DEAR DR. BLONZ: What constitutes "with meals" and "on an empty stomach" when it comes to taking medications with (or without) food? I usually eat small meals every three hours throughout the day, and am not sure if this is considered an empty stomach. -- D.H., Pleasanton, California
DEAR D.H.: There are several factors to be considered. For example, take-with-a-meal might be recommended if a medication tends to cause upset when taken on an empty stomach, or if the gradual emptying of a food-filled stomach helps with how the medicine gets absorbed. On the other hand, take-before-meals might be recommended when a medication's efficacy or bioavailability is affected by other substances found in foods or by the acid environment of a food-filled stomach. In some instances, you want the medication to have been absorbed and on the job before you eat.
All these point to the importance of following instructions that come with medications. Directions to take a medication before meals might suggest an hour before the first bite. The best advice is to check with your pharmacist for clarifications if you have any questions, as this is their area of expertise.
DEAR DR. BLONZ: What is the difference between enrichment and fortification? I notice that vitamins D and A are always added to milk. Vitamin D is probably there because of the calcium, but could you explain how they work together? And why are they adding vitamin A? -- R.Q., Evanston, Illinois
DEAR R.Q.: Vitamin D works with calcium through its role in stimulating the production of a calcium-binding protein. Once a food with calcium is eaten, digested and in solution in the small intestines, it has to combine with that binding protein to get escorted through the intestinal wall. Vitamin D does not need to be in the stomach at the same time as the calcium, but the body must be adequately nourished with vitamin D for the process to work effectively.
To address your broader question: "Enrichment" adds nutrients back to food that have gotten lost during processing. Flour is a good example of an enriched food. If a food is enriched, the label must say so, and to be valid, it has to provide at least 10% of the nutrient's daily value.
"Fortification" is when you add nutrients that are not normally found in that food. This public health policy was begun in the 1920s after data revealed that certain nutrients were chronically deficient in various population groups. The foods chosen for fortification were the staples found in most diets, including cereals and milk products.
Table salt was the first fortified food: Iodine was added to prevent iodine-deficiency goiter in Midwestern schoolchildren. Vitamin D, and later vitamin A, were added to dairy products because such widely consumed foods were considered ideal vehicles. We now find additional examples, including vitamin D, calcium and other nutrients being added to nondairy milk alternatives, and omega-3 fatty acids added to some eggs.
Generally speaking, foods and nutrients selected for fortification are those consumed in sufficient quantities to provide the desired nutritive enhancement while not presenting any dangers for excessive consumption. Fortified nutrients must also be in a form that is stable and easily absorbed.
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