Can Consuming Cashew Nuts Cause Early Period?

I came across a friend of mine ho claims to have sex with my girlfriend in recent days (probably in last 45 days time) though in this period she had sex with me also but i always had sex with protection. Now this guys says he had sex with her without protection. and in meanwhile she had random period which this guy says was result of her taking i pill. when i asked her about her period coming before time she says she had lots of cashew nuts an cause of its heat she got early period. I have 2 questions- 1st.is the reason given by her for early periods right?? 2. Is there any way i find out if she had sex with the other guy, whereas they did not use protection and he ejaculated inside her??? please help me saving my relationship!!!!!