Assessment of carotenoid status and the relation to glycaemic control in type I diabetics: a follow-up study

OBJECTIVE: To assess the carotenoid status in young type I diabetic patients and its relationship to the glycaemic control of the disease. DESIGN: A follow-up study. SETTING: Hospital Universitario Puerta de Hierro, Health Area VI of Madrid (Spain). SUBJECTS: Forty-seven type I diabetic patients, followed for 2.5 years. INTERVENTIONS: Coinciding with physical examination and laboratory tests, serum levels of carotenoids were analysed by HPLC, and dietary intake of carotenoids was evaluated by a semiquantitative food frequency questionnaire and 3-day prospective dietary records. RESULTS: In type I diabetic patients, average intake, serum levels and correlations between diet and serum levels of carotenoids were comparable to those in reference non-diabetic groups. Between-subjects seasonal variations were observed for beta-cryptoxanthin intake and serum levels (higher in winter) and serum lycopene (higher in summer). Significant within-subjects seasonal changes were shown for dietary and serum beta-cryptoxanthin and serum beta-carotene. Serum carotenoids were unrelated to glycaemic control markers. Subjects with clinically acceptable glycaemic control showed lower lycopene intake than those with unacceptable control. Intake of carotenoids did not explain variance in insulin dose, fasting glycaemia, fructosamine or HbA1c. With the exception of lycopene, serum carotenoids were predicted by dietary intake, but in no case by fasting glycaemia, HbA1c or fructosamine. CONCLUSION: In type I diabetic patients, serum carotenoid concentrations and their variance are determined by dietary intake patterns, and are unrelated to the glycaemic control of the disease, as assessed by biochemical markers.