[BlueDingo]

While this is true, infants do not eat grains and many are breastfed almost exclusively especially if money is an issue. A $5 bottle of D3 vitamin drops to supplement breastmilk for months is much cheaper than buying formula.

[dogma1138]

Infants get it through formula and breast milk, the mother gets the folic acid via grains.

Outside of some edge cases vitamin supplements aren't really needed just talk to your doctor.

[necrodome]

Human breast milk is a poor source of vitamin D, that's why it is recommended as a supplement.