Vitamins immune function

Vitamin C status is supposed to play a role in immune function and to influence the progression of some chronic degenerative diseases like atherosclerosis, cancer, cataracts, and osteoporosis. The role of vitamin C in immune function, especially during common cold and upper respiratory tract infection, is the subject of lively debate. The exact mechanisms of action have not yet been fully elucidated, but the results of several trials point to a reduced duration and intensity of infections in subjects consuming high amounts of vitamin C (200-1000 mg/d). However, the incidence of common cold was not influenced significantly (24). 

Rice bran is the richest natural source of B-complex vitamins. Considerable amounts of thiamin (Bl), riboflavin (B2), niacin (B3), pantothenic acid (B5) and pyridoxin (B6) are available in rice bran (Table 17.1). Thiamin (Bl) is central to carbohydrate metabolism and kreb s cycle function. Niacin (B3) also plays a key role in carbohydrate metabolism for the synthesis of GTF (Glucose Tolerance Factor). As a pre-cursor to NAD (nicotinamide adenine dinucleotide-oxidized form), it is an important metabolite concerned with intracellular energy production. It prevents the depletion of NAD in the pancreatic beta cells. It also promotes healthy cholesterol levels not only by decreasing LDL-C but also by improving HDL-C. It is the safest nutritional approach to normalizing cholesterol levels. Pyridoxine (B6) helps to regulate blood glucose levels, prevents peripheral neuropathy in diabetics and improves the immune function. 

The above scientific information on rice bran phytochemicals indicates that a multitude of mechanisms are operating at the cellular level to bring about specific health effects. Several health benefits of rice bran appear to be the result of the synergistic function of the many phytochemicals, antioxidants, vitamins and minerals which operates through a specific immune response. Their role in the biochemical mechanisms at the cellular level which result in major health effects is shown in Fig. 17.1. A short overview summarizing the effect of the various phytochemicals on major health issues such as cancer, immune function, cardiovascular disease, diabetes, altered liver function and gastrointestinal and colon disease will be given below. 

Routine antioxidant vitamin supplementation, e.g. with vitamins C and/or E, of the diabetic diet should be considered. Vitamin C depletion is present in all diabetics irrespective of the presence of vascular disease. A recent study demonstrated no significant difference between the dietary intake of vitamin C (the main determinant of plasma ascorbate) in patients with diabetes and age-matched controls, confirming the view that ascorbate depletion is secondary to the diabetic process and su esting that diabetic patients require additional intakes of the vitamin to maintain optimal levels (Sinclair et /., 1994). Antioxidant supplementation may have additive beneficial effects on a wide variety of processes involved in diabetic vascular damage including blood pressure, immune function, inflammatory reactions. 

Vitamin A deficiency affects more than 100 million children around the world (Miller and others 2002) and thus remains an important public health problem in many countries. Vitamin A is essential for vision, reproduction, growth, immune function, and general health of humans (van Lieshout and others 2001). The major sources of vitamin A in the human diet are retinyl esters (preformed vitamin A) found in foods of animal origin and provitamin A carotenoids from fruits and vegetables. Unfortunately, foods containing preformed vitamin A (meat, milk, eggs, etc.) are frequently too expensive for some economically deprived developing countries, and therefore dietary carotenoids are the main source of vitamin A in these countries. 

The balance between excess and insufficient zinc is important. Zinc deficiency occurs in many species of plants and animals, with severe adverse effects on all stages of growth, development, reproduction, and survival. In humans, zinc deficiency is associated with delayed sexual maturation in adolescent males poor growth in children impaired growth of hair, skin, and bones disrupted Vitamin A metabolism and abnormal taste acuity, hormone metabolism, and immune function. Severe zinc deficiency effects in mammals are usually prevented by diets containing >30 mg Zn/kg DW ration. Zinc deficiency effects are reported in aquatic organisms at nominal concentrations between 0.65 and 6.5 pg Zn/L of medium, and in piscine diets at <15 mg Zn/kg FW ration. Avian diets should contain >25 mg Zn/kg DW ration for prevention of zinc deficiency effects, and <178 mg Zn/kg DW for prevention of marginal sublethal effects. 

Furthermore, mice treated with anti-oxidants (Vitamins C, or E, or beta-hydroxy toluene) prior to JP-8 dermal application exhibit a partial recovery in immune function... 

Vitamin A has a rich associated human physiology. It is associated with vision, regulation of gene expression, reproduction, embryo development, and immune function. We cannot manage all of this but let s get started with vision. 

The family of related compounds known as vitamin A is essential for vision and is an important regulator of gene expression, reproduction, and immune function. 

The activity of vitamin A is related to vision process, tissue differentiation, growth, reproduction, and the immune system. A deficiency of this micronutrient mainly leads to visual problems, impaired immune function, and growth retardation in children. Hypervitaminosis could lead to hepatotoxicity, affect bone metabolism, disrupt lipid metabolism, and teratogenicity [417]. The isomerization of P-carotene, due to technological processes in foods, leads to a reduction of the vitamin A activity it is therefore important to analyze it. 

Maggini, S., Wintergerst, E. S., Beveridge, S., and Hornig, D. H. (2007). Selected vitamins and trace elements support immune function by strengthening epithelial barriers and cellular and humoral immune responses. Br. ]. Nutr. 98(Suppl 1), S29-S35. 

Like folate and vitamin C, vitamin B6 (pyroxidine) is water soluble and like folate has several vitamers. Vitamin B6 may be involved in more bodily functions than any other nutrient (Tambasco-Studart et al., 2005), is a cofactor for many enzymes, especially those involved in protein metabolism, and is also a cofactor for folate metabolism. Vitamin B6 has anticancer activity (Theodoratou et al., 2008), is a strong antioxidant (Denslow et al., 2005), is involved in hemoglobin biosynthesis, lipid and glucose metabolism and immune and nervous system function. Possible consequences of deficiency include anemia, impaired immune function, depression, confusion, and dermatitis (Spinneker et al., 2007). Vitamin B6 deficiency is generally not a problem in the developed world, but there could be as yet poorly defined consequences of suboptimal intake particularly for the elderly. 

Methylcobalamin is the coenzyme form of vitamin It is neurologically active, most bioavailable and best utilized. Unlike cyanocobalamin, it does not require any conversion after absorption by the body and is better retained by the liver and other tissues. It has exhibited beneficial effects against brain aging, irregular sleep patterns. It supports immune function and promote normal cell growth. It represents one of the best values in nutritional products, given its comparably low cost and its wide range of potential benefits. 

Vitamin Vitamin A [retinol] RDA/AI Men 900 pg/d Women 700 pg/d Physiological function Required for normal vision, gene expression, reproduction, embryonic development, and immune function Adverse Effects of Excessive Consumption Teratological effects liver toxicity... 

Other notable findings concerning vitamin-E deficient animals established hepatic lesions [38-40] and accumulation of lipopigment [41], while addition of the vitamin to the diet of rabbits evoked enhanced immune function [42], These early studies in vitamin E deficiency states in animals produced sufficient diverse and interesting observations to generate much of the data currently available. 

Semba, R.D. 1998. The role of vitamin A and related retinoids in immune function. NutrRev 56(1) Part II S38-S48. 

P12. Penn, N. D., Purkins, L., Kelleher, J., Heatley, R. V., Mascie-Taylor, B. H., and Belfield, P. W., The effect of dietary supplementation with vitamins A, C, and E on cell-mediated immune function in elderly long-stay patients A randomized controlled study. Age Ageing 20,169-174... 

Stephensen CB (2001) Vitamin A, infection, and immune function. Annual Reviews of Nutrition 21,167-92. 

Diuretics, by increasing kidney output, deplete calcium, magnesium, potassium, and zinc. This, in turn, depletes energy and lowers immune function. Over-the-counter antacids, as well as the peptic ulcer medication cimetidine, reduce iron and calcium assimilation, vitamin Bj , and intrinsic factor (without which Bi2 can t be absorbed). Drugs prescribed for heart disease reduce libido, and some of them render men impotent. 

Ascorbic Acid Deficiency. Scurvy is the classical disease associated with ascorbate deficiency. It is a disease of the connective tissue and probably is caused by inadequate crosslinking attributed to a lack of hydroxy-lated proline and lysine. Many consider scurvy to be an advanced stage of ascorbate deficiency. Chronic deficiencies may also (l)in-crease risk for malignancies, as evidenced by oxidized DNA markers and increased concentrations of reactive oxygen species (2) decreased immune function, as evidenced by less vitamin in neutrophils and lymphocytes (3) cardiovascular disease caused by the inflammatory response on the blood vessel walls and (4) cataract formation caused by decreased concentrations of ascorbate in the ocular tissues. 

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