The 5 Classes of Nutrition

In many ways, a vegetarian diet is as healthy if not healthier than that of a typical meat-eater

Many people worry that when they stop eating meat and fish, they might be in danger of some nutritional deficiency. This is not the case as all the nutrients you need can easily be obtained from a vegetarian diet.

Nutrients are usually divided into five classes:
1. Proteins
2. Carbohydrates
3. Fats (including oil)
4. Vitamins
5. Minerals

All are equally important to our well-being, although they are needed in varying quantities, from about 250g of carbohydrate a day to less than two micrograms of vitamin B12. Most foods contain a mixture of nutrients (there are a few exceptions, like pure salt or sugar) but it is convenient to classify them by the main nutrient they provide. Still, it is worth remembering that everything you eat gives you a whole range of essential nutrients.

Meat supplies protein, fat, some B vitamins and minerals (mostly iron, zinc, potassium and phosphorous). Fish, in addition to the above, supplies vitamins A, D, and E, and the mineral iodine. All these nutrients can be easily obtained by vegetarians from other sources, as shown below.

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Women need about 45g of protein a day (more if pregnant, lactating or very active); men need about 55g (more if very active). Evidence suggests that excess protein contributes to degenerative diseases. Vegetarians obtain protein from:

  • Nuts: hazels, brazils, almonds, cashews, walnuts, pine kernels etc.
  • Seeds: sesame, pumpkin, sunflower, linseeds.
  • Pulses: peas, beans, lentils, peanuts.
  • Grains/cereals: wheat (in bread, flour, pasta etc), barley, rye, oats, millet, maize (sweet corn), rice.
  • Soya products: tofu, textured vegetable protein, veggie burgers, soya milk.
  • Dairy products: milk, cheese, yoghurt (butter and cream are very poor sources of protein).
  • Free range eggs.

You may have heard that it is necessary to balance the complementary amino acids in a vegetarian diet. This is not as alarming as it sounds. Amino acids are the units from which proteins are made. There are 20 different ones in all. We can make many of them in our bodies by converting other amino acids, but eight cannot be made, they have to be provided in the diet and so they are called essential amino acids. Single plant foods do not contain all the essential amino acids we need in the right proportions, but when we mix plant foods together, any deficiency in one is cancelled out by any excess in the other. We mix protein foods all the time, whether we are meat-eaters or vegetarians. It is a normal part of the human way of eating. A few examples are beans on toast, muesli, or rice and peas. Adding dairy products or eggs also adds the missing amino acids, eggs macaroni cheese, quiche, porridge.

The body has a pool of amino acids so that if one meal is deficient, it can be made up from the body's own stores. Because of this, we don't have to worry about complementing amino acids all the time, as long as our diet is generally varied and well-balanced. Even those foods not considered high in protein are adding some amino acids to this pool.

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Carbohydrate is our main and most important source of energy, and most of it is provided by plant foods. There are three main types: simple sugars, complex carbohydrates or starches and dietary fiber.

1.  Sugars or Simple Carbohydrates:

Can be found in fruit, milk and ordinary table sugar. Refined sources of sugar are best avoided as they provide energy without any associated fiber, vitamins or minerals and they are also the main cause of dental decay.

2.  Complex Carbohydrates:

Found in cereals/grains (bread, rice, pasta, oats, barley, millet, buckwheat, rye) and some root vegetables, such as potatoes and parsnips. A healthy diet should contain plenty of these starchy foods as a high intake of complex carbohydrate is now known to benefit health. The unrefined carbohydrates, like whole meal bread and brown rice are best of all because they contain essential dietary fiber and B vitamins.  The World Health Organization recommends that 50-70% of energy should come from complex carbohydrates. The exact amount of carbohydrate that you need depends upon your appetite and also your level of activity. Contrary to previous belief a slimming diet should not be low in carbohydrates. In fact starchy foods are very filling relative to the number of calories that they contain.

3. Dietary Fiber:

Refers to the indigestible part of a carbohydrate food. Fiber can be found in unrefined or wholegrain cereals, fruit (fresh and dried) and vegetables. A good intake of dietary fiber can prevent many digestive problems and protect against diseases like colon cancer and biventricular disease.

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Fats & Oils

Too much fat is bad for us, but a little is necessary to keep our tissues in good repair, for the manufacture of hormones and to act as a carrier for some vitamins. Like proteins, fats are made of smaller units, called fatty acids. Two of these fatty acids, linoleic and linolenic acids, are termed essential as they must be provided in the diet. This is no problem as they are widely found in plant foods.

Fats can be either saturated or unsaturated (mono-unsaturated or poly-unsaturated). A high intake of saturated fat can lead to a raised blood cholesterol level and this has been linked to heart disease. Vegetable fats tend to be more unsaturated and this is one of the benefits of a vegetarian diet. Mono-unsaturated fats, such as olive oil or peanut oil, are best used for frying as the poly-unsaturated fats, like sunflower or safflower oil are unstable at high temperatures. Animal fats (including butter and cheese) tend to be more saturated than vegetable fats, with the exception of palm oil and coconut oil.

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Vitamin is the name for several unrelated nutrients that the body cannot synthesize either at all, or in sufficient quantities. The one thing they have in common is that only small quantities are needed in the diet. The main vegetarian sources are listed below:

Vitamin A (or beta carotene):  Red, orange or yellow vegetables like carrots and tomatoes, leafy green vegetables and fruits like apricots and peaches. It is added to most margarine.

B Vitamins:  This group of vitamins includes B1 (thiamin), B2 (riboflavin), B3 (niacin), B6 (pyridoxine), B12 (cyanocobalmin), foliate, pantothenic acid and biotin.

All the B vitamins except B12 occur in yeasts and whole cereals (especially wheat germ), nuts & seeds, pulses and green vegetables.

Vitamin B12 is the only one that may cause some difficulty as it is not present in plant foods. Only very tiny amounts of B12 are needed and vegetarians usually get this from dairy produce and free range eggs. It is sensible for vegans and vegetarians who consume few animal foods to incorporate some B12 fortified foods in their diet. Vitamin B12 is added to yeast extracts, soya milks, veggie burgers and some breakfast cereals.

Vitamin C: Fresh fruit, salad vegetables, all leafy green vegetables and potatoes.

Vitamin D:  This is vitamin is not found in plant foods but humans can make their own when skin is exposed to sunlight. It is also added to most margarine and is present in milk, cheese and butter. These sources are usually adequate for healthy adults. The very young, the very old and anyone confined indoors would be wise to take a vitamin D supplement especially if they consume very few dairy products.

Vitamin E: Vegetable oil, wholegrain cereals, eggs.

Vitamin K: Fresh vegetables, cereals and bacterial synthesis in the intestine.


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Minerals perform a variety of jobs in the body. Details of the some of the most important minerals are listed below:

Calcium: Important for healthy bones and teeth. Found in dairy produce, leafy green vegetables, bread, tap water in hard water areas, nuts and seeds (especially sesame seeds), dried fruits, cheese. Vitamin D helps calcium to be absorbed.

Iron: Needed for red blood cells. Found in leafy green vegetables, whole meal bread, molasses, eggs, dried fruits (especially apricots and figs), lentils and pulses. Vegetable sources of iron are not as easily absorbed as animal sources, but a good intake of vitamin C will enhance absorption.

Zinc: Plays a major role in many enzyme reactions and the immune system. Found in green vegetables, cheese, sesame and pumpkin seeds, lentils and wholegrain cereals.

Iodine: Present in vegetables, but the quantity depends on how rich the soil is in iodine. Dairy products also have plenty of iodine. Sea vegetables are a good source of iodine for vegans.