Noninvasive assessment of dermal carotenoids as a biomarker of fruit and vegetable intake.
BACKGROUND
Resonance Raman spectroscopy (RRS) has been suggested as a feasible method for noninvasive carotenoid measurement of human skin. However, before RRS measures of dermal carotenoids can be used as a biomarker, data on intra- and intersubject variability and validity are needed.


OBJECTIVE
The purpose of this study was to evaluate the reproducibility and validity of RRS measures of dermal total carotenoids and lycopene in humans.


METHODS
In study 1, 74 men and women with diverse skin pigmentation were recruited. RRS measures of the palm, inner arm, and outer arm were obtained at baseline, 1 wk, 2 wk, 1 mo, 3 mo, and 6 mo (to maximize seasonal variation). The RRS device used visible light at 488 nm to estimate total carotenoids and at 514 nm to estimate lycopene. Reproducibility was assessed by intraclass correlation coefficients (ICCs). In study 2, we recruited 28 subjects and assessed dietary carotenoid intake, obtained blood for HPLC analyses, performed RRS measures of dermal carotenoid status, and performed dermal biopsies (3-mm punch biopsy) with dermal carotenoids assessed by HPLC.


RESULTS
ICCs for total carotenoids across time were 0.97 (palm), 0.95 (inner arm), and 0.93 (outer arm). Total dermal carotenoids assessed by RRS were significantly correlated with total dermal carotenoids assessed by HPLC of dermal biopsies (r = 0.66, P = 0.0001). Similarly, lycopene assessed by RRS was significantly correlated with lycopene assessed by HPLC of dermal biopsies (r = 0.74, P < 0.0001).


CONCLUSIONS
RRS is a feasible and valid method for noninvasively assessing dermal carotenoids as a biomarker for studies of nutrition and health.
Mayne
Susan T
ST
Yale University Schools of Public Health and Medicine, New Haven, CT 06520-8034, USA. susan.mayne@yale.edu
Cartmel
Brenda
B
Scarmo
Stephanie
S
Lin
Haiqun
H
Leffell
David J
DJ
Welch
Erin
E
Ermakov
Igor
I
Bhosale
Prakash
P
Bernstein
Paul S
PS
Gellermann
Werner
W
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000032:analysis; D002338:Carotenoids / Q000032:analysis* / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004032:Diet / Q000592:standards*; D005260:Female; D005638:Fruit; D006801:Humans; D000077276:Lycopene; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D015203:Reproducibility of Results; D012621:Seasons; D012867:Skin / Q000378:metabolism*; D012880:Skin Pigmentation; D013059:Spectrum Analysis, Raman / Q000379:methods*; D014675:Vegetables; D055815:Young Adult
D015415:Biomarkers; D002338:Carotenoids; D000077276:Lycopene