The science of foods and their components (nutrients and other substances) including the relationships to health and disease (actions, interactions, and balances) processes within the body (ingestion, digestion absorption, transport, and disposal of end products) and the social, economic, cultural and psychological implications of eating. Nutrition facts are a portion of the food label that states the content of selected nutrients in a food in a standard. By law, Nutritional Facts must appear on nearly all processed food products in Canada.
Amino Acids: Amino acids, called
also, the "building stones of the body," are much talked about today. Indeed,
it begins to look as though they are now to go through the same over-emphasis,
high pressure consideration and commercial exploitation that the vitamins are
just now beginning to emerge from. Already synthetic amino acids and amino
acids extracted from food sources are offered for sale to the food-conscious
public. These offers are accompanied with the usual misleading and unfounded
claims for their superior virtues. The body cannot absorb any protein as such.
If protein is absorbed directly into the blood stream, without first undergoing
the processes of digestion, it is poisonous. Proteins must be broken down into
simpler compounds known as amino acids before they can be absorbed and
assimilated. Introduce the amino acids out of which proteins are made and all
is well.Antioxidants: Just like rust
on a car, oxidation can cause damage to cells and may contribute to aging.
Antioxidants help prevent oxidation, may help increase immune function and
possibly decrease risk of infection and cancer. Antioxidants exist as
vitamins, minerals and other compounds in foods. A few of the better known
antioxidants include carotenoids--the substance that gives fruits and
vegetables their deep rich colors. Apricots, broccoli, pumpkin, cantaloupes,
spinach and sweet potatoes, are some good choices in addition to lycopene in
tomatoes. Vitamin C and E are also good antioxidants, as well as, magnesium,
copper and zinc. Increasing the foods you eat is the first step in getting
more antioxidants.
Beta Carotene: Beta-carotene is
the molecule that gives carrots their orange colour. It is part of a family
of chemicals called the carotenoids. Beta-carotene is a substance from plants
that the body converts into vitamin A. It also acts as an antioxidant and an
immune system booster. Beta carotene is one of more than 600 carotenoid
compounds found in animals, plants and microorganisms.Biotin: Biotin, a water-soluble
B vitamin, acts as a coenzyme during the metabolism of protein, fats, and
carbohydrates. Good dietary sources of biotin include organ meats,
oatmeal, egg yolk, soy, mushrooms, bananas, peanuts, and brewer's yeast.
Bacteria in the intestine produce significant amounts of biotin, which is
probably available for absorption and use by the body. Biotin works with
some other B vitamins, such as folic acid, pantothenic acid (also known as
vitamin B5), and vitamin B12; however, no solid evidence indicates that
people supplementing with biotin need to also take these other vitamins.
Symptoms of pantothenic acid or zinc deficiency have been reported to be
lessened with biotin, though people with these deficiencies should
supplement with the nutrients they are deficient in. Researchers have
speculated that biotin and alpha lipoic acid may compete with each other
for absorption or uptake into cells; but little is known about the
importance of these interactions in humans.Boron: Boron is a trace element
found widely in the environment. It�s found in the oceans, rocks, soils
and plants. Food sources of boron include green vegetables, fruit and nuts.
You should be able to get all the boron you need from your daily diet.
Boron is thought to help the body make use of the glucose, fats, oestrogen
and other minerals, such as calcium, copper and magnesium, in the food we
eat. Taking high doses of boron for long periods of time may reduce
fertility in men.
Cadmium: Most of the interest in
the element cadmium derives from its potentially toxic effects on the lungs,
and also on the kidneys, leading to high blood pressure and bone disease.
However, the function of certain proteins may be dependent on the presence
of cadmium. Cadmium levels in our bodies progressively increase with age.
Cigarettes also contribute additional cadmium.Caffeine: Caffeine occurs naturally
in a variety of plants. The main dietary sources of caffeine are coffee, tea,
cocoa and cola-type beverages. In addition, some drugs contain caffeine.
Undoubtedly the popularity of these beverages is due to the stimulant effect of
caffeine. Individuals react differently to caffeine and, in addition to
stimulation, caffeine can cause other effects, such as insomnia, frequent
urination, stomach upsets, nervousness and irritability. Caffeine and coffee
drinking have also been associated with heart disease and birth defects.
Although there is no clear-cut evidence to support these studies, it would be
prudent if you are pregnant to limit caffeine intake. The amount of caffeine
consumed in tea or coffee depends on factors such as the variety used, the
length of brewing time, and the size of the cup. With decaffeinated coffee,
over 95 per cent of the caffeine is removed prior to roasting. Cocoa contains
only a small amount of caffeine, but has larger amounts of theobromine, a
substance that has somewhat similar effects to those of caffeine.Calcium: Calcium is the mineral
in your body that makes up your bones and keeps them strong. Ninety-nine
percent of the calcium in your body is stored in your bones and teeth. The
remaining 1% is in your blood and soft tissues and is essential for life
and health. Without this tiny 1% of calcium, your muscles wouldn't
contract correctly, your blood wouldn't clot and your nerves wouldn't
carry messages. It is mainly the calcium in your diet that spares, or
protects, the calcium in your bones. In addition to their structural role,
your bones are your emergency supply of calcium. Your body actually tears
down and builds bone all of the time in order to make its calcium
available for your body's functions. If you don't get enough calcium from
the food you eat, your body automatically takes the calcium you need from
your bones. If your body continues to tear down more bone than it replaces
over a period of years to get calcium, your bones become weak and break
easily. This leads to the crippling bone disease called "osteoporosis".
The most available source of calcium in our food supply comes from milk
and foods made with milk. Calcium is also found in foods such as dark
green vegetables, nuts, grains, beans, canned salmon and sardines (if you
eat the bones). These foods can help contribute to your calcium quota. But
without dairy in your diet, it may be difficult to meet your daily calcium
requirements. It's very difficult to get too much calcium. Any excess
which the body cannot use is excreted from the body in the urine and
stool. Daily consumption up to 2,500 mg has been shown to be safe.Calorie: A calorie is a unit of
heat equal to the amount of the heat necessary to raise the temperature of
1 gram of water by 1�C at normal atmospheric pressure. A Calorie (or
kilocalorie, or Cal) is equal to 1000 calories; this unit is used in
dietetics to measure the energy value of foods and the energy needs of
humans, although the international (SI) unit for expressing energy
production is the joule (1 kilojoule = 1.24 Cal). (More Information)Carbohydrates: Carbohydrates
come in two basic forms: complex and simple. Simple carbs are one, two, or
at most three units of sugar linked together in single molecules. Complex
carbs are hundreds or thousands of sugar units linked together in single
molecules. Simple sugars are easily identified by their taste: sweet.
Complex carbs, such as potatoes, are pleasant to the taste buds, but not
sweet. There are two groups of complex carbs: high fiber and low fiber.
High-fiber, complex carbs are not digestible, at least not by human
beings, because we do not have the enzyme to do the job. Cows have that
enzyme; that is why they can get calories out of grass, and we cannot. The
main stuff in high-fiber, complex carbs which is indigestible by humans is
called "cellulose". It matters not if a carb is simple or complex. After
digestion, it appears in the circulatory system in the simple form, as
glucose, on its way to the cells where it is used for energy. To be
transformed into simple sugars, complex carbs must be digested by the
enzyme amylase. Amylase is secreted by the salivary glands, which empty
into the mouth, and by the pancreas, which empties into the head of the
duodenum. (More Information)Carotenoids: Carotenoids are
found in many fruit and vegetables, as well as some animal products such
as egg yolks. Carotenoids were first isolated in the early 19th century,
and have been synthesised for use as food colourings since the 1950s.Cholesterol: There is another type
of fat, called sterols. Cholesterol is the sterol found in all animal tissues;
in plants, the sterols are of a different kind. Cholesterol forms a part of
all animal cell walls (membranes). It is also used to make hormones like
cortisol and to make bile acids. Unfortunately, it can also accumulate in the
inner parts of arteries, leading to progressive reduction in the diameter of
blood vessels and in blood flow. This in turn leads to heart attacks, angina,
abnormal heart rhythms and heart failure when the vessels affected are the
coronary arteries supplying the heart. Arteries supplying blood to the brain,
the legs, the kidneys and the gut can also be affected. The extent to which
cholesterol accumulates in arteries depends in part on the level of cholesterol
in the blood. When high, this is called hypercholesterolaemia. Not only dietary
cholesterol, but also dietary saturated fat, elevate the blood cholesterol
level. Polyunsaturated fat and certain kinds of dietary fibre lower the blood
cholesterol level. It is worth remembering that the body can make its own
cholesterol so that dietary cholesterol is not an essential nutrient. In
seafood, some of the sterols that were once believed to be cholesterol are
actually a different kind. (More Information)Choline: The newest official
member of the B vitamin family, had its Adequate Intake levels (AIs)
established for the first time by the National Academy of Sciences in 1998.
choline came in the late 1930s, when scientists discovered that tissue from
the pancreas contained a substance that could help prevent fatty build-up in
the liver. This substance was named choline after the Greek word chole, which
means bile. Since the 1930s, research has shown that choline is found not only
in the pancreas and liver, but is also, in fact, a component of every human
cell. Choline is a key component of many fat-containing structures in cell
membranes. Since cell membranes are almost entirely composed of fats, the
membranes' flexibility and integrity depend on adequate supplies of choline.
Membrane structures that require choline include phosphatidylcholine and
sphingomyelin. In the brain, these fat-like molecules account for an
unusually high percentage of total solids, so choline is particularly important
for brain health, and its potential for use in brain disorders is great.Chromium: Chromium is considered to be
an essential element for humans. Those without it in their diets, such as hospital
patients on artificial feeds, develop a diabetes-like condition, with high blood
sugar (glucose) levels. The availability of chromium to the body may depend on the
form in which it is present in food. For example, it is found in a form in
association with other compounds in Brewer's Yeast and known as 'Glucose Tolerance
Factor (GTF)'. Elderly people may be an at-risk group from chromium deficiency.
Relatively few foods have been analysed for chromium.Cobalt: Cobalt is essential for humans
because it is a part of vitamin B-12. This form of cobalt is obtainable from
micro-organisms or from animal sources. Vegetable sources of cobalt are more
important to animals that are ruminants (sheep and cattle). Cobalt deficiency in
humans is like vitamin B-12 deficiency, with anaemia and nervous system problems.
As little as 0.1 microgram cobalt as vitamin B-12 per day is needed by adults.
Total cobalt intake may be in a range from 10 to 1800 micrograms per day. Cobalt
in a different chemical form (i.e. not as part of vitamin B-12) will stimulate
blood formation, but this is probably not a normal action. When cobalt was used
to stabilize beer froth, it was found to have a toxic effect on the heart. Its
toxicity, at cobalt intakes of about 8000 micrograms per day, probably arose
from its interaction with alcohol itself, and other nutritional problems created
by alcohol.Copper: Copper is an essential part of
several body enzymes (natural substances required for chemical reactions in the
body). It is necessary for iron metabolism, for the formation of the brown pigment,
melanin, in hair and skin, and in the functioning of the body's central nervous
system. Copper deficiency due to inadequate dietary intake is rare. However, a
deficiency may arise due to an inherited metabolic abnormality. Sources of copper
include shellfish, liver, kidney and nuts. The amount of copper in household water
supplies depends on the type of pipe and the hardness of the water. More copper is
present in water from the hot tap than from the cold. For preparing hot drinks it
is probably safer to heat cold water rather than use water from the hot tap,
particularly for children.
Elements: By food elements is meant the
various distinct compounds that exist in foods and that are useful, after digestion,
as nourishment for the body. The chemical elements of the body do not exist in the
body in their "free" (uncombined) or pure state. They are always present in various
complex combinations, both in the human body and in the simplest forms of food-stuffs.
The animal body does not make use of the "free" elements, with the exception of oxygen,
but employs only certain acceptable compounds prepared by the synthetic processes of
the plant. The plant is the ultimate source of all animal food. Foods are materials
which supply the "elements" necessary for promoting growth of the body and repairing
its waste, yield energy for muscular work, yield heat, regulate the body processes,
and make reproduction possible.Enzymes:
Fats: There are four different
kinds of fats in human nutrition. Fat is categorized according to its
saturation. Saturation refers to the number of hydrogen atoms attached to
the fat molecule. When a fat molecule contains the maximum number of
hydrogen atoms, it is said to be "saturated." It is called "hard fat,"
because it remains hard at room temperature. If one pair of hydrogen atoms
is missing, the molecule is said to be "monounsaturated." An example is
olive oil. Monounsaturated fat is the healthiest, most easily digested
form of fat. If more than one pair of hydrogen atoms is missing, it is
said to be "polyunsaturated." These are the thin oils commonly used for
frying and for salad dressing. If an unsaturated vegetable fat is altered
by adding hydrogen atoms, which did not exist in nature, the fat molecule
is said to be "hydrogenated." Hydrogenation transforms the shape of a
fatty acid to a "trans" form. You can visualize this by imagining a
boat-shaped molecule being transformed to a chair-shaped molecule. This
molecule does not occur in nature, and the body has difficulty digesting
it. This is the problem with margarine, it contains hydrogenated,
trans-fatty acids. Studies show this type of molecule to be more
associated with artery disease than the saturated ("hard") fat found in
butter. Hydrogenated fat also is commonly associated with junk food:
potato chips. cookies, etc. It is very hard to digest and is strongly
associated with vascular disease. A fat molecule is composed of three
fatty acid molecules, sixteen to eighteen carbons long, bound to each
carbon of the three-carbon-long glycerol molecule. It is in the fatty acid
chains where saturation, monounsaturation, polyunsaturation, and
hydrogenation occur. There are one, maybe two fatty acids which cannot be
manufactured by the body and must be consumed from outside sources.
Linoleic acid is definitely necessary for human nutrition, and it may be
that linolenic acid also is necessary. Animal foods, except for fish and
poultry, are low in linoleic acid, but they do meet human needs. Linoleic
acid is abundant in vegetables. Linolenic acid is abundant in both
vegetables and animal foods, and it is practically impossible to be in
short supply of this nutrient unless starvation also is at your doorstep.
The body knows how to manufacture the fatty substances it needs with the
exceptions of linoleic and linolenic acids. (More Information)Fibre: Dietary fibres are
structural components of plants. The type and amount of fibre in plants
vary from species to species. A common misconception about fiber is that
it is not digested by enzymes in the body and therefore provides no
calories or nutrients. But the category "fibre" includes chemicals that
are not fibrous, materials that can be dissolved, and some substances that
can be digested partially. We eat quite a complex mixture of fibers.
Fiber's ability to hold water and to bind minerals and cholesterol-like
materials results in a number of physiological effects which vary
depending on the type of fiber and/or where it is in the digestive tract.
Because of these physiological effects, fiber is considered beneficial in
preventing, alleviating or curing a number of diseases. Recent
recommendations suggest that we should be getting fiber from a variety of
foods high in different types of fibers, rather than from dietary
supplements. A healthy diet should provide a mixture of both soluble and
insoluble fibers. A healthy adult should get 20-25 grams of fiber a day,
based on the assumption that we need 10-13 grams of fiber a day for every
1,000 calories consumed. Unfortunately, most Canadians consume only about
10 grams. Children ages 3-18 need less fiber than adults, and they need
different amounts at different ages. To calculate a child's daily fiber
requirements, add the child's age to the number five (for five grams). For
example, a four-year-old needs nine grams of fiber a day. (More Information)Fluorine: Fluorine is found in
the blood, teeth and bones and in the iris of the eye. There are about 3 oz.
in a body weighing 150 lbs. It is essential to the formation of enamel and
to hardness of the bones. The richest sources in the order named are,
Vegetables: watercress, cauliflower, swiss chard, red cabbage, cabbage,
garlic; Fruits: olives. Other fruits and nuts as well, contain this
element, but analyses are lacking.Folacin: Folacin is present in many
forms in food. It is sometimes referred to as folic acid, or folate. The
availability to the body of folacin in food depends not only on the form, but
also on other food properties, such as acidity, the amount of dietary fibre and
the amount of carbohydrate. Folacin is water soluble and easily lost in discarded
cooking water. It is also sensitive to heat, to air or oxygen and to alkaline
conditions. Folacin, like vitamin B-12, is involved in the formation of the
genetic material of newly forming cells and in protein formation. The consequences
of deficiency include anaemia and defective lining of the gut, adversely affecting
absorption of many nutrients. Since the number of blood platelets (which play a
part in blood clotting) can be low with folacin deficiency, a tendency to prolonged
bleeding can also occur.Folic Acid: Folic acid is a
water-soluble B vitamin that is also known as PGA (pteroylglutamic acid).
The precise term for folic acid from food sources is folate. Folacin is
another term that is often used to refer to folic acid. Folic acid plays
an important role in cell division and growth by acting as a co-enzyme
that transports carbon from one compound to another during amino acid
metabolism and nucleic acid synthesis. By preventing damage to cellular
DNA, folic acid may reduce the risk of colon polyps, colorectal cancer and
cervical cancer. During pregnancy, folic acid can be vital to healthy
fetal growth. Folic acid is found in many types of foods, particularly
liver, yeast, green leafy vegetables, legumes, orange juice, oranges,
cereals, breads and wheat germ. Folate, the form of folic acid that occurs
naturally in food, is only about half as available to the body as the
folic acid in supplements or in fortified foods that have had folic acid
added to them. Because folic acid is not a very stable vitamin, about half
the amount that comes from food is easily lost during cooking, processing,
meal preparation and storage. To preserve it, use quick-cook methods (such
as steaming in very little water), avoid overcooking vegetables, and eat
raw fruits and vegetables frequently. People with folic-acid deficiencies
risk adverse effects that include: impaired cell division; adverse effect
on growth in rapidly growing tissues; clinical depression, especially
melancholia, as well as less responsiveness to anti-depressants such as
fluoxetine (Prozac).
Germanium: Germanium is a trace
element found in a wide range of foods including beans, tomato juice, oysters,
tuna and garlic. Germanium isn�t needed for good health. It has no known
function in the body but it may help us get energy from the carbohydrates we
eat.Gluten: Gluten is a part of the
protein found in wheat, and to a lesser extent in rye, barley and oats.
Gluten is largely responsible for the ability of wheat flour to form 'elastic'
batters and doughs. Without gluten in flour it would not be possible to
produce light-baked products or the well-risen breads that are characteristic
of wheat flour. (More Information)
Hydrocarbons: Hydrocarbon foods are
those rich in hydrocarbon, fats and oils. Hydrocarbons are composed of carbon,
hydrogen and oxygen. In the animal body, fats may be manufactured out of sugars
and proteins. Fats are produced in the plant out of sugar. There are many kinds
of fats, solid and liquid. Fats and oils are formed in plants, and fruits when
ripening. A decrease in sugars accompanies the increase in fats. It is but
another evidence of the importance of sugar in the life of the plant and,
thereafter, in the life of the animal. While the animal is capable of
synthesizing fats out of starches and sugars, it is not capable of taking
hydrogen, oxygen and carbon and synthesizing fats out of these.Hydrogenation / Trans Fats: When
hydrogen is bubbled through polyunsaturated and monounsaturated fats and oils,
they are changed from their natural liquid form to a more solid form. This
makes them saturated, in a process called hydrogenation. These oils may be
partly or almost completely hydrogenated or saturated, and thus partly or
completely solid at room temperature. This process also causes the oil to
develop trans fats, also called trans fatty acids. Trans fats are what make
vegetable margarines have a butter-like texture, and prolong the shelf life of
packaged foods. The effects of trans fats are still not known, but it is
believed that they, like saturated fats, cause blood cholesterol levels to
increase. Try to limit your use of hydrogenated products. Because manufacturers
are not required to list how much trans fats are included in a product, you need
to read the list of ingredients carefully. As a rule, you will reduce your intake
of trans fats in products using oil if liquid vegetable oil is ranked high in
the list of ingredients and hydrogenated or partially hydrogenated oil is listed
toward the middle or end. For example, soft tub spreads list water and liquid
vegetable oil first, whereas solid margarines list it later.
Iodine: Our bodies must have an
adequate intake of iodine to form the hormones produced by the thyroid gland.
These hormones regulate our bodies' metabolic rate. If the dietary level of
iodine is inadequate, the gland, which is in the neck, swells and produces
goitre. Unless treated, this condition can cause mental retardation and
stunted growth in children, and hair loss, slowed reflexes, dry, coarse skin
and other effects in adults. Foods produced in regions where soils are low in
iodine, such as Tasmania in Australia, the Thames Valley in the U.K., and the
north-west region of the U.S.A., are deficient in this element. Goitre caused
by iodine deficiency can be prevented by supplementing the diet with added
iodine. This is commonly done by adding sodium iodide to table salt to produce
iodized salt. For some people, iodized salt can be an important source of iodine
and a change to a low-salt diet should make allowance for the decrease in iodine
intake. Some foods, such as cabbage, sprouts and other brassicas contain natural
anti-thyroid substances. In circumstances where both large quantities of these
foods are eaten and the levels of dietary iodine are marginal, goitre could
develop. Excessive amounts of iodine can also lead to goitre. This has occurred
where foods, such as seaweeds, which are rich in iodine, are commonly eaten.
Although excessive iodine intake is not common, it should be noted that, in
addition to food, many cough medicines and milk contaminated with an iodine
containing sanitizing agent also contribute to iodine intake. But it is unlikely
that any harmful effects would occur with habitual intakes up to 300 micrograms
per day.Iron: The mineral iron is an
essential nutrient for humans because it is part of blood cells, which
carry oxygen to all body cells. About 30% of the iron in our bodies is in
storage to be readily available to replace lost iron. Iron is essential to
the formation of hemoglobin and myoglobin, which carry the oxygen in the
blood and the muscle. It also makes up part of many proteins and enzymes
in the body. Iron deficiency is the most common nutritional deficiency
worldwide. Although full-blown anemia is rarely evident, partial
deficiency is widespread. Symptoms of decreased iron stores include
general fatigue, shortness of breath, headache, irritability, and/or
lethargy. Those at risk for low iron stores include: 1. Women of
child bearing age - mdue to menstruation. 2. Pregnant women - due
to baby's needs and blood loss during childbirth. 3. Infants -
usually are born with iron stores to last about six months. An infant's
iron needs are met by breast milk. A non-breast-fed infant's iron needs
can be met with an iron supplement or iron-fortified infant formula. As
babies move to solid foods, foods containing high amounts of iron should
be selected to prevent the development of iron deficiency. 4.
Children between one and four years of age are at risk for developing iron
deficiency because of rapid growth and a lack of sufficient iron in their
diets unless iron-fortified foods or a supplement is available. Milk is a
very poor source of iron. Children who drink large quantities of milk at
the expense of other foods may develop "milk anemia". Limit milk to about
one quart or less per day. Recommended milk intake is two to three cups
per day for toddlers. 5. Adolescents - both boys and girls
traditionally have been prone to anemia because of rapid growth rates,
erratic eating habits, and concerns about body image. 6. Other
groups at higher than average risk are long-distance runners (whose
demanding exertions may somehow damage red blood cells), and strict
vegetarians (because they do not eat animal products, which contain the
most bioavailable form of iron.).
Lecithin: Lecithin belongs to a
class of lipids (fats) known as phospholipids, because they contain phosphorus.
Lecithin also contains choline, which can be used to make a brain chemical,
acetylcholine, used to transmit information between some nerve cells, and also
between nerve and muscle. Only in one rare disorder of movement, tardive
dyskinesia, has dietary choline supplementation been shown to be of value.
Lecithin also contains fatty acids, which may be saturated, monounsaturated or
polyunsaturated. These same fatty acids can be obtained from lipids other than
lecithin. Lecithin is not an essential dietary item as the body can produce
enough of its own. It is a component of bile, produced by the liver, which is
used to aid the digestion of fat. Lecithin is sometimes used as a food additive.
It acts as an emulsifier and helps to disperse oils in water. It can be found in
chocolate, salad dressings, frozen desserts and baked goods. The lecithin
occurring naturally in eggs helps to perform the same function.Lutein: Lutein is an antioxidant
in the carotenoid family (a group of naturally occurring fat-soluble
pigments found in plants). Lutein is the primary carotenoid present in the
central area of the retina called the macula. Lutein may act as a filter to
protect the macula from potentially damaging forms of light. Consequently,
lutein appears to be associated with protection from age-related macular
degeneration (the leading cause of blindness in older adults).
Magnesium: Magnesium, a mineral,
is used in building bones, manufacturing proteins, releasing energy from
muscle storage, and regulating body temperature. Eating a variety of foods
that contain magnesium is the best way to get an adequate amount. Healthy
individuals who eat a balanced diet rarely need supplements. Intakes of
magnesium tend to be low in relation to recommendations, and there aren't
that many foods that are really good sources; thus, it may take special
care to ensure an adequate intake.Manganese: Although the element
manganese forms a part of substances essential for body metabolism, known
as enzymes, no definite deficiency has been recognized in humans. In animals,
deficiency can lead to abnormalities of the developing skeleton, of balance
and of carbohydrate and fat metabolism. Manganese poisoning from food is
very unlikely.Minerals: Minerals are essential
nutrients that your body needs in small amounts to work properly. We need
them in the form they are found in food. Minerals can be found in varying
amounts in a variety of foods such as meat, cereals (including cereal
products such as bread), fish, milk and dairy foods, vegetables, fruit
(especially dried fruit) and nits. Minerals are necessaty for three main
reasons. 1) The building for strong bones and teeth. 2) controlling body
fluids inside and outside cells. 3) Turning the food we eat into energy.Molybdenum: Molybdenum is a trace
element found in a wide variety of foods. Foods that grow above ground, such as
peas, leafy vegetables (including broccoli and spinach) and cauliflower, tend to
be higher in molybdenum than meat and foods that grow below the ground, such as
potatoes. You should be able to get all the molybdenum you need from your daily
diet. It helps make and activate some of the enzymes involved in repairing and
making genetic material. Some evidence suggests taking molybdenum supplements
might cause joint pain.Monounsaturated Fats: Monounsaturated
fats are mainly found in foods that come from plants. They are liquid at room
temperature and can reduce blood cholesterol levels, but less than polyunsaturated
fats do. They can, however, raise HDL cholesterol (the �good� kind of cholesterol)
levels.
Niacin: Niacin (also known as vitamin B3)
is found in dairy products, poultry, fish, lean meats, nuts, and eggs. Legumes and
enriched breads and cereals also supply some niacin. Niacin is a water-soluble
vitamin necessary for many aspects of health, growth, and reproduction. Niacin assists
in the functioning of the digestive system, skin, and nerves. It is also important for
the conversion of food to energy.
Nickel: Nickel is probably an essential
element for humans, with several possible roles in maintenance and production of
body cells. Adequate amounts are probably obtained from most diets, provided that
the gut is functioning properly. There is some evidence that a few people may develop
a skin sensitivity reaction to nickel. For these people, acid food cooked in stainless
steel utensils and canned food may need to be avoided.
Omega-3 Fatty Acids:
Pantothenic Acid: Pantothenic acid is
found in virtually all meat and vegetable foods. Good sources include chicken,
beef, potatoes, porridge, tomatoes, liver, kidney, yeast, eggs, broccoli and whole
grains such as brown rice and wholemeal bread. Breakfast cereals are also a good
source if they have been fortified with pantothenic acid. Pantothenic acid is one
of the B-group vitamins. It�s water-soluble, which means you need it in your diet
every day because it can�t be stored in the body. You should be able to get all the
pantothenic acid you need from your daily diet. Pantothenic acid has a number of
important functions. For example it works in the body to help release energy from
the food we eat. There isn�t enough evidence to know what the effects might be of
taking high doses of pantothenic acid supplements each day.Phosphorus: Phosphorus is a
mineral. It is a major component of bones and teeth and makes up part of
DNA and RNA. Phosphorus serves as the main regulator of energy metabolism
in cells, helps the body absorb glucose and transport fatty acids, and is
part of the buffer system that helps control the acid-base balance of the
body. Almost all foods contain phosphorus, including: protein-rich foods
like milk, meat, fish, eggs and poultry; legumes and nuts; foods with
phosphorus-boosting additives, such as baked goods, bread, processed meats
and cheeses, and soft drinks. The phosphorus levels in normal diets are
not likely to be harmful. It is possible that excessive amounts may lower
the levels of calcium in the blood and cause too much calcium to be lost
through urine, especially if the intake of calcium and vitamin D is
insufficient or marginal. Bone loss then could result.Polyunsaturated Fats: Polyunsaturated
fats come mainly from plants. They are liquid at room temperature. Eating
polyunsaturated fat can reduce blood cholesterol levels.Potassium: Potassium is a very
significant body mineral, important to both cellular and electrical
function. It is one of the main blood minerals called "electrolytes" (the
others are sodium and chloride), which means it carries a tiny electrical
charge (potential). Potassium is the primary positive ion (cation) found
within the cells, where 98 percent of the 120 grams of potassium in the
body is found. The blood serum contains about 4-5 mg. (per 100 ml.) of the
total potassium; the red blood cells contain 420 mg., which is why a
red-blood-cell level is a better indication of an individual's potassium
status than the commonly used serum level.Magnesium helps maintain the
potassium in the cells, but the sodium and potassium balance is as finely
tuned as those of calcium and phosphorus or calcium and magnesium.
Potassium is well absorbed from the small intestine, with about 90 percent
absorption, but is one of the most soluble minerals, so it is easily lost
in cooking and processing foods. Most excess potassium is eliminated in
the urine; some is eliminated in the sweat. When we perspire a great deal,
we should replace our fluids with orange juice or vegetable juice
containing potassium rather than just taking salt tablets. Potassium is
found in a wide range of foods. Many fruits and vegetables are high in
potassium and low in sodium and, as discussed, help prevent hypertension.
Most of the potassium is lost when processing or canning foods, while less
is lost from frozen fruits or vegetables. (More
Information)Proteins: Proteins are the
building blocks that grow and repair your body. Proteins are needed not
only for muscle but also for hair, skin and internal organs. Some proteins
travel around your body in the blood as hormones, enzymes and red blood
cells. Protein is unique because it is the only food source of nitrogen,
which is essential to all plant and animal life. Proteins are made up of
chains of amino acids. For each protein, there are specific amino acids in
a specific amount, and they are joined in a unique order. This is what
makes a chicken different from cheese or a fingernail different from a
strand of hair. There are 22 amino acids. Eight of these are called the
essential amino acids because they cannot be made by the body and must be
provided by the diet.
Riboflavin: Riboflavin, also
known as vitamin B2, is found in small amounts in many foods. Good sources
include milk, eggs, fortified breakfast cereals, rice and mushrooms. UV
light can destroy riboflavin, so ideally these foods should be kept out of
direct sunlight. Riboflavin is water-soluble, which means you need it in
your diet every day because it can�t be stored in the body. You should be
able to get all the riboflavin you need by eating a varied and balanced diet.
But if you decide to take supplements it�s a good idea not to take too much
because this might be harmful.
Saturated Fats: Saturated fat
is mainly found in foods of animal origin, but some vegetables also have l
arge amounts. These are called saturated vegetable fats and are often found
in processed bakery goods and nondairy milk or cream substitutes. As a rule
of thumb when shopping, saturated fats are solid at room temperature. When
you have a lot of saturated fat in your diet, your liver responds by making
more cholesterol. This raises your blood cholesterol level. It is the most
harmful type of fat you can eat.Selenium:
Silicon: After oxygen, silicon
is the most abundant element on earth. Its presence in our bodies might be
thought of as that of an environmental contaminant. From the health point
of view, most interest has centered on toxicity to the lungs from inhalation
of silica dust. However, it has been shown in animals that silicon is
essential for normal growth. Its action appears to be connected with bone
mineralization and formation of connective tissue. The best known form of
silicon is silica or sand, but this is not the form that has been used to
prevent growth abnormalities in animals. In a different chemical form,
known as a 'salt' form, it appears to be more available to metabolic
processes. Good sources are wholegrain cereals and citrus fruits.Sodium: Sodium and sodium
chloride (known commonly as salt) occur naturally in foods, usually in
small amounts. Salt and other sodium-containing ingredients are often used
in food processing. Some people add salt and salty sauces, such as soy
sauce, to their food at the table, but most dietary sodium or salt comes
from foods to which salt has already been added during processing or
preparation. Although many people add salt to enhance the taste of foods,
their preference may weaken with eating less salt. In the body, sodium
plays an essential role in regulation of fluids and blood pressure. Many
studies in diverse populations have shown that a high sodium intake is
associated with higher blood pressure. Most evidence suggests that many
people at risk for high blood pressure reduce their chances of developing
this condition by consuming less salt or sodium. Some questions remain,
partly because other factors may interact with sodium to affect blood
pressure. Fresh fruits and vegetables have very little sodium. The food
groups in the Food Guide Pyramid include some foods that are high in
sodium and other foods that have very little sodium, or can be prepared in
ways that add flavor without adding salt. Read the Nutrition Facts Label
to compare and help identify foods lower in sodium within each group. Use
herbs and spices to flavor food. Try to choose forms of foods that you
frequently consume that are lower in sodium and salt. (More Information)Sodium Chloride: Sodium chloride is commonlt known as salt
Sulphur: We obtain most of our
sulphur from proteins in the diet. The essential amino acid methionine is
one of several sulphur-containing components of protein. The proteins are
broken down into their constituent amino acids, and the sulphur-containing
amino acids are reused for the formation of body proteins needed for growth,
tissue maintenance and enzyme production. New sulphur-containing compounds
are also made by our bodies from the protein components. Some of these have
metabolic function, and some are used to remove potentially toxic substances,
including certain drugs, from the body.
Thiamin:
Tin: Tin is a trace element
found in fresh and tinned foods. The amounts found in fresh food depends
on how much tin there is in the soil where the food is grown. In some
cases, the process of canning also leads to tin being present in tinned
food. By law, the maximum amount of tin allowed in tinned foods is 200 mg
of tin per kg of food. Normally the amount of tin is way below this legal
saftey limit. Tin is an essential element for the growth of rats, but
wheather it applies to human growth is unknown.
Vanadium: Vanadium is an
essential element in the diets of chickens; deficiency affects bones,
feathers and blood. It is not known whether it is essential for humans.
Toxicity has not been seen with intakes below 4500 micrograms per
day.Vitamin: Vitamins are organic
substances present in small amounts in many foods. They are required for
carrying out vital functions of the body and many of them are involved in
the utilization of major nutrients like proteins, fats and carbohydrates.
Although they are needed in small amounts, they are essential for the
health and well being of the body. Vitamins also help regulate metabolism,
help convert fat and carbohydrates into energy, and assist in forming bone
and tissue.Vitamin A: Vitamin A is a
fat-soluble vitamin which comes in two forms. The first is retinol, which
is found already pre-formed in animal foods. The other is pro-vitamin A,
which is found in plant foods in the forms of compounds called
carotenoids. The best known and most prominent carotenoid is
beta-carotene, which provides about two-thirds of vitamin A in our diets.
Beta-carotene is not as well absorbed as retinol, and it is only about
half as active in vitamin activity. Other carotenoids are even less active
than beta-carotene. Vitamin A is often measured in retinol equivalents --
RE, for short. The Recommended Daily Allowance, or RDA, is: 1,000 RE for
boys and men; 800 RE for girls over 12 and adult women (1,300 RE if
breast-feeding). Vitamin A also can be measured in international units,
which is abbreviated as IU. This is how it is normally measured for food
labels and supplements. To calculate IU, multiply the RE number by 5. For
example, a male needs 5,000 IU. If you are considering vitamin A
supplements, keep in mind that deficiency is extremely rare in the U.S.
and that there are health risks associated with taking too much. In
excessive amounts, vitamin A can be toxic. The use of high-potency vitamin
supplements, fad diets, and the tendency to over- and self-medicate have
led to many cases of vitamin A intoxication. Acute toxicity results from
extremely high doses (500,000 IU) of vitamin A consumed over a short
period of time. The symptoms include nausea, headache, bone pain, blurred
vision and flaking skin. The symptoms resolve if the high doses are
discontinued. Chronic toxicity may occur in adults with long-term intakes
of 25,000 IU per day. Symptoms include headache, bone thickening, anemia,
enlarged liver and spleen, menstrual abnormalities, stiffness and joint
pain.Vitamin B1 (Thiamine): Whether
there is a thiamin deficiency or not can depend not only on the amount of
thiamin ingested, but on the presence of thiamin antagonists in food. For
example, an enzyme (a natural substance that speeds up a chemical reaction),
called thiaminase, occurring in raw fish can break down thiamin, and cause
beri-beri in some people. One of the most significant losses of thiamin
from food occurs in the milling of cereals. But thiamin is also water
soluble and can be lost in cooking water. It can also be destroyed on
heating and is sensitive to air or oxygen and also to alkaline conditions.
In addition, alcohol can reduce the availability of thiamin to the body.
For these various reasons, in both developing and developed countries,
thiamin deficiency can be a problem. Thiamin is involved in the action of
certain enzymes in the body, especially one that enables carbohydrate to be
used as energy. Thus, with thiamin deficiency, a number of important body
functions can be disturbed. They include brain function, nerve function
(especially of the legs), and heart function; these three impairments are
called Wernicke-Korsakoffs psychosis', dry beri-beri and wet beri-beri,
respectively.Vitamin B2 (Riboflavin): Riboflavin,
like other water-soluble vitamins, can be lost when cooking water containing
the dissolved vitamin is discarded. Riboflavin can be destroyed by the action
of ultraviolet radiation in sunlight. A particularly important loss of this
vitamin can occur in mill packed in clear containers when they are exposed to
sunlight during or after delivery. The products of this destruction can also
cause a loss of vitamin C. Riboflavin deficiency results in inflammation of
the tongue and lips and also cracking and dryness of the lips and corner of
the mouth (cheilosis) and other symptoms. Riboflavin deficiency in children
causes growth retardation. Inadequate intakes of riboflavin would normally be
associated with a deficiency of other B-group vitamins, which would result in
multiple problems.Vitamin B3 (Niacin):
Vitamin B6 (Pyridoxine): You may see vitamin
B-6 called by different names. They are different forms of the vitamin, but they have
the same function in our bodies. The forms of vitamin B-6 found in food are pyridoxine,
mainly in vegetables, and pyridoxal and pyridoxamine, mainly in foods from animal sources.
Vitamin B-6 is water soluble and can be lost by discarding water in which it is dissolved.
It is also sensitive to light, air or oxygen and to alkaline conditions. Vitamin B-6 is
involved in the functioning of some enzymes (natural substances that speed up chemical
reactions), especially those involved in protein metabolism, the formation of chemicals
for transmission of impulses in brain and nerves, and in red blood cell formation. With
early deficiency of vitamin B-6, ill-defined symptoms such as sleeplessness, irritability
and weakness may occur, but, of course, their presence may be for other reasons. If you
have been on high-dosage vitamin B-6, you may develop these symptoms during its withdrawal
as your body readjusts to more normal intakes. A bigger vitamin B-6 deficiency may lead to
depression, convulsions, abnormal nerve functions (especially in the limbs), dermatitis,
cracking of skin at the corner of the mouth and the lips, a smooth tongue, and anaemia.
Those at risk from vitamin B-6 deficiency include alcohol abusers. Certain medication,
such as the oral contraceptive pill and isoniazid, which is used to treat tuberculosis,
may increase vitamin B-6 requirement. In some metabolic diseases the requirement of vitamin
B-6 is increased.Vitamin B12: Also called cobalamin, is important
to good health. It helps maintain healthy nerve cells and red blood cells, and is also
needed to make DNA, the genetic material in all cells (1-4). Vitamin B12 is bound to the
protein in food. Hydrochloric acid in the stomach releases B12 from protein during digestion.
Once released, B12 combines with a substance called intrinsic factor (IF) before it is
absorbed into the bloodstream. Vitamin B12 is naturally found in animal foods including fish,
milk and milk products, eggs, meat, and poultry. Fortified breakfast cereals are an excellent
source of vitamin B12 and a particularly valuable source for vegetarians.Vitamin C: First isolated in 1928 by the Hungarian biochemist and Nobel prize winner Dr. Szent-Gyorgyi. Vitamin C plays an important role as a component of enzymes involved in the synthesis of collagen and carnitine; however, its most vital role is no doubt that of the primary, water-soluble antioxidant in the human body. Recent medical research has confirmed Dr. Pauling's original idea. Not only does a high vitamin C intake markedly reduce the severity of a cold, it also effectively prevents secondary viral or bacterial complications. Vitamin C works by stimulating the immune system and protecting against damage by the free radicals released by the body in its fight against the infection. Many experts are now realizing that the RDA (Recommended Daily Allowance) of 60 mg/day is far too low to provide for optimum health and protection against disease. A team of medical researchers at the National Institutes of Health in the USA recently completed a study designed to determine the vitamin C requirements of healthy, young men. They found that a minimum intake of 1000 mg/day was required to completely saturate the blood plasma with vitamin C. They also found that vitamin C should be taken in divided doses throughout the day as urinary excretion increases rapidly when individual doses exceed 500 mg. The researchers conclude that the RDA should be raised to 200 mg/day. This amount of vitamin C can be obtained from a diet containing five daily servings of fresh fruit and vegetables. While 200 mg/day of vitamin C may be sufficient to maintain a reasonable health status in healthy, young men, it is clear that such a relatively low intake is far from adequate for older and sick people. It is also evident that far greater amounts are required to provide optimum protection against degenerative diseases such as cancer and heart disease. Large doses (1-2 g/day) of vitamin C have been found to reduce asthma symptoms significantly. Recent studies have shown that vitamin C concentrations in the blood from rheumatoid arthritis patients are extremely low and that vitamin C may protect against further damage to inflamed joints.Vitamin D: Vitamin D, calciferol, is a fat-soluble vitamin. It is found in food, but also can be made in your body after exposure to ultraviolet rays from the sun. Vitamin D exists in several forms, each with a different activity. Some forms are relatively inactive in the body, and have limited ability to function as a vitamin. The liver and kidney help convert vitamin D to its active hormone form. Fortified foods are the major dietary sources of vitamin D. Prior to the fortification of milk products in the 1930s, rickets (a bone disease seen in children) was a major public health problem in Canada. One cup of vitamin D fortified milk supplies about one-fourth of the estimated daily need for this vitamin for adults. Although milk is fortified with vitamin D, dairy products made from milk such as cheese, yogurt, and ice cream are generally not fortified with vitamin D. Only a few foods naturally contain significant amounts of vitamin D, including fatty fish and fish oils. There is a high health risk associated with consuming too much vitamin D. Vitamin D toxicity can cause nausea, vomiting, poor appetite, constipation, weakness, and weight loss. It can also raise blood levels of calcium , causing mental status changes such as confusion. High blood levels of calcium also can cause heart rhythm abnormalities. Calcinosis, the deposition of calcium and phosphate in soft tissues like the kidney can be caused by vitamin D toxicity. Consuming too much vitamin D through diet alone is not likely unless you routinely consume large amounts of cod liver oil. It is much more likely to occur from high intakes of vitamin D in supplements. The Food and Nutrition Board of the Institute of Medicine considers an intake of 25 mcg (1,000 IU) for infants up to 12 months of age and 50 mcg (2,000 IU) for children, adults, pregnant, and lactating women to be the tolerable upper intake level (UL). A daily intake above the UL increases the risk of adverse health effects and is not advised.Vitamin E: Vitamin E is a fat-soluble vitamin that exists in eight different forms. Each form has its own biological activity, the measure of potency or functional use in the body. Alpha-tocopherol is the most active form of vitamin E in humans, and is a powerful biological antioxidant. Antioxidants such as vitamin E act to protect your cells against the effects of free radicals, which are potentially damaging by-products of the body�s metabolism. Free radicals can cause cell damage that may contribute to the development of cardiovascular disease and cancer. Studies are underway to determine whether vitamin E might help prevent or delay the development of those chronic diseases. Vegetable oils, nuts, and green leafy vegetables are the main dietary sources of vitamin E. Fortified cereals are also an important source of vitamin E in Canada. Vitamin E deficiency is rare in humans. There are three specific situations when a vitamin E deficiency is likely to occur. It is seen in persons who cannot absorb dietary fat, has been found in premature, very low birth weight infants (birth weights less than 1500 grams, or 3 1/2 pounds), and is seen in individuals with rare disorders of fat metabolism. A vitamin E deficiency is usually characterized by neurological problems due to poor nerve conduction. Individuals who cannot absorb fat may require a vitamin E supplement because some dietary fat is needed for the absorption of vitamin E from the gastrointestinal tract. Anyone diagnosed with cystic fibrosis, individuals who have had part or all of their stomach removed, and individuals with malabsorptive problems such as Crohn�s disease may not absorb fat and should discuss the need for supplemental vitamin E with their physician (3). People who cannot absorb fat often pass greasy stools or have chronic diarrhea. The health risk of too much vitamin E is low. A recent review of the safety of vitamin E in the elderly indicated that taking vitamin E supplements for up to four months at doses of 530 mg or 800 IU (35 times the current RDA) had no significant effect on general health, body weight, levels of body proteins, lipid levels, liver or kidney function, thyroid hormones, amount or kinds of blood cells, and bleeding time. Even though this study provides evidence that taking a vitamin E supplement containing 530 mg or 800 IU for four months is safe, the long term safety of vitamin E supplementation has not been tested. The Institute of Medicine has set an upper tolerable intake level for vitamin E at 1,000 mg (1,500 IU) for any form of supplementary alpha-tocopherol per day because the nutrient can act as an anticoagulant and increase the risk of bleeding problems. Upper tolerable intake levels "represent the maximum intake of a nutrient that is likely to pose no risk of adverse health effects in almost all individuals in the general population".Vitamin K: Vitamin K can be produced in the intestines and this function is improved with the presence of cultured milk, like yogurt, in the diet, Vitamin K is classified as a fat-soluble vitamin. Vitamin K is found in nature in two forms - K1, also called phylloquinone, is found in plants and vitamin K2, also called menaquinone, which can be synthesized by many bacteria. Vitamin K3, menadione, is a synthetic form of this vitamin which is manmade. Vitamin K is used in the body to control blood clotting and is essential for synthesizing the liver protein that controls the clotting. It is involved in creating the important prothrombin, which is the precursor to thrombin - a very important factor in blood clotting. It is also involved in bone formation and repair. In the intestines it also assists in converting glucose to glycogen, this can then be stored in the liver. There are some indications that Vitamin K may decrease the incidence or severity of osteoporosis and slow bone loss. A deficiency of this vitamin in newborn babies results in hemorrhagic disease, as well as postoperative bleeding and hematuria while muscle hematomas and inter-cranial hemorrhages have been reported. A shortage of this vitamin may manifest itself in nosebleeds, internal hemorrhaging. The dosage underneath is the Recommended Dietary Allowance (RDA), but be aware that this dosage is the minimum that you require per day, to ward off serious deficiency of this particular nutrient. In the therapeutic use of this nutrient, the dosage is usually increased considerably, but the toxicity level must be kept in mind. Males 80 micrograms per day and females 70 micrograms per day. Toxicity does not easily occur with normal dietary intake of this vitamin, but can happen if synthetic compound vitamin K 3 is taken. High to toxic uptake in the synthetic form can cause flushing and sweating. Jaundice and anemia may also develop. Dietary fat is necessary for the absorption of this vitamin. his nutrient can be destroyed by freezing and radiation as well as air pollution. Absorption may be decreased when rancid fats are present, as well as excessive refined sugar, antibiotics, high dosages of vitamin E, or calcium and mineral oils. Vitamin K is found in leafy vegetables, cheese and liver. It is also found in asparagus, coffee, bacon and green tea. Some people are of the opinion that it also promotes longevity.Vitamin P:
Water: Water is perhaps the most
essential of nutrients since we can do without it for only a short time - days
at the outside. This is because, without an adequate flow of urine, waste products
would build up in the body, and with the absence of moisture loss it would not be
possible to regulate body temperature. However, we can obtain water from a number
of sources, as can be seen by reference to Figure 18. Water may be taken as a
beverage and as part of food; water is produced in our body cells following the
metabolism (chemical breakdown) of fat, alcohol, protein and carbohydrate. Food
usually provides more than half our daily water requirement. The more water a food
contains, the less energy dense it is, that is, water-rich foods have few kilocalories
(or kilojoules) per 100 grams. The need for water is influenced by environmental
conditions. For example, in a hot climate a great deal of water can be lost not only
as sweat, but also in expired air. Making water supplies hygienic has contributed
greatly to human health. More recently, the addition of fluoride to water supplies
deficient in it has reduced dental decay. In Australia, nutritionists are encouraging
people to drink water in preference to other beverages and to drink it in adequate
amounts in dry conditions and with increased physical activity. It is sensible to have
four or five glasses of 200 millilitres each day; by so doing, less energy and alcohol
will be consumed. With that much water you'll be less thirsty for alcohol, coffee and
other beverages and probably eat less food. Fluoride intake will be improved for many.
Urine flow will increase and the risk of kidney stones decrease. It is a most unusual
event to be able to overload the body with water by drinking too much. The body
compensates by increasing urine output. However, there can be an accumulation of body
water in certain disease states. Occasionally, for psychological reasons,
over-consumption of water does occur.
Zink: Zinc is an essential
trace element found in every cell of the human body. What does it do?
Zinc plays many diverse roles in enabling healthy growth and development
and in promoting good health in general. A deficiency of zinc can result
in problems such as poor growth, difficulty in wound healing, loss of
appetite, undesirable skin changes, and adverse effects on immune-system
components. Most of the zinc in the typical U.S. diet comes from animal
products, such as meat, liver, eggs and seafood (especially oysters). Zinc
is also available from other food sources, such as legumes, whole-grain
cereals, wheat germ and nuts. However, as explained in the following
section, zinc from these sources may not be absorbed as well as zinc from
animal products. The Recommended Dietary Allowance (RDA) for zinc is 15
milligrams per day for men and 12 milligrams per day for women. For women
who take large amounts of calcium (1400 milligrams) every day, 18
milligrams a day may be recommended. One very important thing to
understand is that the amount of zinc you consume is not the only factor
that affects whether you are getting enough zinc. You also must take into
account the amount that your body actually absorbs. Taking more than 100
milligrams of zinc per day can be dangerous. With zinc gluconate now being
promoted as a means of warding off colds, it is especially important to be
aware of the risks of taking too much zinc.