Caught cold

[mico]

Hello, forum! This is my first post here and it is actually a question about health. I'm on vegan diet about 5 months already and I am pretty happy with this except little health problems. I thought that cold would not catch me anymore because of the food I eat: plenty of fresh fruits, vegetables, nuts (almonds, hazelnuts, cashew, brazil nuts), vegetable soups, buckwheat, tofu. Today I woke up moderately ill: sniffles, my throat was not good and cough - default symptoms, may be temperature was a little high but I'm not sure, because didn't measure it. I live in Russia and it is pretty cold here but I guess climate is not the reason :) I am visiting gym 3 days a week doing weight training for about 1.5 hours. May be my immune system is not very good, because I have white sniffels almost every morning and then they disappear. Any advice on how to be more healthy?
P.S. I am also drinking Centrum vitamins every day.