not necessarily a Probiotics. Usage of probiotic and Probiotics together is often known as synbiotic, if the net health benefit is synergistic27 Probiotics and synbiotics are taken in multiple and varied forms, like yogurt and other fermented milks, cheese and various fermented foods besides in the prevention and treatment of different gastrointestinal (GI) tract dysfunctions and other diseases like allergy.28 However the actual effects of how probiotic changes intestinal ecology is still debatable, in view of various confounding elements, like dissimilarities in microbial strains, concentrations of viable cells and product formulations.29–31 Yao and Kim showed that probiotics and Probiotics affect type2 diabetes mellitus (T2DM), and cardio vascular disease (CVD) by changing gut microbiota, regulating insulin signaling, along with lowering cholesterol.32 Thus the aim of