Background Recent evidence from case reports suggests that a ketogenic diet may be effective for bipolar disorder. To date, no clinical trials have been conducted. Aims To assess the recruitment and feasibility of a ketogenic diet intervention in bipolar disorder. Methods Euthymic individuals with bipolar disorder were recruited to a 6-8 week trial of a modified ketogenic diet and a range of clinical, economic and functional outcome measures were assessed. Results Of 27 recruited participants, 26 commenced and 20 completed the modified ketogenic diet at 6-8 weeks. The completeness of the outcomes dataset was 95% for daily ketone measures, 95% for daily glucose measures and 95% for daily Ecological Momentary Assessment of symptoms during the intervention period. Mean daily blood ketone readings were 1.3 mmol/L (SD= 0.77, Median = 1.1), and 91% of all readings indicated ketosis indicating a high degree of adherence to the diet. Over 91% of daily blood glucose readings were within normal range with 9% indicating mild hypoglycaemia. Eleven minor adverse events were recorded, including fatigue, constipation, drowsiness and hunger. One serious adverse event was reported (euglycemic ketoacidosis in a participant taking SGLT2-inhibitor medication). Conclusions The recruitment and retention of euthymic individuals with bipolar disorder to a 6-8 week ketogenic diet intervention was feasible, with high outcome measure completion rates. The majority of participants reached and maintained ketosis and adverse events were generally mild and modifiable. A future randomised controlled trial is now warranted.

Dr Iain Campbell has a diagnosis of bipolar disorder and follows a ketogenic diet to manage his symptoms. His current fellowship is funded by the Baszucki Brain Research Fund.

ISRCTN61613198

https://www.isrctn.com/editorial/retrieveFile/2a5fdffc-0ed7-4779-8b09-4785e6d69055/41259

This study was funded by the Baszucki Brain Research Fund.

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The study received a favourable ethical opinion from the South East Scotland Research Ethics Committee 02

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