Inappropriate serum levels of retinol, α-tocopherol, 25 hydroxyvitamin D 3 and 24,25 dihydroxyvitamin D 3 levels in healthy Spanish adults: Simultaneous assessment by HPLC

Abstract

Objective Simultaneous assessment of the status of lipid-soluble vitamins; retinol, α-tocopherol, 25 hydroxyvitamin D 3 and 24,25 dihydroxyvitamin D 3 in serum of blood donors, paradigm of a healthy population. Patients and methods Serum samples were supplied by the Regional Blood Donors Center in Cordoba from 215 healthy Spanish individuals (166 males and 99 females). Target analytes were determined using liquid–liquid extraction and separation–detection by HPLC. Results The method was validated using standard reference material (SRM 968c, NIST). Standard errors were 1.4%, 2.1% and 1.8% for 25OHD 3, vitamin A and vitamin E, respectively. The ranges thus assessed were as follows: 17.1 ± 8.0 nmol/L, for 24,25(OH) 2D 3, 40.3 ± 34.6 nmol/L for 25OHD 3, 2.57 ± 0.7 μmol/L for retinol and 22.13 ± 8.30 μmol/L for α-tocopherol. Females showed lower serum levels of retinol ( p < 0.01), α-tocopherol ( p < 0.01) and 25OHD 3 ( p = 0.028). A total of 10.4% subjects showed vitamin E deficiency, 85.4% had normal levels and 4.2% had high levels of vitamin E. 65.6% of the target subjects showed normal levels of retinol, and 1.6% had moderate or severe vitamin A deficiency. High levels of vitamin A were found in 32.8% of the subjects. Fourteen percent of the healthy subjects showed severe vitamin D deficiency (serum levels of 25OHD 3 < 25 nmol/L), 50.8% had vitamin D 3 insufficiency (25OHD 3 from 25 to 50 nmol/L), 17.6% of the subjects had suboptimal 25OHD 3 serum levels (25OHD 3 from 50 to 75 nmol/L), only 16.8% had an adequate status of 25OHD 3 and 0.8% had high levels of vitamin D (25OHD 3 > 200 nmol/L). Among subjects with vitamin D below 50 nmol/L, 49.38% had high levels of retinol (over 2.4 μmol/L). This association is considered a risk factor for osteoporosis and fracture. Conclusions The reported data of high prevalence of lipid-soluble vitamin values outside the physiological range have important repercussions on public health. These data also uphold the need for simultaneous measurement of fat-soluble vitamins as a valuable tool in clinical practice as well as in epidemiological studies for awareness and correction.