Table 4. Positive impact of probiotic treatment on bone health (human studies)

Probiotic strain	Type of study	Positive impact on bone health	Reference
Lactobacillus fermentum SRK414	6 mon randomized, double-blind, placebo-controlled trial	↑ Femur, neck bone mineral density (BMD); maintenance of osteocalcin (OC) levels, indicating improved bone turnover	Han et al. (2022)
Bacillus subtilis C-3102	6 mon randomized, placebo-controlled, double-blind clinical trial	↑ Hip BMD, ↓ urinary type I collagen cross-linked N-telopeptide (uNTx), ↓ tartrate-resistant acid phosphatase isoform 5b (TRACP-5b), modulation of gut microbiota	Takimoto et al. (2018)
Lactobacillus reuteri ATCCPTA 6475	12 mon randomized, placebo-controlled, double-blind clinical trial	↓ Loss of tibia volumetric BMD; protective effects on bone microarchitecture	Nilsson et al. (2018)
Lactobacillus casei, Bifidobacterium longum, Lactobacillus acidophilus, Lactobacillus rhamnosus, Lactobacillus bulgaricus, Bifidobacterium breve, Streptococcus thermophilus	6 mon randomized, double-blind, placebo-controlled clinical trial	↓ Bone turnover markers (BALP, CTX) and pro-inflammatory cytokine; slowed bone turnover, beneficial for osteopenic postmenopausal women	Jafarnejad et al. (2017)
Proprietary lactic acid bacteria culture in red clover extract (RLE)	12 mon double-blind, placebo-controlled randomized trial	↓ BMD loss in lumbar spine, femoral neck, and trochanter; ↓ CTX; improved estrogen metabolism	Lambert et al. (2017)
L. reuteri NCIMB 30242	13 wk double-blind, placebo-controlled, randomized trial	↑ Serum 25-hydroxyvitamin D levels by 25.5%	Jones et al. (2013)
Lactobacillus helveticus LBK-16H (fermented milk)	1 mon randomized, double-blind, crossover clinical study	↓ Serum parathyroid hormone levels↑ Serum calcium concentrations	Narva et al. (2004b)