Many foods are fortified with vitamin D nowadays, and eggs and fish provide it naturally.
I wonder what her diet was like?
Vitamin D is found naturally in very few foods.
Foods containing vitamin D include some fatty fish (mackerel, salmon, sardines), fish liver oils, and eggs from hens that have been fed vitamin D.
In the U.S., milk and infant formula are fortified with vitamin D so that they contain 400 IU (10 mcg) per quart.
However, other dairy products, such as cheese and yogurt, are not always fortified with vitamin D.
Some cereals and breads are also fortified with vitamin D.
Recently, orange juice fortified with vitamin D has been made available in the U.S.
Accurate estimates of average dietary intakes of vitamin D are difficult because of the high variability of the vitamin D content of fortified foods (30).
Vitamin D contents of some vitamin D-rich foods are listed in the table below in both international units (IU) and micrograms (mcg).