The Effects of Red Rooibos Intervention in Combination with Two Different Levels of Dietary Calcium and Vitamin D on Mandible and Maxilla Bone Mineral Density in Ovariectomized Sprague-Dawley Rats

In the ovariectomized (OVX) rat model, the mandible exhibits a loss of trabecular BMD whereas the whole mandible does not exhibit a change in BMD, and there is a paucity of findings for the maxilla. Polyphenols that are naturally found in tea, such as red rooibos (RR) tea, may support bone health. The objective of this study was to determine if RR tea consumption can stimulate an increase in BMD in the whole mandible and the maxilla post-OVX. In addition to OVX, bone health can be further challenged by providing lower levels of dietary calcium (Ca) and vitamin D (vit D) in a modified AIN-93M diet compared to a control AIN-93M diet. For this research, 112 six-month-old Sprague-Dawley rats were randomized to one of four groups (n=14/group) for each diet (control AIN-93M: 5 g Ca & 1000 IU vit D/kg diet; or modified AIN-93M: 3 g Ca & 100 IU vit D/kg diet): SHAM+water, SHAM+RR, OVX+water, or OVX+RR. Rats were provided food and water or RR tea ad libitum for 12 weeks. Tea was provided at a supplemental level (2.6 g RR tea/kg body mass) and was freshly prepared in water every 2-3 days. Food intake and body mass were measured once weekly. At study endpoint (week 12), BMD, bone mineral content (BMC), and bone area of the whole mandible and a region of interest (ROI) of the maxilla were measured using dual energy X-ray absorptiometry (DXA). There was no effect of RR for any of the outcomes measured. There was a main effect for surgery with OVX rats having higher (p < 0.001) BMD in the mandible compared to SHAM rats. This may be due to the higher (p < 0.05) food intake and the resultant mechanical load that may have stimulated mineralization. There was a main effect for diet with low Ca and vit D diet groups having lower BMD in the mandible (p < 0.05) and maxilla (p < 0.001) compared to the control diet groups. While intervention with RR tea did not support BMD, lowering the dietary levels of Ca and vit D compromised BMD in the mandible and maxilla, which provides direction for future studies to determine the levels of dietary Ca and vit D that support BMD in the OVX model.

Name thesis:degree_name

M.Sc. Applied Health Sciences

Level thesis:degree_level

Master

Discipline thesis:degree_discipline

Faculty of Applied Health Sciences

Department dc:contributor.department

Applied Health Sciences Program

Grantor dc:publisher

Brock University

Year dc:date.issued

2025

Author dc:creator

• Ianiero, Mitchell

Advisor dc:contributor.advisor

• Ward, Wendy

• Ovariectomy
• Calcium
• Polyphenols
• Vitamin D

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/10464/20078

OAI record oai:identifier

https://brocku.scholaris.ca/server/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Abrocku.scholaris.ca%3A10464%2F20078