Dodier T, Anderson KL, Bothwell J, Hermann J, Lucas EA, Smith BJ. U.S. Montmorency tart cherry juice decreases bone resorption in women aged 65–80 years. Nutrients. February 7, 2021;13(2):544. doi: 10.3390/nu13020544.
During the five to 10 years after menopause, a decrease in estrogen can lead to bone loss and the development of osteoporosis in women. In the following decades, a more gradual decline in bone mass occurs as decreasing estrogen levels stabilize, and bone turnover slows. Healthy diets and plant-based foods could help prevent age-related bone loss by targeting inflammatory and oxidative processes. Tart cherries (Prunus cerasus, Rosaceae) are rich in polyphenols with noted osteoprotective effects. These authors conducted a pilot study to determine the effect of two different doses of tart cherry juice supplementation on bone formation and resorption in postmenopausal women.
Participants were recruited through email flyers distributed to individuals in universities, community groups, senior centers, and local clinics. Eligible participants were aged 65-80 years and able to walk without assistance. Thirty-three participants were chosen for the study and allocated to drink 240 mL tart cherry juice once daily (low-dose group, n = 15) or to drink 240 mL tart cherry juice twice daily (high-dose group, n = 18) for 90 days.
The participants were instructed to mix 30 mL tart cherry juice concentrate with about 10 mL water, and to drink the juice at the same time each day, with about eight hours between doses in the high-dose group. Produced from Montmorency tart cherries grown in the US, a 30 mL serving of the tart cherry juice concentrate provided 70 kcal, with 19 g of carbohydrate (15 g total sugar), 15 mg of sodium, and approximately 225 gallic acid equivalents of total phenolics.
The study was conducted at the Nutritional Sciences Clinical Research Laboratory, Oklahoma State University, Stillwater, Oklahoma. The participants visited the study site at baseline and after 45 days and 90 days of treatment. At baseline, participants underwent a blood draw, anthropometric measures, and strength testing. They completed questionnaires about their medical history, physical activity, sun exposure, and calcium intake. Dual-energy x-ray absorptiometry (DXA) scans were conducted, and biomarkers of bone formation, resorption, and turnover were assessed. Other outcome measures included biomarkers for inflammation, oxidative stress, and vitamin D status. At the second visit, participants reported any changes in their health status or medications, were measured for height and weight, and compliance was assessed. Proceedings of the final visit were similar to those at baseline.
Three participants withdrew from the study before the second visit because of dizziness, worsening of an undisclosed ulcer, and sleep interference. Of the 30 participants who completed the study, three were excluded from the final analysis for the following reasons: an unanticipated knee procedure, treatment for a poisonous spider bit, and a gastrointestinal infection. The compliance rate for the remaining 27 participants was greater than 90%.
The two groups were similar in age and distribution of ethnicity, marital status, and education. The participants reported that they were 23.0 ± 5.6 years postmenopause.
Baseline BMD T-scores from the DXA scans revealed osteopenia at one or more sites in 82% of the participants. The distribution of osteoporosis between the two groups was similar at all sites, except for the femur neck, where osteoporosis tended to be more prevalent in the low-dose group compared with the high-dose group (P = 0.088). Other bone parameters were similar between the two groups.
Dietary intake, physical activity, and grip strength did not change significantly in either group during the study. No between-group differences in vitamin D status were observed at baseline or at the end of the study.
The bone resorption marker, tartrate-resistant acid phosphatase type 5b, decreased significantly in the high-dose group compared with baseline (P = 0.0117); no change was observed in the low-dose group. The decrease in bone resorption observed in the high-dose group was not associated with risk for osteoporosis or vitamin D status at baseline. No other significant changes were observed in any other outcome measures, including those for bone formation, inflammation, and oxidative stress.
Limitations of this study include the possibility that the juice preparation used resulted in a reduced concentration or bioavailability of bioactive components needed to produce osteoprotective effects; the lack of a placebo-controlled design; and that the study may have been underpowered to detect small effects on biomarkers of interest or more subtle changes at lower doses.
According to the authors, "this study showed that supplementation with tart cherry juice reduced bone resorption in a cohort of older postmenopausal women. … the findings of this study can be used to inform the planning of future long-term clinical studies examining the effects of tart cherry juice, but highlight the need to consider the investigation of the skeletal response to the whole fruit."
This study was funded by the Cherry Research Committee of the Cherry Marketing Institute in Dewitt, Michigan. The authors declare no conflicts of interest.