Table 2.

Clinical studies related to variations in immunity and gut microbiota in the elderly^∗.

Study details	Sample details	Methods	CFU	Outcome	Ref
Placebo controlled RCT	n = 24 (i) Probiotic (L. johnsonii) La1 (NCC533) n = 12 (ii) Placebo (nonprobiotic) n = 12	ELISA, C-reactive protein test, PHAGOTEST, faecal microbiota enumeration	109 CFU/day/12 weeks	Daily consumption of L. johnsonii La1 (NCC533) may contribute to suppressing infections by improving nutritional and immunological status	[19]
RCT	n = 209 (i) Probiotic group: B. longum 2C (DSM 14579) n = 56, (ii) DSM 14583 n = 46 (iii) Placebo group n = 67 (iv) Control group n = 86	qPCR, ELISA and faecal microbiota enumeration	109 CFU/day/6 months	Bifidobacterium levels in the in microbiota may be associated with change of cytokine levels	[20]
Comparative analysis	n = 84 (i) Adults n = 20, age 25 to 40 years; (ii) Elderly n = 22, age 63 to 76 years; (iii) Centenarians n = 21, age 99 to 104 years.	Tract Chip (HITChip), qPCR, 16S rRNA gene sequencing, ELISA and Flow cytometry		The proportion of centenarians showing a high inflammation score was significantly higher than in the other age groups, confirming the inflamm-ageing hypothesis	[6]
RCT	n = 45 (i) B. longum BB536 n = 23 (ii) Placebo (Dextrin) n = 22	RT-PCR, ELISA, T-RFLPs	5 × 1010/day/12 weeks	The potential of long-term ingestion of BB536 in increasing the cell number of bifidobacteria in intestinal microbiota and modulating immune function	[21]
Investigative RCT	n = 33 (Bacillus coagulans GBI-30, 6086 (BC30))	FISH, Gas chromatography and Flow cytometry	1 × 109/day/28 days	The dietary inclusion of probiotics such as BC30 may provide a beneficial option for enhancing markers of GI health comparison with placebo	[22]

^∗Table sorted by year of publication; RCT: randomized double-blinded clinical trial.