Vitamins are natural compounds that are required in small quantities, but cannot be produced by our own bodies. Vitamins are normally absorbed through our diet, but can also be taken as dietary supplements. Vitamins have multiple biological functions, some vitamins act as hormones while others function as enzyme co-factors. Vitamins can be either water soluble or fat soluble. Long before the discovery of vitamins, people knew that eating certain foods could prevent diseases. The chemical structure for most vitamins was not discovered until the early to mid 20th century. Vitamins can be classified as follows:
- B vitamins (B1, B2, B3, B5, B6, B7 and B9)
- Vitamin K
- Vitamin E
- Vitamin D
- Vitamin A
- Vitamin C
Vitamin A or retinol is fat soluble vitamin and has many biological functions. A deficiency in vitamin A can cause blindness (in extreme cases). The first signs of a vitamin A deficiency is night blindness (the inability to see in the dark). Vitamin A occurs naturally in liver, butter fat, dark colored fruits and dark leafy vegetables. Vitamin A is also important for a healthy immune system and for healthy looking skin. Vitamin A is also considered an antioxidant.
B vitamins are water soluble vitamins that often act as co-factors of enzymes. The first discovered B vitamin was vitamin B1 (Thiamine) that when deficient causes the disease “beri-beri”, which is characterized by extreme lethargy, fatigue, muscular and neurological symptoms. Thiamine is present in rice bran, diary products, meat, whole grains and fruit. Beri-beri used to be confined to Asian countries, where white rice is a food staple.
Niacin (Vitamin B3) prevents the disease pellagra, which is often seen in communities that use un-processed corn as their main food supply. Processing corn with lime increases the bio-availability of niacin. Symptoms of pellagra include diarrhea, dermatitis, dementia, thickening of the skin, anxiety, depression and fatigue. Niacin is present in meat, liver, vegetables and fruits and mushrooms. Niacin can be synthesized from the amino acid tryptophan. Taking too much niacin (as a supplement) can cause flushing of the skin.
Vitamin B6 is an important co-factor for many reactions involved in amino acid metabolism. It is also important for many neurological functions as it is required for the synthesis of the neurotransmitters serotonin, adrenaline, nor-adrenaline and GABA. It is also needed for the release of glucose from glycogen. Deficiency of vitamin B6 leads to neuropathy, sleep disturbances and skin problems.
Vitamin C (ascorbic acid) is a water soluble vitamin present in high quantities in citrus fruits, tomatoes, potatoes and green peppers. A vitamin C deficiency causes the disease scurvy, which symptoms include spongy bleeding gums and bleeding wounds on the body. Untreated scurvy is fatal. Vitamin C is necessary for the formation of collagen. Vitamin C an important nutrient for the proper functioning of our skin, mucous membranes and immune system.
Vitamin D is a group of fat soluble pro-hormones, vitamin D2 and vitamin D3 (cholecalciferol). Vitamin d plays a major role in bone formation and bone maintenance and is necessary for a healthy immune system. Vitamin D is present in fish oils, fatty fish (such as salmon), liver, egg and beef. Vitamin D is also produced by our skin when exposed to UV-B sunlight.
Vitamin E pertains to a family of 8 fat soluble vitamins, of which alpha-tocopherol is the most widely known. E vitamins are powerful antioxidants as they protect lipid membranes by neutralizing highly-reactive free radicals. Foods that are high in vitamin E are asparagus, avocado, green vegetables, vegetable oils, egg, milk, nuts and whole grains.
Read More About: Health Benefits of Vitamins
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