Dietary habits can modulate the pathogenesis of atopic dermatitis. We evaluated these habits in adult Japanese patients with atopic dermatitis using a validated, brief‐type self‐administered diet history questionnaire and compared the results to those of age‐ and sex‐matched healthy controls. Patients with atopic dermatitis showed higher intakes of carbohydrate and potatoes and lower intakes of alcohol, niacin, meat and oils/fats compared with those of the healthy controls. The results of logistic regression analysis showed that the intake of alcohol was negatively associated with atopic dermatitis (odds ratio, 0.905; 95% confidence interval, 0.832–0.983; P = 0.0181). The intakes of vitamin B6 and fruit were positively correlated with the severity scoring of atopic dermatitis. Multiple regression analysis revealed that vitamin B6 intake was a predictor of the severity scoring of atopic dermatitis (β = 26.98508709, t = 2.3995292, P = 0.01933781). The intakes of vegetable fat, n‐6 polyunsaturated fatty acid, and confections were lower in the severe atopic dermatitis group (severity scoring of atopic dermatitis, ≥33) than those in the mild group. Atopic dermatitis is negatively associated with alcohol intake, and intake of vitamin B6 is a predictor of severity scoring of atopic dermatitis. The intake of n‐6 polyunsaturated fatty acid is lower in the severe atopic dermatitis group than that in the mild group. Further study is warranted on the relationships of these results with abnormal immune responses, impaired skin barrier or pruritus in atopic dermatitis.