Articles
Types of Vegetarian Diets
Vegan
Vegans include in their diet:
- Legumes eg dried peas, lentils and beans (including soy products - soy milk, cheese, yoghurt, tofu, tempeh and miso).
- Grains eg Breads and Cereals.
- Nuts and seeds eg peanuts, almonds, walnuts, sunflower seeds, pumpkin seeds, linseed.
- Fruit and vegetables eg orange, mango, apple, carrot, broccoli, potato.
Vegans exclude all animal products, i.e. meat, fish, poultry, eggs and dairy products (milk, cheese, yoghurt). This is a restrictive diet and nutrients at risk of being below recommended levels include protein, iron, calcium, zinc, niacin and vitamin B12.
Adequate protein, iron and zinc can be achieved by including at least 2 different food groups at each meal (see complementary protein).
Adequate calcium can be achieved by choosing calcium fortified soy products (calcium fortified soy milk, yoghurt, cheese and tofu).
Adequate vitamin B12 is difficult to achieve in the long term as products are rarely fortified and it is only found in animal products. It is advisable for all vegans to take a vitamin B12 supplement of 2 - 3 micrograms per day.
With adequate planning a vegan diet can meet the requirements for most adults but the nutritional adequacy of a vegan diet for pregnant women and children is questionable.
Lacto - Vegetarian
Lacto-vegetarians include legumes, grains, nuts and seeds, fruits and vegetables and dairy products but exclude meat, poultry, fish and eggs.
Lacto - Ovo - Vegetarians
Lacto-ovo-vegetarians include legumes, grains, nuts, seed, fruits and vegetables, dairy products and eggs but exclude all meat, poultry and fish.
Lacto vegetarian and lacto-ovo-vegetarian diets can be nutritionally adequate providing sufficient servings of each food group are included every day. Poorly balanced vegetarian diets are often low in protein, iron and zinc.
Complimentary Protein In A Vegetarian Diet
Protein has numerous roles in the body including growth and repair of muscle and tissue as well as supplying enzymes, hormones and essential amino acids. Lack of protein can lead to muscle wasting, lethargy and malnutrition.
Protein is made up of building blocks called amino acids; there are 20 altogether, 8 of which are essential in the diet. Plant proteins are incomplete, as they do not have the 8 essential amino acids. By mixing plant proteins, the various amino acids complement each other to make a complete protein:
Grains and legumes - Nuts and legumes - Grains and milk products.
It is an interesting fact that complimentary proteins are the basis of many of the world's vegetarian diets eg Mexican (tacos and beans), Indian (rice and dhal) or Chinese (tofu and rice).
A peanut butter sandwich or baked beans on toast or breakfast cereal with milk are further examples of protein complementation.
Protein Requirement
Vegetarians need approximately 1 gram of protein per kilogram ideal body weight per day eg 60.0kg female would require 1gram x 60 = 60grams of protein per day. A higher requirement is needed for the young, athletes and in some illnesses.
Good sources of protein: all dairy, meat, fish, chicken, eggs, nuts, beans and lentils and soy products.
CalciumCalcium has several roles in the body including maintenance of the central nervous system and strong teeth and bones. Lack of calcium can lead to thinning of the bones (osteoporosis).
The recommended daily intake:
Men | 800mg |
Women | 800 - 1000mg |
Pregnancy & Lactation | 1100 - 1200mg |
Children | 700 - 1200mg |
2 - 4 servings of dairy products or calcium fortified soy products are required each day.
Fruits, vegetables, nuts and legumes contain varying amounts of calcium but absorption can be affected by several factors. Excess alcohol, caffeine, salt, protein, iron and soft drinks can reduce calcium absorption. Smoking and lack of weight bearing exercises can also increase losses of calcium from the bone. Vitamin D and lactose found in milk products increases absorption of calcium.
NB: Vegans must ensure that they choose calcium fortified soy products.
Iron
Iron is responsible for transporting oxygen around the body. Insufficient iron in the diet will lead to tiredness, lethargy and anaemia.
There are 2 types of iron in food; Haem-iron found in animal protein and non-Haem found in vegetable proteins. Although non-Haem is not very well absorbed, vitamin C containing foods (eg tropical, berry and citrus fruits, green leafy vegetables and capsicum) can increase the absorption. Try to include a vitamin C source at each meal.
Tannins, oxalates, and phytates found in tea, spinach and bran can decrease absorption, therefore do not take excessive amounts of these foods.
The recommended daily intake:
Men | 7mg |
Women | 12 - 16mg |
Pregnancy & Lactation | 22 - 36mg |
Children | 6 - 13mg |
Zinc
Zinc is an essential trace mineral and plays a role in the growth and maintenance of tissues such as the nervous system, the liver and the pancreas. Lack of zinc leads to poor growth and decreased appetite.
The recommended daily intake:
Adults | 12 - 16mg |
Pregnancy & Lactation | 16 - 30mg |
Children | 5 - 18mg |
Zinc is less abundant and not as well absorbed from vegetable foods compared with animal foods. Phytates in vegetables and cereals decrease zinc absorption. Zinc is also lost in food processing. Foods rich in iron are usually rich in zinc.
Vitamin B12
Vitamin B12 is a water-soluble vitamin and has a role in the nervous system and manufacture of red blood cells. Lack of vitamin B12 can lead to decreased mental function and pernicious anaemia.
The recommended daily intake:
Men | 2 micrograms |
Women | 2 micrograms |
Pregnancy & Lactation | 3 micrograms |
Children | 3 micrograms |
Excessive intake of fibre can interfere with the absorption of vitamin B12. Lack of intrinsic factor in malabsorption syndromes or resections of the bowel can also inhibit vitamin B12 absorption. Vitamin B12 is found exclusively in animal products. Eggs, cheese and fortified soy products are the main sources in a vegetarian diet.
NB: Vegans will generally require a vitamin B12 supplement.
Added to site on : Wednesday, 17 March 2004