TABLE 2.
Summary of clinical studies linking bifidobacteria with potential health benefits
| Health benefit | Study summary | Reference |
|---|---|---|
| Prevention of diarrhea | Large murine study (29 to 41 mice per group) showing a statistically significant (P < 0.001) protective effective of B. bifidum and B. longum subsp. infantis supplementation against rotaviral diarrhea | 238 |
| Large murine study (22 to 46 mice per group) with non-statistically significant data, but proposing a protective effect of heat-killed B. breve against rotaviral diarrhea | 347 | |
| Large murine study (52 to 111 mice per group) showing a small, statistically significant (P < 0.05) protective effective of B. bifidum supplementation, with reduced shedding of rotavirus (P < 0.01) | 80 | |
| Small piglet study (8 or 9 piglets per group) showing a moderate, statistically significant (P < 0.01) protective effect of B. animalis subsp. lactis against all forms of diarrhea and a higher titer of antirotaviral antibodies in the feces | 288 | |
| Large human study (26 or 29 infants per group) showing a barely statistically significant (P = 0.035) protective effect of B. bifidum and Streptococcus thermophilus supplementation, with reduced shedding of rotavirus (P = 0.025) | 262 | |
| Large human study (44 or 46 infants per group) showing a non-statistically significant protective effect of B. animalis subsp. lactis | 47 | |
| Large human study (464 or 449 infants per group) with B. breve and S. thermophilus supplementation; did not show a decrease in number of diarrhea episodes over a 5-month period but did show a reduced severity (P < 0.01) | 312 | |
| Small preterm pig study (5 to 13 pigs per group) showing some reduction (P < 0.05) in the incidence of necrotizing enterocolitis from supplementation with B. animalis and 4 species of Lactobacillus | 290 | |
| Establishment of a healthy microflora in premature infants | Small human study (10 preterm infants per group) showing that supplementation with B. breve resulted in establishment of a bifidobacterial flora in the majority of infants during the first week of life, whereas it took the control group several weeks, with only 3 of 9 infants showing bifidobacteria by week 7 | 167 |
| Large human study (33 preterm infants per group) showing that supplementation with B. breve reduced (P < 0.05) fecal butyric acid levels, but only in the subgroup of infants that weighed <2,500 g | 342 | |
| Colon regularity | Small human study (17 subjects with irritable bowel syndrome [IBS] per group) showing some reduction (P < 0.05) in colonic transit times from supplementation with B. animalis subsp. lactis and yogurt cultures | 2 |
| Large human study (132 or 135 subjects with IBS per group) showing no statistically significant reduction in colonic transit times, except in a small subset of 19 subjects who had <3 stools/week initially, from supplementation with B. animalis subsp. lactis and yogurt cultures | 106 | |
| Small human study (15 or 17 women per group) showing some reduction (P < 0.05) in colonic transit times from supplementation with B. animalis subsp. lactis | 172 | |
| Large human study (100 elderly subjects), without a control group, showing a reduction (P < 0.001) in colonic transit after 2 weeks of supplementation with B. animalis subsp. lactis | 184 | |
| Lactose intolerance | Small human study (15 people with lactose intolerance) showing some reduction (P < 0.05) in breath hydrogen from supplementation with B. longum | 133 |
| Small human study (11 Chinese individuals with lactose intolerance) showing some reduction (P < 0.05) in symptom scores from supplementation with B. animalis subsp. lactis and yogurt cultures | 114 | |
| Cholesterol reduction | Small human study (7 subjects per group) showing some reduction (P < 0.05) in serum cholesterol levels following supplementation with B. animalis subsp. lactis and L. acidophilus | 15 |
| Small human study (11 or 18 women per group) showing no reduction in total cholesterol but an increase in high-density lipoprotein (HDL) levels (P = 0.001) | 139 | |
| Medium-sized human study (37 women), without a control group, showing that supplementation with B. longum and L. acidophilus did not affect cholesterol levels | 102 | |
| Immunostimulatory effects | Small mouse study (5 mice per group) showing some reduction (P < 0.05) in CD4+ T cells in the spleen and colon following supplementation with B. bifidum | 142 |
| Small mouse study (10 mice per group) showing some reduction in the proinflammatory cytokines IFN-γ, TNF-α, and IL-12 from supplementation with B. longum subsp. infantis | 182 | |
| Small mouse study (5 mice per group) showing some increase (P < 0.05) in mucosal IgA following supplementation with B. longum | 303 | |
| Large human study (5 groups of 13 to 15 subjects receiving different amounts of B. animalis subsp. lactis and Lactobacillus paracasei) showing no statistically significant changes in cytokine levels | 48 | |
| Small human study (12 or 13 elderly subjects per group) showing some increase (P < 0.05) in the anti-inflammatory cytokine IFN-α and in phagocytic activity following 6 weeks of supplementation with B. animalis subsp. lactis | 13 | |
| Small human study (8 subjects with ulcerative colitis per group) showing no significant change in symptom scores but showing some decrease (P < 0.05) in expression of genes encoding human proinflammatory cytokines from supplementation with B. longum, inulin, and fructooligosaccharides | 90 | |
| Large human study (77 subjects with IBS receiving 1 × 1010 live cells of B. longum subsp. infantis) showing reductions in symptom scores and in the ratio of IL-10 to IL-12 (anti-inflammatory to proinflammatory cytokines), normalized to that of healthy individuals | 210 | |
| Cancer prevention | Medium-sized mouse study (12 mice per group) showing some reduction (P < 0.01) in the incidence of tumors when heat-killed B. infantis cells or cell wall preparations were injected into mice along with tumor cells, with a significant increase (P < 0.001) in the number of mice that were cured of tumors | 279 |
| Large mouse study (4 groups of 15 mice) showing some decrease (P < 0.05) in carcinogen-induced aberrant crypt foci following supplementation with B. longum and a significant decrease (P < 0.001) following cosupplementation with B. longum and inulin | 257 | |
| Large mouse study (30 mice per group) showing a significant reduction (P < 0.001) in carcinogen-induced colonic neoplasms following supplementation with both B. animalis subsp. lactis and resistant starch but no reduction with either supplement individually | 163 | |
| Large human study (4 groups of 18 to 22 colon cancer or polypectomized patients) showing some improvement (P < 0.05) in epithelial barrier function and cell toxicity only in polypectomized patients following supplementation with B. animalis subsp. lactis, L. rhamnosus, and inulin | 240 |