Key points from article :
Experts say that supplements cannot boost brain health of healthy people.
More than 1/4 of US adults over 50 take such brain supplements.
Doesn't delay onset of dementia and cannot treat or reverse Alzheimer's or neurological diseases.
Marketing claims about their impact on mental health are exaggerated.
Healthy diet, good sleep, regular exercise and mental stimulation can maintain brain health.
This Cochrane review of 28 studies included 83,000 participants.
