Postmenopausal bone mineral density in relation to soy isoflavone-metabolizing phenotypes

Area of Science:

• Microbiology
• Endocrinology
• Bone Metabolism

Background:

• Intestinal bacteria metabolize soy isoflavones like daidzein into O-desmethylangolensin (O-DMA) and equol.
• Some individuals lack the gut bacteria necessary for this metabolism, impacting metabolite excretion.
• Soy isoflavones are studied for their potential effects on bone health, particularly in postmenopausal women.

Purpose of the Study:

• To investigate the relationship between bone mineral density (BMD) and the presence of urinary O-DMA and equol metabolites.
• To evaluate if the ability to produce these soy metabolites influences BMD in postmenopausal women.

Main Methods:

• A study involving 92 postmenopausal women (aged 50-75) was conducted.
• Bone mineral density (BMD) was measured using whole-body dual X-ray absorptiometry.
• Participants consumed soy foods for 3 days, and urine samples were collected to determine O-DMA and equol producer phenotypes.

Main Results:

• O-DMA producers exhibited significantly greater total, leg, and head BMD compared to O-DMA non-producers (p<0.05).
• Total BMD was 6% higher in O-DMA producers.
• No significant differences in BMD were found between equol producers and non-producers (p>0.05).
• Exploratory analyses suggested potential interactions between equol production, soy consumption, and spinal BMD, as well as associations with hormone levels.

Conclusions:

• Intestinal bacterial composition appears to play a role in determining BMD in postmenopausal women.
• The ability to produce O-DMA from daidzein is associated with higher BMD.
• Further research is needed to explore the specific associations between gut bacterial profiles and BMD.