Background: An association between bone health and consumption of citrus fruits have been previously reported; however, the effect of lemon juice on bone metabolism have not been explored yet.

Objectives: To investigate bone metabolic changes in postmenopausal women assuming lemon juice.

Methods: Participants were postmenopausal osteoporotic women without history of clinical fractures who agreed to enrich their diet with lemon juice (Acti Lemon, Polenghi) over a 2-month period. The daily juice dose of 30 ml we suggested was equivalent to one Sicilian organic lemon. Surrogate markers of bone formation as procollagen type 1 N-propeptide (P1NP) and of bone resorption as C-terminal telopeptide of type I collagen (CTX), but also some regulators of bone metabolism as RANK-L, OPG, RANK-L/OPG ratio and sclerostin were assessed at baseline and then at 1 and 2 months after lemon juice administration. Controls were represented by a placebo group of age-matched osteoporotic postmenopausal women.

Results: 47 participants [mean age 60.2 ± 4.1 yr.] completed the study, without reporting any adverse events. Lemon juice was well tolerated. Over the observation period modifications of bone metabolism occurred: we detected a decreased RANK-L/OPG ratio and increased CTX levels at all time points vs. baseline. Particularly, change at month-1 of sclerostin (versus baseline) has been positively associated with change at month-1 and month-2 of CTX (r=0.46, p=0.01 and r=0.43, p=0.01, respectively). Change at month-1 of OPG was positively associated with change at month-1 of P1NP (r=0.49, p=0.006). Change at month-1 of RANKL/OPG has been related with variation at day 30 of P1NP (r=-0.44, p=0.013). Variation of P1NP at month-1 was related with sclerostin variation at day 30 (r=-0.56, p=0.02) and month-2 vs. baseline value (r=0.44, p=0.017) and with sclerostin variation between month-1 and month-2 (r=0.69, p<0.001). Variation of P1NP between month-1 and month-2 was associated with RANKL change at month-1 (r=-0.35, p=0.05), with sclerostin change at month-1 (r=-0.49, p=0.008) and with sclerostin change between month-1 and month-2 (r=0.41, p=0.028). At a multiple regression analysis the change of P1NP between month-1 and month-2 was independently predicted by the change of sclerostin at month-1 (ß=-1.5, SE 0.5, p=0.006), after correcting for age, BMI and change of RANKL and CTX levels at month-1. No significant modifications raised from controls.

Conclusion: Drinking lemon juice may boost bone metabolic changes involving both bone resorption and bone formation.

Disclosure of Interests: None declared