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Unit 14
VITAMINS AND MINERALS
Objectives
 To recognise that vitamins and minerals are essential for good health
 To identify the two major classes of vitamins
 To understand the reason why we need vitamins and minerals and their
content in our foods
 To develop an understanding of supplements, their use and abuse
DEFINITION OF VITAMINS
“A vitamin is an organic compound that occurs in small concentrations in food. Each
of the 13 known vitamins has certain specific and vital functions in the cell and
tissues of the body that one vitamin cannot replace or act for another… The body
needs only small amounts each day... to sustain the normal metabolic processes of
life5.”
THE IMPORTANCE OF VITAMINS4
Vitamins are essential organic substances required in minute quantities so that we
can process the proteins, fats, carbohydrates and minerals from the foods that we
eat. They are vital components of the enzymes, which carry out the body’s basic
functions. The body cannot produce them so they must be obtained from the food
we eat (a couple can be made by bacteria in the intestine).
Vitamins are formed almost entirely by plants, the exceptions being:
1. Vitamin D is formed in the body by the action of the sun on the skin.
2. Vitamin B12 is formed by bacteria in the soil and is found in all animal
foods and products
Without vitamins, various chemical reactions in the body will not proceed and
deficiencies will show up in malfunctioning blood cells, disorders of the skin, eyes,
nervous and immune systems. With so many roles to play, there is no doubt that
vitamins are important. They were identified in the 20th Century, even though some
deficiency diseases were recognised before. At first it was believed that each vitamin
was a single chemical but now it is known that most are actually families of related
substances that carry out the same task in the body4.
There are thirteen known vitamins essential for health and growth, and eight of them
are grouped together as the B group or ‘B-complex’ vitamins. These are:
Thiamine (B1)
Riboflavin (B2)
Niacin (B3)
Pyridoxine (B6)
Cyanocobalamin (B12)
Folate
Biotin
Pantothenic acid
The others: Vitamin C, and Vitamins A, D, E and K.
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Vitamins have very specific functions. One cannot do the work of another. A
deficiency of one vitamin can interfere with the function of other vitamins. Excess
doses can cause an imbalance in the system resulting in poor health and even death
in some cases5.
CLASSES4
There are two major classes of vitamins: those which dissolve in fat and those which
dissolve in water. (fat-soluble and water soluble)
The fat-soluble vitamins A, D, E and K, are stored in the body, so an excess of these
vitamins can cause unpleasant side effects. They occur in the company of food fats
and are fairly stable during cooking and processing.
It has been known for years that the fat-soluble vitamins are potentially dangerous if
taken in large doses since the body’s safe storage sites are limited.
Water soluble vitamins, the B group and vitamin C dissolve in water or fluids and
excess intake can be excreted in the urine. However, we now know that even though
excess quantities of water-soluble vitamins can be excreted, mega doses can cause
problems.
These vitamins are more susceptible to damage from excessive heat or water used
in cooking. Over cooking, especially vegetables should be avoided. A regular supply
of water-soluble vitamins is thus essential. Fortunately, this creates no problem since
they can be easily supplied by foods such as vegetables, legumes, fruit, and grains 4.
VITAMIN CONTENT OF FOODS4
The vitamin content of various foods differs, depending on the time of growth,
harvesting, storage and processing methods. There is also some individual variation
between, for instance, one carrot and another. The same situation exists with
protein, fat, carbohydrate and water content of various foods.
This natural variation is not a reason to take your vitamins from pills rather than from
foods. Foods do not produce vitamins for our benefit: vitamins are vital to their own
structures and functions. If a plant does not receive the nutrients it needs, it simply
does not grow. So plants, which reach maturity, do not lack vitamins, even though
any one plant may have a little more or a little less of a particular vitamin than its
neighbour. These perfectly natural variations are taken into account when foods are
analysed for their vitamin content4.
Note: Vitamin B12 is covered in detail in Unit 13, (Nutrients of Challenge).
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SUPPLEMENTS: THEIR USE AND ABUSE
People in Western countries tend to be great pill-poppers and many women, as well
as men, now like to take vitamin supplements. To many people, nutrition means
taking vitamins4.
Magazines and books abound everywhere extolling the virtues of vitamin
supplements to fight cancer, heart disease and the advances of old age. While
research on vitamins initially was concerned with the role in combating nutritional
deficiencies, more recent vitamin research focuses on their action in preventing
chronic disease2,4.
It is best to obtain all your vitamins from food, not pills. Whole grains, legumes, fruit,
vegetables, nuts and seeds provide vitamins in the most biologically available form,
in the right amounts, and combined with other complementary nutrients and
elements. So why is so much money spent on vitamin pills4?
Many apparently healthy people believe they need supplements every day; often
vitamin pills are taken for nutritional insurance. If you do not know which foods
contain vitamins and if you believe that today’s foods are deficient in the vital
nutrients, a bottle of pills seems the easiest course of action. A recent survey found
that more than half of the population has been conned by this nutritional insurance
theory2,4.
There is also a popular belief that vitamins will provide extra energy and perk you up
when you feel down. One study found that only 12% of adults were aware that
vitamins do not provide the body with a direct source of energy4.
Many Western diets are deficient in complex carbohydrate and dietary fibre and
suffers from an excess of fat, salt, sugar and alcohol. None of these problems will be
cured by even the most expensive vitamins4.
True deficiency is rare in our well-fed community. When it does occur, it is usually
the result of an inadequate diet, as could be the case with elderly people living alone,
alcoholics, or people on faddist diets. There are people who must take particular
drugs, which alter their requirements for vitamins. Supplements are often essential in
such circumstances. However, we can state that:



Vitamin supplements do not provide balance to a poorly selected diet.
Megadoses of vitamins are entirely unnatural.
Eating wisely from a variety of nutritious food provides us with all the vitamins
(and other key substances) we need naturally4.
Megadoses4
Cars will not go without petrol, but a car will not go any better of you try to pour more
petrol into the tank than it will hold. In fact, the petrol spilling over the car’s body and
paintwork can cause problems. Vitamins are similar. You need enough for the body
to function properly, but taking excess amounts will not make your body work better.
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And just as extra petrol will not make up for a lack of oil in your car’s engine, neither
will taking extra vitamins make up for neglect in other areas of your daily diet4.
Vitamin deficiencies are rare in Western countries. In fact, the excess consumption
of vitamins is probably a greater problem than any deficiency.
Vitamin supplements are often sold in large doses (megadoses), which can be a
thousand times more than the body needs. In such huge amounts, vitamins act as
drugs, not ‘harmless’ vitamins.
Taking megadoses of vitamins will achieve a vitamin-enriched sewerage: it may also
damage some more delicate parts of the body. Another concern is that the body can
become so used to excessive doses of vitamins that a drop in the flood can actually
produce deficiency symptoms. Once addicted to high-dose supplements, the body
may become dependent on a continued high level. To add insult to injury, taking
large quantities of one vitamin (or mineral) may increase or decrease your need for
other nutrients. Taking extra vitamins can lead to an imbalance in the diet: the very
thing they are advertised to correct4.
SUMMARY
To avoid a deficiency of vitamins there are two points to remember.
1. Be active so you can eat an adequate nutritious diet and not gain weight.
2. Choose your diet from a wide variety of nutrient dense foods1.
Vitamins are absolutely essential for optimum health. When your diet includes a
variety of unrefined cereals, fruits and vegetables you will receive all the nutrients
you need in the form that the body can best handle1.
Our bodies were not designed to cope with concentrated doses of any nutrient. God
has supplied us with such wonderful variety of foods let us use them wisely1.
Some vitamins are lost in processing and cooking, but if care is taken and your diet
contains a good supply of fresh produce, there is no need for concern 1.
Remember that vegetables cooked quickly, in a little or no water, or baked in their
skins, retain more goodness. Cooking vegetables in a steamer, microwave or
pressure cooker are all good methods. If you do boil vegetables, preserve the liquid
for soups and casseroles so the vitamins are not being tipped down the sink1.
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MINERALS
INTRODUCTION4
Many people take supplements in their quest for an antidote to a poor diet. In spite
of the proliferation of junk foods, few people suffer from vitamin deficiencies. A lack
of particular minerals in the daily diet give much greater cause for concern 4.
Minerals are important constituents of the blood; they take part in various chemical
reactions, strengthening the bones and are involved in the functioning of nerves and
muscles4.
All the minerals needed are available from food, a varied diet of fruits, vegetables,
whole grains, legumes, seeds and dairy products, or a fortified alternative, will supply
an abundance of minerals4.
The human body contains small amounts of many minerals. These are absolutely
essential for many body processes. Some minerals, like calcium and phosphorus,
are found in larger amounts and make up the large portion by weight of our
skeleton1,4.
Others like iron is found in smaller amounts, the equivalent of a large nail, is stored in
the body. But that tiny four grams of iron is vital for good health and peak
performance2. A lack of iron is the most common nutritional deficiency in the world2.
It is not confined to third-world countries, but occurs in a significant number of women
in developed countries4.
The eight major minerals are:
Calcium
Phosphorus
Iron
Magnesium
Sodium
Chlorine
Potassium
Sulphur
Note: Calcium and Iron are dealt with in detail in Unit 13, (Nutrients of
Challenge).
At least seventeen trace elements have been recognised as essential for humans,
but because of the difficulty of measuring such tiny amounts the experts are not sure
just how much we need of some of them. The most important ones are:
Zinc
Copper
Iodine
Fluorine
Manganese
Chromium
Selenium
Cobalt
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SODIUM
Salt is made up of sodium and chloride, both essential minerals3. Sodium has a vital
role in controlling the pressure and volume of the blood. It also governs the balance
of water inside our body cells and in the spaces surrounding the cells4.
This is particularly important during strenuous activity when water is needed inside
the cells to allow for energy to be produced. Too much salt pulls the water out of the
cells and the energy-producing reactions in the muscle cells cannot function
efficiently. Sodium (and potassium, chlorine and magnesium) are termed
‘electrolytes’ since they are present in the body as electrically charged particles.
Their control over the balance of fluids allows dissolved nutrients to enter the cells
and waste products to be removed4.
The kidneys control the amount of sodium in the body. When we eat too much salt,
the kidneys excrete the excess sodium in the urine. Ever wondered why you feel
thirsty after a meal that contained excess salt? It is because the kidneys need extra
water to get rid of the salt, so we feel thirsty4.
If you are sweating heavily and thus losing some extra sodium in your sweat, the
kidneys simply reabsorb a little more sodium. Except with kidney failure or after a
period of vomiting or diarrhoea, there is no problem in keeping enough sodium in the
body. The kidneys are perfectly capable of cutting down on the amount lost in the
urine. The big problem for the body with sodium is disposing of the excess 4.
Too much sodium can also affect our bones. Strong, healthy bones require sufficient
calcium each day. An excess of sodium can interfere with the absorption of calcium
from food. Those at risk of osteoporosis should avoid eating too much salt 3,4.
The best way to ‘shake the salt habit’ is to avoid or restrict the use of high-salt foods.
This includes foods such as salted meats and fish, like corned beef and anchovies,
smoked salmon and tuna in brine. It also includes snack food items like salted nuts,
crackers and potato crisps, and many other foods such as pickles, chutney, olives,
canned and packet soups, bottled and packet sauces, yeast and meat extracts and
some cheeses like parmesan3.
THE ROLE OF POTASSIUM4
The sodium from salt should ideally be balanced with potassium from foods. In
natural foods, potassium is present at far higher levels than sodium. Many
processed foods however, have lost some of their natural potassium and gained
large quantities of sodium from salt. This distorts the natural balance of these two
minerals.
For example a fresh tomato has more than 50 times as much potassium as sodium,
canned tomatoes have only one tenth of this quantity, while the more processed
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tomato sauce has almost twice as much sodium as potassium (a good reason to buy
salt reduced products).
Fruit and vegetables are excellent sources of potassium. Grains are also rich in
potassium and low in sodium, while many prepared breakfast cereals and bread
have more sodium. Potassium rich foods can help balance some of the salt that we
cannot always avoid. For example, a salad sandwich and some fresh fruit will
contain plenty of potassium to balance the salt which as been used in the making of
bread.
SALT SUBSTITUTES4
A variety of salt substitutes are available to ease the move into a low-salt lifestyle.
Most contain potassium chloride in place of some or all of the regular sodium
chloride. To some people potassium chloride leaves an unpleasant bitter flavour,
others find it perfectly acceptable.
Salt substitutes can be useful but most people find it simpler to gradually use less
salt. The bonus in adjusting the taste buds to less salt is that the true flavours of
foods become more enjoyable.
Salt substitutes can be dangerous for anyone with kidney problems. It is also
important to note that some products still contain 50% salt.
Sea salt is sometimes sold as an alternative to regular salt. It is still sodium chloride
and has absolutely no advantages. Don’t waste your money on it and don’t expect
any benefits.
Vegetable salts are also promoted as a healthy alternative to regular salt. These
products are still based on salt but have various vegetable extracts added to provide
flavour. They, too, offer little health advantage over ordinary salt and won’t do a thing
for your blood pressure4.
ZINC4
Zinc is potentially a toxic mineral and excess can come from industrial contamination
or from over-zealous use of zinc supplements. These can also have a secondary
effect of causing iron deficiency and interfering with the body’s ability to use other
minerals, such as copper2.
Symptoms of zinc excess include dehydration, diarrhoea, nausea, abdominal pains,
dizziness, a lack of muscular coordination and feelings of lethargy.
It is most unlikely that anyone would have an overdose of zinc from foods, but megadose supplements are hazardous. A dose equal to 10 times the daily needs is
dangerous.
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Symptoms of zinc deficiency include impaired growth of the foetus as well as the
infant, impaired reproduction, impaired wound healing, leg ulcer and burn healing,
loss of taste1.
The absorption of zinc, like other minerals, depends on several factors. To some
extent, the more zinc you need, the more you can absorb. Anyone who has been
fasting will absorb large quantities, a potential danger for those who fast and take
supplements.
Phytic acid and phosphates present in soybeans and wholegrain products can
interfere with zinc absorption as well as calcium and iron. Phytic acid is present in
the fibre of grains in the raw state. Cooking destroys some of the substances that
inhibit the absorption of some minerals, so does the action of yeast as in wholemeal
bread. Taking large quantities of unprocessed bran can lead to zinc deficiency; one
to two tablespoons of bran is fine, larger quantities should be avoided.
Some nutritionists question high fibre diets in that they lower the absorption rate of
certain minerals, including zinc, calcium, magnesium and iron. This is not a
significant problem because it is known that strict vegetarians, people in third world
countries and European populations who live on high-fibre diets have shown no
clinical signs of mineral deficiency.
One reason a mineral deficiency doesn’t develop may be explained by the fact that
high fibre diets usually contain 50 to 700% more vitamins and minerals that the same
foods after refining. Dietary fibre is not thought to contribute to mineral deficiencies
unless a population is living on a very limited diet, such as found in starvation-prone
areas of Africa.
Good vegetarian sources of zinc include: Whole grain products of which oats are the
highest, legumes where lentils are the best source and nuts, in particular Brazil nuts4.
SUMMARY
Eating a variety of foods generally ensures that our bodies get all the minerals they
need. Include wholegrain foods, legumes, fruit and vegetables, nuts and seeds, milk
or a fortified substitute such as So Good.
PRACTICAL GUIDELINES
1. Keep salt (sodium chloride) down. The body needs approximately a teaspoon
a day, however the average person uses 3+ teaspoons of added salt per day.
Excess salt is a contributing factor to hypertension (high blood pressure) in
sensitive people1.
2. Grains should be well cooked as the phytic acid in raw grains binds with
calcium, iron, zinc and other minerals, carrying them out of the intestine with
the waste matter1.
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3. Most minerals are not destroyed by cooking or baking but many are poured
down the drain with the water from cooked vegetables. Save that water for
soups and sauces1.
REFERENCES:
1. Butler T, Butler D, Stanton H;
VEGETARIAN COOKING DEMONSTRATOR’S MANUAL –
2nd EDITION
Adventist Health Department &
Sanitarium Nutrition Education Service, 1995: E65-E85
2. Craig W;
NUTRITION AND WELLNESS
Golden Harvest Books Berrien Springs Michigan 1999:
102-112;184-211
3. Sanitarium Nutrition Education Service;
SHAKE THE SALT HABIT
Sanitarium Health Food Company July 1995
4. Stanton R;
EATING FOR PEAK PERFORMANCE
Allen & Unwin Australia Pty. Ltd, North Sydney, NSW
1988:14-27, 35, 98, 111, 119-122
5. Wahlqvist M. L; FOOD AND NUTRITION – Australasia, Asia and the Pacific
Allen & Unwin Pty Ltd Crows Nest NSW 1997: 222-254
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