have you ever heard of having guys eat pineapple (or other sweet foods) so their semen tastes better? your diet can affect your body in all kinds of ways. now, im no doctor, but ive definitely heard of strong/spicy/salty foods affecting things down there.
I've read online that your vagina and mouth are linked somehow... dunno, it's been a while since I looked it up, or what I was even searching for. That might be something you want to look into.
I just googled this question and it seems that if you do eat strong/spicy things it will come out of your pores, even your vagina. One woman suggested eating a yogurt a day to help. Onion and garlic can stay in your system for 3 days or so if you eat a lot of them you can have an odor. I'm sure if you think people can smell it, they are smelling it come through your skin, not your vagina.