Vitamin C Nutrition

Vitamin C is a water soluble vitamin that is required for growth and repair of tissues in all parts of the body. Vitamin C performs many important functions in the body like strengthening the immune system, building and maintaining tissues. It acts as a coenzyme and cofactor for many reactions in the body like oxidation of phenylalanine and tyrosine, conversion of folacin to tetrahydrofolic acid. Vitamin C is essential for the synthesis of dopamine, adrenaline and nor adrenaline in the adrenal glands or the nervous system. It is required in the synthesis of carnitine – a catalyst which is important in the transfer of energy to mitochondria.

Our body is unable to produce or store this water soluble vitamin thus it must be obtained through diet or in the form of supplements. Some amount of vitamin C is present in all the fruits and vegetables. Foods that are good source of vitamin C include citrus fruits and juices like oranges, tangerines, limes and lemons, guava, tomatoes, strawberries, broccoli, green pepper, turnip green, other leafy greens, cantaloupe, potatoes and sweet potatoes. Other foods like Brussels sprouts, mango, papaya, watermelon, cauliflower, cabbage, blueberries, raspberries, cranberries, red pepper, winter squash and pineapples also provide good amount of vitamin C.

Ascorbic acid or vitamin C nutrition is best from fresh raw fruits and vegetables; because it is a fragile molecule and can be easily lost during cooking, heat or storage. It is often discarded in cooking water as it is highly soluble. Also it can be easily destroyed by oxidation, especially in the presence of alkalinity and heat.
Vitamin C deficiency can lead to under-hydroxylation of lysine and proline in collagen which in turn leads to low melting temperature of the resulting collagen fibers which results in the breakdown of protein collagen for bones, connective tissues and dentin. This can lead to deficiency symptoms like fluid retention, general weakness, anemia and depression. Vitamin C is regularly excreted by the body as it is a water soluble vitamin, so it is generally non-toxic. However a high dose for example 2000 mg or more per day can cause symptoms like gas, diarrhea and stomach upset.

The recommended dietary allowance for a non-smoking man and women is 90 and 75 mg respectively. The need for vitamin C is increased in certain conditions like pregnancy, breastfeeding, smoking, gastrointestinal diseases and hyperthyroidism.