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Vitamins are essential nutrients that must either be ingested or synthesised to maintain health. There are two main varieties: water-soluble and fat-soluble. Because some vitamins are only soluble in fat, a totally fat-free diet can be unhealthy.
- Vitamin A (also known as retinol) is a fat-soluble vitamin found in dairy products and in liver. Excessive vitamin A can poison you. The body can create vitamin A as needed from beta-carotine , which is water-soluble and not dangerous (large amounts can turn your skin and eyes orange, though). You can get plenty of beta-carotine from carrots, squash, and spinach. Vitamin A deficiency can affect the eyesight, so the popular belief that carrots help you see in the dark is not wholly false.
- The Vitamin B group of water-soluble vitamins contains a number of separate vitamins. An excess of these vitamins is not harmful.
- Vitamin B1 (or thiamine) can be found in beef, pork, legumes, yeast, egg yolks, milk, green leafy vegetables, and many grains, nuts, and seeds. Deficiency can cause beriberi.
- Vitamin B2 (or riboflavin) can be found in beef, dairy products, nuts, and green, leafy vegetables.
- Vitamnin B3 (or niacin) can be found in fish and poultry meats, liver, nuts, seeds, legumes, and green, leafy vegetables. Deficiency can lead to pellagra.
- Vitamin C (or ascorbic acid) is a water-soluble vitamin found in citrus fruits and green vegetables. A deficiency can lead to scurvy.
- Vitamin D (or calciferol) is a fat-soluble vitamin found in oily fish. With sufficient exposure to sunlight, most of the requirement can be met through the synthesis of vitamin D by the skin.
- Vitamin E (or tocopherol) is a fat-soluble vitamin found in vegetable oils, nuts and green leafy vegetables.