VSports - Using probiotic supplementation to support bone health in postmenopausal women: a randomized, double-blind, parallel, placebo-controlled, multi-center study

Introduction

Emerging evidence suggests that probiotics support bone health outcomes through the modulation of the gut microbiome [1, 2]. Probiotics are defined by the World Health Organization as “live microorganisms which, when administered in adequate amounts, confer a health benefit on the host” [3]. Among the many microorganisms identified, the most commonly studied species are from the Lactobacillus and Bifidobacteria genera, both of which are naturally present within the gastrointestinal flora [4]. While probiotic effects in humans and rodents have been shown to be usually strain- and disease-specific [5–7], studies in rodent models support the possibility of using probiotics containing Lactobacillus bacteria to attenuate ovariectomy-induced bone loss and promote favorable bone structure at the femur, tibia, and/or spine [1, 2, 8–16]. A recent systematic review and meta-analysis reported several benefits of probiotics for bone health in ovariectomized rodent models [17] V体育官网. Moreover, probiotic treatments modified the composition of the gut microbiome, reduced serum markers of inflammation, and suppressed osteoclast differentiation and/or activity, resulting in decreased bone resorption accompanying ovariectomy-related estrogen deficiency [1, 2, 8–11, 13].

In humans, few randomized control trials have investigated the effects of probiotics on bone health outcomes in postmenopausal women [18–20]. These trials provided Lactobacilli either as an isolated strain or a combination of strains. For example, in older women (N = 90; aged 75 to 80 years) with low bone mass (osteopenia), L. reuteri supplementation for 12 months resulted in greater bone mineral density (BMD) at the tibia compared to the control group using high resolution peripheral quantitative computed tomography (HR-pQCT) (primary outcome) with no effect on secondary outcomes including BMD measured by dual-energy X-ray absorptiometry (DXA) at the hip and spine [18]. Some bone protective effects were also demonstrated in a multicenter trial with postmenopausal women aged 45 to 70 years (N = 249). At baseline, 43% of participants were classified as having osteopenia [19]. Consumption of a multispecies probiotic (L. paracasei DSM 13434, L. plantarum DSM 15312, and L. plantarum DSM 15353; 1 × 1010 CFU) for 12 months prevented the loss of BMD at the lumbar vertebrae but not the hip [19]. The authors noted that the lack of difference at the hip may have been due to differential effects of the probiotic treatment on trabecular and cortical bone. The smaller region of trabecular bone at the hip, compared to the lumbar vertebrae, could have contributed to the differences in the findings between these bone sites. Using a different combination of species (L. casei 1. 3 × 1010 CFU; B. longum 5 × 1010 CFU; L. acidophilus 1. 5 × 1010 CFU; L. rhamnosus 3. 5 × 109 CFU; L. bulgaricus 2. 5 × 108 CFU; B. breve 1 × 1010 CFU; Streptococcus thermophiles 1. 5 × 108 CFU), no probiotic effect on BMD of the spine was demonstrated at 6 months in postmenopausal women with osteopenia (N = 50; age 50 to 72 years). However, the consumption of the probiotic treatment reduced serum markers of bone formation (bone-specific alkaline phosphatase, BALP), bone resorption (cross-linked C-telopeptide of type I collagen, CTx), and inflammation (tumor necrosis factor alpha) [20] VSports手机版. A longer study duration of 12 months may be required to observe beneficial changes to BMD [21].

The present study adds to this existing literature, to further understand the potential supportive role of different probiotic strains on bone health in postmenopausal women (age 40 to 59 years). The primary objective was to determine if probiotic consumption (L. brevis HA-112 and L. paracasei HA-274) could attenuate the loss of femoral neck BMD while also determining an effect on fracture risk and markers of bone cell activity as secondary outcomes. This study was designed a priori as an extension of a randomized, double-blind, placebo-controlled trial that investigated the effects of the probiotic supplement on menopausal symptoms (primary objective) V体育安卓版.

Methods

The study was performed over 48 weeks and involved two data collection sites based in the USA. The study was prospectively registered on ClinicalTrials.gov (Identifier: NCT04001088, 06/25/2019) and was approved by the Advarra Institutional Review Board (CR00228042; CR00232642) and the Brock University Health Science Research Ethics Board (File #20–319). Conduct of the study assessments were in accordance with the International Conference on Harmonisation—Good Clinical Practice principles and applicable US Code of Federal Regulations.

Results

The participant flow diagram showed that of the 72 women that were included in this extension study, 64 women completed the 48-week intervention (n = 33 women receiving the placebo [age 53.4 ± 4.5 years (min–max = 42.1–60.0)]; n = 31 women receiving the probiotic [age 54.0 ± 3.9 years (min–max = 46.6–59.5)], Fig. 1). Eight participants were excluded due to unavailable DXA scans at baseline and end of study. Findings from Little’s test of missing completely at random determined that the missing data was completely at random (p = 0.935) and mean imputation was used for further analyses.

There were no significant differences in participants’ demographic characteristics between intervention groups at baseline (Table 1). Most participants self-identified as Hispanic or Latino ethnicity (85%), White race (100%), and reported some high school education (50%). According to average height and weight, participants in the placebo group were considered obese (BMI = 31.5) while participants in the probiotic group were considered overweight (BMI = 27.8). Of consideration is that BMI does not measure body fat and given the significant body composition changes that may occur during the menopause transition [25], BMI may not be an accurate outcome to assess obesity status among this population. Using the screening questionnaire, 79% of participants in the placebo group (n = 26) and 82% of participants in the probiotic group (n = 26) reported having a history of cardiovascular and/or endocrine conditions (Table 1). Overall compliance was 94.4% for probiotic consumption (318 ± 32 tablets) and 98.1% for placebo consumption (330 ± 6 tablets). No serious adverse events were reported.

At baseline, femoral neck BMD did not significantly differ between groups. Sixty percent of women in the placebo group (n = 20) and 75% of women in the probiotic group (n = 21) had low bone mass (T-score between − 1.0 and − 2.5). One participant in the placebo group had osteoporosis (T-score − 2.5 or below), and all other participants had normal bone mass (T-score − 1.0 or above). At week 48, the distribution of participants with low bone mass increased to 69.7% in the placebo group (n = 23), and no change occurred in the probiotic group.

Discussion

Daily oral intake of the probiotic supplement for 48 weeks had no significant effect on femoral neck BMD, the risk of hip fracture, and the risk of major osteoporotic fracture. Regardless of the intervention, femoral neck BMD was lower at week 48 compared to baseline, and this loss was aligned with an increased risk of hip fracture and major osteoporotic fracture over time. There was no mean difference in bone marker levels between groups from baseline to endpoint. The lack of probiotic effect on BMD and fracture risk could be attributed to the fact that the study sample was inclusive of postmenopausal women with normal bone mass (average T-score =  − 0.90 ± 0.97). Additionally, it is acknowledged that there is rapid bone loss following menopause [26–28], making it challenging to measure an effect of an intervention during these rapid changes in bone cellular activity. Of note is that previous studies that support the use of probiotic supplementation on bone health have been conducted in postmenopausal women with low bone mass [18, 19]. The studies conducted in Sweden suggested not all skeletal sites may benefit from probiotic supplementation and that there were no differences in serum bone markers (NTx or BALP) [18, 19]. In postmenopausal women ages 75–80 years (average T-score = − 0.66 ± 0.83) consuming L. reuteri ATCCPTA 6475 (1 × 10¹⁰ CFU) for 12 months, there was no effect on BMD of the total hip, femur neck or spine assessed by DXA, compared to the control [18]. However, in this same study, tibia analysis using HR-pQCT demonstrated significant differences in BMD and lower reduction in trabecular bone volume fraction, favoring the probiotic intervention [18]. Imaging with HR-pQCT may yield different results due to greater sensitivity for detection of subtle changes in BMD [29]. This imaging technique can also provide insight on trabecular and cortical bone structure properties that contribute to bone strength.

The bone promoting effects of L. reuteri ATCCPTA 6475 (1 × 10⁹ CFU) from this previous study [18] aligns with findings from studies in ovariectomized rodents. L. reuteri ATCCPTA 6475 attenuated ovariectomized-induced trabecular bone changes [1]. Greater bone volume fraction and trabecular number along with lower trabecular separation at the femur and greater trabecular thickness at the vertebrae was observed compared to the ovariectomized control group [1]. A combination of Lactobacillus strains (L. paracasei DSM 13434, L. plantarum DSM 15312 DSM 15313) showed similar effects on trabecular bone structure when the probiotic intervention was provided 1.5 weeks after ovariectomy surgery and greater cortical thickness when the intervention was provided 2 weeks prior to ovariectomy surgery [11, 12]. This research group also demonstrated greater BMD at the lumbar spine following 12 months of consumption of the probiotic treatment (L. paracasei DSM 13434, L. plantarum DSM 15312 DSM 15313) in postmenopausal women age 45–75 years (T-score/bone mass) [19]. Interestingly, no differences were observed at the hip or femur neck or for serum bone turnover markers (P1NP, CTx, OC) between groups [19]. Understanding the response of systemic bone cellular changes to probiotics requires further investigation.

A strength of our study is the dominant representation of Hispanic postmenopausal women given the paucity of data for this population. While there is some evidence to support ethnic differences in BMD, rate of bone loss with aging and risk of fracture [30–33] results from studies investigating differences in mean BMD between Hispanic and non-Hispanic individuals have been inconsistent [34–37]. Eighty-five percent of participants in the current study self-identified as Hispanic or Latino. The vast majority of bone research evaluating BMD and risk of fracture in the USA has been conducted among non-Hispanic populations, and less is known about ethic and/or racial differences in bone health [30–39]. Based on the sensitivity check, the similar results between entire sample and when stratified by ethnicity (“Hispanic or Latino,” “not Hispanic or Latino”) suggest the findings are related to a Hispanic sample, despite inclusion of the small proportion of Caucasian women included in the sample population. With a combination of biological, environmental, and cultural factors that can influence the evolution of the gut microbiome [40], the strain-specific role of probiotics for modulating the gut microbiome may differ across ethnic groups.

Limitations of this study include sample size and a focus on a single skeletal site. The use of medications that can modulate bone health was recorded at screening and participants were instructed to continue reporting concomitant medication(s) in their daily diary throughout the study duration. No use of osteoporosis medications was reported, and this is likely because participants were not recruited based on BMD. Most of the participants in our sample (n = 57; 93%) reported active use of numerous concomitant medications to address cardiovascular and/or endocrine medical conditions reported at screening (Table 1; Table SI4). The anti-inflammatory effects of the medications reported may have obscured bone findings. It can be speculated that the long-term use of the combination of drugs that have been shown to have an effect on BMD and/or fracture risk, such as angiotensin-converting enzyme inhibitors [41–43] and statins [44], could mask potential probiotic effects due to their role in regulating inflammatory cytokines. Given this was a modest sample size and underpowered for detecting differences in bone health outcomes, this probiotic supplement should be studied in a future trial that includes BMD and/or fracture as a primary outcome. Moreover, a longer study duration, a higher dose, or assessment at multiple bone sites using HR-pQCT at the tibia or radius, as well as DXA measurement of other bone sites (i.e., lumbar spine and/or ultradistal radius), should be considered in the design of future studies. Furthermore, not all skeletal sites may experience a benefit of the probiotic supplement, and additional skeletal sites may need to be considered.

In summary, there was no effect of a novel combination of L. brevis HA-112 and L. paracasei HA-274 on BMD or fracture risk. Consideration of diverse populations is valuable for understanding potential mechanisms as well as the sociodemographic factors that may influence how we can tailor the use of probiotic treatments as a strategy to promote bone health.

V体育安卓版 - Supplementary Information

Below is the link to the electronic supplementary material.

Data availability

The data that supports the findings of this study are available on request from the Study Sponsor. The data is not publicly available due to privacy or ethical restrictions.

Declarations (V体育ios版)