While your body needs the water-soluble vitamins in certain foods, it also needs additional types of dietary vitamins and other nutrients. You obtain fat-soluble vitamins, minerals and calorie-producing protein, carbohydrates and fats from food sources as well. The water-soluble vitamins include vitamin C and the eight B vitamins -- thiamin, riboflavin, niacin, pantothenic acid, biotin, B-6, folate and B-12. These vitamins exist naturally in many healthy whole foods and are synthesized to produce vitamin supplements.
You get natural vitamin C from fruits and vegetables. It is present in large amounts in many of these plant-based foods, especially citrus fruits and juices, peppers, cabbage, berries, tomatoes and potatoes. In general, these foods are nutrient dense, meaning they are greater in vitamin and beneficial nutrient content than in calories.
The B vitamins occur naturally and most abundantly in grains, leafy green vegetables and animal-based foods such as fish, beef, chicken, eggs and milk. Different foods have different amounts and assortments of B vitamins, and some, such as cereal and breads, are fortified with extra B vitamins. Among all of these foods, low-fat sources are the best for your weight and your heart health.
The U.S. Department of Agriculture, or USDA, advises getting the majority of your nutrition from foods but acknowledges the usefulness of multivitamins to address health problems. Including food sources of water-soluble vitamins B and C in your diet ensures that you will get additional related nutrients, such as dietary fiber from fruits and iron from grains. Your doctor may prescribe a multivitamin, vitamin C tablets or vitamin B-complex pills to bolster your immune system or to alleviate a disorder such as vitamin-deficiency anemia.
Safety of Dosages
Because your body easily excretes excess water-soluble vitamins, you are unlikely to get harmful doses of vitamins B and C from good food sources. The U.S. Food and Drug Administration notes, however, that vitamin supplements are more likely to cause problems at high dosages. Too much vitamin C can create digestive illness, and vitamin B-6 may cause reversible nerve damage.
Additional Dietary Considerations
Vitamins come from food, but they don’t supply calories. Besides the water-soluble and fat-soluble vitamins and minerals such as iron and calcium, your body needs a daily supply of protein, carbohydrates and fats to break down into glucose. The energy provided by this process is measured in calories. The USDA considers 1,600 to 3,000 calories the average amount required to complete metabolic tasks without causing health problems. For this reason, simply taking vitamin supplements will not provide the balanced nutrition you need to stay alive and healthy.