VITAMIN C AND THE IMMUNE SYSTEM
The structure of the immune system is very complex, as are the tasks that the human immune system performs: It protects our body from pathogens by making it immune to their influences. This happens because the immune system distinguishes between self and foreign and triggers an appropriate immune response.
VITAMIN C IS THE MOST IMPORTANT WATER-SOLUBLE ANTIOXIDANT IN THE BODY THAT SUPPORTS THE IMMUNE SYSTEM. VITAMIN C ALSO STIMULATES THE FORMATION OF LEUKOCYTES (WHITE BLOOD CELLS) AND INTERFERON
Various studies show the positive influence of vitamin C on the immune system:
EFFECT OF VITAMIN C ON COMMON COLD: RANDOMIZED CONTROLLED TRIAL. EUROPEAN JOURNAL OF CLINICAL NUTRITION 24 AUGUST 2005, DOI: 10.1038/SJ.EJCN.1602261 // A 5-year double-blind study was recently completed, which, in agreement with other studies, showed that taking vitamin C prevents colds. Half of the 244 subjects took 50 mg of vitamin C daily, the other half 500 mg of vitamin C. Colds occurred occurred least frequently in group A, whose participants took the highest dose of vitamin C.
PLASMA CONCENTRATIONS OF DIETARY AND NONDIETARY ANTIOXIDANTS ARE LOW IN SEVERE ASTHMA. EUROPEAN RESPIRATORY JOURNAL 2005; 26(2):257-264. // This study shows that the vitamin C and vitamin E levels in the blood of men and women with severe asthma are lower than in people with mild asthma. The study suggests that taking vitamin C and vitamin E for is useful for people who suffer from severe asthma.
ANTIHISTAMINE EFFECT OF SUPPLEMENTAL ASCORBIC ACID AND NEUTROPHIL CHEMOTAXIS. JOURNAL OF AMERICAN COLLEGE OF NUTRITION 1992; 11(2): 172-176. // During this study, the subjects were given a placebo for some weeks and vitamin C for other weeks. The effect of vitamin C on histamine and neutrophil granulocytes (a type of white blood cell) was then examined. In the weeks in which vitamin C was taken chemotaxis (attraction of immune cells triggered by messenger substances) increased by 19% and decreased by 30% after vitamin C was stopped. The amount of histamine in the blood decreased by 38% when vitamin C was taken. This study shows that vitamin C, as a histamine inhibitor, indirectly stimulates chemotaxis.
PREVENTING THE COMMON COLD WITH A VITAMIN C SUPPLEMENT: A DOUBLE-BLIND, PLACEBO-CONTROLLED SURVEY. ADVANCES IN THERAPY 2002; 19(3):151-159. // This double-blind, placebo-controlled study involved 168 subjects. Those who took vitamin C had fewer colds and recovered from colds more quickly than those who were given a placebo. This study shows that vitamin C can help prevent colds to heal and prevent (new) infections.
IMMUNE FUNCTION IN AGED WOMEN IS IMPROVED BY INGESTION OF VITAMINS C AND E. CAN. J. PHYSIOL. PHARMACOL 1998; 76:373-380. // This study shows that the immune systems of older women are strengthened by taking vitamins C and E.
CELLULAR IMMUNE RESPONSES TO VITAMIN C SUPPLEMENTATION IN AGING HUMANS ASSESSED BY THE IN VITRO LEUCOCYTE MIGRATION INHIBITION TEST. MEDICAL SCIENCE RESEARCH 1998; 26:227-230. // A group aged 20 to 30 years and a group aged over 60 years took 200 mg of vitamin C daily for 30, 60 and 90 days. This study shows that vitamin C improves the effectiveness of immune cells in older people.
IN VIVO EFFECT OF ASCORBIC ACID ON ENHANCEMENT OF HUMAN NATURAL KILLER CELL ACTIVITY. NUTRITION RESEARCH 1993; 13:753-764. // This study shows that vitamin C is a powerful modulator of the immune system. The positive effect on natural killer (NK) cells partially explains the observed effect of vitamin C against tumors.
VITAMIN C PROPHYLAXIS IN A BOARDING SCHOOL. NEW ENGLAND JOURNAL OF MEDICINE 1974; 290:6-10. // In a placebo-controlled, double-blind study, 641 children at a boarding school took 1 or 2 g of vitamin C or a placebo daily for 14 days. The children of all age groups who were given vitamin C missed school less often due to illness. The biggest difference in terms of illness was for colds and coughs.
VITAMIN C AND THE JOINTS
Vitamin C plays an important role in the formation and maintenance of collagen. Vitamin C is therefore essential for the formation and maintenance of connective tissue in bones, cartilage, teeth, skin, muscles and tendons. Studies have shown that vitamin C is essential for healthy joints .
VITAMIN C SUPPLEMENT USE AND BONE MINERAL DENSITY IN POSTMENOPAUSAL WOMEN. J. BONE MINERAL RES 2001; 16:135-140. // 994 women participated in this study, 227 of whom regularly took vitamin C. The daily dose varied between 100 and 5000 mg and was on average 745 mg. The study showed that vitamin C had a positive effect on the mineral density of the bones. This was especially true for postmenopausal women who were receiving hormone therapy and also taking a calcium supplement.
EFFECT OF VITAMIN C ON FREQUENCY OF REFL SYMPATHETIC DYSTROPHY (RSD) IN WRIST FRACTURES. J Adv 1999; 354:2025-28. // This double-blind study involved 123 people with wrist fractures. Half of the people took 500 mg of vitamin C daily for 50 days. All people were followed for one year. This study showed that vitamin C reduces the risk of RSD and may also be can be used to treat other fractures.
DO ANTIOXIDANT MICRONUTRIENTS PROTECT AGAINST THE DEVELOPMENT AND PROGRESSION OF KNEE OSTEOARTHRITIS? ARTHRITIS & RHEUMATISM APRIL 1996; 39(4):648-656. // This study showed that increased intake of antioxidants could reduce the risk of cartilage degeneration and joint problems in older people.
SAFETY OF VITAMIN C
It is generally assumed that taking vitamin C as a dietary supplement is safe if "reasonable" usage instructions are followed. The usual daily dose is 250 mg, in clinical studies the daily amount usually varies between 60 and 2000 mg.
VITAMINS E AND C ARE SAFE ACROSS A BROAD RANGE OF INTAKES. AMERICAN JOURNAL OF CLINICAL NUTRITION, APRIL 2005; 81(4):736-745. // In this review article, various authors confirm the safety of daily intake of up to 2000 mg of vitamin C and up to 1600 IU of vitamin E.