The relationship of caffeine and headaches is somewhat confusing. A small amount of caffeine can relieve a headache, but too much may bring one on. Coffee initially constricts the blood vessels, reducing the pain, but too much causes the blood vessels to dilate, causing more pain. Brewed coffee has much more caffeine than tea or cola. Some medications contain caffeine.
Most people can tolerate one to two caffeine drinks a day.
However, if you decide to cut caffeine out of your diet, do this gradually over a week. Researchers have suspected that lower magnesium levels in relationship to higher calcium levels may cause migraines. Another study found that riboflavin, vitamin B2, reduced frequency and duration of migraines. Diet is only one of the many suspected triggers for a migraine, so do not unnecessarily restrict your diet if these are not your triggers. Keep a food diary for a month, tracking your headaches.