This study investigated the relationship between dietary intake of antioxidants and the risk of Alzheimer disease. The Rotterdam Study, a population-based, prospective cohort study, followed 5395 participants aged 55 years and older, free of dementia, and with reliable dietary assessments. Participants were monitored for incident dementia over a mean follow-up period of 6 years. The main outcome measures were the incidence of Alzheimer disease, based on DSM-III-R and NINCDS-ADRDA criteria, associated with dietary intake of beta carotene, flavonoids, vitamin C, and vitamin E. After adjusting for various factors, including age, sex, education, smoking habits, and use of antioxidant supplements, high intake of vitamin C and vitamin E was associated with a lower risk of Alzheimer disease. The risk reduction was most pronounced in current smokers. Additionally, high intake of beta carotene and flavonoids was also associated with a lower risk of Alzheimer disease. However, these associations did not vary by education or APOE genotype. The study found that higher dietary intake of vitamin C and vitamin E was associated with a lower risk of Alzheimer disease. The results suggest that high dietary intake of these antioxidants may lower the risk of Alzheimer disease. However, the study also acknowledges potential limitations, including the possibility of residual confounding and the impact of subclinical dementia on dietary reporting. The study also notes that results from supplement use may not be directly comparable to results from dietary intake due to differences in duration and dosage. The study concludes that higher intake of vitamin C and vitamin E from food may be associated with a lower risk of Alzheimer disease. However, whether this reflects a causal association remains to be determined. Further research, including randomized controlled trials, is needed to evaluate the relationship between antioxidant intake and Alzheimer disease.This study investigated the relationship between dietary intake of antioxidants and the risk of Alzheimer disease. The Rotterdam Study, a population-based, prospective cohort study, followed 5395 participants aged 55 years and older, free of dementia, and with reliable dietary assessments. Participants were monitored for incident dementia over a mean follow-up period of 6 years. The main outcome measures were the incidence of Alzheimer disease, based on DSM-III-R and NINCDS-ADRDA criteria, associated with dietary intake of beta carotene, flavonoids, vitamin C, and vitamin E. After adjusting for various factors, including age, sex, education, smoking habits, and use of antioxidant supplements, high intake of vitamin C and vitamin E was associated with a lower risk of Alzheimer disease. The risk reduction was most pronounced in current smokers. Additionally, high intake of beta carotene and flavonoids was also associated with a lower risk of Alzheimer disease. However, these associations did not vary by education or APOE genotype. The study found that higher dietary intake of vitamin C and vitamin E was associated with a lower risk of Alzheimer disease. The results suggest that high dietary intake of these antioxidants may lower the risk of Alzheimer disease. However, the study also acknowledges potential limitations, including the possibility of residual confounding and the impact of subclinical dementia on dietary reporting. The study also notes that results from supplement use may not be directly comparable to results from dietary intake due to differences in duration and dosage. The study concludes that higher intake of vitamin C and vitamin E from food may be associated with a lower risk of Alzheimer disease. However, whether this reflects a causal association remains to be determined. Further research, including randomized controlled trials, is needed to evaluate the relationship between antioxidant intake and Alzheimer disease.