You find this advice all over the web: Use your non-dominant hand to do simple tasks such as brushing your teeth because it will make new brain cells grow.
On the other hand, it is suggested that it is potentially harmful to retrain left handed people to write with the right hand.
So, is there any evidence to support the first claim, i.e., that engaging the off-hand more in minor tasks fosters growth of brain cells?
EDIT: Some sources for where this claim is made:
I cannot further substantiate what "keeping your brain active" means because the sources I give also don't really substantiate it. But maybe there is some scientific research that is more specific.