Table 3:

Studies of the gut microbiome in Europe and Asia from 2015 to 2019

Location of study and reference	Disease or condition	Age of participants	Number and/or nutritional status of participants	Study design	Study outcomes
Russia Volokh et al. 2019	Normal health	18–40 years; male and female	n=150 fermented dairy product	Part of large open prospective controlled study	Gut microbiota
Germany Bamberger et al. 2018	Normal health	63 ± 7 years; male and female	n=96 intervention (walnuts) first; n=98 control first	Randomized, controlled, prospective, cross-over study	Gut microbiota,
Germany Trautvetter et al. 2018	Normal health	29 ± 7 years; male and female	n=62 intervention (phosphorus & calcium); n=62 control first	Double-blind randomized controlled intervention trial	Gut microbiota, fecal fat, short chain fatty acids
Sweden Zhang et al. 2018	Normal health	39 ± 10.1; 34.7 ± 10.4; 33.5 ± 7.4	n=17 switched to vegetarian diet n=14 control diets (7 omnivorous, 7 vegetarian)	Sub-study of a randomized trial	Gut microbiota, immune analysis
China Wan et al. 2019	Normal health	18–35 years	n=217; n=73 lower-fat, n=73 moderate-fat, n=71 higher-fat diets	Randomized controlled-feeding trial	Gut microbiota, fecal metabolomics, plasma proinflammatory factors
Japan Kushida et al. 2019	Normal health	20–29 years	n=11 1975 Japanese diet, n=10 modern Japanese diet	Randomized controlled clinical trial	Gut microbiota
China Zhao et al. 2018	Type 2 diabetes	Adults	n=43 type 2 diabetes; n=16 control diet or n=27 WTP diet	Randomized clinical trial	Gut microbiota, hemoglobin A1c (HbA1c)
China Yuan et al. 2018	Normal health or obese	27–46 years	n=12, green tea liquid	Observational study	Gut microbiota, oral microbiota
China Zhang et al. 2017	Obesity	3–16 years	n=17 Prader-Willi syndrome; n=21 simple obesity intervention: diet of whole grains, traditional Chinese medicinal foods, prebiotics (WTP)	Open-labeled and self-controlled clinical trial	Gut microbiota, urinary metabolites, fecal metabolites, inflammation analysis
China Xie et al. 2017	Epilepsy	1.95 ± 3.10 years (epilepsy), up to 3 years (healthy control)	n=14 epilepsy, n=30 control before and after ketogenic diet	Controlled clinical trial	Gut microbiota
China Li et al. 2017	Constipation	Adults under 65 years	n=100; n=50 (Deshipu stachyose granules), n=50 (control)	Non-blind randomized control trial	Gut microbiota, bowel function
China Xu et al. 2015	Type 2 diabetes	54.23 ± 8.56 (placebo), 55.06 ± 7.49 (low dose), 53.18 ± 8.89 (median dose), 51.24 ± 9.10 (high dose)	n=187; n=44 high dose, n=52 moderate dose, n=50 low dose Gegen Qinlin Decoction, n=41 placebo	Randomized double-blinded, placebo-controlled clinical trial	Gut microbiota, fasting blood glucose, HbA1c,