In the winter you'll need to take at least 250 IU vitamin D. Look for vitamin D in calcium supplements or multivitamins. If all your vitamins and supplements add up to more than 600 IU of vitamin D, you may be getting too much. Check with your doctor if you're taking more than this. People who cannot absorb vitamin B-12 from foods or supplements may require periodic injections from their physician. A supplement of 100-200 IU vitamin E a day is perfectly safe and in some studies has helped seniors have fewer sick days.
Many people take a standard daily multivitamin as nutrition insurance.
Choose a multivitamin without iron unless your doctor specifically tells you otherwise. Follow your physician's advice about higher doses of vitamin E, vitamin C, folic acid and B vitamins.