Abstract text (incl. figure legends and references)

Question: ketogenic diet (KD) is gaining attention as a possible non pharmacological approach for migraine prevention, supported by many pre-clinical and clinical observations. KD is also used for weight loss purposes, and there is a well defined relationship between migraine and weight excess. However, it is not known if the effect of KD on migraine is only due to weight reduction or if it depends on mechanisms which are specific for the ketogenic nature of the intervention.

Methods: we conducted a retrospective observational study on patients suffering from migraine who received a KD as a preventive treatment. All the patients were evaluated both from a neurological and a nutritional point of view, including bioimpedance analysis.

Results: 23 migraine patients were considered in the analysis, 10 (43.5%) were affected by chronic migraine and 6 (26.1%) were suffering from medication overuse headache. The number of previously failed preventive treatments was 1.78±2.21. After KD, we observed a reduction in monthly headache days (12.5±0.5 v.s. 6.7±8.6; p<0.001) and in days of acute medication intake (11.06±9.37 v.s. 4.93±7.99; p=0.008). We also observed a reduction of patients" weight (73.8±15.2 v.s. 68.4±14.6; p<0.001) and BMI (26.9±6.2 v.s. 23.7±8.1; p<0.001), with decrement of the fat mass (28.6±12.5 v.s. 20.6±9.8; p<0.001). Responders and non-respondersto KD did not differ for weight loss (5.6±2.7 v.s. 6.2±5.1; p=0.299) or fat mass loss (6.1±2.1 v.s. 5.0±4.1; p=0.120). In addition, we observed no significant difference in the reduction of headache days between patients who had normal BMI or who were overweight or obese at baseline (9.2±11.5 v.s. 3.7±3.2; p=0.545).

Conclusions: these data corroborate the use of KD as a preventive treatment for migraine. Moreover, since KD improved migraine independently from weight or fat mass loss, its action is probably mediated by mechanisms specific for this kind of nutritional intervention.