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What Are Vitamins? What Are Vitamins? Vitamins are organic compounds that are essential for growth, maintenance, and reproduction of the body. The human body can synthesize some of these vitamins in small quantities, but in the vast majority of cases, it is necessary to consume them in a variety of foods to meet the body's requirements. Unlike macronutrients that are consumed in relatively large quantities (grams per day), the recommended daily intake of vitamins varies from a few micrograms to around 100 milligrams. Classification of Vitamins To date, there are 13 vitamins that are recognized as being essential to the body, 9 of which are water soluble (B vitamins and vitamin C), and 4 which are fat soluble (vitamins A, D, E and K) - The video in the previous section will help you understand the difference in terms of transport of water soluble and fat soluble vitamins within our body . Vitamins (13) Water soluble vitamins (9) Fat soluble vitamins (4) Pantothenic acid B 5 Vitamin A Riboflavin B 2 Vitamin D Cobalamin Vitamin

B 12 E Folate B 9 Vitamin K Niacin B 3 Pyridoxine B 6 Biotin B 8 Vitamin that isn't in the B group C Thiamin B 1 Many researchers agree that someday there may be a 14th essential vitamin in the Dietary Reference Intakes (DRIs). What might be this nutrient? Iron is a mineral, whereas vitamin F and vitamin B 13 don't exist. Choline is not yet considered a vitamin because of a lack of scientific evidence. However, we know that choline is an essential nutrient since choline is not synthesized in sufficient amounts in the body (with the exception of breast milk!). It has multiple roles in the body, including being involved in the synthesis of neurotransmitters, involved in myelin

sheath formation, and it is a precursor of phosphatidylcholine which is a phospholipid that is part of cell membranes, bile, and lipoproteins. Where can you find choline in your diet ? Egg yolks! Understanding Vitamin Functions Vitamins play a multitude of roles in the body. The following diagram illustrates some of the main functions of vitamins, and provides examples. Bone Health Vitamin D is an important component in the structure of bones and teeth Growth and development Vitamin A plays an important role in cell differentiation necessary for the maintenance of epithelial cells which cover body surface. Energy metabolism Most B-vitamins act as coenzymes that are involved in energy metabolism Blood cell formation Folate plays a role in the formation of red blood cells. Antioxidant defense Vitamins C and E, as well as the carotenoids, prevent cellular oxidation. Immune function Vitamins A, C, and D help the body fight infections. Although vitamins do not provide energy to the body in the form of kcalories, they are involved in the process of energy production (ex. B vitamins) and fulfill several functions that are essential for body maintenance and growth. The next sections will help you learn more about these essential vitamins. Water-Soluble Vitamins

As their name suggests, water-soluble vitamins are soluble in water. Following their absorption in the small intestine, they travel in the blood throughout the body. With the exception of Vitamin B 12 that accumulates in the liver, it is usually hard to build up good reserves of water soluble vitamins since any surplus is excreted in the urine . It is therefore necessary to consume these vitamins daily and to avoid cooking foods for too long in water in order to limit the loss of these water-soluble vitamins. These vitamins are divided into two groups; eight vitamins from B group, and the Vitamin C . The B-vitamins and vitamin C As shown in the following figure, each of the B-vitamins function as components of coenzymes. Coenzymes are organic compounds that bind together with enzymes and enables the enzyme to function. The active enzyme is formed from the binding of an incomplete enzyme with a coenzyme comprised of the B-vitamin and another chemical group. Active enzymes can bind to substrates and accelerate a multitude of chemical reactions, including those involved in energy metabolism (of carbohydrates, lipids and proteins).

1. Thiamin, riboflavin, niacin, pantothenic acid, and biotin, all serve as coenzyme for reactions that release energy from carbohydrate, protein and fat. o True Many B vitamins function together in metabolic pathways related to energy metabolism. 2. Coenzyme A is a coenzyme that contains vitamin B 6 . o False Coenzyme A is derived from pantothenic acid and not vitamin B 6 . Mnemonic tric: To remember that "thiamin" is also called vitamin B 1 , Julie notes that the letter "T" is very similar to the number "1". T = 1 Thiamin = B 1 Mnemonic trick: To remember that the term "riboflavin" is also called vitamin B 2 , Julie notices that it contains the letter "b" which is the "2 nd " letter of the alphabet. RiB = B = 2 nd letter Riboflavin = B 2 Mnemonic trick: To remember that Niacin is also called vitamin B 3 , Julie tells herself that it has the letter "c" which is the "3 rd " letter of the alphabet.

NiaC = C = 3 rd letter Niacin = B 3 During pregnancy, folate is essential to the normal development of your baby's spine, brain and skull. Folate deficiency increases the risk of your baby having a neural tube defect, such as Spina Bifida. Spina Bifida is characterized by an incomplete closing of the spine and the membranes around the spinal cord during early weeks of pregnancy, which can lead to legs paralysis. For this reason, taking a daily 400 µg folic acid supplement before you become pregnant and in the early weeks of pregnancy is recommended. Folate is a generic term for many forms of this vitamin that exist in its natural state in foods, while folic acid is the term used for the synthetic form of this vitamin that is found in fortified foods and supplements. Knowing that the recommended intake (RDA) for folate during pregnancy is 600 µg and that 400 µg should come from a prenatal vitamin, which foods have the highest content of folate to provide the remaining 200 µg ? Legumes nuts and seeds; Flour and fortified grains; Green leafy vegetables Excellent dietary sources of folate include dark green leafy vegetables, certain fruits (ex. avocado, papaya), offal (organ meats), legumes nuts and seeds (ex. lentils, chickpeas, sunflower seeds and peanuts). White flour and cereal products are fortified in folic acid, which is the synthetic form of folate, and account for more than half of the daily folate intake. In Canada, since 1998, foods such as white flour has been fortified with thiamin, riboflavin, niacin, folic acid and iron. Specifically, the decision to fortify white flour with folic acid was to improve the overall intake of folate among women of child-bearing age and to reduce the incidence of

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