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Science Index

Vitamin C

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Title
Vitamin C and human health--a review of recent data relevant to human
requirements.
Author
Weber P; Bendich A; Schalch W
Address
Roche Vitamins & Fine Chemicals' Paramus' NJ 07652' USA.
Source
Int J Vitam Nutr Res, 66(1):19-30 1996
Abstract
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.

Title
vitamin C abrogates the deleterious effects of UVB radiation on
cutaneous immunity by a mechanism that does not depend on TNF-alpha.
Author
Nakamura T; Pinnell SR; Darr D; Kurimoto I; Itami S; Yoshikawa K;
Streilein JW
Address
Schepens Eye Research Institute and Department of Dermatology' Harvard
Medical School' Boston' Massachusetts 02114' U.S.A.
Source
J Invest Dermatol, 109(1):20-4 1997 Jul
Abstract
Acute low-dose treatment of murine skin with ultra violet B (UVB) light
impairs induction of contact hypersensitivity (CH) to
dinitrofluorobenzene (DNFB) in certain inbred strains of mice (termed
UVB-susceptible)' but not in others (termed UVB-resistant)' and
promotes tolerance. These deleterious effects of ultraviolet radiation
(UVR) are mediated in part by TNF-alpha' which is released from
UVR-exposed epidermal and dermal cells. Because UVR damage to skin has
also been ascribed in part to the generation of reactive oxygen
intermediates (ROIs) such as superoxide anion (O2-)' hydrogen peroxide
(H2O2)' hydroxyl radical (OH-)' and singlet oxygen ((1)O2)' we
investigated whether vitamin C (ascorbic acid)' which can nullify ROIs'
prevents the deleterious effects of UVR on the cutaneous immune system.
We found that epicutaneous application of vitamin C (10% L-ascorbic
acid solution) abrogated the deleterious effects of acute low-dose UVR
on induction of CH and prevented the induction of tolerance. Vitamin C'
however' did not reverse the effects of TNF-alpha on CH induction and
tolerance. These results indicate that (i) ROIs generated
intracutaneously by UVR contribute to the impaired ability of exposed
skin to support the induction of CH and to promote the induction of
tolerance and (ii) these effects are not dependent on TNF-alpha.

Title
Effects of supplemental vitamins E and C on the immune responses of
calves.
Author
Hidiroglou M; Batra TR; Ivan M; Markham F
Address
Centre for Food and Animal Research' Agriculture and Agri-Food Canada'
Ottawa' ON' Canada.
Source
J Dairy Sci, 78(7):1578-83 1995 Jul
Abstract
Two experiments were conducted to evaluate the effects of oral
supplementation of vitamin C and vitamin E (alpha-tocopherol)' alone
and in combination' on immune responses of calves. In Experiment 1' 18
Holstein newborn female calves were supplemented with 0' 1' and 2 g/d
of vitamin C from birth to 6 wk of age. Concentrations of ascorbic acid
in blood plasma were significantly higher for supplemented calves than
for control calves. No significant differences among treatments
occurred in the concentrations of IgG1' IgG2' and titer to keyhole
limpet hemocyanin. In Experiment 2' effects of oral supplementation of
vitamins E and C on immune responses were studied using 18 Holstein
female calves. Concentrations of alpha-tocopherol in blood plasma were
significantly higher for supplemented than for control calves. The
concentrations increased from birth to wk 1' and then very little
change occurred from wk 1 to 6. Differences among treatments in the
concentrations of IgG1' IgG2' IgM' and titer to keyhole limpet
hemocyanin were not significant; however' concentrations of IgM in
calves supplemented with vitamins E and C generally tended to be higher
than those of control calves. Antibodies to keyhole limpet hemocyanin
were higher at 6 wk than at 4 wk of age.

Title
Enhancement of natural killer cell activity and T and B cell function
by buffered vitamin C in patients exposed to toxic chemicals: the role
of protein kinase-C.
Author
Heuser G; VoJdani A
Address
Neuromed & Neurotox Associates' Thousand Oaks' CA 91361' USA.
Source
Immunopharmacol Immunotoxicol, 19(3):291-312 1997 Aug
Abstract
After exposure to many toxic chemicals' NK function can be decreased
significantly. Weeks or months later' natural killer (NK) function can
rebound to normal levels in some and can be suppressed for prolonged
periods of time in other patients. In view of this' we decided to study
the effect of buffered vitamin C on NK' T and B cell function in
patients who had been exposed to toxic chemicals. After the first blood
draw' 55 patients immediately ingested granulated buffered vitamin C in
water at a dosage of 60 mg/Kg body weight. Exactly 24 hours later'
blood was again drawn for a follow-up study of NK' T and B cell
function. vitamin C in high oral dose was capable of enhancing NK
activity up to ten-fold in 78% of patients. Lymphocyte blastogenic
responses to T and B cell mitogens were restored to the normal level
after vitamin C usage. Signal transduction enzyme protein kinase C
(PKC) appeared to be involved in the mechanism of induction of NK
activity by vitamin C. We conclude that immune functional abnormalities
can be restored after toxic chemical exposure by oral usage of vitamin
C.

Title
vitamin C and common cold incidence: a review of studies with subJects
under heavy physical stress.
Author
Hemil a H
Address
Department of Public Health' University of Helsinki' Finland.
Source
Int J Sports Med, 17(5):379-83 1996 Jul
Abstract
Several studies have observed an increased risk of respiratory
infections in subJects doing heavy physical exercise. vitamin C has
been shown to affect some parts of the immune system' and accordingly
it seems biologically conceivable that it could have effects on the
increased incidence of respiratory infections caused by heavy physical
stress. In this report the results of three placebo-controlled studies
that have examined the effect of vitamin C supplementation on common
cold incidence in subJects under acute physical stress are analyzed. In
one study the subJects were school-children at a skiing camp in the
Swiss Alps' in another they were military troops training in Northern
Canada' and in the third they were participants in a 90 km running
race. In each of the three studies a considerable reduction in common
cold incidence in the group supplemented with vitamin C(0.6-1.0 g/day)
was found. The pooled rate ratio (RR) of common cold infections in the
studies was 0.50 (95% CI: 0.35-0.69) in favour of vitamin C groups.
Accordingly' the results of the three studies suggest that vitamin C
supplementation may be beneficial for some of the subJects doing heavy
exercise who have problems with frequent upper respiratory infections.

Title
vitamin C and the genesis of autoimmune disease and allergy (review).
Author
Kodama M; Kodama T
Address
Kodama Research Institute of Preventive Medicine' Nagoya' Japan.
Source
In Vivo, 9(3):231-8 1995 May-Jun
Abstract
The purpose of this review paper is to present relevant information for
assessing the validity of our clinical investigation on the clinical
usefulness of vitamin C infusion treatment tested in the control of
autoimmune disease and allergy. Firstly' we describe the historical
background of this study and then present the results of both
experimental and clinical investigations as regards the therapeutic
effect of vitamin C infusion treatment for the control of immune
disorders including diabetes mellitus. Secondly' we discuss the
interdisciplinary nature of our studies in the light of recent progress
in clinical vitaminology' endocrinology and immunology. Thirdly' we
suggest the possibility that the use of our vitamin C infusion
treatment may be beneficial in the clinical management of AIDS' of
which the immunological background data are in favor of the
participation of an autoimmune mechanism in the genesis of this
disease. Finally' we stress the importance of paradigm change in the
achievement of a breakthrough in natural science.

Title
Carotenoids and antioxidant vitamins in patients after burn inJury.
Author
Rock CL; Dechert RE; Khilnani R; Parker RS; Rodriguez JL
Address
Department of Surgery' the University of Michigan' Ann Arbor' USA.
Source
J Burn Care Rehabil, 18(3):269-78; discussion 268 1997 May-Jun
Abstract
Oxidative stress may contribute to secondary tissue damage and impaired
immune function in patients after burn inJury. The purpose of our study
was to describe plasma antioxidant micronutrient concentrations in 26
adult patients admitted with extensive burn inJuries (> 20 % total burn
surface area) to a level-1 trauma burn center during a 21-day period
after admission. The effect of administering beta-carotene was also
examined with use of a prospective randomized subJects design: patients
received either placebo or 30 mg/day in an enteral feeding. Plasma
concentrations of alpha- and gamma-tocopherol' carotenoids (alpha and
beta-carotene' lycopene' beta-cryptoxanthin' lutein)' and retinol were
measured with high- performance liquid chromatography' and vitamin C
was quantified with spectrophotometry' at baseline and twice per week.
Vitamin C' tocopherol' and retinol concentrations were low at baseline'
but levels increased significantly over the study period in both groups
(p < 0.05). Plasma beta-carotene concentration increased when this
carotenoid was provided in the oral feeding. Otherwise' plasma
carotenoid concentrations were low at baseline and remained low
throughout the study period despite normalization of associated lipids.

Title
Sustained levels of ascorbic acid are toxic and immunosuppressive for
human T cells [see comments]
Author
Eylar E; B]aez I; Navas J; Mercado C
Address
Department of Biochemistry' Ponce School of Medicine' PR.
Source
P R Health Sci J, 15(1):21-6 1996 Mar
Abstract
Ascorbate (vitamin C) can protect from oxidative damage to DNA and
lipids that may lead to aging' cancer' and other dysfunctions. However'
we find that purified human T cells deteriorate if maintained in
ascorbate in culture for 18 hrs. or more; viability and Il-2 synthesis
are over 90% curtailed by ascorbate at 50 micrograms/ml. T cell
proliferation and adhesion are severely suppressed at 10-25
micrograms/ml. Dihydro-ascorbate was much less toxic or suppressive.
The suppressive effect of ascorbate appears irreversible' since removal
of ascorbate after 18 hrs. did not restore the mitogenic response.
Although moderate dietary levels of ascorbate often reach 250-1000 mg
or more daily and appear beneficial' our data caution against sustained
megadoses of ascorbate for treatment of patients with AIDS and cancer.

Title
Vitamin C' neutrophil function' and upper respiratory tract infection
risk in distance runners: the missing link.
Author
Peters-Futre EM
Address
Division of Physical Education' University of the Witwatersrand'
Johannesburg' South Africa.
Source
Exerc Immunol Rev, 3():32-52 1997
Abstract
Moderate submaximal exercise results in neutrophilia and enhanced
phagocytic and oxidative capacity of neutrophils. It has been
hypothesized' however' that during intensive exercise and periods of
intensive training this pro-oxidative effect becomes suppressive.
vitamin C is widely recognized for its antioxidant function in
extracellular fluid' and it has been shown to neutralize O2-' HOCl' and
.OH and to attenuate the suppression of phagocytic function. Clinical
manifestation of reduced neutrophil function following participation in
ultramarathon races has' however' not been observed. Although
neutrophils constitute 50-60% of leukocytes and although they are the
first line of defense to bacteriological invasion' postrace episodes of
upper respiratory tract infection (URTI) are not correlated with a
decrement in the function of this individual parameter of immune
function. The efficacy of vitamin C supplements in reducing the
incidence of postrace URTI symptoms' therefore' cannot be fully
explained at this stage.

Title
Antioxidant vitamins affect food animal immunity and health.
Author
Chew BP
Address
Department of Animal Sciences' Washington State University' Pullman
99164-6320' USA.
Source
J Nutr, 125(6 Suppl):1804S-1808S 1995 Jun
Abstract
Carotenoids (beta-carotene and lycopene)' vitamin E (alpha-tocopherol)
and vitamin C (ascorbate) are naturally-occurring antioxidant nutrients
that play important roles in animal health by inactivating harmful free
radicals produced through normal cellular activity and from various
stressors. Both in vitro and in vivo studies showed that these
antioxidant vitamins generally enhance different aspects of cellular
and noncellular immunity. The antioxidant function of these
micronutrients could' at least in part' enhance immunity by maintaining
the functional and structural integrity of important immune cells. A
compromised immune system will result in reduced animal production
efficiency through increased susceptibility to diseases' thereby
leading to increased animal morbidity and mortality.

Title
Exercise' immunology and upper respiratory tract infections.
Author
Peters EM
Address
Division of Physical Education' University of the Witwatersrand'
Johannesburg' South Africa.
Source
Int J Sports Med, 18 Suppl 1():S69-77 1997 Mar
Abstract
The literature reveals a paradoxical response of the immune and host
defense systems to endurance exercise apparent stimulation following
long-term regular training and suppression in response to acute
exposure to exhaustive endurance exercise. Several epidemiological
surveys have confirmed a clinical manifestation of immunosuppression in
the form of increased incidence of upper respiratory tract infection
symptoms following participation in competitive marathon and
ultramarathon running events. Prerace training status and racing
intensity have been related to the incidence of this symptomatology
during the postrace fortnight. Nutritional intervention studies have
shown the antioxidant nutrient' vitamin C' to be effective in reducing
the incidence of upper respiratory tract infection symptoms following
competitive distance events. Laboratory studies have revealed this
vitamin to be the first line of defense in neutralizing the
auto-oxidative activity of phagocytes. It is hypothesized that
exercise-induced neuroendocrine stimulation of the oxidative burst in
neutrophils increases the rate of release of reactive oxygen species
and that these are' in turn' neutralized by high plasma ascorbate
levels. Enhancing intrinsic antioxidant defense by increasing exogenous
antioxidant intake is thus theorized to be of long-term benefit to
serious endurance athletes engaged in heavy training and competition.

Title
Nutritional modification of inflammatory diseases.
Author
Schoenherr WD; Jewell DE
Address
Mark Morris Institute' Topeka' KS' USA.
Source
Semin Vet Med Surg (Small Anim), 12(3):212-22 1997 Aug
Abstract
Regulation of the immune system is extremely complex. We are only
starting to understand how the immune system coordinates the body`s
response to a disease or invading pathogen. Immunomodulation' as the
term implies' can be used to designate either a suppression or an
augmentation of an immune response. Suppressing the function of the
immune system may be important in cases of inflammation and augmenting
the immune response when increased resistance to disease is required.
Nutrition does and can play an important role in modulation of the
animal`s immune system. The maJority of scientific literature published
on the interaction of nutrition and the immune system correlates the
effects of nutrient deficiency and modulation of an immune response.
These studies have evaluated deficiencies of protein; energy; the fat
soluble vitamins A' D' and E; the B-complex vitamins; vitamin C; and
the minerals selenium' iron' zinc' and copper and their relationship to
immune dysfunction. Most recently' researchers have concentrated
efforts on evaluating the impact specific fatty acids have on
modulation of the immune system. Undoubtedly' the nutritional status of
the animal plays an important role in resistance mechanisms against
disease causing organisms and may influence the outcome of disease in
infected animals. The focus of this chapter is to concentrate on the
role specific polyunsaturated fatty acids have on the immune response
of animals and to consider the potential for nutritional modification
of diseases related to inflammation.

 

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