EPI LIFE COACH articles
|DATE||Friday, March 03|
|AUTHOR||Dr. Carlos Orozco (BSc, MSc, ND, MD, PhD, FPAMS)|
Vitamin C, also known as ascorbic acid, is a water-soluble vitamin. Unlike most mammals, humans do not have the ability to make their own vitamin C. Therefore, we must obtain vitamin C through our diet.
Vitamin C is required for the synthesis of collagen, an important structural component of blood vessels, tendons, ligaments, and bone. Vitamin C also plays an important role in the synthesis of the neurotransmitter, norepinephrine. Neurotransmitters are critical to brain function and are known to affect mood. In addition, vitamin C is required for the synthesis of carnitine, a small molecule that is essential for the transport of fat to cellular organelles called mitochondria, for conversion to energy (1). Recent research also suggests that vitamin C is involved in the metabolism of cholesterol to bile acids, which may have implications for blood cholesterol levels and the incidence of gallstones (2).
Vitamin C is also a highly effective antioxidant. Even in small amounts vitamin C can protect indispensable molecules in the body, such as proteins, lipids (fats), carbohydrates, and nucleic acids (DNA RNA) from damage by free radicals and reactive oxygen species that can be generated during normal metabolism as well as through exposure to toxins and
pollutants (e.g. smoking). Vitamin C may also be able to regenerate other antioxidants such as vitamin E (1).
Signs and Symptoms of Deficiency
Severe vitamin C deficiency has been known for many centuries as the potentially fatal disease, scurvy. By the late 1700’s the British navy was aware that scurvy could be cured by eating oranges or lemons, even though vitamin C would not be isolated until the early 1930’s. Symptoms of scurvy include bleeding and bruising easily, hair and tooth loss, joint pain and swelling. Such symptoms appear to be related to the weakening of blood vessels, connective tissue, and bone, which contain collagen. Early symptoms of scurvy such as fatigue may result from diminished levels of carnitine, needed to derive energy from fat, or decreased synthesis of the neurotransmitter norepinephrine (see Function). Scurvy is rare in developed countries because it can be prevented by as little as 10 mg of vitamin C daily (2). However, recent cases have occurred in children and the elderly on very restricted diets (4,5).
- Brody T. Nutritional Biochemistry. 2nd ed. San Diego: Academic Press; 1999.
- Shane B. Folic acid, vitamin B-12, and vitamin B-6. In: Stipanuk M, ed. Biochemical and Physiological Aspects of Human Nutrition. Philadelphia: W.B. Saunders Co.; 2000:483-518.
- Baik HW, Russell RM. Vitamin B12 deficiency in the elderly. Annu Rev Nutr. 1999;19:357-377. (PubMed).
- Herbert V. Vitamin B-12. In: Ziegler EE, Filer LJ, eds. Present Knowledge in Nutrition. 7th ed. WashingtonD.C.: ILSI Press; 1996:191-205.
- Food and Nutrition Board, Institute of Medicine. Vitamin B12. Dietary Reference Intakes: Thiamin, Riboflavin, Niacin, Vitamin B-6, Vitamin B-12, Pantothenic Acid, Biotin, and Choline.
- WashingtonD.C.: NationalAcademy Press; 1998:306-356. (National Academy Press).
- Ho C, Kauwell GP, Bailey LB. Practitioners’ guide to meeting the vitamin B-12 recommended dietary allowance for people aged 51 years and older. J Am Diet Assoc. 1999;99(6):725-727. (PubMed).
- Weir DG, Scott JM. Vitamin B-12 “Cobalamin”. In: Shils M, ed. Nutrition in Health and Disease. 9th ed. Baltimore: Williams & Wilkins; 1999:447-458.
- Homocysteine Lowering Trialists’ Collaboration. Lowering blood homocysteine with folic acid based supplements: meta-analysis of randomised trials. Homocysteine Lowering Trialists’ Collaboration. BMJ. 1998;316(7135):894-898. (PubMed).
- Quinlivan EP, McPartlin J, McNulty H, et al. Importance of both folic acid and vitamin B12 in reduction of risk of vascular disease. Lancet. 2002;359(9302):227-228. (PubMed).
- Stabler SP, Lindenbaum J, Allen RH. Vitamin B-12 deficiency in the elderly: current dilemmas. Am J ClinNutr. 1997;66(4):741-749. (PubMed).
- Fenech M. Micronucleus frequency in human lymphocytes is related to plasma vitamin B12 and homocysteine. Mutat Res. 1999;428(1-2):299-304. (PubMed).
- Wu K, Helzlsouer KJ, Comstock GW, Hoffman SC, Nadeau MR, Selhub J. A prospective study on folate, B12, and pyridoxal 5′-phosphate (B6) and breast cancer. Cancer Epidemiol Biomarkers Prev. 1999;8(3):209-217. (PubMed).
- Eskes TK. Open or closed? A world of difference: a history of homocysteine research. Nutr Rev. 1998;56(8):236-244. (PubMed).
- Mills JL, Scott JM, Kirke PN, et al. Homocysteine and neural tube defects. J Nutr. 1996;126(3):756S-760S. (PubMed).