A meta-anaysis of all published and unpublished studies they could find studying whether or not meditation helps anxiety and depression. They found yes for both account, and the positive effect would require 700 studies on anxiety showing the opposite and 400 on depression to cancel out. So for both of these issues, science has landed, it's helpful. The study she is mentioning is: Mindfulness-Based Stress Reduction and Anxiety.

From Abstract:

The complete sample showed medium to large effect sizes on measures of anxiety, and a large effect size for symptoms of depression... ... Gains were maintained at six months follow-up ... Mediation analyzes indicated that mindfulness fully mediated changes in acute anxiety symptoms, and partially mediated changes in worry and trait anxiety.