The claims about omega 3 are many and varied, but evidence suggests it may reduce the risk of heart disease, strokes and arthritis.
Omega 3 supplements are big business, although some are much better quality than others.
Two studies - one in Britain and one in Australia - have also found omega 3 can help children with learning difficulties do better at school.
An hour and a half north of Auckland, a teacher at Wellsford Primary School was so impressed by such findings he suggested an omega 3 trial there.
Campbell Live went to see the results.