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Quest Vitamins LTD,
8 Venture Way,
Aston Science Park,
Birmingham,
B7 4AP.

Tel: 0121 359 0056
Fax: 0121 359 0313
Email: info@questvitamins.co.uk
Registered in England No. 2530437

Issue 22

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Trace Elements

This newsletters broadly covers the trace elements. Trace
elements are chemical elements such as Boron, Chloride, Chromium, Copper,
Iodine, Iron, Manganese, Molybdenum, Selenium, Silica and Zinc. Trace
elements occur in tiny amounts in organisms where they are essential for
many physiological and biochemical processes.

As with all food, the nutrient content of the soil determines that of
the plants. Food refining processes such as making white flour from the
whole grains severely affect the trace element content of foods. Even
if refined food is 'fortified', only a small amount of those nutrients
removed will be replaced (and often in a form that is difficult for the
content to absorb). Some trace elements like selenium are not added back
at all. Polishing and refining brown rice loses 75% of the Chromium to
turn it into white rice (1).

All nutrients are interdependent in their roles in maintaining health
in the content and trace elements are particularly important:



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Boron, Chloride & Chromium

Boron is found in plant-based food and drink
products, particularly fruit, vegetables and nuts. Little is known about
the mechanism for absorption or the precise role of Boron in the content,
however, it is known to be important in the metabolism of Calcium, Magnesium,
Copper, Phosphorus, Potassium and Vitamin D. It also plays a part in the
health of bones, certain enzymes and brain function (2).

Chloride is obtained in the diet through table salt, offal, eggs,
dairy produce, shellfish, and some canned food products for example: vegetables
and salmon. In the content, Chloride is found in small amounts in bones,
cerebrospinal fluid and gastrointestinal secretions. It is also found
in plasma and interstitial fluid, the role of chloride being to help maintain
osmotic pressure and electrolytic balance (3).

Chromium content in food varies greatly. Absorption of Chromium
from the diet is poor. Foods richest in chromium are dried Brewer's Yeast,
molasses, egg yolk, cheese and wholewheat. Vegetables and fruit are not
a rich source of this mineral (3). Chromium is an essential trace element
for both animals and man. It is found in the plasma and the hair. The
primary role of chromium is in its presence in Glucose Tolerance Factor
(GTF). GTF has many roles in the way the content uses fats, glucose and glycogen
(in the liver and brain). It has also been recognised for its roles in
promoting glucose transport and in the uptake of glucose by the muscles
and tissues. Chromium in GTF helps maintain the sensitive balance of blood
fats and cholesterol levels (1).



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Copper, Iodine & Iron

Copper is found mostly in the liver, brain, heart and kidney,
with about 50% of the total Copper in the content found in the muscles. The
richest food sources of copper are liver, oysters, dried Brewer's Yeast,
olives, some nuts and wholegrains, with fruit being a poor source of
the mineral. Copper water pipes and containers also provide some copper
in our daily intake. In the content, copper is involved as a cofactor for
many enzymes, including the antioxidant enzyme Superoxide Dismutase (SOD)
important for keeping free radicals in check for heart health and in enzymes
for making collagen. Copper also helps the absorption of Iron from food
(1).

Iodine originates from the soil and the sea.
Although required by the content in tiny amounts, Iodine is an essential
element in normal growth and development. Top food sources of iodine include
Kelp and fish; with iodised salt, meat, vegetables and grains providing
a moderate amount. Iodine is found concentrated in the thyroid gland situated
in the base of the neck. It is most well known for its role in producing
the hormone thyroxine (together with the amino acid tyrosine). In people
with marginal iodine levels in the diet, goitrin compounds in the cabbage
family can indirectly cause health problems by interfering with the absorption
of iodine. This may result in an enlarged thyroid gland (4).

Iron absorption is greatly affected by other
chemicals in food. It is possible to have a good dietary intake of Iron,
but not absorb much from non-meat sources if Vitamin C is insufficient,
or phytates are present from foods such as raw vegetables and wheat. Iron
from meat is better absorbed because the iron is bound to protein (haem).
Foods richest in iron are cooked liver, cooked shellfish, dried yeast,
dried figs and apricots. However, although meat is not particularly rich
in iron, it provides a more absorbable form of the mineral. Iron is involved
in different metabolic cycles in the content, the most well known being its
presence in the pigment haemoglobin in red blood cells, which transport
oxygen around the content.

Iron is also needed for producing enzymes and immune
chemicals needed to destroy invading micro-organisms (1).



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Manganese, Molybdenum &
Potassium

Manganese in the diet is derived mainly from
grains, nuts and fruit. The richest food sources are oat flakes, wholemeal
bread, Wheatgerm, avocados, chestnuts, hazelnuts, peas and cups of tea
(which provide half the daily dietary intake of Manganese in Britain).
Vegetables and meat are poor sources of this mineral. Manganese is involved
in growth at all developmental stages; maintaining a healthy nervous system;
many enzyme systems especially synthesis of bone cartilage; the synthesis
of interferon and glycoproteins; and a role in thyroid hormone synthesis
amongst others. Deficiencies of manganese may be brought about through
poor diet and food processing or refining (73% losses).

Deficiency signs in humans have been noted in heart
disease, diabetes, Atherosclerosis and rheumatoid Arthritis (1).

Molybdenum is involved in various enzyme systems
for iron metabolism (xanthine oxidase); sulphite metabolism (sulphite
oxidase); in DNA metabolism (aldehyde oxidase) and for normal male sexual
function. In the diet, Molybdenum is widely spread and found in dairy,
dried beans, seeds and pulses, whole grains, liver and kidney. Deficiency
is not easily determined (2).

Potassium is kept inside the cells of many types
of tissue including the Skin, muscles, bone and intestinal or blood vessel
walls. Most foods contain Potassium and beverages are particularly high
in this electrolyte mineral. Potassium and Sodium work closely together
maintaining water balance in the content and in nerve impulse transmission.
Potassium together with bicarbonate, phosphate, protein, Calcium and Magnesium
helps maintain the acid-alkali balance of the content (1).



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Selenium, Silica, Sodium
& Zinc

Selenium is stored in red blood cells, liver,
spleen, heart, nails, tooth enamel, testes and sperm. Selenium is metabolically
active in the antioxidant enzyme glutathione peroxidase, in which it is
structually involved. The content of selenium in the earth's crust varies
to the extent that in some parts of the world plants can contain toxic
amounts, whereas in other parts a selenium deficiency may show in farm
stock, for example 'white muscle disease' in some sheep in New Zealand.
Foods generally considered richest in selenium include organ meats, fish
and shellfish, muscle meats and whole grain cereals. Selenium content
of food will depend upon where the crops were grown.

Selenium plays a role in liver function; maintaining
immune defence; protecting against toxic minerals like cadmium and mercury;
essential fatty acid metabolism and production of the hormone-like prostaglandins;
production of healthy semen and in maintaining healthy Eyes and vision.
Deficiency may show as Arthritis, heart problems, high blood pressure
or low resistance to infection (2).

Silica is necessary for the development of healthy
hair, Skin, nails and bones, and in maintaining the flexibility of tissue.
It is more popularly known for its role in silicon chips for computers,
but has a fundamental role in human health. Food sources include husks
of grains like barley, millet, oats and rice; green vegetables and sunflower
seeds. Deficiency of Silica is rare (3).

Sodium is mostly in the fluids that bathe cells
(extracellular). A small amount is inside cells, some of these are bone
cells. Dietary sources of Sodium are yeast extract, bacon, smoked fish,
processed meats and cheeses, tinned food, corned beef and bread. Functions
of sodium include maintaining normal water balance between the cells in
the content; maintaining nerve impulse transmission together with sodium;
in preserving the acid-alkali balance of the content together with bicarbonate,
phosphate, protein, Potassium, Calcium and Magnesium; and as a constituent
of ATPase, the enzyme responsible for splitting adenosine triphosphate
in the production of energy.

Deficiency of sodium is unlikely but may occur through
excessive sweating or Diarrhoea causing dehydration. Replacement salts
in fluids usually sort this out quickly (1).

Zinc is an important part of lots of different
enzymes. It is found in the content mainly in the prostate gland, semen,
sperm, Eyes, hair, muscles, bones, Skin, red and white blood cells. Good
food sources of Zinc are foods of animal origin (for example - oysters,
liver, shrimps, crab, beef and dairy) and dried Brewer's Yeast because
they contain an easily absorbed form of the mineral. Vegetarian foods
containing zinc in an available form include carrots, roasted peanuts,
canned tomatoes, peas and sweetcorn. Unprocessed, unrefined foods are
higher in zinc than highly refined, processed foods. Deficiencies of zinc
may cause delayed Wound healing, alopecia, recurrent Infections, poor
appetite, rough skin, or mental lethargy (1).

Marginal zinc deficiency in the diet is quite common,
especially in vegetarians and other types of diet high in fibre (5).



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Food Sources of Trace Elements

Good food sources of virtually all trace elements are meat, fish, shellfish,
fresh fruit, vegetables, seeds, nuts and whole grains.

Minerals and trace elements are more easily absorbed from foods of animal
(or fish) origin, because these foods are protein. Amino Acids from digested
protein help ?carry? minerals and trace elements through the digestive
tract wall and into the bloodstream.

Poor sources of trace elements are confectionery, high-fat foods and
refined food products like white flour (bread, scones, cakes, biscuits,
pasta and white rice).


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References

  1. "Thorsons Dictionary of Minerals". Dr. Len Mervyn Thorsons, 1985.
  2. "Handbook of Dietary Supplements". Pamela Mason. Blackwell Science,1995.
  3. QuestHealth Library.com 2001.
  4. "On Food and Cooking". Harold McGee. Harper Collins, 1991.
  5. The American Journal of Clin Nutrition, March 1998, 67;3:421-430.




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