Obesity epidemic responsible for increase in diabetes, heart diseases, infections and cancer shows no signs of abating. Obesity in children is also on rise, indicating the urgent need of strategies for prevention and intervention that must begin in early life.While originally posited that obesity results from the simple concept of consuming more calories, or genetics, emerging research suggests that the bacteria living in our gut (gut microbiome) and its interactions with immune cells and metabolic organs including adipose tissues (microbiome-immune-metabolic axis) play significant role in obesity development in childhood. Specifically, abnormal changes (dysbiosis) in the gut microbiome, stimulation of inflammatory cytokines, and shifts in the metabolic functions of brown adipose tissue and the browning of white adipose tissue are associated with increased obesity. Many factors from as early as gestation appear to contribute in obesity, such as maternal health, diet, antibiotic use by mother and/or child, and birth and feeding methods. Herein, using evidence from animal and human studies, we discuss how these factors impact microbiome-immune-metabolic axis and cause obesity epidemic in children, and describe the gaps in knowledge that are warranted for future research.

<b><i>Background:</i></b> Alzheimer’s disease (AD) is the most common form of dementia, particularly in older adults, with clinical manifestations of progressive cognitive decline and functional impairment. The prevalence of AD and related dementia is mounting worldwide, but its etiology remains unresolved, with no available preventative or ameliorative therapy. Emerging evidence suggests that the gut microbiota of patients with AD is different from cognitively normal counterparts. <b><i>Summary:</i></b> Communication between gut and brain (gut-brain axis) plays a crucial role in AD pathology. Bacteria inhabiting the gut strongly influence this gut-brain axis and thus may participate in AD pathology. Diet, one of the strongest modulators of gut microbiota, also strongly influences brain health and AD pathology. Gut microbiota metabolites including short-chain fatty acids, pro-inflammatory factors, and neurotransmitters may also affect AD pathogenesis and associated cognitive decline. Therefore, investigation of diet-microbiota-brain axis is important to better understand its contribution in AD pathology and its potential use as a target to prevent and treat AD. Herein, we discuss the link between AD and gut microbiota and ponder how microbiota modulation through nutritional approaches may offer avenues for discovering novel preventive and therapeutic strategies against AD. <b><i>Key Message:</i></b> A strong association exists between lifestyle factors and AD prevalence wherein unhealthy dietary factors have been linked to neurodegeneration. Specific prudent dietary patterns might help in preventing or delaying AD progression by affecting β-amyloid production and tau processing and regulating AD-associated inflammation, metabolism and oxidative stress, plausibly via modulating gut microbiota.