University of Iowa Health Science Relations and
Phil Kissack
Associate Director of Food and Nutrition Services
First Published: January 2003
Peer Review Status: Internally Peer Reviewed

Vitamins are good for you. They're vital for normal body functions, mental alertness, and resistance to infection. Since your body doesn't make vitamins, it is up to you to supply your body with these mircronutrients. So what could possibly be wrong with taking more than the recommended dosage? Sometimes nothing. Sometimes that "more" can lead to problems, says Phil Kissack, of the UI Hospitals and Clinics Food and Nutrition Department.

Vitamin toxicity is a condition in which a person develops side effects from taking massive doses of vitamins. And it is becoming more common because of the increased use and popularity of vitamin supplements. Supplements are not substitutes. They can't replace the hundreds of nutrients in the foods of a balanced diet.

What is the recommended dietary allowance for vitamins? These will vary according to age, build, and sex. The daily values listed here are for healthy, non-pregnant, non-lactating adults.

• Vitamin A: 700-900 micrograms
• Vitamin D: 5-10 micrograms
• Vitamin E: 15 milligrams
• Vitamin K: 60-70 micrograms
• Vitamin B1 (Thiamin): 1.1-1.2 milligrams
• Vitamin B2 (Riboflavin): 1.1-1.3 milligrams
• Vitamin C: 75-90 milligrams
• Niacin :14-16 milligrams
• Folic Acid (Folate): 400 micrograms
• Vitamin B6: 1.3-1.7 milligrams
• Vitamin B12: 2.4 micrograms