OsteoPreP: Food Supplements for Postmenopausal Bone Health

It is well established that bone loss occurs throughout life after the attainment of peak bone mass which is usually reached by the end of the second decade of life. During the first 5-8 years following menopause, women experience an accelerated bone loss, which is then followed by a slower phase of decline in bone mineral density (BMD). As over 40% of all women in Australia will suffer an osteoporotic (fragility) fracture in their lifetime, investigating interventions that can prevent bone loss in postmenopausal women is a critical focus. The menopausal transition is also associated with an increased risk of cardiovascular disease, diabetes, and cognitive decline. These conditions and their treatments can also affect bone health.

Previous research has indicated a potential link between the gut microbiome and bone health. Animal studies indicate that interventions affecting the gut microbiome may be successful in reducing bone loss, but human data is limited. Moreover, there is an emerging body of evidence linking the gut microbiome to cognitive, muscle and cardiometabolic function. Such studies indicate that probiotics (healthy gut bacteria) or prebiotics (food for healthy bacteria, e.g. fibre) can increase the amount of short chain fatty acids - such as butyrate -produced by the bacteria in the gut which may mediate the beneficial effects of improving gut health.

The proposed study is a double-blind, placebo-controlled randomised trial, which will investigate whether consuming a probiotic supplement containing inulin (a prebiotic soluble fibre) twice daily for 12 months will improve bone health in postmenopausal women. In addition, secondary outcomes will measure the effect of the intervention on immune system modulation and cognition as well as musculoskeletal and metabolic function as potential mediators.

One hundred and sixty postmenopausal women residing in Melbourne (Victoria, Australia) who are at least one year from their final menses will be recruited from the community via a mail out, advertisements in newspapers, social media, flyers as well as a landing page on an ACU managed website. The investigators have also applied for assisted mail outs through Services Australia for recruitment purposes. Services Australia is able to extract names and addresses of some target study demographics (females living in Melbourne aged between 40 and 65) from the Medicare database and mail them the study details on our behalf. Those wishing to participate will undergo a series of baseline assessments inclusive of bone mineral density scans, blood and stool sampling and physical activity and lifestyle questionnaires. They will then be randomised, in a blinded fashion, to consume one of the following two supplements:

• Placebo control group (n = 80): Placebo capsule - 2 capsules per day

• Probiotics group (n=80): Probiotic capsule - 2 capsules per day

Study outcomes will be measured at baseline, 6 months, and 12 months. In addition, participants will be contacted via the telephone and email at three-month and nine-month timepoints to report any adverse responses to the supplementation. At the 12-month time point, participants will cease supplementation and immediately (within 24 hours) attend a post intervention assessment and will complete identical assessment measures to those they did at baseline. Finally, at 2 weeks post supplementation cessation participants will be asked to attend an appointment to provide a final stool sample.

If it can be confirmed that long term consumption of a probiotic supplement can have beneficial effects on bone health, muscle health, and metabolic health in postmenopausal women, this intervention could be recommended in the prevention of osteoporosis and associated musculoskeletal and metabolic conditions.