Your body will process synthetic vitamins just the same and just as efficiently as vitamins from natural sources. But synthetic vitamins and dietary supplements are not substitutes for gaining the nutrients your body needs from actual food. Whole foods contain other properties that can protect the body from disease, as well as necessary fiber content. And while some vitamins can be harmful in excess, it is difficult, if not impossible, to get too much of any given vitamin from food sources. If you must take vitamin supplements because of special circumstances, be aware of recommended amounts and potential side effects.
Vitamin A can be dangerous in high doses, so it's best to get this particular vitamin from food sources whenever possible. If you do take a vitamin A supplement, make sure it delivers at least 50 percent in the form of beta-carotene, which converts to vitamin A in the body as needed. This prevents you from consuming too much. Cereals and dairy products are frequently fortified with vitamin A, and a deficiency of this vitamin is rare in the United States.
Vitamin C helps your body absorb iron, and it performs this task equally well whether you get it from food sources or synthetic vitamins. However, because citrus fruits, berries, tomatoes, broccoli, spinach and red and green peppers are all rich in vitamin C, you will get all you need if you include some of these foods in your diet. If you eat a great deal of these foods and take synthetic supplements, too, you run the risk of diarrhea and nausea.
Vitamin D is difficult to get sufficient quantities of through food sources. Sunlight is the only natural source of this vitamin, though dairy products are usually fortified with it. You can supplement with synthetic vitamins in doses up to 1,000 IU daily without harm, but don't go higher than that because it can be dangerous in high levels.
Vitamin E is contained in nuts, seeds and dark, leafy vegetables and these sources will give your body all it needs if you include them in your diet. In synthetic form, it can act as a blood thinner, so if you're already taking a prescribed blood thinner or are scheduled for surgery, check with your physician before taking any supplements.
In most individuals, sufficient folate is available through a diet that includes adequate fruits, vegetables, beans and whole grains. However, additional folate -- often called folic acid in synthetic or supplement form -- is crucial for women who may become pregnant. Taken before pregnancy and during the first trimester, supplements can prevent neural tube defects in developing fetuses. Prenatal vitamins contain ample folic acid, but if you're of childbearing age and there is any possibility you could conceive, you should take supplements in addition to your diet. Talk to your doctor for the dosage that's best for you.
Healthy individuals can usually get sufficient vitamins from a healthy diet, but some people may require more. If you are on a low-calorie diet and consuming fewer than 1,600 calories a day, speak to your doctor about taking synthetic supplements. Postmenopausal women and women who experience heavy menstrual periods might also benefit from added supplements. If you suffer from any condition that interferes with your digestion, you should also ask your physician whether supplements can help you.