A vegan is a strict vegetarian who does not eat any dairy products, eggs or 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.
Obtaining adequate protein on a vegan diet is not a problem. Nuts & 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 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 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 oudoors 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 reasons.
The major source of calcium in British diets is generally milk and dairy products. Vegans can obtain adequate calcium from plant foods. Good sources include tofu, leafy green vegetables, watercress, dried fruit, seeds and nuts. Also, white bread is fortified with calcium, as are some soya milks. Hard water can also provide significant amounts of calcium.
Milk is the primary source of iodine in the British diet and studies have indicated some vegans may have a low iodine intake. Seaweeds are a good source of iodine, and vegetables and grains can contain iodine depending on the amounts in the soil.
=The Vegan Society=