Effects of a Long-term Grapefruit Juice Consumption on Vascular Protection and Bone Metabolism

Epidemiological studies definitively show that fruit and vegetable consumption is an important factor for the prevention of age-related diseases such as cardiovascular diseases (CVD) and osteoporosis. Citrus fruits are among the fruits which are the most frequently consumed worldwide, essentially as juices.

Citrus fruits are the exclusive sources of a particular class of dietary flavonoids, namely flavanones. Grapefruit consumed as whole fruit or juice corresponds to a quantitatively significant source of a specific flavanone called naringin.

Some scientific data obtained from animal studies or in vitro experiments suggested that flavanones could exert positive effects on several biomarkers of the cardiovascular or osteoporosis risks. However, until now, the clinical proof of the efficacy of these compounds is far to be obtained and more clinical trials are needed.

The main goals of this project are (1) to characterize the effect of a long-term grapefruit juice consumption on both vascular and bone protections and (2) to assess the specific role of naringin, in these potential protective effects.

To reach these goals, a randomized, cross-over clinical trial will be performed on 52 healthy post-menopausal women (50 to 65 years old, 3 to 10 years since menopause, waist > 88 cm). Such a population shares an increased risk of CVD and osteoporosis.

They will consume for two periods of 6 months either 340 ml of grapefruit juice or a control isoenergetic beverage.

Major outcomes will be measured at baseline and at the end of each experimental period.

Inclusion criteria

• Caucasian healthy post-menopausal women
• 19≤ BMI ≤29 and waist measurement > 88 cm

Exclusion criteria

• Metabolic diseases
• Hypertension
• Taking CYP3A4-metabolized drugs
• Taking blood lipids lowering drugs or antihypertensive drugs
• Hypercholesterolemia with HDL < 1.30 mmol/L (i.e. < 0.5 g/L)
• Osteoporosis (defined by T-score of -2.5 SD at hip and/or lumbar spine)
• Taking hormone replacement therapy (HRT)
• Smokers
• Taking dietary supplements