I
found some high - quality, grass fed
organic beef
liver from Neiffer Ranch, which I can highly recommend if you have access to their products here in Eastern Washington State.
Vitamin D is difficult to get through the diet alone, but it can be
found in fatty fish like salmon, trout, mackeral and tuna, some mushrooms, fortified milk, egg yolks,
organic beef
liver, and cod
liver oil (2).