The increase in space designated for vitamin supplements in supermarkets and convenience stores reflect a consumer focus on optimal health. Supplements appear to be an attractive solution to dietary nutrient deficiencies, but this is not always the case. Sometimes the disadvantages of vitamin supplement intake outweigh the advantages.
Decreased Fiber Intake
Vitamin supplements ordinarily do not contain fiber. Replacing nutritious food with vitamin supplements may therefore decrease fiber intake. Fiber is a substance derived from food that helps to clear out and regulate your intestinal tract. It is also filling, which helps decrease appetite, and soluble fibers play a role in lowering blood cholesterol.
Taking vitamins may decrease your natural phytonutrient intake. Phytonutrients are chemical substances in foods that likely protect against certain types of cancer and cardiovascular disease. They are found in a variety of foods including fruits, vegetables, nuts and legumes.
Other Nutrient Loss
When taking vitamin supplements, you may miss out on the intake of other needed vitamins and minerals. A multivitamin may make up for this deficiency to an extent; however, your risk of vitamin toxicity increases. Eating a balanced diet consisting of a variety of fruits, vegetables, whole grains, protein and dairy is more likely to give you the appropriate balance of all needed nutrients.
Most vitamins are water soluble and will quickly be used or flushed out of your body without building up to toxic levels; however, there are some vitamins that may build up to dangerous levels in the body. The fat-soluble vitamins A, D and E are stored in the body for long periods of time and unhealthy build-up can cause health issues such as birth defects, nausea, kidney damage and digestive tract disorders. Supplementation can lead to toxicity of these nutrients. Healthy adults should intake no more than 10,000 IU -- International Units -- of vitamin A, 2,000 IU of vitamin D and 1,100 IU of vitamin E in supplement form per day to avoid toxic levels of these vitamins.
Adverse Drug Interactions
Vitamins have the potential to interact with drugs or exacerbate certain health problems and it's recommended that you inform your doctor if you are taking them. Vitamin E is one of the primary nutrients which has great potential to interact with certain medications. This nutrient may increase risk of blood clotting in people taking anti-clotting drugs, may interact with chemotherapy or radiation therapy and has the capacity to lessen the effectiveness of certain cholesterol-lowering medications.
There is still a lot of research that needs to be done to confirm the effectiveness of certain vitamin supplements. Many people take them with the assumption that they will work just as well as natural nutrients from foods. In reality, supplements are man made “nutrients” which are not always as effective in improving health as their natural counterparts. For example, vitamin C ingested from food sources may help reduce risk of certain cancers of the mouth and breast and lower high blood pressure -- with the help of blood pressure medication -- while their synthetic counterparts have been shown to have no beneficial effect in reducing certain cancers of the mouth and breast or lowering high blood pressure.