Smoking has been identified as a key risk factor for the development of cardiovascular diseases (CVD). It was found that a persistent increase in levels of oxidative stress and prolonged inflammation play a pivotal role in the pathogenesis of smoking associated CVD. Oligomeric proanthocyanidins (OPCs) are widely known for their anti-oxidant and anti-inflammatory effects, in vitro and in vivo. However, there are hardly any studies available that systematically investigated their acute and long-term effects on vascular function as well as on established biomarkers of oxidative stress and inflammation in an "at risk" population such as smokers.

Therefore, the aim of the present study is to investigate the effects of an eight-week supplementation with OPCs on vascular function as well as biomarkers of oxidative stress and inflammation in blood of smokers.

Inclusion Criteria:

• healthy male subjects smoking ≥ 10 cigarettes per day with a regular smoking history of ≥ 5 years
• BMI ≥ 20 and ≤ 27 kg/m2

Exclusion Criteria:

• Occurence of any adverse event, in particular those which require the use of medication that might interfere with the effects and/or the uptake of the investigational products
• Intolerance of study products
• Occurence of a serious adverse event
• Use of supplements, functional foods and/or other products containing vitamins, antioxidants and polyphenolic compounds or other ingredients with potential influence on vessel function for at least one month before the beginning of the study and during the entire study
• Use of a medically prescribed diet or slimming diet
• Vegetarian or vegan lifestyle
• Excessive alcohol consumption (< 28 consumptions (approximately 250 g alcohol) per week)
• Participation in a clinical trial within 4 weeks before the study
• Non-compliance with the demands of the study