In order to further investigate the effects of diet on headache occurrence, the researchers randomized 390 study participants to either the Dietary Approaches to Stop Hypertension (DASH) diet - which is rich in fruits, vegetables and low-fat dairy products with reduced saturated and total fat - or to a control diet that was a typical Western diet.

During the study, which consisted of three 30-day periods, each participant ate food with high sodium during one period, intermediate sodium during another and low sodium during another period. Then, at the end of each feeding period, the participants completed questionnaires on occurrence and severity of headache.

Results showed that people who ate foods high in sodium - around 8 g per day - had one third more headaches than those who ate foods low in sodium - around 4 g per day. Additionally, the researchers observed that this difference remained whether the volunteers ate the standard Western diet or the DASH diet.

The researchers say their results depart from the popular belief that a diet rich in fruits, vegetables and potassium and low in saturated fat can ease or prevent headaches.

Though the study benefits from its randomized design, there were some limitations, including lack of information on prevalence of headaches in study participants at baseline. Additionally, the data collected on headache occurrence and severity was self-reported, which could be another limitation.

Still, Dr. Appel says their findings suggest that by reducing salt consumption, people might be able to avoid some headaches. He and his colleagues note that "additional studies are needed to replicate these findings and to explore mechanisms that mediate the association between sodium intake and headache

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