Introduction
A vegan is a strict vegetarian who does not eat any dairy products or
eggs. Most vegans do not eat honey. A well balanced vegan diet can
provide all the essential nutrients you require and shares the same
health advantages as a vegetarian diet.
Nutritional guidelines for vegans are essentially similar to those
for vegetarians. However, vegetarians gain certain nutrients from dairy
products and eggs. Vegans need to ensure their diets contain plant food
sources of these nutrients, the main ones of which are discussed below.
Protein
Obtaining adequate protein on a vegan diet is not a problem. Nuts and
seeds, pulses, wholegrain and grain products and soya products all
supply protein. Previously, it has been thought that plant proteins are
of a lower quality than animal proteins in terms of their essential
amino acid content. However, this is no longer regarded as a problem and
eating a balanced diet of plant foods will provide all the essential
amino acids in adequate amounts.
Essential Fatty Acids
There are two essential fatty acids which must be supplied by the
diet. These are linoleic acid and a-linolenic acid. Essential fatty
acids are important for cell membrane function, cholesterol metabolism
and the synthesis of various metabolites. Good sources of essential
fatty acids are vegetable oils. It is important to have the correct
balance between linoleic acid and a-linolenic acid. It has been
suggested that vegans should use soyabean or rapeseed oils rather than
sunflower or corn oils as these help give a better dietary balance.
Vitamin B2 (Riboflavin)
Certain studies have found vegans to have a low intake of the
vitamin, riboflavin. Riboflavin is important in converting protein, fats
and carbohydrates into energy, and the synthesis and repair of body
tissues. Good sources of riboflavin include whole grains, mushrooms,
almonds, leafy green vegetables and yeast extracts.
Vitamin B12
Vitamin B12 is found primarily in meat, dairy products and eggs and
is absent from plant foods. Considerable research has been carried out
into possible plant sources of B12. Fermented soya products, seaweeds
and algae such as spirulina have all been proposed as containing
significant amounts of B12. However, the present consensus is that any
B12 present in plant foods is likely to be in a form unavailable to
humans and so these foods should not be relied upon as safe sources.
Vitamin B12 is important in the formation of red blood cells and the
maintenence of a healthy nervous system. When deficiency does occur it
is more likely to be due to a failure to absorb B12 from the intestine
than a dietary deficiency.
Vegans can obtain B12 from a wide range of foods which have been
fortified with the vitamin. These include certain yeast extracts,
veggieburger mixes, breakfast cereals, vegetable margarines and soya
milks. You should check the packaging to see which individual products
are fortified with B12.
Vitamin D
Vitamin D is present in oily fish, eggs and dairy products in
variable amounts. It is not found in plant foods. However, vegans can
obtain vitamin D from vegetable margarines, some soya milks and certain
other foods which are fortified with the vitamin.
Vitamin D is also synthesised by the skin when exposed to sunlight.
Synthesis of vitamin D in this way is usually adequate to supply all the
body's requirements. Most vegans will obtain sufficient vitamin D
providing they spend time outdoors on bright days. Fortified foods
further ensure adequate amounts.
Vegans who may be confined indoors may be recommended a vitamin D
supplement. Also, infants who are seldom outdoors or who are
dark-skinned may require supplements. Asian vegans may also be at risk
of deficiency, particularly Asian women who may be required to keep
their skin covered for cultural reas