I heard somewhere (different subject) that the whole business of …

Comment on My all-time favourite juice by Neil Porter.

I heard somewhere (different subject) that the whole business of 5 a day for fruits and veg was made up over fifty years ago, and has no scientific basis at all, with no tests run, no studies etc etc.
Now I have forgotton where I read this, but I remember it was from some trusted person or other.
Can you shed any light?