Taking dietary supplements can be beneficial for some people, but it is important to understand the potential risks of taking too much. Manufacturers can add vitamins, minerals and other supplement ingredients to the foods you eat, so you may be consuming more than you think. Too much of any nutrient can be dangerous, and combining several supplements or taking doses higher than recommended may increase the risk of harm. This article will discuss the safety of taking dietary supplements in high doses, as well as the potential risks and side effects. Any ingredient in a multivitamin supplement can be toxic in large quantities, but the most serious risk comes from iron or calcium.
According to the National Institutes of Health, taking high doses of vitamin C can cause stomach cramps and diarrhea. A multi-vitamin overdose occurs when someone takes more than the normal or recommended amount of multivitamin supplements. Excess iron causes nausea and vomiting and can damage the liver and other organs, while too much vitamin A can cause headaches and liver damage, reduce bone strength, and cause birth defects. The federal government can take legal action against companies and websites that sell dietary supplements when companies make false or misleading statements about their products, if they promote them as treatments or cures for diseases, or if their products are not safe. So why do so many people take supplements if the health benefits are negligible or non-existent for the average healthy person? People often think that they are something extra they can do to ensure that they meet their basic nutritional needs. Supplement companies are responsible for having proof that their products are safe, and the claims on the label are truthful and not misleading.
However, supplements cannot replace the variety of foods that are important to a healthy eating routine. The RDA (recommended daily amount) and the IA (adequate intake) are the amounts of a vitamin or mineral that are needed to stay healthy and well nourished. The UL (Maximum Tolerable Intake Level) is the maximum amount of daily vitamins and minerals you can safely take without the risk of overdose or serious side effects. Even if none of the supplements separately exceeds the maximum limit for a given nutrient, combining several pills, such as a multivitamin and an additional vitamin D capsule, for example, can result in doses higher than recommended. For more information on what constitutes a healthy eating routine, the Dietary Guidelines for Americans and MyPlate are good sources of information. If you have any health problems, check with your doctor before taking supplements.
They will tell you if they have side effects or interfere with other medications you are using. If you think you've had an adverse reaction to a dietary supplement, tell your healthcare provider. This fact sheet from the Office of Dietary Supplements (ODS) of the National Institutes of Health (NIH) provides information that should not replace medical advice. While the government doesn't oversee the safety of vitamins, standard vitamin and mineral tablets are considered relatively risk-free if high doses are avoided. Just because supplements are safe in moderation doesn't mean that more is better.
Combining several supplements or taking doses higher than recommended may increase the risk that they could cause harm. Taking more than you need costs more and may also increase the risk of side effects. Many nutrients, in doses that are too high, can be dangerous. To be safe, stay away from the UL for any nutrient. Some studies show no evidence that many popular supplements have real health benefits, leading many scientists to change some of their recommendations. However, people should remember that supplements cannot replace a healthy diet.
Thomas, EdD, RD, scientific consultant, National Institutes of Health Office of Dietary Supplements, Bethesda, MD.