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Geriatric University Clinic, Kantonsspital, 4031 Basel, Switzerland
Summary
The antioxidant defense system is important in maintaining cellular homeostasis and preventing oxidative stress. Antioxidants are important dietary components contributing to a general slowing of ageing processes (e.g. cataract formation), but also in protecting particularly vulnerable sites from developing tissue injuries resulting in chronic diseases. This suggests that we should aim at certain minimum threshold concentrations of plasma antioxidants. In the near future, it is well possible that the amount of nutrients necessary to prevent or to reduce the risk for chronic diseases will be the more important issue than the amount it takes to prevent deficiencies. In order to achieve optimal nutritional levels, particularly elderly may benefit from the use of supplements during periods of stress or compromised nutrient intake. The highly interactive antioxidative system in the body strongly suggests that a well-balanced adequate intake of different antioxidants will be superior in its protective action to the supplementation with one single compound. It should be possible to resolve in the near future the question whether two days' RDA's are still adequate or whether the intake should be revised upwards.
International Journal for Vitamin and Nutrition Research, Band 69, 1999, Heft 3 © Verlag Hans Huber AG, Bern
Department of Surgery, University of Tübingen, Tübingen, Germany
Summary
Average life-span and maximum life-span are the two basic parameters
by which the processes of ageing and senescence of individuals of a species
are characterized. Although each individual of a species if affected by
both parameters can only be studied in populations of individuals. The survival
curve of a cohort of individuals reflects the different influences of constitutional
and environmental factors on life expectancy.
The intrinsic molecular and cellular mechanisms by which the physiological
process of ageing and senescence is controlled and regulated are far from
being understood although a large number of hypotheses have emerged over
the decades. Stochastic and deterministic models of the ageing process have
been developed but a theory unifying the large body of experimental, epidemiological
and clinical findings is still lacking.
In this contribution a brief review is presented on the different hypotheses
aiming at explaining the physiology and pathophysiology of ageing and senescence.
Keywords
Ageing, senescence, somatic mutation, wear and tear, oxidative stress, longevity, life-span
International Journal for Vitamin and Nutrition Research, Band 69, 1999, Heft 3, © Verlag Hans Huber AG, Bern
Institut für Ernährungswissenschaft der Universität Bonn, Endenicher Allee 11-13, 53115 Bonn, Germany
Summary
In the last decade several attempts (Nationale Verzehrsstudie, NVS; Verbundstudie
Ernährungserhebung und Risikofaktoren-Analytik, VERA; Bethanien-Ernährungsstudie,
BEST) have been made to assess the nutritional status of the elderly in Germany.
A careful evaluation of those data describing the vitamin status clearly
indicate that healthy older people are not at higher risk for vitamin deficiency
compared to younger adults. The results of the NVS showed that, except for
folic acid, mean intake of all vitamins exceeded 80% of the current recommendations.
Only 5% of blood vitamin concentrations analyzed in a subpopulation (VERA-Study)
were founded to be below the physiological range. Only the incidence of
low cobalamin values increased with age, presumably due to gastrointestinal
problems (atrophic gastritis). In contrast, geriatric patients showed markedly
lower vitamin blood concentrations compared to healthy subjects of the same
age (BEST-Study). This might be explained by physical and mental deterioration,
handicaps, chronic diseases and multiple chronic drug use.
Underrepresentation of very old people, lack of reliable reference values
for biomarkers and uncertainties in data collection may have contributed
to misinterpretations. Representative studies are needed to objectively
assess the nutritional status of the elderly population in Germany.
Keywords
Vitamins, intake, vitamin status, elderly, geriatric patients, Germany
International Journal for Vitamin and Nutrition Research, Band 69, 1999, Heft 3, © Verlag Hans Huber AG, Bern
Human Nutrition and Health, Vitamins Fine Chemicals Division, F. Hoffmann-La Roche Ltd., 4070 Basel, Switzerland
Summary
Age-related changes in nutrition can affect the nutritional status of
the elderly in a number of ways. Food intake is affected by socio-economic,
physiological and pathological factors. The major physiological age-related
change is the decrease in the energy requirement due to a reduction in lean
body mass and a reduction in physical activity leading to a compensatory
decrease in macro- and micronutrient intake of approximately 30% by the
age of 80 years. Morbidity and some types of medication, smoking and alcohol
consumption also affect the absorption and metabolism of vitamins. The plasma
levels of fat-soluble vitamins and carotenoids tend to increase with age
with the exception of vitamin D, while certain water-soluble vitamin levels
decrease, particularly vitamin B6 and vitamin B12.
Many epidemiological studies have examined the vitamin intake and the plasma
concentrations of large elderly populations in many regions of the world,
but few have specifically determined the incidence of vitamin deficiencies.
The criteria for defining deficiency varies between studies making it difficult
to compare data from different studies.
In the SENECA Study on European elderly evidence for biochemical vitamin
deficiency was found in 47% for vitamin D, 23.3% for vitamin B6, 2.7% for
vitamin B12 and 1.1% for vitamin E.
Keywords
Epidemiology, elderly, retinol, a-tocopherol, pyridoxine, vitamin B12, folic acid, carotenes, vitamin D, riboflavin
International Journal for Vitamin and Nutrition Research, Band 69, 1999, Heft 3, © Verlag Hans Huber AG, Bern
Medizinische Klinik, Universität Würzburg, Josef-Schneider-Str. 2, 97080 Würzburg, Germany
International Journal for Vitamin and Nutrition Research, Band 69, 1999, Heft 3, © Verlag Hans Huber AG, Bern
Walther Straub-Institut für Pharmakologie und Toxikologie, Ludwig-Maximilians-Universität, München, Germany
Summary
Drug consumption increases at advanced age due to increased morbidity. At the same time the state of repletion is reduced for several vitamins. Physiological and kinetic alterations in the elderly are reviewed in order to analyse possible interrelations between these two phenomena. At high age the status of all vitamins is compromised by reduced food intake. Decreased active intestinal transport and an increased propensity for atrophic gastritis may reduce the absorption of vitamins A, B1, folate and B12. Decreased exposure to sunlight and reduced cutaneous synthesis impair the vitamin D status. Studies on the state of vitamin repletion in hospital patients indicate a specific response of vitamins A, B1, B6 and C to drug administration at advanced age. Reduced food intake in the elderly is further compromised by drugs that impair appetite and absorption. Anticonvulsives and other drugs that induce hepatic microsomal enzymes accelerate vitamin D metabolism and aggravate postmenopausal osteoporosis. Acid inhibiting agents increase achlorhydria and reduce vitamin B12 absorption. Renal clearance of acidic drugs such as acetylsalicylic acid and barbituric acid, which is impaired at high age, is further reduced by high doses of vitamin C. Vitamin B6 reduces the therapeutic effect of L-dopa. When recognised, the negative effects of drug-vitamin interactions can be compensated by adequate vitamin supplementation and by adaptation of drug dosing.
Keywords
Interaction, vitamins, drugs, age
International Journal for Vitamin and Nutrition Research, Band 69, 1999, Heft 3, © Verlag Hans Huber AG, Bern
Institut für biologische Chemie und Ernährungswissenschaft, Universität Hohenheim, 70593 Stuttgart, Germany
International Journal for Vitamin and Nutrition Research, Band 69, 1999, Heft 3, © Verlag Hans Huber AG, Bern
Institute of Nutritional Science, Department of Pathophysiology, University of Bonn, Endenicher Allee 1113, 53115 Bonn, Germany
Summary
B-vitamin supplementation has previously been shown to lower the concentration
of plasma total homocysteine, a risk factor for cardiovascular disease.
Little is known about the homocysteine-lowering effects of low-dose B-vitamins
in elderly individuals, who are prone to higher homocysteine levels due
to advanced age and a greater frequency of impaired vitamin status.
We aimed to identify if and to what extent B-vitamins lower total homocysteine
and its subfractions in elderly individuals. Men and women (> 60 years)
received either B-vitamins (400 mg folic acid +1.65 mg pyridoxine +3 mg
cyanocobalamin) or a placebo daily for 4 weeks. Subjects in the vitamin
group showed a significant decrease in plasma total homocysteine during
the first 2 weeks; thereafter, total homocysteine only slightly decreased
further resulting in a geometric mean reduction of 16.3% (95% CI: 11.3%
to 21.0%) over the entire treatment period. Free homocysteine decreased
as well. However, the observed higher ratio of free/total homocysteine after
4 weeks of supplementation suggest a more pronounced reduction in protein-bound homocysteine.
Low-dose B-vitamin supplementation is effective in lowering homocysteine
in elderly individuals. Further studies are needed to be able to depict
the effect of B-vitamin supplementation on different homocysteine subfractions in plasma.
Keywords
Homocysteine, subfractions, elderly, supplementation, folic acid, vitamin B12, vitamin B6
International Journal for Vitamin and Nutrition Research, Band 69, 1999, Heft 3, © Verlag Hans Huber AG, Bern
F. Hoffmann-La Roche Ltd, Vitamins and Fine Chemicals Division, Human Nutrition & Health, 4070 Basel, Switzerland
Summary
This papers summarizes the main role vitamins are believed to play in
the prevention of osteoporosis, a common disease which is anticipated to
rapidly increase because of the aging of the population.
Vitamin D, the classical vitamin related to bone health, improves bone strength
mainly by increasing intestinal calcium absorption and reabsorption of calcium
by the kidney. Several intervention studies demonstrated in humans that
vitamin D can improve bone status as measured by bone density.
Vitamin C is considered an essential cofactor of collagen formation. Epidemiological
studies report a positive association between vitamin C intake and bone
density. Intervention studies on the effect of vitamin C on bone status
are missing.
Vitamin B6 could function as a cofactor to build up cross-links. In humans,
however, there is little evidence to support this.
Vitamin K is required for the biological activity of several coagulation
factors; the classical function of vitamin K. Recent research also points
to a role of vitamin K in bone metabolism. Vitamin K mediates the ¨-carboxylation
of glutamyl residues on several bone proteins, notably osteocalcin. Epidemiological
studies and results from first intervention trials are consistently suggesting
that vitamin K may improve bone health.
Keywords
Osteoporosis, vitamin K, vitamin C, vitamin B6, vitamin D, intervention, epidemiology, review
International Journal for Vitamin and Nutrition Research, Band 69, 1999, Heft 3, © Verlag Hans Huber AG, Bern
Jean Mayer-USDA Human Nutrition Research Center on Aging, Tufts University Boston, USA
Summary
Age-related cataract and age-related macular degeneration (AMD) are important public health problems. Approximately 50% of the 30 to 50 million cases of blindness worldwide result from unoperated cataract. In the US and other developed countries AMD is the leading cause of blindness, but age-related cataract remains the leading cause of visual disability. Age-related cataract and AMD represent an enormous economic burden. In the United States more than 1.3 million cataract extractions are performed annually at a cost of approximately $ 3.5 billion. Much of the experimental research on the etiology of cataract and AMD has focused on the role of nutritional antioxidants (vitamin C, vitamin E, and carotenoids). Evidence from epidemiologic studies support a role for nutritional antioxidants in delaying the onset of these age-related vision disorders. Although it is not yet possible to conclude that antioxidant nutrients have a role in prevention of cataract or AMD, a summary of the epidemiologic evidence suggests that it is prudent to consume diets high in vitamins C and E and carotenoids, particularly the xanthophylls, as insurance against the development of cataract and AMD.
Keywords
Vitamin C, vitamin E, carotenoids, antioxidants, cataract, maculopathy
International Journal for Vitamin and Nutrition Research, Band 69, 1999, Heft 3, © Verlag Hans Huber AG, Bern
Diabetesforschungsinstitut an der Heinrich-Heine-Universität, Auf'm Hennekamp 65, 40225 Düsseldorf, Germany
International Journal for Vitamin and Nutrition Research, Band 69, 1999, Heft 3, © Verlag Hans Huber AG, Bern
Max Planck Institute of Psychiatry, Munich, Germany
Summary
Several pathological conditions are believed to be causally related to the generation of reactive oxygen species and free radicals including various neurodegenerative disorders. In the histopathology of Alzheimer's disease (AD) many signs of oxidative reactions can be found building the basis of the oxidative stress hypothesis of AD. One major player in the generation of an overall oxidative microenvironment for the nerve cells is the amyloid b protein (Ab) of the senile plaques in brain areas affected in AD. Ab can be neurotoxic and this toxicity is mediated by peroxides and by the peroxidation of membrane lipids leading to the lysis of the cell. Consequently, lipophilic free radical scavengers such as vitamin E and the recently discovered antioxidant activity of the female sex hormone estrogen protects neurons against the oxidative toxicity of Ab and other AD-related oxidative insults. In a first clinical trial using vitamin E in therapy, this antioxidant could slow down the course of the disease launching further clinical investigations. Although antioxidants act as non-specific protective chemical shields for neurons and do not target specific pathological events, they are highly effective and further investigations on their activity might lead to an even more effective application of antioxidants. Since the knowledge of the pathways of neuronal cell death that occur during oxidative challenges is increasing, it will be of central interest how antioxidants can interfere with signal transduction mechanisms and therefore also modify genetic programs. As long as specific interventions are not available the optimistic data concerning the neuroprotective activity of antioxidants in vitro and in vivo underline an important role for antioxidative acting compounds for the prevention and therapy of oxidative stress-related conditions including AD.
Keywords
Vitamin E, oxidative stress, neuronal cell death, antioxidants, transcription factor NF-kB
International Journal for Vitamin and Nutrition Research, Band 69, 1999, Heft 3, © Verlag Hans Huber AG, Bern
Lady Sobell Gastrointestinal Unit, Wexham Park Hospital, Slough, United Kingdom
International Journal for Vitamin and Nutrition Research, Band 69, 1999, Heft 3, © Verlag Hans Huber AG, Bern
1 Institute of Clinical Pharmacology, Johann Wolfgang Goethe University, Theodor Stern Kai 7, 60590 Frankfurt, Germany 2 Department of Medicine I, Johannes Gutenberg University, Langenbeckstraße 1, 55131 Mainz, Germany
Summary
Because of the large liver stores (about 5 mg), low turnover rate (0.143%)
and small daily requirement (3 mg), vitamin B12 deficiency does not occur
under normal circumstances. This is not the case in individuals with chronic
inflammatory or trophic changes at vitamin B12 absorption sites. Without
supplementation, vitamin B12 deficiency can be expected within 5 years of
gastrectomy. Characteristic features of type A gastritis are hyposecretion
and mucosal atrophy in the fundus and body of the stomach, with absent intrinsic
factor. In the small intestine, active and/or passive absorption is impaired
by extensive ileal resection, exocrine pancreatic insufficiency and chronic
inflammatory disorders such as Crohn's disease. Definitive plasma concentrations
cannot be quoted for vitamin B12 deficiency. Dietary habits, subjective
symptoms, hematological laboratory results, function tests and gastrointestinal
endoscopic and histological findings must all be taken into account in the
diagnosis. Modern diagnostic parameters, such as methylmalonic acid and
homocysteine serum assays, are useful for achieving early diagnosis and
hence optimal treatment.
With their assured availability, parenteral vitamin B12 preparations remain
the treatment of choice. Results from vitamin B12 bioavailability studies
in healthy subjects suggest that > 300 mg probably suffices as an oral
maintenance dose after parenteral loading. Further well-documented cases
are needed in order to establish whether these doses are adequate in malabsorption
syndromes and gastrointestinal diseases. Various case reports indicate the
value of prophylactic and therapeutic oral vitamin B12 administration, especially
in disorders of homocysteine metabolism, a substance postulated as a further
important risk factor for atherosclerosis.
International Journal for Vitamin and Nutrition Research, Band 69, 1999, Heft 3, © Verlag Hans Huber AG, Bern
Department of Biochemistry, Swiss Vitamin Institute, University of Basel, Basel, Switzerland
International Journal for Vitamin and Nutrition Research, Band 69, 1999, Heft 3, © Verlag Hans Huber AG, Bern