Nutrients, 2016, September Volume 8; Issue 10

Providing Flaxseed Oil but Not Menhaden Oil Protects against OVX Induced Bone Loss in the Mandible of Sprague-Dawley Rats.

Longo AB. Ward WE.

Key Findings

The characteristic decline in bone mineral density (BMD) at the hip, spine, and wrist that is associated with an increased risk of fragility fracture, is also associated with tooth loss in postmenopausal women. Ovariectomy (OVX) in the rat results in systemic bone loss and deterioration of the bone microarchitecture, similar to the loss of bone mass and structure in women following menopause. The objective of this study was to determine whether flaxseed oil or menhaden oil would preserve the trabecular microarchitecture, a major determinant of the structural integrity of the alveolar bone, using μCT in the OVX rat model of postmenopausal osteoporosis. No interactions were found between dietary oil source and hormone status for any of the outcomes assessed, including food intake, final body weight and trabecular microarchitecture outcomes. Differences in microarchitecture outcomes between SHAM and OVX rats existed only in those fed menhaden oil. Feeding rats flaxseed oil from one to six months of age provides protection against the OVX-induced bone loss at the mandible when OVX is performed at three months of age. Similar protection to the trabecular bone microarchitecture is not observed when rats are fed menhaden oil. These results suggest a benefit to incorporating ALA in the diet during the lifespan to help support the structural integrity of the mandible, and thus promoting retention of teeth.


Higher intakes of polyunsaturated fatty acids (PUFA) are associated with benefits at several skeletal sites in postmenopausal women and in rodent models, but the effect of PUFA-containing oils on tooth-supporting alveolar bone of the mandible has not been studied. Moreover, direct comparison of the effect of flaxseed oil (a source of alpha-linolenic acid (ALA)) and menhaden oil (a source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)) is unknown. One-month old female Sprague-Dawley rats (n = 48) were randomized to and fed a diet containing flaxseed oil or menhaden oil from one to six months of age. At three months of age, rats were randomized to receive SHAM or ovariectomy (OVX) surgery (n = 12/diet). The inter-radicular septum below the first molar of the mandible was imaged at 6 months of age (study endpoint) using micro-computed tomography (μCT) at a resolution of 9 μm. As expected, OVX significantly reduced percent bone volume (BV/TV), connectivity density (Conn. D.), trabecular number (Tb. N.), and increased trabecular separation (Tb. Sp.) compared to SHAM rats (p < 0.001). However, post hoc analysis revealed these differences were present in rats fed menhaden oil but not those fed flaxseed oil. These results suggest that providing flaxseed oil, possibly through its high ALA content, provides protection against the OVX-induced alveolar bone loss in rats.

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