Quercetin's Effect on Bone Health and Inflammatory Markers

Quercetin is a plant-based flavonoid that is naturally found in many fruits and vegetables such as onions, apples, berries, green tea, and red wine and is currently an FDA approved supplement. Quercetin is considered to be a potent antioxidant with several expected health benefits. Both in vivo and in vitro studies have demonstrated that quercetin acts as a potent natural osteogenic agent with benefits that include anti-inflammatory effects and bone-conserving properties. Quercetin is suggested to protect against bone loss by inhibiting bone resorption and stimulating bone formation which is indicated by an increase in bone mineral density and bone formation markers such as osteocalcin.

The purpose of this study is to investigate the effects of quercetin supplementation on bone, specifically on bone turnover markers, in postmenopausal women. The interplay between cytokines (i.e., IL-6, CRP, and TNF-alpha) and bone turnover markers was also considered.

In a double-blind, placebo-controlled fashion, we aimed to recruit 50, healthy, postmenopausal women between the ages of 45-75 years to participate in a 90-day supplement trial. Participants will be randomly assigned to one of two supplement groups: 1) quercetin 500 mg, once per day, or 2) placebo (methyl cellulose E4M) 500 mg, once per day for 90-days.

Participants will be asked to visit the laboratory (KSU Human Performance Laboratory) on 2 separate occasions for pre- and post-testing visits consisting of body composition measurements and blood draws by a CITI approved/IRB approved research team member trained in phlebotomy under the supervision of Dr. VanDusseldorp.

Inclusion criteria

• Clinically defined as postmenopausal (absence of menstrual cycle for 12 months without contraceptives or the surgical removal of the reproductive organs)
• Activity levels ranging from sedentary to recreationally active were included in the study.

Exclusion criteria

• Hyper- or hypothyroidism (uncontrolled)
• Hyper- or hypoparathyroidism
• Gastrointestinal disorders
• Renal disorders
• Orthopedic disorders
• Rheumatological disorders
• Immunological disorders
• Type I diabetic
• Being treated with any diabetic injectable medication(s).
• Taking any non-steroidal, steroidal, or anti-inflammatory drugs
• Currently, or in the past 1 month, were consuming daily calcium
• Currently, or in the past 1 month, were consuming more than 5,000 IU's of vitamin D supplements
• Taking any anti-obesity medications
• Taking any osteoporotic medication(s)
• Taking any long-term antibiotics.
• Current smoker
• Diagnosed with osteoporosis, or if their BMD was equal to, or fell below -2.50 via dual x-ray absorptiometry (DXA) during visit 1
• Involved in heavy resistance training
• Began a new unaccustomed exercise routine during the 90-days
• Allergies to food(s) rich in QUE such as onions, apples, or berries; or if they were unwilling to avoid quercetin-containing foods.