TABLE 2.

Summary of clinical studies linking bifidobacteria with potential health benefits

Health benefitStudy summaryReference
Prevention of diarrheaLarge 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 diarrhea238
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 diarrhea347
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 feces288
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. lactis47
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 Lactobacillus290
Establishment of a healthy microflora in premature infantsSmall 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 7167
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 g342
Colon regularitySmall 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 cultures2
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 cultures106
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. lactis172
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. lactis184
Lactose intoleranceSmall human study (15 people with lactose intolerance) showing some reduction (P < 0.05) in breath hydrogen from supplementation with B. longum133
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 cultures114
Cholesterol reductionSmall 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. acidophilus15
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 levels102
Immunostimulatory effectsSmall 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. bifidum142
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. infantis182
Small mouse study (5 mice per group) showing some increase (P < 0.05) in mucosal IgA following supplementation with B. longum303
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 levels48
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. lactis13
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 fructooligosaccharides90
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 individuals210
Cancer preventionMedium-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 tumors279
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 inulin257
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 individually163
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 inulin240