Many supplements are taken on the advice of friends, relatives, or magazines that may not be reliable sources of information. Knowing the pros and cons of the supplementation issue and knowing how to choose a supplement can help persons with gastrointestinal disease make an informed decision. Pros of Supplementation Nutrition surveys of the United States and Canada have detected deficiencies of protein , vitamins, and minerals. The incidence of these deficiencies is low, but they do exist, providing the basis for the argument that ordinary people may need to take supplements. A favorite argument is that if deficiency symptoms are known, then marginal deficiencies must also exist, causing symptoms that have not been well characterized yet and are probably not always recognized even by skilled, experienced health care providers.
Marginal deficiencies are states of unwellness just shy of classical deficiencies.
Somewhere between the adequate intake of a nutrient and the development of a physically obvious deficiency, there is a gray area where people don't feel well and don't function well. Several groups of people are at risk for marginal deficiencies, including those with gastrointestinal disease. In some cases there are predisposing conditions for marginal deficiencies. These include people who are not healthy, people who are addicted to alcohol , or who have diseases which interfere with nutrient action. People taking medications need to check with their care providers before taking supplements, as they may interfere with the action of the drug.