Nutrients are divided into macronutrients and micronutrients. Macronutrients include large energy-rich substances such as carbohydrates, fats and proteins. Micronutrients are needed in small amounts and include vitamins and minerals. Vitamins generally perform one of three functions. The most common function is for them to bind to special proteins called enzymes, which help carry out chemical reactions. Less commonly, vitamins act as antioxidants, which neutralize damaging chemicals called free radicals. Some vitamins can act as hormones, signaling cells to perform a special function. Discuss your vitamin needs with a nutritionist or doctor, and mention any concerns you have about vitamin deficiencies.
Vitamin A Deficiency
Vitamin A is needed for proper function of the eye and many other types of cells, such as skin cells. According to the World Health Organization, vitamin A deficiency is the primary cause of preventable blindness in children. In addition, it increases the risk of contracting and dying from severe infections. Vitamin A deficiency causes night blindness in pregnant women and may increase the risk of maternal death.
Vitamin B-12 and Folate Deficiency
Vitamin B-12 is also known as cobalamin. It is used by every cell in the body. It helps with DNA metabolism and fatty acid synthesis. A deficiency of B-12 causes anemia, characterized by low red blood cell counts, which lead to fatigue and pale skin. It also causes nerve damage, with common symptoms including numbness, tingling and difficulty sensing the body in the environment. Folate, which works closely with vitamin B-12, causes anemia without the nerve problems.
Vitamin D Deficiency
Vitamin D acts as a hormone. It is obtained by the diet, or synthesized from a chemical reaction in the skin with light, followed by reactions in the liver and kidney to make its final form. Vitamin D deficiency causes rickets in children and osteomalacia in adults. Rickets causes short stature and abnormally formed bones. Osteomalacia is a loss of bone mass, making you prone to fractures. Vitamin D also has effects on the immune system. Low levels have been linked to cancer, susceptibility to cancer and cardiovascular disease.
Vitamin K Deficiency
Vitamin K is important for blood clotting. A deficiency leads to easy bruising and prolonged bleeding times. Some medications, such as warfarin, interfere with vitamin K metabolism to increase bleeding time.
Thiamine Deficiency
Thiamine, also known as vitamin B-1, is important for transferring phosphate units among molecules. Deficiency causes beriberi, of which there are two types in adults. Dry beriberi is characterized by pain, tingling, and sensory and motor problems in the nerves. Wet beriberi causes nerve problems, heart disease, muscle weakness and swelling.
Niacin Deficiency
Niacin, vitamin B-3, helps with DNA repair, energy metabolism and production of steroid hormones. Deficiency causes pellagra, with its symptoms classically described by the four D's: diarrhea, dermatitis, dementia and death.
Vitamin C Deficiency
Vitamin C is important for iron metabolism, as an antioxidant and for collagen synthesis. Deficiency causes scurvy. This disorder leads to easy bruising, bleeding, spots on the skin, and mental and emotional symptoms.
References
- "Nutrition Concepts and Controversies"; Frances Sizer, et al.; 11th Ed 2007
- "Robbins and Cotran Pathologic Basis of Disease"; Vinay Kumar, et al.; 8th Ed 2009
- "Lehninger Principles of Biochemistry"; David L. Nelson, et al.; 4th Ed 2004
- World Health Organization: Nutrition: Micronutrient Deficiencies: Vitamin A Deficiency
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