Table 1.

Mean (± SEM) values of study variables by season among US women (N = 52) living in North Dakota, USA

	Spring	Summer	Fall	Winter	P-value
	Mean ± SEM
Skin carotenoid status
RRS intensitiesb	38,238x ± 2617	34,629y ± 1910	37,044x ± 2043	36,563xy ± 1818	< 0.001
RS intensitiesb	0.091 ± 0.004	0.087 ± 0.004	0.088 ± 0.004	0.088 ± 0.004	0.500
Dietary Intakea
Vegetable and fruit (g/d)	188 ± 16	220 ± 16	194 ± 16	187 ± 18	0.441
Dietary carotenoids (mg/d)	12.1 ± 0.76	12.0 ± 0.97	11.9 ± 0.72	11.9 ± 1.11	0.983
	Geometric mean -1SEM, +1SEM
Total plasma carotenoids (μM/L)c	2.53; 2.36, 2.71 x	2.26; 2.11, 2.42 y	2.46; 2.30, 2.64 xy	2.34; 2.18, 2.51 xy	0.025

^aMeasured by the Automated Self-Administered 24-Hour (ASA24) Dietary Assessment Tool at 36 times over the year

^bMeasured at 12 times over the year

^cMeasured at 4 times over the year

•Analyzed carotenoids were α- and β-carotene, β-cryptoxanthin, lycopene, lutein and zeaxanthin.

x,y, Values between seasons with the same superscript letters are not significantly different (P > 0.05) by Tukey contrasts.

RS, reflection spectroscopy.

RRS, resonance Raman spectroscopy.