Fermented Foods and Bone Health: Investigating the Gut-Bone Axis in Premenopausal Vegan Women

ConditionsBone Bone Health

Trial statusNot yet recruiting

Trial phaseNot applicable

Trial typeInterventional

Biological sexFemale

Age28-43

SponsorIsabelle Herter-Aeberli

About this trial

Plant-based diets are increasingly adopted for health and environmental reasons, but they are associated with lower bone mineral density, higher fracture risk, and elevated bone turnover markers, particularly in women. These effects are partly explained by lower intakes of calcium and zinc, and higher concentrations of phytates and oxalates, substances that inhibit mineral absorption from plant foods. Evidence-based dietary strategies to support bone health in vegan populations beyond supplementation remain limited.

Fermented plant-based foods may help address this gap through two complementary mechanisms: first, by delivering live microorganisms that beneficially modulate gut microbiota and promote the production of short-chain fatty acids, which support mineral absorption and reduce bone resorption, and second, by reducing antinutritional factors such as phytates during microbial fermentation, thereby improving mineral bioavailability.

This study investigates whether the daily consumption of fermented plant-based foods, specifically lacto-fermented vegetables, calcium-fortified plant-based yogurt alternatives with live cultures, and Rhizopus-fermented tempeh, reduces bone resorption and improves calcium metabolism in premenopausal women following a vegan diet. Participants will follow each dietary condition (fermented or matched non-fermented control foods) for 12 weeks in randomized order, separated by an 8-week washout period. Blood, urine, and stool samples are collected at each study visit to assess bone turnover markers, gut microbiota composition, short-chain fatty acid production, inflammatory markers, and a range of metabolic and nutritional parameters.

Eligibility criteria

This trial accepts healthy volunteers

Qualifiers

Female, aged 28-43years.

Body mass index (BMI) between 18.5 and 24.9 kg/m².

Premenopausal, with regular menstrual cycles. *

Adherence to a vegan diet for ≥1 year, confirmed by questionnaire.

Disqualifiers

Chronic diseases or conditions affecting bone metabolism (e.g., osteoporosis, thyroid disorders, chronic kidney and liver disease, menstrual cycles disorders affecting bone health, conditions associated with malabsorption).

History of diagnosed eating disorders.

Chronic inflammatory or gastrointestinal diseases (e.g., IBD, celiac disease).

Recent antibiotic use (within 3 months prior to screening).

Trial design

Design model

Crossover

Treatments tested in this trial

Fermented Plant-Based Foods
Other intervention
Daily consumption of three categories of fermented plant-based foods for 12 weeks: lacto-fermented vegetables, fermented plant-based yogurt alternatives with live cultures and calcium fortification, and Rhizopus-fermented tempeh. Minimum combined weekly target: 14 portions.
Non-Fermented Plant-Based Foods
Other intervention
Daily consumption of non-fermented plant-based equivalents for 12 weeks, matched to the intervention arm for portion size, energy, protein, and calcium content: non-fermented calcium-fortified plant-based milk, fresh raw vegetables, and cooked non-fermented legumes.

Treatment groups

50 Participants

are divided into 2 treatment groups

Group A: Fermented Plant-Based FoodsExperimental treatment 1 intervention

Group B: Non-Fermented Control FoodsActive comparator 1 intervention

Trial outcomes

Primary outcomes

Fasting serum CTX concentration

Within-subject difference in fasting serum C-terminal telopeptide of type I collagen (CTX) concentration between the end of the fermented food intervention phase and the end of the matched control phase, measured by electrochemiluminescence immunoassay (ECLIA).

Time frame