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This symposium, organized by
Institut Rosell and the International Association of Bioinorganic
Scientists (IABS), provided an opportunity for leading scientists to
share their current work and discuss future research directions. The
symposium was an invaluable opportunity to further understanding of
minerals in nutrition, health and disease both within the scientific
community and among interested parties. The symposium was also a
venue for the presentation of the Klaus Schwarz Commemorative Medal,
given by IABS, for outstanding accomplishments in biological trace
element research. We were proud to hold a banquet in that honor.
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- Selenium: A trail of research
Dr. James E.
Oldfield, Ph.D.
Department of Animal Sciences
Oregon State
University, Corvallis, USA
The trail followed by
research into the biological properties of selenium has not been a
direct one; indeed it has doubled back on itself at least a couple
of times. First impressions were negative. Berzelius discovered
selenium in 1817 when he was looking into causes of worker illness
in a Swedish sulphuric acid plant, and its next emergence about a
century later, was as a poisoner of livestock on rangelands in the
north-central United States. Then, in 1957, Klaus Schwarz showed
that, at very low dietary levels, selenium was an essential
nutrient. Application of this knowledge was slowed in the U.S.,
however, by concerns of the Food and Drug Administration that
selenium might be a carcinogen. Further research dispelled these
fears and in fact evidence began to accumulate that selenium might
have anti-carcinogenic properties.
About mid-20th century,
studies with farm animals demonstrated that a number of metabolic
problems in domestic livestock were 'selenium-responsive,' that
is, they could be prevented or cured by supplemental dietary
selenium. These conditions included exudative diathesis and
pancreatic degeneration in poultry, hepatosis dietetica in pigs
and a myopathy called 'white muscle disease,' which occurred
across a number of animal species, including ruminants. In the
course of investigating the effects of selenium on these
conditions, it became evident that selenium was essential for both
normal growth and reproduction in animals, and selenium
supplementation became an accepted practice in areas of selenium
deficiency, worldwide.
The success of selenium
supplementation in farm animal production naturally raised
questions as to whether it might also confer health benefits to
humans. The immediate response to this question was that human
benefits would be unlikely due to the marked differences in animal
and human diets. Whereas animals, and particularly grazing
species, often consumed a single-source diet (e.g., pasture or
range forage), the human diet comes from multiple sources and
diverse production areas which tended to reduce the likelihood of
a selenium deficiency. Some evidence of selenium deficiency among
people raising their own food crops did occur, however, in China
as Keshan disease - a cardiomyopathy - and Kashin-Beck disease, or
"big joint."
But studies with slightly higher levels of
dietary selenium than were necessary to meet nutritional needs,
suggested that at such levels of intake, selenium might be
protective against some of the troublesome diseases of humans,
including cardiovascular disease and certain types of cancer.
Impressive evidence came from a large-scale, human study run by
the University of Arizona's Cancer Center in which significant
reductions were demonstrated in cancers of the lung, colo-rectum
and prostate. Further, international trials are now planned to
confirm or deny these initial results.Original studies at North
Carolina showed recently that selenium deficiency also contributed
to the pathogenicity of certain virus species, and selenium was
suggested to be a stimulant of the body's immune system.
The health-protective effects of selenium have generated
interest in the selenium status of foods and populations around
the world and much of this information has been gathered together
in a Selenium World Atlas. It is obvious that there are great
differences in selenium availability in different areas and that
selenium deficiencies, according to accepted standards are
extensive and occur worldwide. With this information as a base,
various methods of selenium supplementation have been devised and
two small countries, Finland and New Zealand, each of which
include extensive areas of selenium deficiency, have embarked on
programs of adding selenium to fertilizers, on a national basis,
to bring selenium contents of feed, food and forage crops up to
levels considered adequate. We now have available, therefore,
workable techniques for supplementing selenium directly to
individuals, or indirectly in improving the selenium status of
food and feed crops.
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- Amounts and sources of Selenium for maximum human
health
Dr. Philip D. Whanger, Ph.D.
Department of Agricultural Chemistry
Oregon
State University, Corvallis, USA The recommended daily allowance
(RDA) for selenium has been set at 55 micrograms per day, but
there is evidence that additional selenium will result in improved
human health. Significant reductions in prostate, colon and lung
cancers were found when American subjects were supplemented with
200 micrograms of selenium per day as selenium enriched yeast.
This suggests that levels of selenium above the RDAs are
beneficial. Selenomethionine is usually the predominant form of
selenium in enriched yeast, but animal data suggests that this may
not be the most effective form against tumors.
Selenium
enriched garlic was recently shown to be twice as effective as
enriched yeast in reduction of chemically induced mammary tumors
in rats. The primary form of selenium in enriched garlic was shown
to be Se-methylselenocysteine, which is consistent with data where
pure compounds of selenium were investigated in the reduction of
mammary tumors. Enriched broccoli florets and sprouts, onions and
wild leeks also reduced chemically induced mammary tumors in rats.
The major form of selenium in these enriched plants was determined
to be also Se-methylselenocysteine, suggesting that plants with a
high content of this methylated selenocompound may be more
effective in the prevention of cancer than sources with
selenomethionine as the major selenocompound.
A method is needed
to monitor the selenium status for people who take excess
selenium. Glutathione peroxidase, selenoprotein P and albumin are
the major selenium containing components in plasma. With adequate
intakes of selenium, selenoprotein P contains over 60% of the
plasma selenium, but with excess intakes the amount in albumin
increases with the production of a fourth plasma fraction. The
content of selenium in this fourth fraction is suggested as a
method to predict impending selenium toxicity. Further research is
needed to fully evaluate the sources of selenium, which are most
effective in reduction of cancer in humans.
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Selenium in human Health: An overview
Dr.
Margaret P. Rayman, Ph.D. School of Biomedical and Life
Sciences University of Surrey, Guildford, England. The essential trace element selenium has
recently revealed exciting new aspects, both in terms of its
metabolic roles and of its relevance to human health. In addition
to the well-known enzymic activities, new health-related functions
have been identified for some selenoproteins. For instance,
important roles in the male reproductive system have been
suggested for at least three selenoproteins, either protective
(redox enzymes) or structural. In this context, concern
has been expressed that selenium levels are now relatively low in
many European countries. UK daily selenium intake, for instance,
is now between 29 and 39 mcg while the figure is around 42 mcg for
Denmark and 31 mcg for Sweden. (For comparison, the UK Reference
intake is 75 mcg/day for men and 55 mcg/day for women, while the
American RDA for selenium is 55 mcg/day for both men and women.)
Blood and plasma selenium levels are correspondingly low in many
parts of Europe. Adequate selenium levels are important
because selenium is known to be crucial to human health, partly
through the known functions of the selenoproteins referred to
above, but also through mechanisms, which are not yet fully
understood. There is now considerable evidence that selenium plays
a key role in the functioning of the immune system. Theoretical
considerations indicate that several T-cell-associated genes, such
as that for the IL-2 receptor ?-subunit, can encode
selenoproteins. Se has been shown to increase the number of IL-2
receptors on the T-cell surface in various systems, thereby giving
an enhanced response to IL-2. (IL-2 acts on T-helper cells to
increase the proliferation and lytic activity of other cells of
the immune system.) Recent work on viruses has led to some
surprising findings. Beck and co-workers showed that in a
selenium-deficient host, harmless viruses can become virulent but
that glutathione peroxidase (GPx1) is able to protect against this
development of virulence, which is believed to result from
oxidative damage to the RNA viral genome. Baum and colleagues have
related an adverse outcome in HIV infection to poor selenium
status. Moss and Taylor have separately provided evidence that
viruses themselves can make glutathione peroxidase homologues, the
implications of which are yet to be fully realized.
Selenium is essential for successful reproduction.
Miscarriages have been shown to be associated with low serum
selenium while selenium supplementation has increased sperm
motility in sub-fertile men. That brain function is dependent on
Se is shown by its preferential supply to that organ when Se is
limiting. Human studies have linked depression and other adverse
mood states to Se deprivation.
There is persuasive epidemiological
evidence that selenium reduces cancer risk. A recent double-blind
placebo-controlled study by Clark and colleagues in the US, showed
that in those taking a selenium supplement, there was a 50%
reduction in cancer mortality, and a 37% reduction in cancer
incidence with the risk of prostate, colorectal and lung cancers
being reduced by 63%, 58% and 46% respectively. The strongest
treatment effect was observed in subjects in the lowest tertile of
plasma Se at baseline, a category into which the whole UK
population and a number of other European populations would fall.
Further independent evidence to suggest that Se status is sub-
optimal in populations of adults in the US (and by implication, in
many other European countries where dietary intakes and plasma
levels of Se are substantially lower) has been afforded by the
prospective study by Walter Willett's group at Harvard. This
showed a 65% reduction in the risk of advanced prostate cancer
among men with the highest, as compared to the lowest, Se status
(by quintile of toenail Se). Major US and international trials are
now planned to see if the results of the Clark study can be
replicated in other populations. Pilot studies for the PRECISE
trial are well advanced in Denmark and the UK, in the latter case
funded by the generosity of the Cancer Research Campaign.
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The biological effects of dietary Selenium in humans:
Can Selenium supplementation decrease the risk of chronic
diseases?
Dr. Wayne C. Hawkes, Ph.D. USDA-ARS
Western Human Nutrition Research Center University of
California, Davis, California, USA. Although selenium has been recognized as an
essential animal nutrient for nearly half a century, selenium's
health benefits in humans are still debated. Selenium
supplementation has increased many-fold since the NPC trial
reported dramatic reductions in secondary cancer endpoints in
1996. We conducted a confined study with 11 men fed
conventional foods naturally high or low in selenium to control
intake at 47 µg/d for the first 3 weeks, then either 13 µg/d or
297 µg/d for 14 weeks. Blood plasma selenium decreased 40% and
increased 70%, respectively. Food selenium had no discernible
effect on antioxidant status, oxidative damage, glucose
metabolism, ketone bodies, immunoglobulins, iron status, or blood
clotting, as were reported for other forms of selenium.
High selenium decreased T3, increased TSH, and caused
isocaloric weight increase, while low selenium increased T3,
increased serum triglycerides, decreased body fat, and caused
isocaloric weight loss. Sperm motility decreased 35% with high
selenium and increased 18% with low selenium. Seminal plasma
selenium changed markedly, but sperm selenium and serum androgens
were unchanged, suggesting involvement of the accessory sex
glands. Neutrophils decreased with high selenium and increased
with low selenium, but increases in cytotoxic T lymphocytes and
activated lymphocytes with high selenium only approached
significance. B-Lymphocyte mitogenesis was stimulated 7 weeks
earlier with high selenium.
We
have started a 2-year study of high-selenium yeast (300 µg/d) in
48 healthy men to test our preliminary observations on energy
metabolism and sperm motility. We are also measuring lymphocyte
gene expression and immune function to understand how selenium may
protect against cancer, and brachial artery responsiveness as an
index of vascular health. This year, we will start a pilot study
of high-selenium yeast in 200 volunteers age 60-74 to obtain
preliminary data on cancer biomarkers and carotid artery
thickening in preparation for full-scale prevention trials.
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The role of Selenium in HIV / AIDS Dr.
Marianna K. Baum, Ph.D. School of Health Florida
International University, Miami, Florida, USA. The trace element, selenium, is essential for
maintaining a viable and responsive immune system. Selenium
supplementation has been shown to significantly reduce cancer
mortality and be protective against a number of viral pathogens in
a variety of clinical settings. Recent reports indicate that
selenium status is predictive of HIV-1 related prognosis, and may
have an important role in preventing HIV-1 replication. Our
studies in HIV-1 seropositive drug users demonstrate that selenium
is a powerful predictor of HIV-1 disease progression and
mortality. These findings suggest that selenium administered as a
chemopreventive agent may effectively modulate HIV disease
progression. Moreover, our previous experience and the literature
indicate that administering selenium in nutritional doses is
feasible and safe in HIV-1 infected individuals. The role
of selenium in HIV-1 infection appears to be multifactorial. As a
biological antioxidant, selenium is required for the activity of
glutathione peroxidase. Adequate selenium status may also be
essential in controlling viral emergence and evolution. In
addition, adequate selenium may enhance resistance to infection
through modulation of interleukin (IL) production and subsequent
changes in Th1/Th2 cytokine responses. Other nutritional factors
may be interacting with selenium status, and contribute to the
HIV-1 progression and mortality.
Controlled clinical trials in HIV seropositive
individuals are needed to determine whether supplemental selenium,
as a chemopreventive agent, can enhance the immune system and
reduce viral load to slow HIV-1 disease progression. Preliminary
data from on-going selenium supplementation trials will be
presented.
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Zinc and cell mediated immunityDr.
Ananda S. Prasad, Ph.D. Professor of Medicine, Wayne State
University University Health Center, Detroit, Michigan, USA.
Zinc (Zn) is known to play a central role in the immune
system and Zn deficient individuals experience increased
susceptibility to a variety of pathogens. The immunological
mechanisms whereby Zn modulates the increased susceptibility to
infection have been studied for two decades. Zn affects multiple
aspects of the immune system from the barrier of the skin to gene
regulation within lymphocytes. Zn is crucial for normal
development and function of cells mediating non-specific immunity
such as neutrophils and natural killer cells. Zn deficiency also
affects development of acquired immunity by preventing both the
outgrowth and certain functions of T cells such as activation, Th1
cytokine production, and B cell help. Likewise, B cell development
and antibody production, particularly IgG, is compromised. The
macrophage, a pivotal cell in many immunological functions, is
adversely affected by Zn deficiency, which can dysregulate
intracellular killing, cytokine production, and phagocytosis. Zn
deficiency affects the development of acquired immunity by
regulating growth and function of T and B cells. Zn is needed for
DNA replication, RNA transcription, cell division, and cell
activation. Apoptosis is potentiated by Zn deficiency and Zn also
functions as an antioxidant and can stabilize membranes.
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Calcium uptake and cell proliferation in cultured
murine fibroblasts are impaired by Zinc
deprivationBoyd L. O'Dell, Ph.D. Biochemistry and
Nutritional Sciences University of Missouri, Columbia,
Missouri, USA. This project is a continuation of our goal
to determine the first limiting function of zinc, following its
deprivation. Zinc deficiency leads to platelet malfunction due to
impaired calcium uptake and to impaired nervous system function,
which is associated with impaired calcium uptake by brain synaptic
vesicles. Both cell colony growth rate and the mitogenic effect of
insulin-like growth factor-I (IGF-I) in cultured fibroblasts are
dependent upon available zinc. The purpose of this study was to
determine if zinc dependence of the proliferative process is
related to impaired calcium uptake. Swiss 3T3 cells were deprived
of zinc during the IGF-I stimulation phase of the cell cycle by
addition of a zinc chelator, DTPA (0.6 mM), to serum-free
Dulbecco's Modified Eagles's Medium (DMEM). Control medium
contained in addition 0.4 mM Zn. Ca uptake was measured by the
10-min uptake of 45Ca in cells after pretreatment with PDGF and
EGF and stimulation with IGF-I. The interaction of a calcium
channel blocker and available zinc, as regards DNA synthesis
(Thymidine incorporation) and Ca uptake, were determined by
addition of verapamil (50 ??????he essentiality of Ca for DNA
synthesis and colony growth were determined by addition of DTPA
and Zn to a modified DMEM that contained no Ca except that
supplied by 10% calf serum. The results showed that IGF-I
stimulated Ca uptake by 3T3 cells only in the presence of
available Zn. Verapamil inhibited both thymidine incorporation and
Ca uptake in the presence of available Zn but had no effect beyond
that of Zn deprivation. A low concentration of available Ca in the
medium impaired colony growth and thymidine incorporation in a
manner analogous to that of Zn deprivation. In summary, Zn
deprivation impairs cell proliferation by a mechanism that
involves malfunction of the plasma membrane in the uptake of
calcium, which serves as a second messenger. There is also a class
of food known as "medical foods", but these will not be discussed
here.
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Advances in Copper research
Dr. Leslie M.
Klevay, Ph.D. USDA, ARS, Grand Forks Human Nutrition Research
Center Grand Forks, North Dakota, USA. The Western
diet, so closely associated with heart disease risk, is often low
in copper when compared to suggested intakes and to diets proven
insufficient for men and women in controlled experiments. Heart
disease is the most likely result of this dietary situation
because copper deficiency is the only nutritional insult that
elevates cholesterol, blood pressure and uric acid, has adverse
effects on electrocardiograms, impairs glucose tolerance, promotes
thrombosis and to which males respond differently than females.
Nearly 80 anatomical, chemical and physiological similarities
between animals deficient in copper and people with ischemic heart
disease have been identified. Some of the effects on heart disease
of aspirin, beer, homocysteine and salt may reflect changes in
copper utilization.
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Physiology of mineral enriched yeast
Dr.
Graeme M. Walker, Ph.D. School of Science &
Engineering University of Abertay-Dundee, Dundee, Scotland,
England. Yeasts are microorganisms, which represent
valuable supplements to the human diet. This is not simply due to
provision of cellular proteins, carbohydrates, vitamins etc by
yeast, but also to the propensity of yeast cells to accumulate a
variety of nutritionally useful metal cations. Easily-grown and
readily available species such as the baker's yeast, Saccharomyces
cerevisiae, are excellent natural sources of essential metals
(e.g. K, Mg, Ca, Mn, Fe, Zn) and this yeast can be further
"enriched" with other inorganic micronutrients, including selenium
and chromium. Such mineral-enriched yeasts may serve as effective
carriers of key trace elements in alleviation of occasional
inorganic dietary deficiencies in humans and animals. In
order to maintain their viability and vitality, yeast cells adopt
several strategies for transporting and localizing
growth-requiring metal ions and additional strategies exist for
neutralizing potentially cytotoxic metals, depending on the
prevailing environmental conditions. The molecular biology of
several yeast transmembrane ion transporters has been studied and
it has recently been established that some metal ion transport
mechanisms (e.g. for iron and copper) are remarkably similar in
both yeast and human cells. In fact, S. cerevisiae is now regarded
as an invaluable model eukaryotic organism for studies of human
disorders linked to dysfunction of metal ion homeostasis (e.g.
Menkes disease).
In
addition to serving this important role in fundamental studies of
cell physiology and pathophysiology, yeasts are finding
increasingly significant practical roles in several diverse areas
of bioinorganic science and technology. For example,
mineral-enrichment of yeast cells is relevant environmentally (in
the bioremediation of heavy metals), industrially (in fermentation
processes) and medically (in provision of trace
elements/functional foods). Results will be presented which
specifically deal with mineral enrichment of S. cerevisiae cells,
including protocols for optimizing bioaccumulation of magnesium
and zinc. This presentation will also discuss the basic cell
physiology of metal accumulation by yeast and will address the
exploitation of yeast-metal interactions by industrial
biotechnologists and human nutritionists.
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Insulin, glucose intolerance and diabetes: the
Chromium connectionDr. Richard A. Anderson, Ph.D.
USDA, ARS, Beltsville Human Nutrition Research
Center Beltsville, Maryland, USA Insulin insensitivity, leading to glucose
intolerance and ultimately diabetes is widespread in the US and
other westernized countries. Diabetes is one of the leading causes
of death and increases in blood glucose are associated with
increases in the incidence of cardiovascular diseases, the leading
cause of death in the western world. It was estimated that there
were 143 million people worldwide with diabetes in 1998, which was
almost 5-fold, that of 1983. Genetics play a role in
diabetes but certainly cannot be used to explain increases in the
incidence of diabetes of several-fold in a decade. Diet, and
lifestyle seem to be major contributing factors in the rapid
increases in glucose intolerance and diabetes. One nutrient that
is low in many modern diets that are high in refined sugars and
fats is chromium. High sugar diets are not only low in chromium
but enhance chromium losses. Chromium has been shown to reverse
the signs and symptoms of varying stages of glucose intolerance
ranging from hypoglycemia to type 2, gestational and
steroid-induced diabetes. Chromium functions by improving insulin
function, which leads to a normalization of blood glucose.
Improved chromium nutrition leads to increases in insulin binding,
increases in insulin receptor number and activation of insulin
receptor kinase leading to increased insulin sensitivity.
Improvements in humans associated with improved chromium
nutrition that have been documented in farm animals include
increased insulin sensitivity, increased HDL- cholesterol,
decreased total, LDL and VLDL cholesterol, decreased percent body
fat and increased lean body mass. More severe signs of chromium
deficiency observed in humans on total parenteral nutrition such
as nerve and brain disorders have not been documented in farm
animals. The magnitude of the improvements due to improved
chromium nutrition have ranged from normalization of blood glucose
in people with mild glucose intolerance to improvements in
hemoglobin Alc from 8.5 ± 0.02% to 6.6 ± 0.1% in people with type
2 diabetes to reversal of nerve and brain disorders in people on
total parenteral nutrition. However, several studies have reported
no beneficial effects due to supplemental chromium.
There are numerous causes of glucose
intolerance and diabetes and since chromium is a nutrient and not
a drug, it will only be of benefit to those whose abnormalities in
glucose and insulin metabolism are related to suboptimal intakes
of chromium.
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The essentiality of LithiumDr. Gerhard
N. Schrauzer, Ph.D. Department of Chemistry and
Biochemistry University of California, San Diego, California,
USA. Lithium is normally
present in trace amounts in both food and water, but daily intakes
vary significantly depending on location and the type of food
consumed. In rats maintained on lithium deficient diets,
deleterious effects on reproduction, lactation, activity, and
social interactions have been observed. In goats, lithium
deficiency resulted in reproductive abnormalities, increased
abortion rates, diminished weight gains and shorter life
expectancy.
In humans, defined lithium deficiency
syndromes so far have not been described. However, inverse
associations have been observed between lithium concentrations in
drinking water and the rate of mental hospital admissions,
homicide, suicide, rape, arrests for drug use, and in juveniles,
with the rate of runaways from home. Results of supplementation
studies indicate that lithium, in the nutritional dosage range,
has mood- improving and stabilizing effects.
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The emergence of Boron, Nickel, Silicon, Vanadium and
Arsenic as elements of nutritional and pharmacological
relevance
Dr. Forrest H. Nielsen, Ph.D. USDA, ARS,
Grand Forks Human Nutrition Research Center Grand Forks, North
Dakota, USA If the lack of
an element cannot be shown to cause death or interrupt the life
cycle, many scientists do not consider that element essential
unless it has a defined biochemical function. Furthermore, the
nutritional community is reluctant to provide dietary guidance for
any element without a defined function, which can help indicate
status. Not being accepted as essential and not having dietary
guidance such as a Dietary Reference Intake (DRI) often is equated
to not being nutritionally important. This is unfortunate
because several mineral elements have recently been shown to have
beneficial effects at nutritionally relevant intakes in animals
and sometimes in humans; these elements include boron, nickel,
silicon, vanadium and arsenic. Nutritionally relevant
intakes of boron have been found to affect biochemical indicators
in humans related to bone turnover, physiological indicators of
psychomotor and cognitive function, and blood cellular
composition. Recent research with animals has shown that boron is
needed in the early stage of life; this includes the demonstration
that the lack of boron adversely affects reproduction and embryo
development in both the African clawed frog and zebrafish.
Findings from animal experiments with nickel suggest it is
beneficial to cardiovascular health. Nickel deprivation affects
the response of the rat to excessive intakes of methionine and
deficient intakes of vitamin B12. Recently, it was found that
nickel deprivation of rats increased blood pressure and
exacerbated the response to a high salt intake and an acute salt
load. Some of the findings suggest that nickel is physiologically
important in functions involving the cyclic GMP signal
transduction system. The distribution of silicon in the
body and the biochemical changes in bone cause by silicon
deprivation indicate that silicon influences bone formation by
affecting cartilage composition, and ultimately the initiation of
cartilage calcification and the regulation of bone crystal growth.
Evidence is emerging suggesting that there are nutritionally
relevant dietary silicon intakes that positively influence bone
mineral density in postmenopausal women. Also, because silicon
affects collagen formation, it may influence wound healing.
On the basis of its functional roles in lower forms of
life, vanadium possibly is important for some enzyme reactions in
higher animals and humans. Vanadium is receiving much attention at
present as an element that can be used therapeutically for
diabetes.
The
responses of experimental animals to arsenic deprivation suggest
that this element affects the utilization of labile methyl groups
arising from methionine. Low arsenic intakes have been suggested
to result in hypomethylation of DNA, which has been associated
with an increase risk for some types of cancer. These elements
might be of more practical nutritional importance that the
nutritional community acknowledges at present.
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Regulatory Considerations for labeling foods and
supplements with health statements in the U.S.
Dr.
Mary E. Sanders, Ph.D. Dairy and Food Culture
Technologies Littleton, Colorado, USA. Consumers in the
United States are very interested in foods and dietary supplements
that can enhance their health. Food regulators in the United
States are very interested in making sure food is safe and labeled
in a truthful and not misleading manner. Sometimes efforts of
companies to provide "functional foods" for consumers are thwarted
by regulatory barriers. Regulatory issues can be central to the
development of new, healthful food products. The avenues available
to a company to label and promote a product have much to do with
the success of the product. In the end, a company must perceive
that the expected return on development of a new product will
warrant the required investment. In the U.S., many companies are
discouraged from investment in costly efficacy or mechanistic
research by regulatory restrictions on labeling and promotion.
In the U.S. there is no legal definition of "functional
food". There are drugs and conventional foods, and since 1994, a
subset of conventional foods, known as dietary supplements . Each
of these categories is regulated differently. Many dietary
supplements have been marketed using a type of health statement
known as a "structure/function" claim. In recent years, the FDA
has made it clear that structure/function claims are also
allowable on conventional foods. Since dietary supplements are
allowed to take the form of a conventional food, in the end, the
differentiation of a product as a food or as a dietary supplement
is based on how the product is represented to the consumer.
Although the common U.S. consumer impression is that labeling on
dietary supplements is not regulated, according to the Dietary
Supplement Health and Education Act, structure/function statements
must meet the truthful and not misleading standard. However, no
FDA standards exist that define the type of evidence that is
needed to satisfy the "truthful and not misleading" criteria for
labeling products with structure/function statements.
This talk will focus on a
review of the regulatory structure of foods and supplements in the
United States. Issues surrounding use of health statements on
these products' labels will also be discussed. The impact of
recent actions, including the Pearson and Shalala Supreme court
decision, the FDA Modernization Act and newly allowed health
claims will be presented. Finally, the possible role of 3rd party
review in safety and efficacy determinations will be discussed.
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