The effect of Lactiplantibacillus plantarum 299v together with a low dose of iron on iron status in healthy pregnant women: A randomized clinical trial

ILSI Europe perspective review: site-specific microbiota changes during pregnancy associated with biological consequences and clinical outcomes: opportunities for probiotic interventions

Pregnancy induces notable alterations in the gut, vaginal, and oral microbiota driven by hormonal, immune, metabolic, dietary, and environmental factors. During pregnancy, the gut microbiota is characterized by increased proportions of the genus Bifidobacterium and the phyla Pseudomonadota (formerly Proteobacteria) and Actinomycetota (formerly Actinobacteria). These changes occur alongside reduced alpha diversity and greater beta diversity, changes that influence maternal metabolism and fetal development. Shifts in gut and oral microbiota have been associated with complications such as preterm birth (PTB), pre-eclampsia, and gestational diabetes (GDM), though patterns are sometimes inconsistent. The vaginal microbiota remains Lactobacillus-dominant during pregnancy, with reduced diversity leading to reduced risk of pathogenic infection and increased diversity has been linked with a higher risk of PTB. Hormonal changes also affect the oral microbiota, potentially increasing pathogenic species and contributing to adverse outcomes like PTB. Probiotic supplementation during pregnancy has significant potential to reduce adverse pregnancy outcomes; however, clinical studies are still limited. Probiotics may be effective in alleviating maternal constipation and lead to lower PTB risk, particularly by modulating the vaginal microbiota, but they have limited impact on GDM. In the context of maternal mental health, some studies suggest benefits of probiotics in reducing anxiety, but effects on depression are inconclusive. This perspective examines how pregnancy-related microbial shifts, both natural and probiotic-induced, affect maternal and fetal health and highlights potential opportunities for the innovative use of probiotics during the gestation period.

The Effect of the Combination of Probiotics and Heavy Metals From Various Aspects in Humans: A Systematic Review of Clinical Trial Studies

Background and Aims

Probiotics usually have beneficial effects on the absorption of trace elements and detoxification of toxic metals in human. Hence, the aim of the systematic review was to evaluate various aspects of the effect of the combination of probiotics and heavy metals in human clinical trial studies.

Methods

Nine databases were searched for clinical trials up to June 2024 investigating probiotics for heavy metal exposure in humans. Two reviewers independently screened records and extracted data on study characteristics, interventions, outcomes, and results. Risk of bias was assessed.

Results

The analysis included 31 clinical trials with a total of 4,611 participants, focusing on the effects of probiotics, prebiotics, and synbiotics. Among the trials, 23 investigated probiotics, five looked at prebiotics, and three explored synbiotics, with probiotic doses ranging from 107 to 2.5 × 1010 CFU/day. Results indicated that probiotics combined with zinc significantly reduced the time to resolution of vomiting and diarrhea compared to zinc alone, improved the treatment efficacy of antibiotic-associated diarrhea linked to pneumonia, and shortened hospital stays relative to probiotics alone. Probiotics did not show significant effects on blood parameters compared to placebo; however, prebiotic galactooligosaccharides enhanced iron absorption in women and children. The addition of probiotics to bismuth quadruple therapy did not improve Helicobacter pylori eradication rates but reduced side effects like diarrhea and vomiting. One trial reported a decrease in toxic metal levels in pregnant women due to probiotics, but no similar effects were observed in children.

Conclusions

Probiotics are one of the new methods employed to improve or eliminate the adverse effects of heavy metals in the body. Although many studies have investigated the effects of probiotics on heavy metals, there is still a need for more in-depth and extensive studies.

Effect of probiotic and prebiotics supplementation on hemoglobin levels and iron absorption among women of reproductive age and children: a systematic review and meta-analysis

BACKGROUND

This review aims to assess the effect of oral administration of probiotics and/or prebiotics in children and women of reproductive age (WRA) to improve intestinal iron absorption, hemoglobin, and ferritin levels.

METHODS

Randomized controlled trials from published literature on probiotics and or prebiotics for prevention or treatment of anemia as a supplement or fortification in children or WRA till Jan 31, 2023, were included. Studies on probiotics and prebiotics in patients with anemia due to other causes were excluded. Screening and data extraction was done using Distiller SR and meta-analysis was performed using Revman 5.4.1.

RESULTS

A total of 1925 records were identified from Pubmed, Embase, and Cochrane, of which 29 were included in the systematic review (14 supplementation and 15 fortification studies; 15 studies in children and 14 studies in WRA). The major interventions included galacto-oligosaccharide, inulin, heat-killed H61, Lactobacillus plantarum 299v, Lactobacillus reuteri, Lactobacillus acidophilus. Meta-analysis of 5 studies in WRA showed that the use of prebiotics and/or probiotics with or without iron was associated with little or no effect on hemoglobin. However, there is low certainty of evidence that the intervention led to improvement in fractional absorption of iron as compared to placebo or iron [8 studies, n = 335, mean increase 0.74%, 95%CI-0.11-1.38, p = 0.02]. Meta-analysis of 6 studies in WRA using prebiotics and/or probiotics with or without iron led to a significant increase in ferritin levels in WRA (mean increase 2.45 ng/ml, 95% CI 0.61-4.3, p = 0.009, n = 320) [Moderate certainty of evidence]. In children, meta-analysis of up to 8 studies did not result in any significant change in hemoglobin, ferritin and fractional iron absorption [low or very low certainty of evidence].

CONCLUSION

There is some evidence to show that the use of prebiotics or probiotics (especially Lp299v and GOS) with or without oral iron can improve iron absorption in women and lead to improvement in ferritin levels in women. However, the current evidence does not conclusively show the benefit of these interventions in improving hemoglobin levels in women and children.

Improved gastrointestinal tolerance and iron status via probiotic use in iron deficiency anaemia patients initiating oral iron replacement: a randomised controlled trial

This study aimed to investigate gastrointestinal tolerability, treatment persistence and iron status markers in patients with iron deficiency anaemia (IDA) who received oral iron replacement therapy (IRT) with v. without concomitant Lactobacillus plantarum 299v (L. plantarum 299v) probiotic supplementation. A total of 295 patents with newly diagnosed IDA were randomly assigned to receive either IRT alone (n 157, IRT-only group) or IRT plus L. plantarum 299v (n 138, IRT-Pro group) in this prospective randomised non-placebo-controlled study (ClinicalTrials.gov Identifier: NCT06521879). Gastrointestinal intolerance symptoms (at baseline, within the first 30 d of IRT and at any time during 3-month IRT), serum Hb levels (at baseline and 3rd month of IRT) and iron status markers (at baseline and 3rd month of IRT) were recorded. IRT-Pro group, when compared with IRT-only group, experienced significantly lower rates of gastrointestinal intolerance over the course of IRT (13·0 % v. 46·5 %, P < 0·001) and treatment discontinuation within the first 30 d (3·6 % v. 15·9 %, P < 0·001). At 3rd month of therapy, IRT-Pro v. IRT-only group had significantly higher serum levels for iron (76·0 (51·0-96·0) v. 60·0(43·0-70·0) µg/dl, P < 0·001) and transferrin saturation (20·1 (12·5-28·5) v. 14·5 (10·5-19·0) %, P < 0·001) and higher change from baseline Hb (0·9 (0·3-1·3) v. 0·4 (-0·1-1·1) g/dl, P < 0·001) levels. Use of L. plantarum 299v probiotic supplementation during the first 30 d of IRT in IDA patients significantly reduces the gastrointestinal burden of IRT (particularly abdominal pain and bloating), the likelihood of intolerance development (by ∼3 times) and treatment discontinuation (by∼5 times), as accompanied by improved serum Hb levels and serum iron markers.

Nutraceuticals in Pregnancy: A Special Focus on Probiotics

The placenta is crucial to fetal development and performs vital functions such as nutrient exchange, waste removal and hormone regulation. Abnormal placental development can lead to conditions such as fetal growth restriction, pre-eclampsia and stillbirth, affecting both immediate and long-term fetal health. Placental development is a highly complex process involving interactions between maternal and fetal components, imprinted genes, signaling pathways, mitochondria, fetal sexomes and environmental factors such as diet, supplementation and exercise. Probiotics have been shown to make a significant contribution to prenatal health, placental health and fetal development, with associations with reduced risk of preterm birth and pre-eclampsia, as well as improvements in maternal health through effects on gut microbiota, lipid metabolism, vaginal infections, gestational diabetes, allergic diseases and inflammation. This review summarizes key studies on the influence of dietary supplementation on placental development, with a focus on the role of probiotics in prenatal health and fetal development.

The effects of probiotics administration during pregnancy on preeclampsia and associated maternal, fetal, and newborn outcomes: a systematic review and meta-analysis

OBJECTIVE

This study aimed to synthesize the available evidence on probiotic administration during pregnancy for the prevention of preeclampsia and its effects on related maternal, fetal, and newborn outcomes.

DATA SOURCES

Six databases were systematically searched for eligible studies, namely Ovid MEDLINE, Embase, CINAHL, Cochrane, Global Index Medicus, and the Maternity and Infant Care Database, from inception to August 2, 2023.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials that evaluated the effects of probiotic administration on women during any stage of pregnancy were eligible for inclusion.

METHODS

The protocol was registered with the International Prospective Register of Systematic Reviews under identifier CRD42023421613. Evaluating study eligibility, extracting data, assessing risk of bias (ROB-2 tool), and rating certainty (Grading of Recommendations, Assessment, Development and Evaluations) were conducted independently by 2 authors. The primary outcomes were incidence of preeclampsia, eclampsia, and maternal mortality. A meta-analysis was performed, and the results were reported as risk ratios with 95% confidence intervals.

RESULTS

A total of 29 trials (7735 pregnant women) met the eligibility criteria. There was heterogeneity across the trials in the population of enrolled women and the type of probiotic tested (20 different strains), although most used oral administration. Probiotics may make no difference to the risk of preeclampsia (risk ratio, 1.14; 95% confidence interval, 0.84-1.53; 11 trials; 2401 women; low certainty evidence), preterm birth at <37 weeks' gestation (risk ratio, 0.93; 95% confidence interval, 0.66-1.30; 18 trials, 4016 women; low certainty evidence), or gestational age at delivery (mean difference, -0.03 weeks [≈0.2 days]; 95% confidence interval, -0.16 to 0.10 weeks [≈ -1.1 to 0.7 days]; 13 trials, 2194 women; low certainty evidence). It is difficult to assess the effects of probiotics on other secondary outcomes because the evidence was of very low certainty, however, no benefits or harms were observed.

CONCLUSION

Limited evidence suggests that probiotic supplementation does not affect the risk for preeclampsia. Further high-quality trials are needed to definitively assess the benefits and possible harms of probiotic supplementation during pregnancy. There is also a lack of data from trials that included women who were undernourished or who experienced microbial dysbiosis and for whom probiotic supplementation might be useful.

The role of probiotics in women's health: An update narrative review

Probiotics, live microorganisms that confer health benefits to the host when administered in adequate amounts, have gained considerable attention for their potential role in maintaining women's health. This overview summarizes key clinical findings on the beneficial effects of probiotics in various aspects of women's health. Probiotics, particularly Lactobacillus species, contribute to vaginal health by promoting a balanced vaginal microbiome to prevent infections and maintain an acidic environment. In gynecologic conditions, probiotics show potential in preventing and managing bacterial vaginosis, vulvovaginal candidiasis, and sexually transmitted infections. Probiotic supplementation has also been associated with improvements in metabolic parameters and menstrual irregularities in polycystic ovary syndrome patients. During pregnancy, probiotics may be helpful in reducing the risk of gestational diabetes, maternal group B streptococcal colonization, obstetric anemia, and postpartum mastitis. In recent years, the potential role of probiotics in the prevention and management of gynecologic cancer has gained attention. Further research is needed to better understand the specific mechanisms and determine the optimal Lactobacillus strains and dosages regimens for gynecologic cancer prevention and therapy. In conclusion, probiotics offer a non-invasive and cost-effective approach to support women's health and prevent obstetric and gynecologic complications.

Bacteria from the gut influence the host micronutrient status

Micronutrient deficiencies or "hidden hunger" remains a serious public health problem in most low- and middle-income countries, with severe consequences for child development. Traditional methods of treatment and prevention, such as supplementation and fortification, have not always proven to be effective and may have undesirable side-effects (i.e., digestive troubles with iron supplementation). Commensal bacteria in the gut may increase bioavailability of specific micronutrients (i.e., minerals), notably by removing anti-nutritional compounds, such as phytates and polyphenols, or by the synthesis of vitamins. Together with the gastrointestinal mucosa, gut microbiota is also the first line of protection against pathogens. It contributes to the reinforcement of the integrity of the intestinal epithelium and to a better absorption of micronutrients. However, its role in micronutrient malnutrition is still poorly understood. Moreover, the bacterial metabolism is also dependent of micronutrients acquired from the gut environment and resident bacteria may compete or collaborate to maintain micronutrient homeostasis. Gut microbiota composition can therefore be modulated by micronutrient availability. This review brings together current knowledge on this two-way relationship between micronutrients and gut microbiota bacteria, with a focus on iron, zinc, vitamin A and folate (vitamin B9), as these deficiencies are public health concerns in a global context.

The Relationship between Gastrointestinal Health, Micronutrient Concentrations, and Autoimmunity: A Focus on the Thyroid

Currently, there is a lack of understanding of why many patients with thyroid dysfunction remain symptomatic despite being biochemically euthyroid. Gastrointestinal (GI) health is imperative for absorption of thyroid-specific nutrients as well as thyroid function directly. This comprehensive narrative review describes the impact of what the authors have conceptualized as the “nutrient–GI–thyroid axis”. Compelling evidence reveals how gastrointestinal health could be seen as the epicenter of thyroid-related care given that: (1) GI conditions can lower thyroid-specific nutrients; (2) GI care can improve status of thyroid-specific nutrients; (3) GI conditions are at least 45 times more common than hypothyroidism; (4) GI care can resolve symptoms thought to be from thyroid dysfunction; and (5) GI health can affect thyroid autoimmunity. A new appreciation for GI health could be the missing link to better nutrient status, thyroid status, and clinical care for those with thyroid dysfunction.

Intraamniotic Administration (Gallus gallus) of Genistein Alters Mineral Transport, Intestinal Morphology, and Gut Microbiota

Genistein is an isoflavone naturally present in numerous staple food crops, such as soybeans and chickpeas. This study utilized the Gallus gallus intraamniotic administration procedure to assess genistein administration effects on trace mineral status, brush border membrane (BBM) functionality, intestinal morphology, and intestinal microbiome in vivo. Eggs were divided into five groups with 1 mL injection of the following treatments: no-injection, DI H₂O, 5% inulin, and 1.25% and 2.5% genistein (n = 8 per group). Upon hatch, blood, cecum, small intestine, and liver were collected for assessment of hemoglobin, intestinal microflora alterations, intestinal morphometric assessment, and mRNA gene expression of relevant iron and zinc transporter proteins, respectively. This study demonstrated that intraamniotic administration of 2.5% genistein increased villus surface area, number of acidic goblet cells, and hemoglobin. Additionally, genistein exposure downregulated duodenal cytochrome B (DcytB) and upregulated hepcidin expression. Further, genistein exposure positively altered the composition and function of the intestinal microbiota. Our results suggest a physiological role for genistein administration in improving mineral status, favorably altering BBM functionality and development, positively modulating the intestinal microbiome, as well as improving physiological status.

Lactiplantibacillus plantarum 299v (LP299V®): three decades of research

This review aims to provide a comprehensive overview of the in vitro, animal, and clinical studies with the bacterial strain Lactiplantibacillus plantarum 299v (L. plantarum 299v; formerly named Lactobacillus plantarum 299v) published up until June 30, 2020. L. plantarum 299v is the most documented L. plantarum strain in the world, described in over 170 scientific publications out of which more than 60 are human clinical studies. The genome sequence of L. plantarum 299v has been determined and is available in the public domain (GenBank Accession number: NZ_LEAV01000004). The probiotic strain L. plantarum 299v was isolated from healthy human intestinal mucosa three decades ago by scientists at Lund University, Sweden. Thirty years later, a wealth of data coming from in vitro, animal, and clinical studies exist, showing benefits primarily for gastrointestinal health, such as reduced flatulence and abdominal pain in patients with irritable bowel syndrome (IBS). Moreover, several clinical studies have shown positive effects of L. plantarum 299v on iron absorption and more recently also on iron status. L. plantarum 299v is safe for human consumption and does not confer antibiotic resistance. It survives the harsh conditions of the human gastrointestinal tract, adheres to mannose residues on the intestinal epithelial cells and has in some cases been re-isolated more than ten days after administration ceased. Besides studying health benefits, research groups around the globe have investigated L. plantarum 299v in a range of applications and processes. L. plantarum 299v is used in many different food applications as well as in various dietary supplements. In a freeze-dried format, L. plantarum 299v is robust and stable at room temperature, enabling long shelf-lives of consumer healthcare products such as capsules, tablets, or powder sachets. The strain is patent protected for a wide range of indications and applications worldwide as well as trademarked as LP299V^®.

Oral Iron Supplementation—Gastrointestinal Side Effects and the Impact on the Gut Microbiota

Iron deficiency anaemia (IDA) is a worldwide healthcare problem affecting approximately 25% of the global population. The most common IDA treatment is oral iron supplementation, which has been associated with gastrointestinal (GI) side effects such as constipation and bloating. These can result in treatment non-adherence and the persistence of IDA. Intravenous iron does not cause GI side effects, which may be due to the lack of exposure to the intestinal lumen. Luminal iron can cause changes to the gut microbiota, aiding the promotion of pathogenic species and decreasing beneficial protective species. Iron is vital for methanogenic archaea, which rely on iron for growth and metabolism. Increased intestinal methane has been associated with slowing of intestinal transit, constipation, and bloating. Here we explore the literature to understand a potential link between iron and methanogenesis as a novel way to understand the mechanism of oral iron supplementation induced GI side effects.