Vitamins and minerals are essential nutrients that your body needs to function properly. Many adults, adolescents and children in the United States take vitamin and mineral supplements. However, if you take excess levels of vitamins and minerals, you can increase your risk of toxicity and medical complications. Consult your doctor about your diet and any supplements you take to determine if you are consuming safe levels of vitamins and minerals.
Vitamin A
Vitamin A is a family of compounds that include retinoids such as retinol, retinal and retinoic acid; and carotenoids such as beta carotene. Your body needs Vitamin A for growth and development, vision, regulation of genes, immunity and red cell formation. Vitamin A is in fruits, vegetables, fish oil and supplements. The recommended dietary allowance for Vitamin A is 700 IU for women and 900 IU for men. Vitamin A toxicity from doses exceeding 25,000 IU per day can occur from either a high-dose exposure over a short period or from chronic intake of lower levels for a long period of time. Symptoms of Vitamin A toxicity include fatigue, loss of appetite, nausea, headache, dizziness, itchy skin, pain in your bones, liver bleeding and coma. In light of these potentially serious effects, you should not consume more than 10,000 IU of Vitamin A per day.
Vitamin D
Vitamin D helps your body build and maintain bones and regulate the immune system. You can get Vitamin D from exposure to the ultraviolet rays of sunlight, from foods such as milk that are fortified with the vitamin or from vitamin supplements. The recommended daily intake of Vitamin D is from 200 IU for infants to 600 IU for adults who do not get sufficient exposure to the sun. Consumption of Vitamin D at levels exceeding 2000 IU per day is potentially toxic and can cause side effects that include thirst, poor appetite, tiredness, itchy skin, vomiting, diarrhea and bone and muscle pain. Vitamin D supplements can interact with drugs, and people with heart or kidney disease should use them with caution.
Iron
Iron is a mineral your body needs for metabolism of proteins and enzymes, DNA synthesis and hemoglobin, a molecule that transports oxygen in blood. The recommended dietary allowance of iron is 8 mg per day for males and 18 mg per day for females. Iron toxicity is common among supplement users consuming nore than 20 mg per day. Symptoms of toxicity include nausea, vomiting, stomach ache, low blood pressure, difficulty breathing and coma. Iron toxicity might induce cancer growth and increase risk of type 2 diabetes and Alzheimer's disease, according to the Linus Pauling Institute.
Heavy Metals
Heavy metals such as arsenic, lead and mercury can be toxic. Exposure to these metals can come from foods such as fish. Pregnant women exposed to these minerals might have an increased risk of birth defects.
References
- "Archives of Family Medicine"; Vitamin and Mineral Supplement Use in the United States. Results from the Third National Health and Nutrition Examination Survey; Balluz, L.S.; Mar 2000
- "Archives of Pediatrics and Adolescent Medicine"; Vitamin and Mineral Supplement Use by Children and Adolescents in the 1999-2004 National Health and Nutrition Examination Survey: Relationship with Nutrition, Food Security, Physical Activity, and Health Care Access; Shaikh, U.; Feb 2009
- Linus Pauling Institute at Oregon State University: Vitamin A
- University of Maryland Medical Center: Vitamin D
- Linus Pauling Institute at Oregon State University: Iron
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