Table 2.

Summary of beneficial factors under a western lifestyle.

Beneficial factor	Benefits	Benefited population
Exercise	Exercise reduces pro-inflammatory state, liver fat, protects against insulin resistance, and increases the levels of SCFAs and sIgA (Schmitz et al., 2002; Starkie et al., 2003; Matsumoto et al., 2008; Nichol et al., 2008; Campos-Rodríguez et al., 2016).	Beneficial in the general population (its effects are under study for some conditions) (Gleeson et al., 2011).
Dietary polyphenols	Polyphenols function as antioxidants, strengthen intestinal barrier function, maintain beneficial bacterial strains, and prevent endotoxemia and the development of diabetes (Sies et al., 2005; He et al., 2012; Cowan et al., 2013; Anhê et al., 2015; Wang et al., 2016).	Beneficial in the general population (Manach et al., 2005).
ω-3 polyunsaturated fatty acids	ω-3 PUFA can reverse some of the inflammatory effects of ω-6 PUFA, like immune cell infiltration and NF-kβ activation, and enrich Lactobacillus spp. and Bifidobacteria spp. (Thompson and Spiller, 1995; Ghosh et al., 2013).	People with high ω-6 PUFA intake (Ghosh et al., 2013).
Prebiotics	Prebiotics increase abundance of Bifidobacteria, butyrate-producing and mucin-degrading bacteria. They have been observed to reduce body weight gain, dyslipidemia, inflammation, hypertension, and insulin resistance (Marcil et al., 2003; Tappenden et al., 2003; Galisteo et al., 2008; Delzenne et al., 2013; Kimura et al., 2013; Park et al., 2015).	Beneficial for the general population, as long as the individual has a microbiota with the capacity of degrading the prebiotic (Chambers et al., 2015).
SCFAs	SCFAs prevent weight gain, abdominal adiposity, liver fat, and reduced insulin resistance (Chambers et al., 2015).	These compounds have been observed to be beneficial in gastrointestinal disorders and overweight adults, but might be beneficial in other conditions not yet studied (Segain et al., 2000; Chambers et al., 2015).
PROBIOTICS
L. curvatus HY7601 and L. plantarum KY1032	These strains prevent weight gain, and lower plasma glucose, insulin, triglycerides, oxidative stress levels, liver mass, and liver cholesterol (Park et al., 2013a,b).	People following a HFAD and HFUD (Park et al., 2013a,b).
A. muciniphila	This strain reduces plasmatic LPS, adiposity, insulin resistance, body weight, and hyperglycemia. It increases adipocyte differentiation and lipid oxidation, and prevents the thinning of the mucus layer (Everard et al., 2013).	People following a HFAD and/or with low abundance of mucin-degrading bacteria (Everard et al., 2013).
B. uniformis CECT 7771	This strain reduces total body weight gain, intestinal lipid absorption, liver fat, levels of cholesterol and triglycerides. It improves glucose metabolism, insulin and leptin sensitivity, and immune function. A Bacteroides-rich microbiota has been associated with reduced production of pro-atherosclerotic TMAO (Gauffin Cano et al., 2012).	People following a HFAD, and/or with a high inflammatory profile, and/or a high intake of red-meat (Gauffin Cano et al., 2012).
L. reuteri JBD30 l	This strain absorbs FFAs and increases fecal fat excretion (Chung et al., 2016).	People following a HFAD (Chung et al., 2016).
L. fermentum ME-3	This strain reduces post-prandial oxidative stress (Kullisaar et al., 2011).	People with low antioxidant intake (Kullisaar et al., 2011).
L. acidophilus strains NCFM and N-2	These strains lower the production of free amines and the activity of cecal bacterial ß-glucuronidase, nitro-reductase, and azoreductase enzymes (Goldin and Gorbach, 1984a).	People with a high red-meat intake (Goldin and Gorbach, 1984a).
B. bifidum, L. plantarum 8PA3, and L. rhamnosus GG	These strains improve liver function and lower alcohol-induced endotoxemia and hepatic steatosis (Kirpich et al., 2008; Wang et al., 2011).	People with high alcohol-intake (Kirpich et al., 2008; Wang et al., 2011).
L. plantarum 299v	This strain reduces systolic blood pressure, leptin, fibrinogen, IL-6, and monocytes adhesion to vein endothelial cells (Naruszewicz et al., 2002).	Heavy smokers (Naruszewicz et al., 2002).