context: If you have ulcerative colitis ( UC), your doctor may suggest you take vitamins or supplements to help you get the nutrition you need. That's in addition to eating a healthy, well-balanced diet. Keep in mind that the best source for nutrients is the food you eat. Everyone with UC has a different nutrition situation, so always talk to your doctor before you take any supplements. When you have UC, there's a risk you could get malnourished because you don't eat enough food. When you get flares, you can get cramping pain and severe diarrhea, which can sometimes alternate with hard bowel movements and constipation. Certain foods may make your symptoms worse. So on top of a lack of appetite that goes along with flare-ups, you may be tempted to cut back on how much you eat in hopes of easing your symptoms. At the same time, your body needs more calories, protein, vitamins, and minerals to aid the healing process. Also, the inflammation and diarrhea that come with UC interfere with the way you reabsorb water and minerals in your large intestine. There's a risk you could get dehydrated if the fluid isn't replaced. Finally, some medicines you take to treat ulcerative colitis interfere with your body's ability to absorb and maintain the vitamins and minerals it needs. For instance, corticosteroids such as prednisone can get rid of your body's calcium supply. Drugs like sulfasalazine lower your level of folate, an important B vitamin. A well-balanced diet is your first step to guard against malnutrition. You need to eat a variety of things from different food groups and make sure you get enough protein and calories. Work with a dietitian who can help you plan meals that meet your nutrition needs. Even with a well-designed meal plan, you may still need some of these supplements: Vitamin D. You need it to keep your bones strong. It also plays a role in how your immune system -- your body's defense against germs -- works. If you have ulcerative colitis, especially if you need steroids, you may be at risk for having low levels of vitamin D. 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. Researchers are checking a number of supplements to see if they can help people with UC. In at least one study, omega-3 fatty acids found in fish oil reduced symptoms and prevented UC from returning. Other studies, however, have not had the same results. Probiotics are "good" bacteria or other microorganisms that can be healthful. Several studies show they reduce ulcerative colitis symptoms. The thinking is that probiotics, like lactobacillus or live-culture yogurt, help to restore balance to the good bacteria that live inside the intestines. A few studies have seen benefits from aloe vera when you take it in the in the form of a gel that you swallow, but more research is needed to confirm this. Talk to your doctor about other supplements that are being studied to see if they can help you manage ulcerative colitis.