A good source of vitamin D is dairy foods, but a lot of people with UC cut back on dairy to help them curb symptoms of diarrhea.

Experts have different views on vitamin D supplements, so ask your doctor if it it's a good idea for you to take them.

Calcium. It's a mineral your body uses to build bones, help your muscles contract, and send messages through your nervous system.

If your system doesn't have enough calcium, your body removes it from the bones, which causes them to become brittle and leads to a bone-weakening disease called osteoporosis.

If you avoid calcium-rich dairy products or need certain kinds of medicines, you could be at risk for low levels of calcium. If your doctor recommends a calcium supplement, you'll probably need 1,000 to 1,200 milligrams a day.

Iron. When you have UC, you might lose iron through bleeding from the sores in your colon. If you don't have enough iron, you can get a condition called anemia, which can make you tired, dizzy, have a fast or irregular heartbeat, and have problems thinking. Your doctor can tell if you don't have enough iron with a blood test. If that's the case, he'll probably recommend you take an iron supplement.

Folate or folic acid. It's a B vitamin that your body needs to make healthy new cells. In women, it also protects against birth defects of the baby's spine or brain. And it can lower your risk of colon cancer, which is higher in people with ulcerative colitis.

When you have UC you may find it hard to eat folate-rich dark leafy vegetables and may end up with low levels of the vitamin. Those levels can go even lower if you need certain medications. Ask your doctor if you should be taking a folic acid supplement.