3 unexpected headache triggers

I always blame my headaches on food -- not enough food or too much of a certain food usually. Sugar definitely brings them on for me -- it's the reason I gave up sweets more than a year ago -- and sometimes, a snack full of protein helps them fade away. I've never given much thought to these three headache triggers, however. Real Simple magazine thinks they're worthy of a warning, though, so here they are.

• Ice Cream. Yep, I guess this makes sense. I just haven't ever had this type of headache last for very long. That's because it only lasts for about one minute, say the Real Simple folks. "Brain freeze" is caused when cold food touches the roof of your mouth and alters the blood flow in the brain or causes pain on a major nerve.
  
  
• Sex. It's not very common, but it's possible that sexual activity can trigger severe head pain. Usually nothing to worry about, you should see a doctor if the pain recurs.
  
  
• Secondary headaches. Also rare, these headaches are caused by a tumor or aneurysm. If your headaches worsen over time, see a doctor.
  
  

So, these three are possibilities. Think they're responsible for your headaches?