Vitamin metabolic function

A specific role for vitamin E in a required metabolic function has not been found. In addition to its direct antioxidant effects, a-tocopherol has been reported to have specific molecular functions. 

Besides water, the diet must provide metabolic fuels (mainly carbohydrates and lipids), protein (for growth and turnover of tissue proteins), fiber (for roughage), minerals (elements with specific metabolic functions), and vitamins and essential fatty acids (organic compounds needed in small amounts for essential metabolic and physiologic functions). The polysaccharides, tri-acylglycerols, and proteins that make up the bulk of the diet must be hydrolyzed to their constituent monosaccharides, fatty acids, and amino acids, respectively, before absorption and utilization. Minerals and vitamins must be released from the complex matrix of food before they can be absorbed and utifized. 

Besides watet, the diet must provide metaboEc fuels (carbohydrate and fat) fot bodily growth and activity protein fot synthesis of tissue proteins fiber for roughage minerals for specific metabolic functions cettain polyunsamtated fatty acids of the n-3 and n-6 famihes fot eicosanoid synthesis and other functions and vitamins, otganic compounds needed in small amounts for many varied essential functions. 

THE VITAMINS ARE A DISPARATE GROUP OF COMPOUNDS WITH A VARIETY OF METABOLIC FUNCTIONS... 

VITAMIN E DOES NOT HAVE A PRECISELY DEFINED METABOLIC FUNCTION... 

Niacin was discovered as a nutrient during studies of pellagra. It is not strictly a vitamin since it can be synthesized in the body from the essential amino acid tryptophan. Two compounds, nicotinic acid and nicotinamide, have the biologic activity of niacin its metabolic function is as the nicotinamide ring of the coenzymes NAD and NADP in oxidation-reduction reactions (Figure 45-11). About 60 mg of tryptophan is equivalent to 1 mg of dietary niacin. The niacin content of foods is expressed as mg niacin equivalents = mg preformed niacin + 1/60 X mg tryptophan. Because most of the niacin in cereals is biologically unavailable, this is discounted. 

The kidneys are located on the posterior part of the abdomen on either side of the spine, below the diaphragm, and behind the liver and stomach. They are bean-shaped and weigh approximately 150 grams (0.33 lb) each. The primary function of the kidneys is excretion. They work to excrete waste products through a series of steps involving glomerular filtration, secretion, and reabsorption. The kidneys also have several endocrine (e.g., production of erythropoietin and renin) and metabolic (e.g., vitamin D activation and drug metabolism) functions. 

Electrolytes, vitamins, and trace elements are essential for numerous biochemical and metabolic functions and should be added to PN daily unless otherwise not indicated. 

The water-soluble vitamins generally function as cofactors for metabolism enzymes such as those involved in the production of energy from carbohydrates and fats. Their members consist of vitamin C and vitamin B complex which include thiamine, riboflavin (vitamin B2), nicotinic acid, pyridoxine, pantothenic acid, folic acid, cobalamin (vitamin B12), inositol, and biotin. A number of recent publications have demonstrated that vitamin carriers can transport various types of water-soluble vitamins, but the carrier-mediated systems seem negligible for the membrane transport of fat-soluble vitamins such as vitamin A, D, E, and K. 

Metabolic diseases, liquid crystal accumulations and, 15 112-113 Metabolic engineering, 12 412-413 Metabolic functions, of vitamin A, 25 787-789 Metabolic pathways, as target of antibiotics, 3 24... 

Pantothenic acid and biotin were thus found to be growth factors for yeast. Like riboflavin these molecules are incorporated into larger molecules in order to exert their essential metabolic function. Unlike the other vitamins there has been no evidence of pathological signs in man which can be attributed to dietary deficiencies in biotin or pantothenic acid. 

Vitamin B12 (cobalamin 22) and fohc acid (23) are among the essential nutrients and are involved primarily as cofactors in metabolic functions as... 

Cyanocoba/am/n- Cyanocobalamin is rapidly absorbed from IM and subcutaneous injection sites the plasma level peaks within 1 hour. Once absorbed, it is bound to plasma proteins, stored mainly in the liver and is slowly released when needed to carry out normal cellular metabolic functions. Within 48 hours after injection of 100 to 1,000 meg of vitamin B-12, 50% to 98%... 

Thus, the accumulation of vitamins respectively micronutrients in single tissues is not limited to a pure storage process like the storage of vitamin A in the liver, but is often connected with important and tissue-specific metabolic functions. 

Vitamins are exogenous chemical substance required by the body in very small amount for the various metabolic functions of the body and categorized as essential nutrients. They do not yield energy but enable the body to use other nutrients and are primarily used in the prevention and treatment of certain deficiency diseases. 

Brigelius-Flohe, R. Traber, M.G. (1999) Vitamin E function and metabolism. FASEB J. 13, 1145-1155. 

Subscript numerals have a different connotation in connection with vitamin D substances than is true, for example, with B vitamins. Vitamins Bi, B2. B, Bi , etc., represent individual substances which have little or no chemical resemblance to each other and perform different metabolic functions. The various vitamin D s, however, have very similar structures, differing only in the side chains, and perform the same functions. 

Avocado produces a rather viscous oil that penetrates the upper skin layers well and is beneficial for dry skin and is often found in sun preparations. It is versatile, with applications ranging from soothing nappy rash to an ideal choice for damaged, dry and mature skin. It is a mixture of monounsaturated and saturated fatty acids, with oleic (60-70%), linoleic (8-15%), palmitoleic (4-7%), linolenic (2%), palmitic (12-16%) and stearic (2%). Vitamins A, B and D are found along with lecithin. Lecithin is one of the major phospholipids (a lipid combined with a phosphate group) of the body. Phospholipids are vital chemicals needed in the body for structural and metabolic functions. 

---