Blackcurrant Supplementation Reduces the Risk of Bone Loss in Women with Postmenopausal Osteoporosis

by | Jan 11, 2023 | 2022, Bone Health, Flavonoids, Fruits and Vegetables, Women's Health

Written by Taylor Woosley, Staff Writer. 6-month supplementation of 784 mg blackcurrant powder significantly decreased bone loss (p < 0.05) and increased serum levels of P1NP, a marker of bone formation (p < 0.05).

bone healthOsteoporosis is a systemic skeletal disease characterized by low bone mineral density and deterioration of bone architecture, resulting in reduced bone strength1. Structural bone deterioration increased the likelihood of fracture, with about 80% of all fractures being related to osteoporosis2. Fractures are associated with limitation of ambulation, chronic pain, and disability, decreased quality of life, and an increased risk of mortality3. Postmenopausal osteoporosis (PMO) is an estrogen deficiency-induced metabolic bone disorder that affects over 30% of women aged over 50 years that is driven by aging, imbalance of estrogen, and continuous calcium loss4.

Recent research has shown that foods rich in flavonoids, a class of secondary metabolites abundant in certain fruits and vegetables, have been investigated for their potential to improve bone mass5. Blackcurrants contain high concentrations of anthocyanins which have been studied for their antioxidative, anti-inflammatory, and anti-aging properties6. Furthermore, anthocyanins have been found to inhibit the formation of tartrate-resistant acid phosphatase osteoclasts and inhibit lipopolysaccharide-induced inflammation7.

Nosal et al. conducted a pilot double-blind, randomized, placebo-controlled trial to assess the dose-dependent effects of blackcurrant supplementation on bone density in peri- and early postmenopausal women aged 45-60. Study inclusion consisted of not being on hormone replacement therapy for at least one year before the study began, maintaining normal exercise levels, not overconsuming alcohol, and avoiding foods rich in anthocyanins. Subjects had an initial interview pertaining to their medical history and dietary behaviors and physical examination to record anthropomorphic measures. After the initial visit, subjects experienced a 2-week equilibration period, where they began taking a calcium citrate caplet daily that contained 400 mg calcium and 500 IU vitamin D and continued to take through the duration of the study.

After the 2-week period, during study visit 1 participants (n=40) were randomly assigned to three groups: the low BC group (n=16) (one capsule containing 392 mg of blackcurrant powder), high BC group (n=11) (two capsules containing 392 mg blackcurrant powder per capsule, total 784 mg of BC powder), or the control group (n=13) (one placebo capsule) for 6 months. Each BC capsule contained 176 mg anthocyanins. Subjects were instructed to keep a 3-day food record and physical activity record and to complete them for study visits at months 0, 3, and 6.

Participants provided a 12-h fasted blood sample and stool specimen at each visit at months 0, 3, and 6 for biochemical and metagenome sequencing analysis. Serum biomarkers of propeptide of type 1 procollagen (P1NP), bone-specific alkaline phosphatase (BALP), osteocalcin (OC), carboxy-terminal crosslinked telopeptide of type 1 collagen (CTX1), and sclerostin were measured using ELISA kits. Bone mineral density (BMD) analyses were performed by a licensed radiologic technician at baseline and 6 months using DXA.

Data analysis of variance methods was performed with PROC MIXED in SAS to determine the main and interaction effects of the two factors: treatment (placebo, low BC, or high BC group) and time (baseline, 3 months, and 6 months). ANOVA or Chi-square/Fisher’s Exact test was utilized to examine the significance of differences in baseline characteristics. T-tests were used to evaluate percent changes in BMD and bone biomarkers between control and low BC groups and between control and high BC groups.

A total of forty subjects completed the study. Most subjects (92.5%) had a normal bone mass (z-score ≥ -1), while 7.5% of participants (n=3) had z-scores for whole-body BMD ranging from -1.0 to -2.5, indicating that participants had overall good bone condition at baseline. Study findings show that 6-month supplementation of blackcurrant increased whole-body BMD from baseline in blackcurrant treatment groups, while the control group continued to lose bone (p < 0.05). When comparing the efficacy of the low dose BC and high dose BC groups, only daily consumption of the high dose (784 mg) significantly decreased bone loss (p < 0.05).

Results of the study show that blackcurrant supplementation significantly reduced the risk of bone loss related to postmenopausal osteoporosis. Further research should continue to explore the bone protective effects of blackcurrant. Study limitations include the small sample size, the short length of the study, and the lack of ethnic diversity of subjects.

Source: Nosal, Briana M., Junichi R. Sakaki, Zachary Macdonald, Kyle Mahoney, Kijoon Kim, Matthew Madore, Staci Thornton et al. “Blackcurrants Reduce the Risk of Postmenopausal Osteoporosis: A Pilot Double-Blind, Randomized, Placebo-Controlled Clinical Trial.” Nutrients 14, no. 23 (2022): 4971.

© 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

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Posted January 11, 2023.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

References:

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