The word vitamin comes from 'vital amines', reflecting the fact that these substances are vital for body functions. Vitamins A, C, D, E, K and the B group vitamins are discussed in detail below.
Please remember, these are a general guide only. if you are in doubt about your health or diet, consult your doctor or a dietitian.
Vitamin A may be obtained in the diet as the vitamin itself, or as a provitamin (carotenoids). These compounds are important for vision, reproduction, and maintaining healthy mucous membranes, such as in the eye and the lungs, which are important in the defence against infections. Vitamin A is also important for growth, and the provitamin act as an antioxidant.
In a vegetarian diet, vitamin A may be found in milk, butter, cheese and eggs. Vegetarians and vegans can get their requirements from consuming the provitamin, found in dark green leafy vegetables, and red and orange fruit and vegetables such as carrots, red peppers, sweet red potatoes, mangos, peaches and apricots.
Excessive intake of vitamin A (but not the provitamin) is potentially toxic, and care should be taken with high potency vitamin tablets, particularly during pregnancy, when high intakes can cause damage to the fetus.
Vitamin C is found widely in fruit and vegetables, and therefore vegetarians and vegans should all find it easy to get enough, as long as it includes some fresh fruit and vegetables. Vitamin C can easily be lost in cooking and processing.
To maximise your intake, avoid highly refined foods, and steam or boil vegetables in the minimum of water, and do not add sodium bicarbonate to vegetables when cooking.
Rich sources include citrus fruit (including orange juice), mangoes, berries, broccoli and Brussels sprouts.
Deficiency is uncommon, but people exposed to high levels of free radicals, such as smokers, may benefit from a slightly higher intake, due to the antioxidant properties of this vitamin.
Vitamin D may be obtained through diet, or by exposure to the sun. Although in northerly climates like the UK there is insufficient UV in winter sunshine to enable the body to make vitamin D, vitamin D is stored in the body, and stores laid down in the summer can be adequate for the winter months. In the UK, there is no dietary requirement for vitamin D for those aged between 4 and 65 years, assuming they are exposed to sunshine. Vitamin D is important in maintaining calcium levels, and deficiency may lead to rickets in children, or osteomalacia in adults. Those who are housebound, or do not spend much time outside, or cover up to avoid the sun, as well as young infants and breastfeeding mothers, should consider their diet to ensure they are getting some dietary vitamin D, and consider the use of supplements.
Vegetarians may take vitamin D in the diet through eggs, butter and milk, although levels of the vitamin will vary seasonally.
Vegetarians and vegans may consume foods fortified with vitamin D, such as breakfast cereals, soya milk and margarine. Vegans should check that any added vitamin D is suitable for them; if the source is described as vitamin D3, it may be derived from lanolin, whereas D2 should be suitable for vegans. If i doubt, check with the manufacturer.
Vitamin E is found mainly in vegetable oils and the germ of wholegrain cereals, along with green leafy vegetables and nuts.
Deficiency is uncommon, but people exposed to high levels of free radicals, such as smokers, may benefit from a slightly higher intake, due to the antioxidant properties of this vitamin. Deficiency symptoms include oedema (fluid in the tissues (particularly ankles) causing swelling), impaired vision and speech, and reduced muscle coordination.
Vitamin K is important in blood clotting, and deficiency results in an increased tendency to bleed.
Green vegetables (such as broccoli, spinach and peas) and vegetable oils are rich sources suitable for vegetarians and vegans alike. Some vitamin K may also be absorbed from that produced by bacteria in the gut, although this source will be compromised by the use of antibiotics. Individuals who do not absorb fat well (for example, due to biliary disease) are more at risk of deficiency.
The B vitamins are generally important in metabolism and energy release. The B group of vitamins includes B1 (thiamin), B2 (riboflavin), niacin, B6, folate, B12, pantothenic acid and biotin.
Thiamin is used by the body to release energy from carbohydrates (sugars).
Thiamin is found in wholegrain cereals, beans, seeds and nuts, so vegans and vegetarians following a balanced diet should be meeting their needs, although a diet high in carbohydrate will increase the requirement for thiamin, which may not be met if the carbohydrates being eaten are refined (e.g. white rice). White flour in the UK is fortified with thiamin, as are many breakfast cereals.
Very high alcohol intakes can result in thiamin deficiency. Frequent vomiting, or malabsorption diseases, such as inflammatory bowel disease (IBD) can also lead to a risk of deficiency.
Deficiency causes 'beriberi', the symptoms of which include fatigue, breathlessness, mood changes and neurological changes.
Riboflavin is used by the body for energy metabolism
Riboflavin is found in milk and eggs, which are important sources for omnis and vegetarians alike.
Riboflavin may also be found in a range of fruit and vegetables, especially dark green leafy vegetables. Vegans should ensure their diet includes a range of these for sufficient riboflavin intake. Some breakfast cereals are also fortified with riboflavin.
Deficiency of riboflavin may give rise to the following symptoms: sore, cracked or burning lips, burning or itching eyes.
Deficiency is more likely to occur in those who are growing (e.g. teenagers) especially if intake of dairy is low or zero.
Niacin may be taken directly from the diet, or made in the body from a protein called tryptophan.
Vegetarians can get niacin from milk and other dairy sources, and vegetables.
Particularly rich sources of niacin for vegans are peanuts and fortified breakfast cereals, although vegetables also contribute a significant amount.
Deficiency is fairly rare, especially when protein intakes are plentiful, although those whose diet is corn (maize) based, or who have extra needs (e.g. due to illness), should take extra care to ensure their intake is sufficient. High alcohol intakes can also lead to deficiency.
Deficiency of niacin, known as pellagra, can result in a sunburn-like dermatitis, a sore tongue and mouth, heartburn, abdominal pain and diarrhoea (due to inflammation of the digestive tract), headache, anxiety and confusion.
B6 is widely distributed in fruit and vegetables, so vegans and vegetarians following a balanced diet are unlikely to be deficient. However, the elderly, those with a high alcohol intake, growing children/teenagers, and women who are pregnant or taking the contraceptive pill may be at risk of deficiency. Deficiency symptoms include anaemia, dermatitis, irritability and fatigue.
Particularly rich sources include nuts (especially peanuts and walnuts), bananas and wholegrain cereals.
The name folate comes from the same Latin root as foliage, as it is found in leafy green vegetables (e.g. Brussels sprouts, spinach, cabbage) as well as broccoli, cauliflower and cereal products.
Deficiency can lead to a type of anaemia known as megaloblastic anaemia. Symptoms may include fatigue, loss of appetite, sore mouth, and diarrhoea or constipation.
Folate needs are much higher for women pre-conception and during pregnancy. Insufficient intake at this time can increase the risk of neural tube defects in the baby.
B12 is found in animal products. Vegetarians may obtain B12 from milk and other dairy products. Fortified foods are important in vegan diets (e.g. fortified breakfast cereals, yeast extract) and vgeans should consider taking a B12 supplement.
As the body has large stores of B12, deficiency can take years to develop. Deficiency can give rise to anaemia, and neurological problems. Low B12 may also lead to high levels of a substance called homocysteine in the blood, which may lead to other problems such as coronary heart disease and dementia.
Pantothenic acid is available from a wide range of foods, and deficiency is very rare.
The main sources for vegetarians and vegans are vegetables and cereal products.
Biotin occurs in a wide range of foods.
Vegetarians are likely to consume biotin from milk and eggs, while vegans and vegetarians will obtain useful amounts from cereals, peas and beans.
These pages were last updated 22nd May 2010
Copyright © 2004-2010 Vegan Volumes. All rights reserved. Notice. Privacy
Policy.
