Differences in dietary habits and lifestyle factors associated with a high dietary intake of fruit and vegetables are discussed and used to explain the disparity between results of observational epidemiologic studies consistently showing antioxidative vitamins to exert a protective effect on chronic diseases, and intervention studies so far not confirming this association. Within the scope of the "Brandenburger Ernährungs- und Krebsstudie", the East German contribution to the European Prospective Investigation into Cancer and Nutrition (EPIC), we examined whether study participants using supplements on a regular basis--minerals, vitamins, protein formulation, bran/linseed, fiber, yeast or garlic pills--differed from those who did not report use of supplements according to selected lifestyle factors and dietary intake of vitamins, minerals, fiber, cholesterol, and fat from food. The study sample consisted of 10,522 participants (4,500 men and 6,022 women) aged 35-65 years enrolled in the cohort from January 1995 to July 1996. Regular intake of one or more supplements during the past year was reported by 32.6% of women and 25.5% of men. Vitamin supplements were used by 18.8% of the women and 15.8% of the men. Figures for minerals were 14.2% for women and 8.6% for men, respectively. Garlic pills were taken regularly by 9.7% of men and 9.3% of women. Prevalence of supplement use was generally higher in women and was more pronounced in elderly participants. The most frequently used combinations were vitamin and mineral supplements, followed by a combination of garlic and either vitamin or mineral supplements. Increased use of supplements was significantly associated with higher level of education attained, regular engagement in sporting activities, health complaints, and dietary change during the previous year. No association between use of supplements and smoking status nor elevated alcohol consumption was observed. Body mass index above 30 was significantly related to increased intake of garlic pills, and in women to significantly increased use of vitamin and mineral supplements. For both men and women, age-adjusted consumption of fruit and vegetables and intake of vitamins, minerals, and fiber from food was higher for participants using mineral but also vitamin supplements compared to those who did not use these supplements. For the cohort of the "Brandenburger Ernährungs- und Krebsstudie" we observed on the one hand that age, gender, and health-conscious lifestyle factors were related to supplement use. On the other hand presence of subjective health complaints was related to supplement use, especially for use of vitamins and minerals. Participants, who regularly consumed minerals and vitamins were also shown to have a higher intake of foods and nutrients considered to exert an antioxidative effect.