Plasma β-Carotene Is Not a Suitable Biomarker of Fruit and Vegetable Intake in German Subjects with a Long-Term High Consumption of Fruits and Vegetables

Abstract

Background/Objective: β-Carotene is often used as a marker for the amount of fruit and vegetables consumed, but little is known about plasma β-carotene concentrations in subjects whose habitual (long-term) diets are characterized by different amounts of foods of plant origin. We compared dietary β-carotene intake and plasma concentrations in women on habitual diets differing in the consumed amounts of foods of plant origin. Methods: A comparison of dietary β-carotene intakes and plasma β-carotene concentrations in women adhering to an average Western diet (n = 172), wholesome nutrition (following preventive recommendations) (n = 238) or a raw food diet (n = 104). Results: Dietary β-carotene intake was 5.5, 9.3, 14.7 mg/day for women adhering to an average Western diet, wholesome nutrition and raw food diet, respectively (p < 0.001). Corresponding multivariate adjusted plasma β-carotene concentrations were 1.07, 1.65, and 1.16 µmol/l, respectively (p < 0.001). Comparable dietary β-carotene intake resulted in lower multivariate adjusted plasma β-carotene in women adhering to a raw food diet and average Western diet compared to those on wholesome nutrition (p < 0.001 for all intake groups up to 20 mg/day). The amount of fruit and vegetable intake did not predict plasma β-carotene levels in women consuming a raw food diet. Conclusions: Plasma β-carotene concentrations differed among the diet groups, with highest plasma levels in women adhering to wholesome nutrition. Plasma β-carotene concentrations may not reflect β-carotene intake and the amount of fruit and vegetables consumed.