Salt, is to blame for that headache, not high blood pressure

This is the season to be, well, gluttonous. But with increasing intakes of fat and sugar also comes increased salt consumption. Now, a new study published in the journal BMJ Open suggests diets high in salt are implicated in pesky headaches, and this link may be independent of the "well-established link" between salt intake and high blood pressure, which is a common cause of headaches.

The new study suggests a salty diet may be the main culprit when it comes to that pesky holiday headache.

The researchers at the Welch Center for Prevention, Epidemiology and Clinical Research at Johns Hopkins Medicine in Baltimore, MD - note that headache is a common medical problem around the world and is one of the most frequently reported nervous system disorders.

Worldwide, they note that 46% of adults have a reported active headache disorder, causing many to have a poor quality of life and higher number of days absent from work.

The researchers say that current data support a link between blood pressure and headache; however, evidence on the link between headaches and sodium intake or other dietary factors is sparse, with most research focusing on the role of monosodium glutamate (MSG) consumption.

According to the American Heart Association (AHA), most people in the US consume about 3,400 mg of sodium a day, which is more than twice the 1,500 mg suggested by the organization.

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.

'Process independent of blood pressure' may be to blame for headache

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.

They add:

"It is noteworthy that there was no significant relationship between diet pattern and headache. This suggests that a process that is independent of blood pressure may mediate the relationship between sodium and headaches."

What is more, the team says adults in the US are already consuming sodium "in excess of their physiological need," and for many individuals, this intake is higher than the highest level tested in their research.

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, the researchers say their findings suggest that by reducing salt consumption, people might be able to avoid some headaches. The researchers also note that "additional studies are needed to replicate these findings and to explore mechanisms that mediate the association between sodium intake and headache."

References:

Effects of dietary sodium and the DASH diet on the occurrence of headaches: results from randomised multicentre DASH-Sodium clinical trial, Lawrence Appel, et al., BMJ Open, doi:10.1136/bmjopen-2014-006671, published 11 December 2014.
Johns Hopkins Medicine news release, accessed 15 December 2014 via Newswise.
Additional source: AHA, About sodium (salt), accessed 15 December 2014.