Vitamins in Diet

Vitamins are organic compounds that act as catalysts or spark plugs to many chemical reactions and cell functions in your body. In humans, there are 13 vitamins: four fat-soluble (A, D, E and K) and nine water-soluble (eight B vitamins and vitamin C). All work together to provide optimal functions, including hormone balance, immune system maintenance, ridding the body of free radicals and proper digestion.

Fat-Soluble Vitamins

Fat-soluble vitamins do not dissolve easily in water and are absorbed through the intestinal tract with the help of lipids. Since they are not excreted easily, they can easily accumulate in the adipose tissues and lead to lead to hypervitaminosis.
Vitamin A helps maintain proper vision, DNA transcription, and skin health. Good sources include carrots, tomatoes and liver. Vitamin D maintains calcium levels in the bloodstream and reduces risks for cancer (heart, breast, bone). You get vitamin D from exposing your skin to sunlight for about 10 minutes and your body synthesizes it. You can also get it from fortified dairy products and cereals. Vitamin E prevents the production and proliferation of free radicals and is found in vegetable oils, asparagus, whole grains, nuts and seeds. Vitamin K promotes blood clotting in wounds and helps produce bone proteins. Spinach is an excellent source of vitamin K.

B Vitamins

B vitamins were once thought of as a single vitamin before further studies showed that there are eight different kinds. These vitamins are water-soluble, meaning that they easily dissolve in water and are excreted. Therefore, higher amounts of water-soluble vitamins are needed daily.
Thiamine (B1) is essential to carbohydrate and protein metabolism and nerve function. Riboflavin (B2) is the coenzyme for oxidation-reduction reactions in metabolism. This means that riboflavin gives and accepts hydrogen atoms from other compounds to make them stable or unstable. Niacin (B3), pantothenic acid (B5), pyridoxine (B6), and vitamin B12 all work together to maintain proper metabolism, such as production and breakdown of carbohydrates, amino acids, and fatty acids. Biotin (B7) helps the formation of fatty acids and glucose and maintain an energy supply in your nerve cells. Folate (B9) is a coenzyme involved in DNA synthesis and prevents certain birth defects such as spina bifida (incomplete formation of spine around the central nerve).
Since most of the B-vitamins behave and function similarly, they can be found in eggs, milk, whole grains, leafy vegetables, root vegetables, citrus fruits, stalk vegetables, nuts, seeds and mushrooms.

Other Water-soluble Vitamins

Vitamin C maintains healthy collagens in the skin and healthy gums and acts as an antioxidant. It also helps your to body to absorb iron and supports the immune system against free radicals. Vitamin C is commonly found in nearly all fruits and vegetables, particularly citrus fruits, especially in guava, kiwi, and lychees. Daily intake of vitamin C is between 75 to 90mg a day.
Choline acts as a precursor compound to the formation of phospholipids (cell membrane component) and functions as a neurotransmitter. Good sources of choline include liver (poultry, beef), egg yolks, wheat germ, and soy products. Daily intake of choline is between 425 to 550mg a day.