In humans, vitamin C is essential to a healthy diet as well as being a highly effective antioxidant, acting to reduce oxidative stress; a substrate for ascorbate peroxidase; and an enzyme cofactor for the biosynthesis of many important biochemicals. The functions include collagen and neurotransmitter synthesis, synthesis and tyrosine catabolism, metabolism of microsome (Gropper, et al. , 2005) 2. Unprescribed large doses of vitamin C may result in indigestion, particularly when taken on an empty stomach.
As vitamin C improves iron absorption, hence iron poisoning can become an issue to people with rare iron overload disorders, such as haemochromatosis. 3. Vitamin C can affect glucose tests since these two have similar chemical structures. Physicians need to know when a patient is taking large doses of vitamin C so that they won’t misinterpret laboratory tests for the presence of glucose in the urine. This can also create problems diabetic people who need to keep a keen eye on their blood glucose levels 4.
Plant sources include Red pepper, Guava, papaya, orange, lemon, grapefruit, grapefruit, tomato, mango while Animal sources include liver, mother’s milk, pasteurized milk contain only trace amounts. Others include; oysters, cod roe, pork liver, chicken liver, goat and cow milk. 5. Scientific studies using vitamin C for colds show that it can reduce the severity of cold symptoms, acting as a natural antihistamine. The vitamin may be useful for allergy control for the same reason: It may reduce histamine levels.
By providing the immune system with one of the important nutrients it needs, extra vitamin C can often shorten the duration of the cold as well.
References
Gropper SS, Smith JL, Grodd JL. (2004). Advanced Nutrition and Human Metabolism. Fourth Edition. Thomson Wadsworth, Belmont, CA. USA. pp. 260-275. Wikipedia, The Free Encyclopedia, (2009). [Online]. Retrieved on March 31, 2009 from http://en. wikipedia. org/wiki/Vitamin_C#Natural_and_artificial_dietary_sources