In this study, the postprandial glycemia and insulinemia caused by boiled potato with blue-fleshed or yellow-fleshed tubers, or a gel prepared with bilberries and potato starch, is studied in healthy males. Additionally, the appearance and metabolism of the flavonoids and their metabolites is studied in plasma and urine.

Inclusion Criteria:

• Age 18-45
• Male
• No regular medication
• No participation in a drug trial or blood donation within 2 months
• Non-smoker
• Signs informed consent
• Body mass index 18.5-27 kg/m2
• Fasting plasma cholesterol < 5.5 mmol/l
• Fasting plasma triacylglycerols < 2.6 mmol/l
• Fasting plasma glucose 4-6 mmol/l
• blood pressure <140/80 mmHg
• hemoglobin>130 g/l
• Fasting plasma alanine amino transferase (ALAT) <60 U/l (normal liver function)
• Fasting plasma thyroid-stimulating hormone (TSH) 0.4 - 4.5 mU/l (normal thyroid function)
• Fasting plasma creatinine <118 µmol/l (normal kidney function)

Exclusion Criteria:

• Regular smoking
• Alcohol abuse
• Regular medication