| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Review Articles |
1 From the Division of Human Nutrition and Epidemiology, Wageningen University and The Wageningen Centre for Food Sciences, Netherlands.
2 Supported by the Dutch Dairy Foundation on Nutrition and Health, Maarssen, Netherlands.
3 Address reprint requests to N de Roos, Division of Human Nutrition and Epidemiology, Bomenweg 2, 6703 HD Wageningen, Netherlands. E-mail: nicole.deroos{at}staff.nutepi.wau.nl.
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONPREVENTION OF DIARRHEAL DISEASESLOWERING OF SERUM CHOLESTEROLPREVENTION OF CARCINOGENESIS AND...DISCUSSIONREFERENCES |
|---|
Key Words: Probiotic bacteria • lactobacillus • enterococcus • rotavirus • cholesterol • diarrhea • lipid metabolism • carcinogenesis • review
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONPREVENTION OF DIARRHEAL DISEASESLOWERING OF SERUM CHOLESTEROLPREVENTION OF CARCINOGENESIS AND...DISCUSSIONREFERENCES |
|---|
Several reviews describe criteria that should be met before a bacterial strain can be called a probiotic (3, 13, 14). Most importantly, probiotics should have a beneficial effect on human health. To meet this criterion, well-designed human studies with requirements similar to those for pharmaceutical studies are needed (3).
In this review, we evaluate human studies of probiotics. We did not perform a meta-analysis because not enough studies with probiotics have been conducted. Instead, we present an overview of studies on probiotic bacteria published between 1988 and 1998 that used Lactobacillus, Bifidobacterium, and Enterococcus as probiotics. Health effects of traditional yogurt—ie, milk fermented with the starter cultures Streptococcus thermophilus and Lactobacillus delbrueckii subsp bulgaricus—will not be reviewed here; several reviews have already been published on this topic (9, 15). Studies with the probiotic yeast Saccharomyces boulardii were reviewed by Elmer et al (7) and are not included here.
|
PREVENTION OF DIARRHEAL DISEASES |
|---|
|
TOPABSTRACTINTRODUCTIONPREVENTION OF DIARRHEAL DISEASESLOWERING OF SERUM CHOLESTEROLPREVENTION OF CARCINOGENESIS AND...DISCUSSIONREFERENCES |
|---|
Effects of probiotics on the immune system
Several probiotics are claimed to stimulate the immune system. Their modes of action appear to be nonspecific, resulting in increased immune responsiveness to a wide variety of antigens. In most studies, intermediary endpoints instead of disease symptoms were studied.
Spanhaak et al (19) tested the effect of Lactobacillus casei Shirota on various aspects of the immune system in a placebo-controlled study in 20 healthy men. The men were given a controlled diet for 8 wk. On weeks 3–6, 10 men received 100 mL fermented milk/d supplemented with 1 x 1012 colony-forming units (CFU) Lactobacillus casei Shirotas/L and 10 other men received unfermented milk. The treatment had no effect on natural killer cell activity, phagocytosis, or cytokine production.
Malin et al (20) used the immune response of antigen-specific immunoglobulin A (IgA) as an intermediary endpoint in a study of 14 children with Crohn disease and of 9 children with juvenile chronic arthritis. The children were supplemented with Lactobacillus GG (2 x 1010 CFU/d) for 10 d. The immune response of IgA was measured ex vivo: lymphocytes from the patients were transferred into microtiter plates that were coated with casein, ß-lactoglobulin, or gliadin. Lymphocytes that contained specific antibodies against these proteins showed up as colored spots. In the patients with Crohn disease, the number of lymphocytes with specific antibodies against casein and ß-lactoglobulin, but not gliadin, was significantly higher after than before treatment with the probiotic. No effect was seen on clinical status in any of the patients. The authors did not discuss whether an increased formation of IgA antibodies against milk proteins was considered beneficial for these patients.
Lactobacillus GG ameliorated symptoms in infants with atopic eczema and cow milk allergy in a placebo-controlled study (21). Moreover, the concentration of tumor necrosis factor in feces decreased significantly from 709 to 34 pg/g feces in the infants receiving Lactobacillus GG but not in the infants receiving placebo.
The immune response after vaccination is an elegant tool with which to study the effects of probiotics. Link-Amster et al (22) tested whether the consumption of yogurt with B. bifidum and L. acidophilus La1 improved the immune response in 15 healthy volunteers after oral vaccination with Salmonella typhimurium; 15 other volunteers were asked not to consume fermented foods. Vaccination increased total IgA concentrations in serum 2.5 times in the control subjects compared with 4.1 times in the subjects who received the probiotic (P = 0.04). However, significantly more antibodies (per mg IgA) against Salmonella were found in the saliva of the control subjects than in the saliva of the treated subjects (22). Because no placebo yogurt was given to the control group, the effect seen may have been due to the probiotic but also to the consumption of yogurt as such.
These same probiotics, but given separately, doubled the number of white blood cells with phagocytic activity in healthy volunteers (23, 24). B. bifidum Bb12 (1 x 1010 CFU/d) and L. acidophilus La1 (7 x 1010 CFU/d) were each given to 14 volunteers for 3 wk. Phagocytic activity was measured before and after treatment; no control group was included in the study. The treatment period was preceded by a run-in period in which the volunteers consumed 360 mL nonfermented milk/L. The probiotics, however, were consumed as fermented milks. Again, the effect on phagocytosis may have been due to the probiotics but also to the consumption of fermented milk.
In another study, L. acidophilus (Infloran; Istituto Sieroterapico Berna, Como, Italy) and B. bifidum (both 8 x 106 CFU/d for 28 d) had hardly any effect on immune indexes in 15 elderly volunteers; only B lymphocytes increased significantly (P < 0.01), from 72 ± 29 to 119 ± 31 x 106 cells/L serum (25). A control group with 10 subjects remained stable. All subjects underwent colonoscopy; consumption of the probiotic bacteria reduced signs of inflammation in the sigmoid and descending colon, whereas no changes were seen in the control group. In brief, several studies suggest that consumption of fermented milk enriched with probiotics increases the immune response. However, studies using nonenriched fermented milk as a placebo are needed to confirm this.
Acute diarrhea, mainly caused by rotavirus
Rotavirus is the main virus of interest in studies with probiotics. Rotavirus infection causes gastroenteritis, characterized by acute diarrhea and vomiting. Gastroenteritis is a leading cause of death and disease among children worldwide. There is ample evidence that probiotics reduce the duration and severity of rotavirus diarrhea. Consumption of Lactobacillus GG (1010–1011 CFU/d) shortened the diarrheal phase from an average of 3.5 to 2.5 d in children hospitalized (26–32) or treated at home for rotavirus infection (33). Serum concentrations of IgA antibodies against rotavirus increased significantly more in children treated with probiotics than in untreated children (28–30), which might explain the effect on recovery. Moreover, Isolauri et al (34) showed that the immune response to vaccination with a live oral rotavirus vaccine was better in children receiving Lactobacillus GG than in control children.
Although the therapeutic effects of Lactobacillus GG have been well established, it has not been reported whether it can prevent rotavirus infection. However, oral administration of 2 other probiotics, B. bifidum and S. thermophilus, reduced the incidence of diarrhea in a double-blind, placebo-controlled trial in 55 hospitalized infants (35). Of the 10 cases of diarrhea, 7 were due to rotavirus.
L. acidophilus has been tested for its therapeutic effects on acute diarrhea in 2 studies (36, 37). In the study by Bin (36), 50 Chinese children with acute diarrhea were randomly assigned to receive either L. acidophilus (n = 30) or the standard treatment (n = 20). The recovery from diarrhea was not significantly different between the 2 groups. Rotavirus was the main causal agent of the diarrhea in the L. acidophilus group (25 of 30) but not in the control group (7 of 20). In the study by Boulloche et al (37), 103 infants and children with acute diarrhea were randomly assigned to receive L. acidophilus (heat-killed, strain LB), loperamide, or placebo. Recovery times were not significantly different between the groups. However, in 71 children who received oral rehydration, L. acidophilus decreased the diarrheal period by 
20 h (P < 0.05). Because of the different strains of L. acidophilus used, no firm conclusions can be drawn from these studies.
Another strain tested for its therapeutic effect on acute diarrhea was Enterococcus SF68, a strain that is also known as Enterococcus faecium SF68 or Streptococcus faecium SF68. In one study (38), patients with acute diarrhea were randomly assigned to treatment with 2.3 x 108 CFU Enterococcus SF68/d (n = 40) or placebo (n = 38). After 1 d, 5 patients in the experimental group were cured compared with zero in the control group. Life-table analysis showed that patients in the experimental group were cured sooner than were patients in the control group. However, no effect of Enterococcus SF68 was seen in a placebo-controlled study of 183 Bangladeshi adults with acute watery diarrhea caused by Vibrio cholerae (n = 114), enterotoxic Escherichia coli (n = 41), or unknown causes (n = 28) (39). The placebo consisted of heat-inactivated Enterococcus SF68. This study did not rely on reported diarrhea but measured stool output in all patients. However, a large placebo-controlled study of 211 adults with acute diarrhea showed that intake of 15 x 107 CFU E. faecium SF68/d shortened the diarrheal phase from 2.8 d in the placebo group to 1.7 d in the treatment group (40). The effects of this probiotic on diarrhea are therefore inconclusive but tend to be positive.
We conclude that consumption of Lactobacillus GG can shorten the diarrheal phase of rotavirus infection by 1 d. No consistent evidence exists for other probiotics or for the prevention, as distinguished from treatment, of rotavirus-induced diarrhea.
Diarrhea caused by antibiotic use
Diarrhea due to the growth of pathogenic bacteria is the most common side effect of antibiotic use. Probiotics might inhibit this growth by releasing inhibitory substances, as indeed has been shown in vitro for some strains (41–45). So far, only one study has shown that Lactobacillus GG can prevent antibiotic-induced diarrhea (46). This study was done in 16 healthy men aged 18–24 y who received erythromycin for 7 d. Half of the men consumed 125 mL Lactobacillus GG–enriched yogurt/d, whereas the other half received placebo yogurt. The total number of days with diarrhea was 2 d in the Lactobacillus GG group and 8 d in the placebo group.
Two studies investigated the therapeutic effect of Lactobacillus GG in patients with recurrent Clostridium difficile infection (47, 48), an infection that causes severe diarrhea and colitis. The conclusion from both studies was that Lactobacillus GG cured the recurrent infection, but no control groups were included in these studies and the number of patients was small (n = 5 and 4, respectively).
Several strains of L. acidophilus have been tested as a prophylactic against diarrhea caused by antibiotics in 2 studies in patients (49, 50) and in 1 study with healthy volunteers (51). None of these studies provided conclusive evidence that intake of L. acidophilus prevents diarrhea caused by antibiotics. However, because the group sizes were small, significant effects could have been missed. Intake of Enterococcus SF68 (1.5 x 108 CFU/d) for 7 d reduced the incidence of diarrhea caused by antibiotics (38): 2 of 23 patients who received Enterococcus SF68 came down with diarrhea compared with 6 of 22 patients who received a placebo.
In conclusion, several studies have tested whether probiotics can prevent diarrhea due to antibiotic use. However, because of the small numbers of patients, the variety of antibiotics used, and, in many of the studies, the lack of a control or placebo group, this question remains unanswered.
Traveler's diarrhea
Traveler's diarrhea is defined as the passage of 
3 unformed stools in a 24-h period in people who normally live in industrialized countries and who travel to tropical and semitropical areas (52). It affects 20–50% of travelers. The prevention of traveler's diarrhea by lactobacilli could be a safe alternative to antibacterial drugs.
Two studies investigated whether Lactobacillus GG can prevent traveler's diarrhea. In 820 travelers to 2 holiday resorts in Turkey, the incidence of diarrhea was 43% (178 of 418 participants) in the control group and 38% (153 of 402 participants) in the Lactobacillus GG group (53). The difference was not statistically significant when data from both resorts were combined. However, in one of the resorts, the treatment significantly reduced the incidence of diarrhea in the participants from 40% (30 of 76) in the placebo group to 24% (17 of 71 participants) in the Lactobacillus GG group. On the basis of this finding, the authors concluded that the use of Lactobacillus GG can diminish the risk of traveler's diarrhea. In another study with 245 travelers to developing countries, the risk of diarrhea on any given day was 3.9% in travelers who took Lactobacillus GG and 7.4% in control subjects who took a placebo (54). This study did not indicate how many travelers in each study group had diarrhea.
No effect of L. acidophilus strain LA (2 x 1011 CFU/d) or Lactobacillus fermentum strain KLD (2 x 1011 CFU/d) was seen in a double-blind, placebo-controlled study of 282 soldiers who were sent to Belize in Central America (55). The incidence of diarrhea was 24.5% in both treatment groups and in the placebo group. Compliance was >90% in 214 of the 282 volunteers. In the less-compliant volunteers, the incidence of diarrhea was higher but was not significantly different between the 3 groups. In conclusion, the effect of probiotics on the incidence of traveler's diarrhea seems to depend on the bacterial strain and the destination of the traveler and needs further study.
|
LOWERING OF SERUM CHOLESTEROL |
|---|
|
TOPABSTRACTINTRODUCTIONPREVENTION OF DIARRHEAL DISEASESLOWERING OF SERUM CHOLESTEROLPREVENTION OF CARCINOGENESIS AND...DISCUSSIONREFERENCES |
|---|
The cholesterol-lowering potential of L. acidophilus has been most widely studied. Lin et al (62) performed 2 studies: a pilot trial without a placebo and a large placebo-controlled trial. In the pilot trial, 23 subjects received tablets containing 3 x 107 CFU L. acidophilus (ATCC 4962) and Lactobacillus bulgaricus (ATCC 33409) daily for 16 wk, whereas 15 subjects received no tablets. Fasting blood samples were taken before and 7 and 16 wk after the start of the study. Serum cholesterol in the control group remained stable at 4.9 mmol/L; serum cholesterol in the experimental group decreased from 5.7 to 5.3 mmol/L after 7 wk (P < 0.05) and to 5.4 mmol/L after 16 wk (P < 0.05 compared with baseline and week 7). A second study with a double-blind, placebo-controlled and crossover design did not show a significant effect of lactobacilli on serum cholesterol (62). Two 6-wk study periods were separated by a washout period of 3 wk; 460 volunteers were enrolled and 334 completed the study. The mean serum cholesterol concentration after both treatments was 5.5 mmol/L.
A study performed in India showed that consumption of buffalo milk fermented with a specific strain of L. acidophilus reduced serum cholesterol by 12–20% after 1 mo (63). Serum cholesterol concentrations in the control group were not given, so no firm conclusions can be drawn from this study. A placebo-controlled crossover study with 30 volunteers found a 0.23-mmol/L (95% CI: 0.35, -0.11) lower serum cholesterol concentration after consumption of yogurt enriched with a specific strain of L. acidophilus and fructooligosaccharides than after consumption of a placebo yogurt (64). We found no effect of the consumption of yogurt enriched with L. acidophilus L-1 at a dose of 1010 CFU/d in a placebo-controlled study of 78 healthy men and women (65; Figure 1
). Thus, the effects of L. acidophilus on serum cholesterol are inconclusive.
|
|
PREVENTION OF CARCINOGENESIS AND TUMOR GROWTH |
|---|
|
TOPABSTRACTINTRODUCTIONPREVENTION OF DIARRHEAL DISEASESLOWERING OF SERUM CHOLESTEROLPREVENTION OF CARCINOGENESIS AND...DISCUSSIONREFERENCES |
|---|
One hypothesis for the prevention or delay of tumor development by lactobacilli is that they might bind to mutagenic compounds in the intestine (70), thereby decreasing the absorption of these mutagens. Note that mutagenicity is mainly estimated as mutagenic potency in the in vitro Ames Salmonella test; effect of mutagens on cancer risk in humans can differ more than a thousandfold between humans (71).
If lactobacilli bind to mutagenic compounds, then the urinary excretion of mutagens will decrease. If the lactobacilli do not metabolize the compounds, the fecal excretion will increase. Indeed, excretion of mutagens in urine after a hamburger meal was 50% lower (P < 0.05) when the meal was supplemented with milk fermented with a strain of L. acidophilus (2.5 x 1011 CFU/d) than with unfermented milk (72). The fecal excretion of mutagens was not significantly reduced. In a similar experiment with a hamburger meal and L. rhamnosus GG, again no significant effect on the excretion of mutagens in the feces of 30 volunteers was found (73). Unfortunately, no information on the excretion of mutagens in urine was given. Intake of freeze-dried L. casei (Biolactis Powder, 3 x 108 CFU/d; Yakult Honsha Co, Tokyo) for 3 wk reduced the urinary excretion of mutagens after a test meal by 50% in 6 volunteers compared with pretreatment excretion (74). Thus, short-term studies suggest that intake of lactobacilli can reduce the absorption of mutagens from the intestine. Whether this will lead to a decreased incidence of cancer needs to be established.
Another possible explanation for the preventive effect of probiotics on carcinogenesis is their effect on other bacteria in the intestine. Probiotics might suppress the growth of bacteria that convert procarcinogens into carcinogens, thereby reducing the amount of carcinogens in the intestine. The activity of the enzymes that convert procarcinogens into carcinogens is often used as an indicator of the effect of probiotics on the intestinal microflora. Several studies showed an effect of consumption of probiotics on these enzyme activities, which are measured in feces.
Consumption of L. rhamnosus GG was shown to decrease the activity of ß-glucuronidase (8, 75), nitroreductase (75), and choloylglycine hydrolase (75, 76). Consumption of milk enriched with L. casei Shirota for 4 wk temporarily decreased ß-glucuronidase activity in 10 healthy men but not in 10 healthy control subjects and decreased ß-glucosidase activity to a greater degree in 10 healthy men than in 10 healthy control subjects (19). Consumption of milk fermented with a Bifidobacterium species for 12 d decreased ß-glucuronidase activity compared with baseline but had no effect on fecal pH or the activity of nitrate reductase, nitroreductase, and azoreductase (77). Consumption of a fermented milk with L. acidophilus, B. bifidum, Streptococcus lactis, and Streptococcus cremoris for 3 wk decreased the activity of nitroreductase from baseline but not that of ß-glucuronidase and azoreductase (78). Thus, the results of these studies are inconclusive and apart from 2 clinical studies with L. casei, no conclusive evidence for an effect of probiotics on cancer risk or tumor recurrence exists. The relation between enzyme activity and cancer risk needs to be investigated further.
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONPREVENTION OF DIARRHEAL DISEASESLOWERING OF SERUM CHOLESTEROLPREVENTION OF CARCINOGENESIS AND...DISCUSSIONREFERENCES |
|---|
In some studies, milk was given as a placebo whereas the probiotic was given as a fermented milk (23, 24, 72). This could have resulted in false-positive results in studies in which measures of immune status were the outcome variables. There is indeed some evidence that consumption of fermented milk stimulates the immune system (79, 80).
Probiotics are, by definition, live microorganisms and indeed most studies have been done with viable bacteria. Kaila et al (28) compared the effects of viable compared with those of heat-inactivated L. casei GG on diarrhea in 26 infants with acute diarrhea. The recovery time from diarrhea was not significantly different between the 2 groups. However, the patients that had received viable bacteria showed a higher specific IgA antibody response than did the patients who had received heat-inactivated bacteria. Viability might therefore be a prerequisite for effects on the immune system. In conclusion, the therapeutic effect of Lactobacillus GG on rotavirus diarrhea is well established. Other health effects, such as immune system stimulation, cancer prevention, and cholesterol lowering, need further investigation.
|
ACKNOWLEDGMENTS |
|---|
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONPREVENTION OF DIARRHEAL DISEASESLOWERING OF SERUM CHOLESTEROLPREVENTION OF CARCINOGENESIS AND...DISCUSSIONREFERENCES |
|---|
This article has been cited by other articles:
|
|
 |
|
  M. Segarra-Newnham Probiotics for Clostridium difficile-Associated Diarrhea: Focus on Lactobacillus rhamnosus GG and Saccharomyces boulardii Ann. Pharmacother., July 1, 2007; 41(7): 1212 - 1221. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. M. Galdeano, A. de Moreno de LeBlanc, G. Vinderola, M. E. B. Bonet, and G. Perdigon Proposed Model: Mechanisms of Immunomodulation Induced by Probiotic Bacteria Clin. Vaccine Immunol., May 1, 2007; 14(5): 485 - 492. [Full Text] [PDF]
|
|
|
|
 |
|
 M. de Vrese and P. R. Marteau Probiotics and Prebiotics: Effects on Diarrhea J. Nutr., March 1, 2007; 137(3): 803S - 811S. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Hirose, S. Murosaki, Y. Yamamoto, Y. Yoshikai, and T. Tsuru Daily Intake of Heat-Killed Lactobacillus plantarum L-137 Augments Acquired Immunity in Healthy Adults J. Nutr., December 1, 2006; 136(12): 3069 - 3073. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. E. Bergonzelli, D. Granato, R. D. Pridmore, L. F. Marvin-Guy, D. Donnicola, and I. E. Corthesy-Theulaz GroEL of Lactobacillus johnsonii La1 (NCC 533) Is Cell Surface Associated: Potential Role in Interactions with the Host and the Gastric Pathogen Helicobacter pylori Infect. Immun., January 1, 2006; 74(1): 425 - 434. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Lavermicocca, F. Valerio, S. L. Lonigro, M. De Angelis, L. Morelli, M. L. Callegari, C. G. Rizzello, and A. Visconti Study of Adhesion and Survival of Lactobacilli and Bifidobacteria on Table Olives with the Aim of Formulating a New Probiotic Food Appl. Envir. Microbiol., August 1, 2005; 71(8): 4233 - 4240. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. F. Bell Preventing Necrotizing Enterocolitis: What Works and How Safe? Pediatrics, January 1, 2005; 115(1): 173 - 174. [Full Text] [PDF]
|
|
|
|
 |
|
 C. R. Heiser, J. A. Ernst, J. T. Barrett, N. French, M. Schutz, and M. P. Dube Probiotics, Soluble Fiber, and L-Glutamine (GLN) Reduce Nelfinavir (NFV)or Lopinavir/Ritonavir (LPV/r)-related Diarrhea J Int Assoc Physicians AIDS Care (Chic Ill), October 1, 2004; 3(4): 121 - 129. [Abstract] [PDF]
|
|
|
|
 |
|
 S. A. F. T. van Hijum, E. Szalowska, M. J. E. C. van der Maarel, and L. Dijkhuizen Biochemical and molecular characterization of a levansucrase from Lactobacillus reuteri Microbiology, March 1, 2004; 150(3): 621 - 630. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 U. Gluck and J.-O. Gebbers Ingested probiotics reduce nasal colonization with pathogenic bacteria (Staphylococcus aureus, Streptococcus pneumoniae, and {beta}-hemolytic streptococci) Am. J. Clinical Nutrition, February 1, 2003; 77(2): 517 - 520. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. A. F. T. van Hijum, G. H. van Geel-Schutten, H. Rahaoui, M. J. E. C. van der Maarel, and L. Dijkhuizen Characterization of a Novel Fructosyltransferase from Lactobacillus reuteri That Synthesizes High-Molecular-Weight Inulin and Inulin Oligosaccharides Appl. Envir. Microbiol., September 1, 2002; 68(9): 4390 - 4398. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. I. A. Pereira and G. R. Gibson Cholesterol Assimilation by Lactic Acid Bacteria and Bifidobacteria Isolated from the Human Gut Appl. Envir. Microbiol., September 1, 2002; 68(9): 4689 - 4693. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Oozeer, N. Goupil-Feuillerat, C. A. Alpert, M. van de Guchte, J. Anba, J. Mengaud, and G. Corthier Lactobacillus casei Is Able To Survive and Initiate Protein Synthesis during Its Transit in the Digestive Tract of Human Flora-Associated Mice Appl. Envir. Microbiol., July 1, 2002; 68(7): 3570 - 3574. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Duggan, J. Gannon, and W A. Walker Protective nutrients and functional foods for the gastrointestinal tract Am. J. Clinical Nutrition, May 1, 2002; 75(5): 789 - 808. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Kimura, Y. Nagata, C. W. Bryant, and R. K. Buddington Nondigestible Oligosaccharides Do Not Increase Accumulation of Lipid Soluble Environmental Contaminants by Mice J. Nutr., January 1, 2002; 132(1): 80 - 87. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. D. Miller, J. K. Jarvis, and L. D. McBean The Importance of Meeting Calcium Needs with Foods J. Am. Coll. Nutr., April 1, 2001; 20(2): 168S - 185. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. M. Russell and T. R. Klaenhammer Identification and Cloning of gusA, Encoding a New {beta}-Glucuronidase from Lactobacillus gasseri ADH Appl. Envir. Microbiol., March 1, 2001; 67(3): 1253 - 1261. [Abstract] [Full Text]
|
|
|
|
 |
|
) and 6 (
) wk. The net effects were calculated as changes in blood lipid concentrations in the Lactobacillus acidophilus group (n = 39) minus changes in the control group (n = 39). Reprinted with permission from reference 65.