Dietary intake of micronutrient antioxidants in relation to blood levels in patients with systemic sclerosis

Objective. To document habitual intakes of micronutrient antioxidants in patients with systemic sclerosis (SSc) in light of studies reporting subnormal levels of ascorbate and selenium in this patient group. Methods. Dietary intakes of vitamin C, selenium, α-tocopherol, β-carotene, and sulfur amino acid precursors of glutathione were assessed using the 7 day weighed record in 12 patients with SSc and in 12 healthy control subjects. The intakes of the first 4 substances were examined in relation to plasma/serum levels, while intakes of sulfur amino acids were examined in relation to urinary inorganic sulfate. Results. Antioxidant and sulfur amino acid intakes were similar in patients and controls, although the patients had lower levels of selenium in serum (median 74 compared to 87 μg/l in controls; p = 0.014) and of vitamin C in plasma (median 6.0 compared to 11.1 mg/l in controls; p = 0.08). Inorganic sulfate concentration in urine was similar in patients and controls. Conclusion. Our results suggest that reduced blood levels of the water soluble antioxidants selenium and ascorbic acid in patients with SSc are not due to dietary deficiency. Other explanations must therefore be sought.