Vitamine C
Hart en vaatziekten
- Increased risk of cardiovascular disease at suboptimal plasma concentrations of essential antioxidants: an epidemiological update with special attention to carotene and vitamin C
For the prolongation of life expectancy and reduction of ischemic heart disease (IHD) dietary guidelines generally recommend lowering saturated mammalian fat with partial replacement by vegetable oils and increasing generously vegetables, legumes, and fruits, which provide more essential antioxidants. Plasma antioxidants as assayed in epidemiological studies of complementary type (ie the cross-cultural MONICA Vitamin Substudy reevaluation considering the "Finland-Factor", the Edinburgh Angina-Control Study, and the Basel Prospective Study) consistently revealed an increased risk of IHD (and stroke) at low plasma concentrations of antioxidants, with the rank order as follows: lipid-standardized vitamin E >> carotene = vitamin C > vitamin A, independently of classical IHD risk factors. Decreasing IHD risk through nutrition may be possible when plasma concentrations have the following values: > 27.5-30.0 mumol vitamin E/L, 0.4-0.5 mumol carotene/L, 40-50 mumol vitamin C/L and 2.2-2.8 mumol vitamin A/L. Thus, previous prudent regimens may now be updated, aiming at an optimal status of all essential and synergistically linked antioxidants. - Vitamin C intake and mortality among a sample of the United States population
The relation of the standardized mortality ratio (SMR) for all causes of death to increasing vitamin C intake is strongly inverse for males and weakly inverse for females. Among those with the highest vitamin C intake, males have an SMR (95% confidence interval) of 0.65 (0.52-0.80) for all causes, 0.78 (0.50-1.17) for all cancers, and 0.58 (0.41-0.78) for all cardiovascular diseases; females have an SMR of 0.90 (0.74-1.09) for all causes, 0.86 (0.55-1.27) for all cancers, and 0.75 (0.55-0.99) for all cardiovascular diseases. - Ascorbic acid reverses endothelial vasomotor dysfunction in patients with coronary artery disease
Ascorbic acid reverses endothelial vasomotor dysfunction in the brachial circulation of patients with coronary artery disease. These findings suggest that increased oxidative stress contributes to endothelial dysfunction in patients with atherosclerosis and that endothelial dysfunction may respond to antioxidant therapy. - Vitamin C as an Antioxidant: Evaluation of Its Role in Disease Prevention
Vitamin C in humans must be ingested for survival. Vitamin C is an electron donor, and this property accounts for all its known functions. As an electron donor, vitamin C is a potent water-soluble antioxidant in humans. Antioxidant effects of vitamin C have been demonstrated in many experiments in vitro. Human diseases such as atherosclerosis and cancer might occur in part from oxidant damage to tissues. - Vitamin C and risk of death from stroke and coronary heart disease in cohort of elderly people
In elderly people vitamin C concentration, whether measured by dietary intake or plasma concentration of ascorbic acid, is strongly related to subsequent risk of death from stroke but not from coronary heart disease. - Vitamin C deficiency and risk of myocardial infarction: prospective population study of men from eastern Finland
Vitamin C deficiency, as assessed by low plasma ascorbate concentration, is a risk factor for coronary heart disease.
Hoge bloeddruk
- Ascorbic acid improves the intrahepatic endothelial dysfunction of patients with cirrhosis and portal hypertension
Ascorbic acid improved intrahepatic endothelial dysfunction, blunting the postprandial increase in portal pressure. These results encourage the performance of further studies testing antioxidants as adjunctive therapy in the treatment of portal hypertension. - Effect of vitamin C on ambulatory blood pressure and plasma lipids in older persons
In older adults high intakes of ascorbic acid have modest effects on lowering high systolic blood pressure, which could contribute to the reported association between higher vitamin C intake and lower risk of cardiovascular disease and stroke. - Treatment of hypertension with ascorbic acid
In a randomised, double-blind, placebo-controlled study we showed that treatment of hypertensive patients with ascorbic acid lowers blood pressure. Further studies of ascorbic acid to treat hypertension, with clinical endpoints, are warranted. - Vitamin C improves endothelial function of epicardial coronary arteries in patients with hypercholesterolaemia or essential hypertension--assessed by cold pressor testing
The antioxidant vitamin C reverses cold pressor test-induced vasoconstriction of epicardial coronary arteries in patients with hypertension or hypercholesterolaemia. Our data suggest that enhanced oxidative stress contributes to impaired endothelial function in this patient population. - Vitamin C improves endothelial dysfunction of epicardial coronary arteries in hypertensive patients
Vitamin C improves the endothelium-dependent vasomotor capacity of coronary arteries in patients with hypertension and patent coronary arteries. These findings suggest that increased oxidative stress contributes to endothelial dysfunction in hypertensive patients. - Combination oral antioxidant supplementation reduces blood pressure
Short-term oral high-dose combination antioxidant therapy reduces blood pressure, possibly via increased availability of nitric oxide. This study may have implications for the innovative use of antioxidants as an adjunct to anti-hypertensive therapy. - Vitamin C improves endothelium-dependent vasodilation by restoring nitric oxide activity in essential hypertension
In essential hypertensive patients, impaired endothelial vasodilation can be improved by the antioxidant vitamin C, an effect that can be reversed by the nitric oxide synthase inhibitor N(G)-monomethyl-L-arginine. These findings support the hypothesis that nitric oxide inactivation by oxygen free radicals contributes to endothelial dysfunction in essential hypertension.
Veroudering
- Aspects of free radical reactions in biological systems: aging
The role of free radicals and lipid peroxidation is reviewed with regard to the aging process. Free radicals are produced during mitochondrial respiration, during the autooxidation of a variety of biological molecules and chemicals, during irradiation damage, and are found as environmental pollutants. Free radicals induce lipid peroxidation which results in membrane damage, increased disulfide/sulfhydryl ratios, and accumulation of aging pigments. Superoxide dismutase, glutathione peroxidase, vitamin E, vitamin C, and selenium are of importance with respect to free radical and lipid peroxide quenching. During aging, the levels of vitamin C appear to decline in the human, guinea pig, and the mouse. Synthetic antioxidants, added to the diets of mice, have been noted to extend the lifespan and mean half-survivale times. - Vitamin C supplementation and respiratory infections: a systematic review.
Eight of these trials were double blind and placebo controlled and seven were randomized. Five small trials found a statistically significant 45 to 91% reduction in common cold incidence in the vitamin C group. These trials were short and the participants were under heavy exertion during the trial. Furthermore, three other trials found a statistically significant 80 to 100% reduction in the incidence of pneumonia in the vitamin C group. The large number of positive findings seems to warrant further consideration of the role of vitamin C in respiratory infections, particularly in military recruits. - Mineral and vitamin deficiencies can accelerate the mitochondrial decay of aging
Mitochondrial oxidative decay, which is a major contributor to aging, is accelerated by many common micronutrient deficiencies. One major mechanism is inhibition of the pathway of heme biosynthesis in mitochondria, which causes a deficit of heme-a. Heme-a, only found in Complex IV, is selectively diminished, resulting in oxidant leakage and accelerated mitochondrial decay, which leads to DNA damage, neural decay, and aging. We emphasize those deficiencies, which appear to cause damage through this mechanism, particularly minerals such as iron (25% of menstruating women ingest <50% of the RDA) or zinc (10% of the population ingest <50% of the RDA). Several vitamin deficiencies, such as biotin or pantothenic acid, also increase mitochondrial oxidants through this mechanism. Additionally, other minerals such as magnesium and manganese that play a role in mitochondrial metabolism, but do not affect heme directly, are discussed. An optimum intake of micronutrients could tune up metabolism and give a marked increase in health, particularly for the poor, elderly, and obese, at little cost.
RDA
- Vitamin C and human health--a review of recent data relevant to human requirements
The recent scientific literature indicates that beyond merely protecting against scurvy vitamin C contributes to many aspects of human health. The main areas of research reviewed include: 1. Vitamin C requirements of smokers. The data indicate that the vitamin C requirement of smokers is higher by at least 60 mg per day (up to 140 mg per day) than that of nonsmokers. 2. Important functions of the body, such as immune response, pulmonary function, and iron absorption are related to vitamin C intakes. Daily vitamin C intake of at least 150-200 mg per day enhance these functions. 3. Vitamin C may play critical roles in the prevention of CHD, cancer and cataract. Based on the available data, vitamin C intakes of at least 80-120 mg per day are associated with lowering the risk of these chronic diseases. 4. The literature documents that these and much higher intake levels of vitamin C are safe. - Vitamin C (ascorbic acid): new roles, new requirements?
In recent years, research has increasingly focused on this latter function, stimulated by suggestions that "oxidative stress" may be a causal factor in the etiology of such diverse and important disorders of aging as cancer, cardiovascular disease, and cataract formation. The present evidence is strong enough to have convinced nutritionists that daily vitamin C intake should be many times higher than the amount needed to protect against scurvy, and this is reflected in the present Recommended Dietary Allowances.
SITE MAP
Maagdarmstoornissen: Candida infectie - Prikkelbaredarmsyndroom - Crohn - Colitus Ulcerosa - CVS/ME: Chronische vermoeidheid Syndroom - Diabetische complicaties: Bloeduiker stabilisatie - Neuropathie - Retinopathie - Nefropathie - Hart- en vaatziekten: Cardiomyopathie en Hartfalen - Hoge bloeddruk - Cholesterol verlaging - Aderverkalking (atherosclerose) - Spataderen - Levensverlenging: 100 jaren jong - DHEA - Melatonine - 65+ - Kanker: - Ondersteuningstherapie bij kanker - Bot en gewrichtsaandoeningen: - Artrose - Artritis - Osteoporose - Fibromyalgie: - Fibromyalgie - Urinewegaandoeningen: - Prostaatklachten - Blaasontsteking - Vrouwenklachten: Menopauze - Premenstrueelsyndroom - Overgewicht: - Overgewicht - SLIM - Oogaandoeningen: Staar - Slecht zien Andere artikelen: - HPU - Astma - Multiple Sclerose - Psoriasis - Depressie
Maagdarmstoornissen: Candida infectie - Prikkelbaredarmsyndroom - Crohn - Colitus Ulcerosa - CVS/ME: Chronische vermoeidheid Syndroom - Diabetische complicaties: Bloeduiker stabilisatie - Neuropathie - Retinopathie - Nefropathie - Hart- en vaatziekten: Cardiomyopathie en Hartfalen - Hoge bloeddruk - Cholesterol verlaging - Aderverkalking (atherosclerose) - Spataderen - Levensverlenging: 100 jaren jong - DHEA - Melatonine - 65+ - Kanker: - Ondersteuningstherapie bij kanker - Bot en gewrichtsaandoeningen: - Artrose - Artritis - Osteoporose - Fibromyalgie: - Fibromyalgie - Urinewegaandoeningen: - Prostaatklachten - Blaasontsteking - Vrouwenklachten: Menopauze - Premenstrueelsyndroom - Overgewicht: - Overgewicht - SLIM - Oogaandoeningen: Staar - Slecht zien Andere artikelen: - HPU - Astma - Multiple Sclerose - Psoriasis - Depressie
