The minerals iron, calcium, magnesium, phosphorus, iodine and zinc, along with the electrolytes sodium and potassium, are discussed below, in terms of their uses in the body, food sources (in general, and specifically for vegetarians and vegans) and consequences of deficiencies.
Please remember, these are a general guide only. if you are in doubt about your health or diet, consult your doctor or a dietitian.
Iron is an essential component of blood, and deficiency can lead to anaemia.
Symptoms of deficiency may include tiredness, reduced appetite, brittle nails,
and a reduced ability to fight infections. In very young children, iron deficiency
can lead to reduced mental and motor development. It is therefore particularly
important to include iron-rich foods when weaning young children.
There are two forms of iron in the diet: haem, which comes from animal
sources, such as meat and fish (dairy sources are not rich in iron);
and non-haem
iron, which come from non-animal sources.
The good sources of non-haem iron for vegetarians and vegans include dried
fruits, peas and beans, leafy green vegetables and fortified breakfast
cereals.
The amount of iron your body absorbs from the food you eat is influenced
by other components of the diet. Tea, coffee, chocolate, spinach and whole
grains can reduce the amount of iron absorbed, while vitamin C can significantly
increase absorption.
Calcium is important for bone formation, and nerve transmission.
Rich sources for vegetarians are milk and other dairy products.
The main sources of calcium for many vegans are tofu set with calcium salts,
calcium enriched soya milk and cereals, along with dried fruit (such as figs
and apricots), nuts and seeds. Houmous made with tahini (sesame seed paste)
can be a useful vegan source.
Sufficient vitamin D is also needed for calcium absorption.
Oxalates (found in spinach, chocolate and tea) can reduce the absorption
of calcium from foods.
Insufficient calcium may lead to osteoporosis (fragile bones prone to fracture).
Magnesium is important for energy production, muscle contraction and nerve
transmission.
Vegetarian and vegan sources of foods include whole grain cereals, nuts,
legumes and green leafy vegetables.
Absorption of magnesium is enhanced by vitamin D, but reduced by fats and
phytates (found in whole grain cereals).
Phosphorus in the body is found in the bone, along with calcium. It is also
used in the body for energy production, and to maintain a normal pH. Deficiency
may
lead to bone pain, bone loss, anaemia, reduced appetite and muscle weakness.
Phosphorus is found in a wide range of foods, including processed food (as
an additive), meat, poultry and fish. Vegetarians may find eggs and dairy
products useful sources. Vegan sources include cereals, legumes and nuts.
The phosphorus found in cereals and legumes is more difficult for the body
to absorb, therefore vegans, especially those on a diet high in wholegrain
and low in processed foods, may be more at risk of a low phosphorous intake.
Iodine is required for the normal function of the thyroid gland. Iodine
is also especially important during pregnancy, when deficiency can lead to
neurological
problems
in the developing fetus.
Traditionally, seafood is a good source of iodine. However, for vegetarians,
milk is a rich source of iodine, where it comes from supplemented feed and
medicines given to dairy cows and disinfectants used in milking apparatus.
Some seaweeds are good sources of iodine, which may be a useful source for
vegans. Vegans may also consider taking iodine supplements, as tablets, or
iodised salt.
Zinc in essential for a wide range of functions in the body, including growth and tissue repair. Deficiency symptoms may include growth failure, behavioural abnormalities, delayed sexual maturation in children, loss of taste and reduced appetite.
Individuals at risk of deficiency include those with a small appetite, or a low protein intake.
Zinc is frequently found in protein rich foods, such as lean meat and seafood, as well as cereals and dairy products. Significant sources of zinc for vegans include wholegrain foods, and pulses.
Absorption of zinc is reduced by other components of the diet, such as phytates, oxalic acid and folate.
Although some sodium is needed by the body, most people consume too much,
from processed foods (e.g. bread, cheese, baked beans, breakfast cereals),
and table salt added to cooking at home, and at the table.
Sodium is found in low levels in most plant foods, and this is generally
sufficient for most needs.
Those with higher needs include those who have lost body fluids through vomiting,
diarrhoea or high rates of sweating.
Long term high intakes of sodium may lead to hypertension (high blood pressure)
and other cardiovascular diseases.
Potassium is found widely distributed throughout the body, and is an essential component for cells. A high potassium intake may be beneficial in reducing blood pressure.
Potassium is found in many vegan and vegetarian foods, including vegetables (including potatoes), fruits (fresh and dried) and nuts.
These pages were last updated 22nd May 2010
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