Bioavailability Trial

Overview

Carrot is a unique vegetable owing to the availability of bioactive compounds polyacetylenes (PA) as well as carotenoids present in it. These compounds have been shown to be associated with reduced cancer risk in epidemiological-based studies, and also showed anticancer properties in vitro studies and in vivo in mouse and rat models. To investigate whether the PA and carotenoids could have beneficial effects in humans, the present study is designed to determine whether they are detectible in human biofluids after the ingestion of a portion of carrots and whether there is a difference in the magnitude of detection after eating a large (300g) and normal (100g) portion.

The occurrence of PA and carotenoids in carrot is not a guaranteed that they have potential health benefits and biological activity in humans, as there is still insufficient knowledge as to whether they can be absorbed in human bio-fluids (blood, urine and faeces) after the food (carrot) is consumed in the literature. The bioavailability of compounds depends upon both the chemical forms and physical structures which enable a certain proportion of such compounds into circulation when introduced into the body and so are able to have an active effect. The main goal of this trial is to investigate determine the fate of (PAs and carotenoids) found in carrots human plasma, urine and faeces. To achieve this goal, health adult volunteers will be instructed to restrict their diet (To avoid eating food that contain the compounds of interest) for 48hrs and complete 24hr food diary. They will fast overnight and collect urine and faecal samples on the morning of the test session. Once they arrive in the research facility, they will have fasted blood taken before eating a portion of carrots (either 100 or 300g) with bread and butter. Further blood samples will be taken at 1, 2, 4, 6, 8 and 24 hours. Urine sample will be collected at 4, 8, 12 and 24hr and up to 48hr after the carrot consumption, and faecal samples will be collected at any time the participants feel bowel movement during the study duration up to 48hr, noting the time when each sample was generated. The participants will attend two test sessions and will be randomised to receive high (300g) and normal (100g) doses of carrot. The washout period separating the two testing sessions is at least a week. The specific compounds of interest in this trial include PA (falcarinol, falcarindiol, and falcarindiol 3-acetate), carotenoids (α-carotene, β-carotene and lutein) and their concentrations at various time points after consumption and baseline will be measured using HPLC (for carotenoids) and LC-MS (for PA). The concentrations of the compounds at time points after ingestion will be compared with the baseline and also in relation to, normal and high carrot doses.