Acidophilus Information

Facts

Lactobacillus acidophilus is one of the bacterial species that produce lactic acid in the digestive tract.
The human digestive system contains more than 500 different bacterial species. The number of bacteria has been estimated to be approximately 10 ¹³.¹
The prevalent bacteria in the human adult digestive tract include bacteroides, eubacteria, peptostreptococci, bifidobacteria, enterobacteria, streptococci, lactobaccili, clostridia and staphylococci.
Lactobacilli are commercially available in yogurt, fermented milk, capsule, and powder forms.

Functions

Lactobacillus acidophilus has been suggested to:

Improve intestinal motility and relieve constipation
Enhance immune function
Improve digestibility and increase availability of dietary nutrients
Alleviate lactose intolerance
Reduce risk of cancer development
Decrease allergic response by improving mucosal barrier function
Speed recovery from diarrhea caused by antibiotics or pathogens
Block adhesion of pathogens to digestive tract

Dosage

About 10⁹ to 10¹⁰ live bacteria daily are required from various sources (tablet, yogurt, etc.) to promote intestinal health or prevent antibiotic-associated diarrhea.

Toxicity

Not known.

Dietary Sources

Lactobacillus acidophilus and other Lactobacilli are available commercially as freeze-dried powders and capsules and in yogurts and fermented milk products.

Drug-Supplement Interaction

¹ ² ³

Lactobacillus acidophilus and related species are known as "friendly" bacteria that help reduce common side effects (e.g. diarrhea) of antibiotic therapy. Taking acidophilus-containing products may be recommended during and after antibiotic therapy.

Information on the relationship between substances and disease is provided for general information, in order to convey a balanced review of the scientific literature. In many cases the relationship between a substance and a disease is tentative and additional research is needed to confirm such a relationship.

Research Summary

Topic: Intestinal Health



	Effects of a synbiotic milk product on human intestinal ecosystem.
	A randomized, double-blind, placebo controlled, two armed parallel study investigated the effects of a synbiotic milk product on intestinal microbiota. The trial used 2% milk as a placebo and the synbiotic milk product contained 2% skim milk with Lactobacillus acidophilus 74-2 (10⁷ CFU/mL), Bifidobacterium lactis strain 420 (10⁷ CFU/mL), and 2% inulin. All participants consumed 500 mL 2% skim milk for two weeks during a baseline period and then half of the participants were assigned to receive the synbiotic milk product while the other half continued to consume the placebo for four weeks. Twenty-six adults aged 22 to 47 years participated in the trial. Fecal dry weight and L-lactic acid concentration were significantly reduced by the synbiotic milk product (P<0.01 and P<0.05, respectively). Bifidobacteria and lactobacilli counts were significantly increased by the synbiotic product (P<0.05 and P<0.01, respectively). The results of this study suggest that this synbiotic milk product supported growth of bifidobacteria and lactobacilli.²
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	Nonsurgical management of partial adhesive small-bowel obstruction with oral therapy: a randomized controlled trial.
	One-hundred-twenty-eight patients with adhesive partial small-bowel obstruction were randomized to either a control group or a treatment group to evaluate the efficacy of an oral management program on the necessity of surgical intervention. Patients in the treatment group received 500 mg magnesium oxide, 0.3 g Lactobacillus acidophilus, and 40 mg simethicone three times per day; patients in both the control and treatment groups received intravenous hydration and naso-gastric tube decompression. Patients in the treatment group were less likely to require surgical intervention than those in the control group (9% versus 24%, respectively). Hospital stays were significantly longer for the control group.³
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	The effect of probiotic fermented milk and inulin on the functions and microecology of the intestine.
	A randomized, double-blind, placebo-controlled trial investigated the effects of probiotics and inulin on intestinal function in 66 healthy adults (aged 22-60 years). Participants were randomized to receive three 200 mL servings of fermented milk with probiotics (Bifidobacterium longum BB536, Bifidobacterium spp. 420 and Lactobacillus acidophilus 145), a fermented milk with the same probiotics plus 4 g inulin, or a control milk product. A twelve day baseline period was completed prior to the three week trial. Consumption of fermented milk with probiotics with or without inulin increased the fecal number of lactobacilli (P=0.009, P=0.003) and bifidobacteria (P=0.046, P=0.038) versus baseline. Both fermented milk products with probiotics increased lactobacilli (P=0.005, ANCOVA). Gastrointestinal symptoms were noted with the inulin supplements, including flatulence and discomfort. The results of this study indicate that probiotic products positively influenced microbial populations in the colon. ⁴
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Topic: Antibiotic-Associated Diarrhea



	Dose-response efficacy Lactobacillus acidophilus CL1285 and Lactobacillus casei LBC80R for antibiotic-associated diarrhea and Clostridium difficile-associated diarrhea prophylaxis in adult patients.
	A randomized, double-blind, placebo controlled dose ranging study investigated the efficacy of a probiotic containing Lactobacillus acidophilus CL1285 and Lactobacillus casei LBC80R for prevention of antibiotic-related diarrhea. 255 people participated in the trial. Participants were randomized to one of three groups: 2 probiotic capsules daily, 2 placebo capsules daily, or 1 of each daily. Each probiotic capsule contained a mixture of Lactobacillus acidophilus CL1285 and Lactobacillus casei LBC80R for a total of 5x10¹⁰ cfu. Participants began taking the treatments within 36 hours of beginning antibiotics, for 5 days after antibiotics, and they were followed for an additional 21 days. Probiotic supplements reduced incidence of diarrhea and the two-capsule group had lower incidence than the one-capsule group (two-capsules: 15.5%; one-capsule: 28.2%; placebo: 44.1%). Symptom duration was lower for the probiotic supplements who had antibiotic associated diarrhea (two-capsules: 2.8 days; one-capsule: 4.1 days; placebo: 6.4 days). Clostridium dificile associated diarrhea incidence was lower in those taking probiotic supplements than those taking placebo: two-capsules, 1.2%; one-capsule, 9.4%; placebo, 23.8%. The results of this study suggest that probiotic supplements containing Lactobacillus acidophilus CL1285 and Lactobacillus casei LBC80R may reduce the incidence and severity of antibiotic associated diarrhea.⁵
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	Efficacy of probiotics in prevention of acute diarrhoea: a meta-analysis of masked, randomized, placebo-controlled trials.
	A meta-analysis of 34 masked, randomized, placebo-controlled trials investigated the efficacy of probiotic supplements against diarrhea. No difference in effectiveness was found between Saccharomyces boulardii, Lactobacillus rhamnosus GG, L. acidophilus, or L. bulgaricus. Treatment with probiotics such as these strains reduced antibiotic associated diarrhea by 52%, travelers diarrhea by 8%, and diarrhea of diverse causes by 34%. The authors concluded that probiotic supplements have a beneficial effect on prevention of diarrhea, particularly for antibiotic-associated diarrhea.⁶
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	Prevention of antibiotic-associated diarrhoea by fermented probiotic milk drink.
	A double-blind, placebo controlled, randomized trial investigated the efficacy of a fermented milk drink for prevention of antibiotic associated diarrhea in a hospital setting. Eighty-seven people participated in the two-week trial. Participants were randomized to receive a fermented milk drink containing Lactobacillus rhamnosus GG (LGG, minimum level of 10⁸ cfu/mL), Lactobacillus acidophilus La-5 (La-5, minimum level of 10⁷ cfu/mL) and Bifidobacterium Bb-12 (Bb-12, minimum level of 10⁸ cfu/mL) or a placebo containing heat-killed bacteria. Sixty-three participants completed the trial. In all 5.9% of participants receiving the active probiotic drink and 27.6% of the placebo group participants developed diarrhea (P=0.035). The relative risk was 0.21 (95% confidence interval 0.05 to 0.93). The results of this study suggest that this probiotic mixture may be effective for reducing risk of antibiotic-associated diarrhea.⁷
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	Adherence of probiotic bacteria to human intestinal mucus in healthy infants and during rotavirus infection.
	Twenty infants with rotavirus infection and ten age-matched infants without infection were given a supplement containing five probiotic strains (Lactobacillus rhamnosus GG, L. casei Shirota, L. paracasei F19, L. acidophilus LA5, and Bifidobacterium lactis Bb12). Infants with rotavirus infection were also given the supplement after the infection was over. Adhesion of the probiotic strains to intestinal mucus was monitored and ranged from 1 to 34% in all infants. The pattern of adhesion was the same in all patients studied: L. rhamnosus GG, 34%; L. casei Shirota, 1%; L. paracasei F19, 3%; L. acidophilus LA5, 4%; and Bifidobacterium lactis Bb12, 31%. It has been found that probiotic bacteria are able to adhere to the intestinal mucous and therefore provide health benefits to infants, children, and adults suffering from diarrhea. However, the ability to adhere to mucosal lining varies among the different types of probiotic bacteria.⁸
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Topic: Traveler's Diarrhea



	Meta-analysis of probiotics for the prevention of traveler's diarrhea.
	A meta-analysis of published trials was conducted to evaluate the use of probiotics for traveler’s diarrhea. Included trials were randomized, placebo-controlled, blinded, efficacy trials in humans published in peer-reviewed journals. Twelve studies were identified that met the inclusion criteria between 1977 and 2005. Pooled relative risk of traveler’s diarrhea with use of probiotics was 0.85 (95% confidence interval 0.79 to 0.91, p<0.001). These results indicate that probiotics were effective for prevention of traveler’s diarrhea. Specific probiotics found to be effective were Saccharomyces boulardii and mixtures of Lactobacillus acidophilus and Bifidobacterium bifidum. Review of the trials revealed no reported serious adverse events and suggest that probiotics may be safe and effective preventative for traveler’s diarrhea.⁹
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Topic: Irritable Bowel Syndrome



	Probiotic bacteria Lactobacillus acidophilus NCFM and Bifidobacterium lactis Bi-07 versus placebo for the symptoms of bloating in patients with functional bowel disorders: a double-blind study.
	A randomized, placebo controlled, double-blind trial investigated the efficacy of a probiotic supplement for functional bowel disorders. Sixty people with non-constipation irritable bowel syndrome, functional diarrhea, or functional bloating participated in the trial. Participants were randomly assigned to receive a probiotic supplement capsule twice daily (containing equal amounts of Lactobacillus acidophilus NCFM (L-NCFM) and Bifidobacterium lactis Bi-07 (B-LBi07) for a total of 1x10¹¹ cfu/capsule) or a microcellulose placebo. After a two week run-in period, participants consumed the placebo or probiotic supplement for eight weeks and then were followed for an additional four weeks (without supplementation). The probiotic supplement was associated with a reduction in abdominal bloating versus placebo (after four weeks: 4.10 vs 6.17, P=0.009, change in bloating severity P=0.02; after eight weeks: 4.26 vs 5.84, P=0.06, change in bloating severity P<0.01). Results were similar for all participant subgroups: irritable bowel syndrome, functional diarrhea, and functional bloating groups. The results of this study suggest that probiotic supplements containing Lactobacillus acidophilus NCFM (L-NCFM) and Bifidobacterium lactis Bi-07 (B-LBi07) may be helpful for alleviating bloating for people with functional bowel disorders. Further trials are necessary to clarify and evaluate these results.¹⁰
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	Clinical trial: effect of active lactic acid bacteria on mucosal barrier function in patients with diarrhoea-predominant irritable bowel syndrome.
	A randomized, single-blind, placebo-controlled clinical trial investigated the effects of lactic acid bacteria supplements on symptoms for people with diarrhea-predominant irritable bowel syndrome (D-IBS). Thirty people with D-IBS symptoms participated in the four week trial. Participants were randomly assigned to receive either a probiotic fermented milk product daily (containing Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus acidophilus and Bifidobacterium longum) or milk beverage without bacteria. After probiotic milk product consumption, small bowel permeability decreased significantly from 0.038 at baseline to 0.023 (P=0.004). Patients with elevated small bowel permeability was lower that at baseline (28.6% vs. 64.3%, P=0.023). Colonic permeability did not change. Mean global IBS scores were significantly decreased in the probiotics group relative to baseline (9.62 +/- 1.05 vs. 7.64 +/- 1.24, P<0.001). Consumption of this fermented milk product for four weeks had beneficial effects on D-IBS symptoms. ¹¹
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	Therapeutic effect of Lactobacillus acidophilus-SDC 2012, 2013 in patients with irritable bowel syndrome.
	A randomized, placebo-controlled trial investigated the effects of Lactobacillus acidophilus SDC 2012, 2013 for irritable bowel syndrome (IBS) symptoms. Forty people with IBS were randomly assigned to receive a placebo or a probiotic supplement daily for four weeks. Probiotic treatment reduced scores for abdominal pain or discomfort versus baseline (P=0.011). The percent reduction in abdominal pain or discomfort exceeded the placebo scores by more than 20% (23.8% for probiotics and 0.2% for placebo, P=0.003). These results indicate that further study is warranted. ¹²
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Topic: Allergy



	Effect of milk fermented with Lactobacillus acidophilus strain L-92 on symptoms of Japanese cedar pollen allergy: a randomized placebo-controlled trial.
	Two recent single-blind, placebo-controlled, randomized studies investigated the impact of daily L. acidophilus strain L-92 on allergic symptoms. In one study, 23 subjects consumed 100 mL fermented milk with 5 x 10¹⁰ bacteria (L-92) twice daily or placebo for six weeks. In the second trial, 20 subjects consumed 100 mL fermented milk with 2 x 10¹⁰ bacteria (L-92) once daily or placebo for ten weeks. In both trials, a significant reduction in ocular symptom medication scores and in distress of life scores were noted. Reductions in itchy eyes were also noted, although these changes were not significant. These two trials suggest that consumption of at least 2 x 10¹⁰ L-92 bacteria daily may help to reduce pollen allergy symptoms. ¹³
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Topic: Immune Function



	Lactobacillus acidophilus 74-2 and Bifidobacterium animalis subsp lactis DGCC 420 modulate unspecific cellular immune response in healthy adults.
	A placebo-controlled, double-blind, randomized, crossover trial evaluated the effects of a probiotic yogurt on immune response. Twenty-six people participated in the trial. Participants were randomly assigned to receive a daily probiotic yogurt (300 g/day; supplemented with Lactobacillus acidophilus 74-2, 9.3x10⁸ cfu/g, and Bifidobacterium animalis subsp. lactis DGCC 420, 3.0x10⁶ cfu/g) or a placebo. After a three week run in period, half of the participants consumed the probiotic yogurt for two weeks. Then, a second run in period was completed and the assignments were switched. After consuming the probiotic yogurt, L. acidophilus and B. lactis significantly increased in fecal proportion (from 0.02 to 0.19 and 0.4 to 1.4% (P<0.05), respectively). Probiotic supplementation was associated with increases in the percentage f granulocyte and monocyte with phagocytic activity (92 to 95%) and decreased serum triacylglycerol concentration (11.6% (P<0.05)). Oxidative burst activity of granulocytes and monocytes, fecal short chain fatty acids, and serum cholesterol were not affected. The results of this study suggest that this probiotic preparation may have beneficial effects on nonspecific immune response.¹⁴
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	Ingested probiotics reduce nasal colonization with pathogenic bacteria (Staphylococcus aureus, Streptococcus pneumonias, and beta-hemolytic streptococci).
	Two-hundred-nine healthy subjects consumed either a fermented milk drink containing a mixture of Lactobacillus GG, Bifidobacterium sp. B420, L. acidophilus 145, and Streptococcus thermophilus or normal yogurt for three weeks. Nasal microbial flora were monitored on days 1, 21, and 28. Potentially pathogenic bacteria were decreased by 19% in the fermented milk group but not in the placebo group. These results suggest that regular consumption of probiotics may reduce potentially pathogenic bacteria in the upper respiratory tract.¹⁵
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	Effect of Bifidobacterium bifidum and Lactobacillus acidophilus on gut mucosa and peripheral blood B lymphocytes.
	Lyophilized Bifidobacterium bifidum (BB) and Lactobacillus acidophilus (LA) were given orally to 15 elderly subjects while a placebo was given to 10 elderly subjects for 28 days. The BB and LA administration significantly reduced the inflammatory infiltration in the colon. A significant increase was observed in the number of cells in the peripheral blood that produced antibodies necessary for immune responses. This trial indicated that daily intake of probiotics modulated immunological and inflammatory reactions in the elderly.¹⁶
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	Effects of seven potential probiotic strains on specific immune responses in healthy adults: a double-blind, randomized, controlled trial.
	A pilot study investigated the effects of seven probiotic strains versus a placebo on immune function. Eighty-three healthy people aged 18 to 62 years participated in the study. Participants were randomly assigned to receive either 2x10¹⁰ colony forming units of probiotic bacteria or a placebo for three weeks. Participants received a cholera vaccine at days 7 and 14; blood and saliva samples were obtained at days 0, 21, and 28. Immunoglobulin G (IgG) increased in two probiotic groups: Bifidobacterium lactis Bl-04 and Lactobacillus acidophilus La-14, compared with controls (P=0.01). Although not significant, trends for increases in IgG versus controls were found for six of seven probiotic strains. This pilot study suggests that probiotic strains may influence immune function; further studies are needed to explore this result. ¹⁷
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*Topic: Helicobacter pylori* Infection**



	Effect of whey-based culture supernatant of Lactobacillus acidophilus (johnsonii) La1 on Helicobacter pylori infection in humans.
	The effect of Lactobacillus acidophilus La1 on Helicobacter pylori growth urease activity and adhesion to epithelial cells was determined in vitro. Subjects infected with H. pylori were treated with 50 mL L. acidophilus supernatant four times a day with omeprazole for 14 days. Subjects showed decreased colonization of H. pylori by oral administration of acidophilus supernatant. In vitro, bacteria supernatant inhibited urease activity and the adhesion of H. pylori to HT-29 cells. The authors concluded that L. acidophilus strains produce an inhibitory activity on H. pylori growth in vitro and in vivo.¹⁸
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Topic: Renal Health



	Use of a probiotic to decrease enteric hyperoxaluria.
	Alteration of intestinal microflora may influence absorption of oxalate and, thus, influence urinary oxalate excretion. Elevated levels of oxalate may contribute to formation of kidney stones. Ten patients consumed one, two, or three four-gram packets per day of a dietary supplement containing 2 x 10¹¹ bacteria per gram consisting of a mixture of Lactobacillus acidophilus, L. brevis, Streptococcus thermophilus, and Bifidobacterium infantis (1:1:4:4 ratio). Mean urinary oxalate excretion fell by 19% after one month with one capsule per day and by 24% after one month with two capsules per day. However, mean urinary excretion returned to baseline levels with 3 capsules per day, suggesting that there is an optimal level of intake of the probiotic supplement. The researchers suggest that between 8 x 10¹¹ and 1.6 x 10¹² bacteria is the optimal level of supplementation for moderating urinary oxalate excretion.¹⁹
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	Biomodulation of the toxic and nutritional effects of small bowel bacterial overgrowth in end-stage kidney disease using freeze-dried Lactobacillus acidophilus.
	Patients undergoing hemodialysis were treated with Lactobacillus acidophilus (LBA) to alter small bowel bacterial overgrowth (SBBO). The LBA treatment significantly reduced concentrations of toxins and carcinogens in serum such as dimethylamines and nitrosodimethylamine. Nutritional status, serum albumin and body weight were moderately improved.²⁰
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Topic: Blood Lipids



	Cholesterol-lowering effect of probiotic yogurt in comparison with ordinary yogurt in mildly to moderately hypercholesterolemic subjects.
	A randomized, crossover design trial investigated the effects of probiotic yogurt on blood lipid profiles in people with moderate hypercholesterolemia. Participants initially consumed no yogurt for a two week run in period; participants added 300 g milk per day during this period. Participants were then randomly assigned to consume 300 g ordinary yogurt or 300 g probiotic yogurt (fermented with a starter composed of Lactobacillus acidophilus and Bifidobacterium lactis in addition to bacteria in ordinary yogurt) daily for six weeks. After a four week washout period, participants crossed over to the other yogurt for an additional six weeks. Consumption of the probiotic yogurt significantly reduced serum total cholesterol relative to the ordinary yogurt (p<0.05). No other differences between groups were noted. The results of this small study indicate that probiotic yogurt containing L. acidophilus and B. lactis may have beneficial effects on total cholesterol. ²¹
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