Recent studies show that in order to receive the best levels of protection our blood vitamin D levels should be about 120-200 nmol/l. I personally don’t like to recommend cod liver oil as a vitamin D supplement because it also contain Vitamin A and too much vitamin A taken for long periods of time can cause health problems. Some foods that contain vitamin D include: canned sardines, salmon, tuna, shrimp, butter, sunflower seeds, liver, eggs, mushroom.