Many women in the premenstrual period may be faced with physical and psychological changes that restricted the acceptance of the responsibility of daily living, jobs and reduced quality of life outdoors. One of these mental disorders is the changes in appetite. Preventing the initiation is the first step in reducing premenstrual syndrome, is very important. Vitamin B1 (Thiamin) may reduce symptoms of PMS through affecting the performance of coenzymes in the metabolism of carbohydrates.

This study was conducted to determine the effect of vitamin B1 on the change of appetite related to PMS.

In this double-blind placebo-controlled clinical trial, 100 students with PMS residing at dormitories of Jahrom University were divided randomly into two groups, vitamin B1 and placebo. The severity of mental symptoms specially change in appetite and desire to eat sweets in two cycles, before and during the intervention, was recorded by the students. The data were analyzed using descriptive and inferential statistics.

The comparison of vitamin B1 group before and after the intervention showed that vitamin B1 reduced mean mental (35.08%) symptoms significantly (P < 0.0001). The reduction of severity was observed in desire to eat sweets was 2.42%. The average of mental symptoms severity of PMS has been reduced in vitamin B1 group, and the comparison was significantly different.

Therefore, vitamin B1 is recommended for reduction of symptom severity of PMS include desire to eat sweet. This vitamin can be used to reach a major goal of midwifery, without any side effects.

The authors have not supplied their declaration of competing interest.