Status and Dietary Intake of Phytoene and Phytofluene in Spanish Adults and the Effect of a Four-Week Dietary Intervention with Lutein-Rich Fruits or Vegetables.

Phytoene (PT) and phytofluene (PTF) are colourless carotenoids presents in the human diet and in blood, faeces and tissues and are biologically active. However, there is very little data on these carotenoids. This study aims to assess PT and PTF concentrations in serum from healthy Spanish normolipemic subjects ( n = 101, 45-65 years) and the effect of a fruit and vegetable dietary intervention (4 weeks, n = 29) on PT and PTF concentration in serum and faeces and dietary intake. Serum and faecal concentrations were analysed by HPLC and dietary intake by 3 × 24 h recalls. PT showed higher concentrations than PTF in serum, faeces and in the dietary intake. Considering both studies, PT and PTF concentrations in serum were 0.16 ± 0.07 and 0.05 ± 0.04 µmol/L, respectively, in faeces 17.7 ± 20.3 and 6.5 ± 7.9 µg/g, respectively, and in dietary intake the median was 2.4 and 0.6 mg/p/day, respectively. Carrots and tomatoes were the major dietary contributors of these carotenoids. The dietary intervention did not cause significant variations in the PT and PTF intake or serum concentrations, but a lower concentration in faeces was observed for the fruit group (PT: p = 0.024; PTF isomer-3: p = 0.034). These data highlight the need for further research on the activities of these carotenoids in humans.