Serum Concentrations of α-Carotene, β-Carotene, Lycopene, and Retinol-Binding Protein in Human Subjects

Serum concentrations of α-carotene, β-carotene, lycopene, and retionl-binding protein (RBP) in healthy adults were determined by HPLC or immunodiffusion to be the following: 6.7±4.8 μg/dl, 22.8±16.2 μg/dl, 26.3±17.9 μg/dl, and 5.0±0.9 mg/dl, respectively, for males (n=65); and 7.9±4.0 μg/dl, 43.8±21.4 μg/dl, 28.8±15.6 μg/dl, and 3.8 ±0.7 mgJdl, respectively, for females (n=81). Serum β-carotene concentrations were significantly higher in females than in males (p<0.001), while serum RBP values were lower in females than in males (p<0.001). The differences between the sexes in β-carotene and RBP concentrations were apparent in subjects over 15-years of age. Moreover, concentrations of β-carotene and α-carotene were higher with increasing age in females, but not in males. On the other hand, serum RBP values in males were higher with increasing age. Serum lycopene concentration was at its peak between the ages of 20 and 30 for both males and females. In addition, serum concentrations of α-carotene, β-carotene, lycopene, and RBP in outpatient subjects aged from one month to 19 years changed according to advancing age in both males and females. No differences in sexes for these mean values were found for subjects less than 14 years of age; they appeared later along with the secondary sex characteristics.