Carotenoids are consumed mainly via vegetables and fruits. The ingested carotenoids are distributed to various organs, and humans are unable to synthesize them internally. We have developed a device for non-invasive estimation of vegetable intake by measurement of skin carotenoid levels. A population-based cross-sectional study conducted in a rural area of Japan (n＝811; 58％ women; 49.5±15.1 years) showed that the measured values were positively and significantly correlated with serum carotenoid concentration and vegetable intake calculated using the BDHQ (brief-type self-administered diet history questionnaire) (r＝0.678 and 0.210, respectively). The measured values were also significantly associated with many biomarkers of metabolic syndrome. A preliminary intervention study (n＝26; 50％ women; 37.0±8.9 years) suggested that the skin carotenoid level was increased by intake of a carotenoid-rich juice containing 350 g vegetables in a carton for 4 weeks. The developed device is now being utilized at health checkups aimed at dietary instruction.

A three-group, three-period, randomized crossover study was conducted to compare plasma carotenoid absorption after concomitant consumption of vegetables and different doses of fermented milk. Eighteen healthy males participated. The fermented milk included milk protein, lactobacilli metabolites, and vegetable fats. The concentrations of carotenoids in plasma triacylglycerol-rich lipoprotein (TRL) fractions were determined from blood samples collected before and 2, 4, 6, and 8 hours after consumption of the test foods, which comprised either: vegetables (235 g), vegetables plus a low dose (7.5 g) of fermented milk, or vegetables plus a high dose (15 g) of fermented milk. The incremental area under the concentration-time curve (iAUC) for α-carotene, β-carotene, and lycopene in the plasma TRL fraction was significantly higher for consumption of vegetables plus either the low or high dose of fermented milk, in comparison with vegetables alone. The iAUC for lutein in the plasma fraction of whole blood was significantly higher for consumption of vegetables plus a high dose of fermented milk, in comparison with vegetables only. These results suggest that concomitant consumption of vegetables and fermented milk may enhance the absorption of vegetable-derived carotenoids, relative to consumption of vegetables alone.

The honey of the Japanese honeybee, Apis cerana japonica, is known to ferment spontaneously. Fermented honey is an underutilized resource that is rarely sold. Here we report the first analysis of the general composition and free amino acid composition of honey obtained in a fermented state from Japanese honeybees, for use as food. Fermented honey showed a significantly higher content of five of the 25 free amino acids analyzed: glutamine, GABA, cystine, phenylalanine, and proline. Another six amino acids (histidine, citrulline, theanine, cystine, methionine, and tryptophan), which are undetectable in unfermented honey, were confirmed to be present in fermented honey. No significant differences in general components were evident. The free amino acids that are increased in fermented honey are important nutrients for both humans and honeybees. Fermented honey from Japanese honeybees can be used as a new value-added food rich in important amino acids.