Michio Hashimoto

Accumulating evidence suggests the beneficial effect of omega‐3 polyunsaturated fatty acids (PUFAs) on bone mineral density (BMD). However, the effects of perilla ( Perilla frutescens ) seed oil (PO), a rich source of α‐linoleic acid (LNA), on human bone have not yet been elucidated. This randomized, double‐blind, placebo‐controlled trial investigated the effects of long‐term PO intake on bone health in Japanese adults. After screening for eligibility, 52 participants (mean age 54.2 ± 6.4 years) were randomly assigned to placebo ( n = 25) and PO ( n = 27) groups, which received 7.0 ml of olive oil and PO daily, respectively. At baseline and 12‐month, quantitative ultrasound of the right calcaneus was measured with an ultrasound bone densitometer and percentage of the Young Adult Mean (%YAM) was calculated. Serum levels of tartrate‐resistant acid phosphatase 5b (TRACP‐5b), and bone alkaline phosphatase (BALP) were evaluated. In addition, PUFA levels in the erythrocyte plasma membrane (RBC‐PM), serum biological antioxidant potential (BAP), and diacron reactive oxygen metabolites (d‐ROM) were evaluated. Compared with the placebo group, %YAM levels increased and serum TRACP‐5b levels decreased significantly in the PO group at 12‐month, while serum BALP levels remained unchanged. Moreover, RBC‐PM LNA levels and BAP/d‐ROM ratios increased significantly in the PO compared with the placebo group. These results suggest that long‐term PO intake may improve age‐related BMD decline by suppressing bone resorption and increasing LNA levels.