Table 3. Human and animal studies assessing the effect of eggs consumption on the composition of the gut microbiota

Citation	Study design	Intervention	Trial duration	Participants	Effect on the gut microbiota	Other health or physiological observations
Thomas et al. (2022)	Randomized, controlled cross-over	3 eggs/d (4 wk) choline bitartrate (CB) supplement/d (4 wk)	13 wk	23 Men and women classified with metabolic syndrome (MetS) (35–70 yr old)	Phylum Firmicutes/ Bacteroidetes -Shannon -	Not applicable (NA)
Liu et al. (2022a)	Prospective nonrandomized	2 eggs/d (90–100 g, 460–500 mg cholesterol)	2 wk	9 Healthy males [29±1 yr old, body mass index (BMI) 22±1 kg/m2]	Phylum Firmicutes/ Bacteroidetes -Shannon - Simpson - Chao1 -	NA
Zhu et al. (2020)	Randomized, cross-over	2 whole eggs (100 g)/d (4 wk) yolk-free eggs (100 g)/d (4 wk)	12 wk	20 Overweight/obese postmenopausal women [57.7 (±5.64) yr old, average BMI of 28.34 (±2.96)]	Genus Prevotella - Anaeroplasma - Clostridium - Peptostreptococcaceae -	NA