I too can remember getting a teaspoonful of cod liver oil every morning as a child.
Thank goodness it was followed by a teaspoonful of concentrated orange juice.
I think these supplements were free back in nineteen oatcake when I was a child. Everyone I knew got them, though some diluted the orange juice to make a drink rather than getting a teaspoonful of delicious orange gloop.
It was supposed to build up your resistance to colds...who knows...
Hated the cod liver oil, loved the orange juice.
Actually, I think there is a song about it....