On Diet: In the case of meds, what counts as an empty abdomen? | Existence

Dear RQ: Vitamin D works with calcium through its role in stimulating the production of a calcium-binding protein. Once a food containing calcium is eaten, digested, and dissolved in the small intestine, it must combine with this binding protein in order to be passed through the intestinal wall. Vitamin D doesn’t have to coexist with the calcium in the stomach, but the body needs to be nourished enough vitamin D for the process to work effectively.

To answer your more general question, “fortification” adds back nutrients to food that were lost during processing. Flour is a good example of a fortified food. When a food is fortified it must be on the label and to be valid it must provide at least 10% of the daily value of the nutrient.

“Fortification” is when you add nutrients that are not normally found in this food. This public health policy began in the 1920s after data showed that certain nutrients were chronically deficient in various populations. The foods selected for fortification were the staple items of most diets, including cereals and dairy products.

Table salt was the first fortified food: iodine was added to prevent iodine-deficiency goitre in Midwestern school children. Vitamin D, and later vitamin A, were added to dairy products because such widely available foods were considered ideal vehicles. We now find additional examples including vitamin D, calcium, and other nutrients added to non-dairy milk alternatives and omega-3 fatty acids added to some eggs.