A systematic review of research into the use of nutritional supplements for the treatment of anxiety disorders says it has found strong evidence for the use of extracts of passionflower or kava and combinations of L-lysine and L-arginine.

They pooled the results of 24 studies involving a total of more than 2000 participants, showing that some nutritional and herbal supplements can be effective, without the risk of serious side effects.

The research, carried out by Shaheen Lakhan and Karen Vieira from the Global Neuroscience Initiative Foundation charity, advocates for herbal supplements in treatment, said, “Our review and summary of the literature on herbal remedies and dietary supplements for anxiety should aid mental health practitioners in advising their patients and provide insight for future research in this field. We found mixed results - while passionflower or kava and L-lysine and L-arginine appeared to be effective, St John’s Wort and magnesium supplements were not.”

Of the studies included in the review, 21 were randomized controlled trials. Of those, 15 showed positive effects from either a nutritional or herbal remedy and any reported side effects were mild to moderate. According to Lakhan, “For all three of the herbal supplements we reviewed, more research needs to be done to establish the most effective dosage and to determine whether this varies between different types of anxiety or anxiety-related disorders. Herbal medicines hold an important place in the history of medicine as most of our current remedies, and the majority of those likely to be discovered in the future, will contain phytochemicals derived from plants.”

Citation: Shaheen E Lakhan, Karen F Vieira, 'Nutritional and herbal supplements for anxiety and anxiety-related disorders: systematic review', Nutrition Journal (in press)

Also see: Shaheen E Lakhan, Karen F Vieira, 'Nutritional therapies for mental disorders', Nutrition Journal 2008, 7:2 doi:10.1186/1475-2891-7-2