Watermelon Juice: a Novel Functional Food to Increase Circulating Lycopene in Older Adult Women

Abstract

Because of accruing oxidative stress with advancing age, older adults may benefit from increased dietary intake of lycopene, a lipophilic carotenoid with potent antioxidant properties. Yet, intake of dietary lycopene as well as circulating lycopene levels are known to decrease with aging. Watermelon is one of the few food sources of dietary lycopene. Because heat treatment increases lycopene bioavailability, ingestion of watermelon in pasteurized juice form may be an optimal delivery vehicle to increase lycopene levels in older adults. However, due to its lipophilic nature, there are concerns that co-ingestion of dietary fat may be necessary for efficient intestinal absorption of lycopene. Thus, this feasibility study aimed to examine the effects of a one-time dose of 100% pasteurized watermelon juice on circulating lycopene concentrations of postmenopausal women after a 10-h overnight fast. Blood was sampled from eight women before and 2 h after ingestion of 360 ml of juice, and serum lycopene was measured by ultra-high performance liquid chromatography. Circulating lycopene levels increased by three-fold (p < 0.001) with increases observed for every participant. Results demonstrate that 100% watermelon juice is a palatable, effective means of increasing serum lycopene in older adult women, a group at risk for low carotenoid intake. Trial registration: Clinicaltrials.gov identifier: NCT03608254.