Vegetarian diets

What is a vegetarian diet?

A strict vegetarian diet doesn´t include products of animal origin, or products that contain meat, fish, poultry, eggs or milk.

Types of vegetarian diet

This diet is based on the intake of cereals, vegetables, fruit, legumes, seeds, nuts and dried fruit, dairy products and eggs. No meat, fish or poultry is eaten.
This diet excludes eggs, meat, fish and poultry. It is based on vegetables and dairy products.
This diet excludes dairy products and all products of animal origin. The diet consists of cereals, vegetables, nuts and dried fruit, legumes, mushrooms, and fruit.
The aim of this diet is to achieve a balance between Ying or passive foods (sugar, honey, dairy products, meat, eggs, tropical fruit, alcoholic beverages, processed foods, etc.) and Yang or active foods (cereals, seaweed, legumes and vegetables, fruit without pesticides), with the goal to achieve a good health and mental and physical wellbeing. People who follow a Zen macrobiotic diet eat foods at certain stages, including some foods of animal origin to start with, such as fish, whilst at the end only unrefined cereals. Nutritionally, this is very unbalanced.
Given the great variety of vegetarian diets, it is essential to assess them individually. Foods should be selected carefully and their nutritional value calculated if deficiencies are to be avoided, especially in iron, calcium, zinc and vitamins D and B₁₂. The greatest risk of deficiency occurs in periods of greater physical exertion, stress or accelerated growth, such as during breastfeeding or adolescence.

Risks and benefits of vegetarian diets

Vegetarian diets do, one the one hand, offer numerous benefits and nutritional advantages given that they are lower in saturated fats, cholesterol and animal protein, and higher in carbohydrates, fibre, magnesium, potassium, folates,  and antioxidants, like vitamin C, vitamin E and phytochemicals. So vegetarians can have lower levels of blood cholesterol and blood pressure, and a lower risk of dying from a heart attack or thrombosis; they suffer less frequently from constipation, atopic dermatitis, high blood pressure, type 2 diabetes, and prostate or colon cancer. On the other hand, the disadvantages of a vegetarian diet, especially a vegan diet, are that they are low in energy, protein, essential amino acids, omega-3 fatty acids, calcium, vitamins D and B₁₂, iron, zinc, and iodine.


Vegetarian foods are generally lower in calories and have a lower nutritional density, so larger quantities are required. This means that it can be difficult to obtain the necessary energy contribution, especially given the small size of the stomach during infancy.


Necessary for growth, tissue repair, and the proper functioning of the immune system. Meat, eggs and fish supply better quality protein which is absorbed more easily. Protein of vegetable origin is more difficult to digest and absorb, so the quantity of protein-rich foods has to be larger, and, as well as that, it lacks certain essential amino acids (those which the body cannot produce, and which therefore have to be supplied by the diet). It necessary, therefore, to eat a variety of vegetarian foods throughout the day, but not necessarily in the same meal, to acquire all the amino acids required. Legumes and cereals should be included, as they provide essential amino acids: chickpeas and oats; wheat and beans; corn or rice, and lentils; rice and peanuts, etc.

Omega-3 Fatty Acids (ω-3):

The humans body needs to acquire omega-6 (ω-6) series and omega-3 (ω-3) series essential fatty acids from food, and vegetarian diets are generally high in ω-6 fatty acids (sunflower seeds, safflower seeds, corn, peanuts, primrose, soya, grape seeds, and their oils), but they can be low in ω-3 fatty acids (blue fish, including salmon, trout, leaping bonito and enriched foods such as eggs and milk). This imbalance can inhibit the production of ω-3 fatty acids such as docosahexaenoic acid (DHA) which is present in neurone membranes (brain cells) and in the retina (eyes), which is why these fatty acids are critical for brain development and vision, not only for the foetus, but children too. To maintain the recommended levels of the DHA amino acid in a vegetarian diet, it is important to:

  • Eat sufficient quantities of foods that contain omega-3 fatty acids: hemp seeds, flax seeds, pumpkin, walnuts, rosehips, rapeseed oil, whilst lowering the levels of trans fatty acids: margarine, commercially produced cakes and pastries, and avoiding an excess of omega-6 fatty acids, or better:
  • Take a DHA supplement made from microscopic seaweed. These supplements are especially recommended for expectant or breastfeeding mothers, babies, elderly people, and people with neurological problem or diabetes.


Iron is essential for growth and the transport of oxygen to the tissues, as well as for the metabolism in most cells (metabolism refers to the various chemical reactions in our bodies). Iron deriving from the dairy products, eggs and plants is not so readily absorbed. In addition, vegetarian diets are higher in fibre and phytates, nutrients which reduce the absorption of iron. To improve absorption, it is necessary to take vitamin C, found in fruit and vegetables. On the other hand, iron absorption is improved by soaking and sprouting beans, cereals and seeds, as well as using yeast to raise bread, and by other fermentation processes, such as those used in miso or tempeh. Vegetarian foods high in iron include:

  • Dried fruits: figs, dates, grapes, cherries, raisins.
  • Fortified foods such as breakfast cereals, (fortified foods are those with added essential nutrients such as iron or calcium).


Calcium is found in the bones and is involved in blood clotting and muscle contraction. The principal foods high in calcium are milk and dairy products, including yoghurt and cheese. Calcium is also present in many other vegetarian and fortified foods (fruit and tomato juice, and breakfast cereals). Dark green, leafy vegetables are low in oxalate, including Chinese chard, broccoli, Chinese cabbage, collard, kale, okra and turnip greens, and are a source of easily absorbed calcium. However, vegetables high in oxalates, such as spinach, beet greens and chard, are NOT a good source of calcium, as oxalates and calcium compete for absorption in the intestine. Other vegetarian foods that contain calcium, although with lower absorption, are calcium-enriched tofu, fortified soya milk, sesame seeds, almonds, kidney beans and white beans, figs and soya derivatives, (cooked soya seeds, soya snacks, and tempeh).

Vitamin D:

The amount of vitamin D in the body depends on exposure to the sun, vitamin D fortified foods or supplements. Foods fortified with vitamin D include cow´s milk and some brands of soya and rice milk, breakfast cereals and margarines.

Vitamin B₁₂ or Cyanocobalamin:

This is essential for the production of blood cells and the operation of the nervous system. There is no vegetarian food that contains sufficient quantities of active vitamin B₁₂, unless it is fortified with a supplement. Ovo-lacto-vegetarians can reach adequate levels of vitamin B₁₂ from dairy products and eggs if they eat them regularly (two glasses of milk a day, and three eggs a week). Neither soya fermented products, nor spirulina algae are a reliable source of active vitamin B₁₂, as they contain an inactive form of the vitamin that interferes with the absorption of the active form. Only certain algae such as nori or chlorella contain true vitamin B₁₂. It is crucial to ensure a regular source of vitamin B₁₂ for expectant or breastfeeding mothers, and also for breastfed babies, if the mother is not taking supplements. Babies born to strict vegetarian mothers are at a high risk of vitamin B₁₂ deficiency, so mothers have to be informed about the changes to the nervous system that their babies could suffer. The vitamin is better absorbed when consumed regularly and in small quantities. This can be achieved by consuming fortified foods.

Zinc and other Minerals:

Zinc is essential to the manufacture and operation of protein, and deoxyribonucleic acid (DNA). It assists in the working of the immune system and in the healing of wounds. Legumes, cereals, beans and nuts contain copper, zinc and manganese. Soya derivatives, unrefined cereals and bread also make a contribution. Due to the presence of phytates, oxalates and fibre, the absorption of zinc is lower in vegetarian diets. Some food preparation techniques, such as soaking and sprouting beans, cereals and seeds, as well as using yeast to raise bread, can increase the absorption of zinc.

Different stages of childhood

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