Occasionally, drugs used to treat seizures, particularly phenytoin (
Dilantin),
can interfere
with the production of 25-hydroxyvitamin D in the liver. It
can also be due to parathyroid gland problems. Very few foods in nature contain vitamin D. The flesh of fish (such as salmon, tuna, and mackerel) and fish liver oils are among the best sources. Small amounts of vitamin D are found in beef liver, cheese, and egg yolks. Otherwise you can take fortified food like cereals etc. Spend time in Sun.