Basic Approach Of Nutrition: Food

February 26, 2021 by Chad Kimball

The functioning, growth and good health of the human body depend on a daily supply of nutrients. The essential nutrients for life are:

Macronutrients: proteins, lipids, glucides
Micronutrients: vitamins, minerals and oligo-elements.

Proteins and amino-acids

Proteins are elements that play a part in building our cells. They are our primary source of energy, necessary for all kinds of metabolic processes. Our skin, muscles, internal organs, hormones, enzymes, genes and all sorts of tissues are made of proteins.

Because of the major role they play, a diet deprived of proteins is likely to cause problems and various diseases. Food supplies us with animal proteins (meats, fishes, eggs and milk products) and proteins of vegetable origin (dried vegetables, cereals and soya).

A protein is made up of a chain of amino acids. During digestion, the links between these are broken by enzymes, which results in the liberation of amino-acids. All of these are required for our organism to synthesise its own proteins.

Some amino-acids can be produced by the organism, but others can only be supplied by food. The latter is called ‘essential amino acids. This notion of ‘essential amino acids establishes the notion of the ‘biological value’ of a protein.

Thus some vegetal proteins have a limited value, i.e. a poor fraction of amino-acids. It is, therefore, necessary to associate different foodstuffs in one’s diet in order to obtain a good biological protein.

Examples of associations

milk + cereals –> ‘milk-semolina’
cereals + dried vegetables –> ‘couscous’
cereals + dried fruits –> ‘tabbouleh’

Concerning animal proteins, they have a good biological value, and they are often found in giblets or offals or meat.

Energetic equivalence of proteins: 1 g of protein = 4 calories = 17 KJ.

Lipids and fatty acids

Food-fats or lipids are essential parts of our body. Half of our brain, for instance, is made of lipids. However, the need for lipids is not great.

Lipids are useful as a reserve of energy in case of sustained deficiency. Lipids bring us also vitamins A, E and K.

The sources for lipids are either animal (eggs, meats, fishes, cold cuts, butter, cream and cheese) or vegetal (oils, margarine, oleaginous fruits).

Lipids are made of fatty acids. We can distinguish the saturated fatty acids and unsaturated fatty acids.

The saturated fatty acids are present mainly in animal fats, and the unsaturated fatty acids in vegetable fats. Because of their major biological role, some unsaturated fatty-acids are called essential, but our body is unable to synthesize them itself. They are provided to our organism by food, mainly vegetable oils and fish.
Saturated fatty acids are more valuable than the unsaturated type because they keep the cholesterol level down, particularly the ‘bad cholesterol’, thus protecting our cardiovascular system.

Energetic value of lipids: 1 g of lipid = 9 calories = 38 KJ

Glucides or carbo-hydrates

Glucides play essentially an energetic role. They are our main source of energy through the provision of glucose, which is the fuel for all cell-types in the human body. For example, glucides are the only source of energy that the brain can utilize, as it is unable to store energy.

Sources of glucose in food are mainly of vegetable origin: leguminous plants, cereals, potatoes (starch), and also fruits, vegetables, sugar beet, and sugar cane. A small fraction of glucides comes from the animal world: milk products and liver (glycogen).

We can separate :

Rapid sugars: they have a short chain, and are quickly digested, thus rapidly increasing the sugar blood level (glycaemia).
Low sugars: they have a long chain, and are slowly digested, with a progressive increase of glycaemia.

Energetic value of glucides: 1g of glucose = 4 calories = 17 KJ

Food fibres

Fibres are substances that stem from plants and bypass the digestion in the small bowel of a healthy human being. There are two types of de fibres: those that can be broken down by the colic flora, and the insoluble fibres, that are hard, if at all broken down. They stem from the vegetal terrestrial world (cereals, leguminous, fruits and vegetables), and from the see-world (seaweeds).

The feeding fibres play an important part in the nutritional balance and the metabolism: regulation of the intestinal transit, control on food-intake via their effect on satiety.

The energetic value of fibres: 1 g of fibres = 0 calorie

Minerals

Minerals are not a source of energy, but they are incorporated in cell-structures (cell-membranes, bones, etc.). The only source for the body is food because the organism cannot create them by itself. Besides, minerals are necessary for the activity of enzymes and hormones. The main minerals and their effects are described below.

Mineral	Role	Sources
Calcium	Growth and mineralization of the bones Neuromuscular excitability Blood coagulation Control of the heart-rhythm	Milk food
Potassium	Muscular contraction Tissue construction	Coffee, cocoa, yeast, dried fruits and oleaginous fruits
Sodium	Regulates the movements of water inside the organism Hydrates cells	Regular salt, canned food, pork meats, cheeses, crackers
Magnesium	Neuromuscular excitability	Chocolate, cocoa, coffee, wheat germ, dried fruits and oleaginous, cereals
Phosphore	Bone mineralization, enzyme reactions	Present in many foods

Oligo-elements

Very small amounts are present inside our body, but they play a major role in various metabolic reactions. The most significant are Iron, Zinc, Copper, Chromium, Selenium, Iodine, Magnesium and Cobalt.

Vitamins

They are necessary for a healthy life. Varying and balanced food supplies us with our needs for vitamins. Like minerals and oligo-elements, vitamins do not have a nutritional value. They are active molecules required in very small amounts, but a deficiency can cause severe diseases or dysfunctions.

Vitamins are separated in two categories :

Liposoluble vitamins: vitamins A, D, E, K
Hydrosoluble vitamins: vitamins from groups B and C

Vitamines	Rôles	Sources
A	Vision	Eggs, fat-food (cream, butter, full-cream milk, cheeses), vegetables and coloured fruits
D	Calcium metabolism	Egg yolk, full-cream milk, butter, fat fishes, cheeses
E	Anti – oxidant	Oils and wheat-germ
K	Anticoagulant	Leaf-vegetables, tomatoes
B	Protein, lipid, glucoside metabolism	Cereals, dried vegetables, vegetables, yeast, beer, eggs, offal, liver
C	Immunity	Vegetables, fruits and liver

Beverages and water

One has to drink an average of 1.5 litres of water a day. Water is the only liquid essential to the body. This is important to ensure the hydration of our cells and the elimination of wastes through the kidney.

If you find it hard to drink those 1.5 litres, here is a trick that will help to cover your daily needs:

Always carry a bottle of water with you; this will remind you to drink and help you evaluate the amount you have already drunk.
Replace tap-water with other unsweetened waters, such as:
- Mineral waters with gas (e.g. Perrier…) that contain some essential minerals.
- Infusions, herbal teas, light coffee
- Vegetable stock (that deliver vitamins and minerals).

Equivalences

When you are following a diet, it is important to avoid weariness. Equivalences may help to alternate foods. Thus food-intake can vary according to individual tastes.

For example, one can replace:

A pear by an apricot purée (without added sugar)
A chicken leg by a fish filet

Milk food
1 glass (=125 ml) of half-cream milk	= 1 plain yoghourt = 1 white cheese 20% fat content = 2 petits-suisses 20% fat content
Bread
30 g of bread	= 1 slice of bread = 30 g whole-wheat bread, with bran or cereals = 2 Melba toasts = 20g cereals (special K, Fitness…)
Fat food
15 g of butter	= 15g margarine = 60g 15% fresh cream = 20g diet mayonnaise = 10g oil (1 table-spoonful)
Fruits
1 fruit	= 1 apple, 1 pear, 1 orange = 1 fruit purée without added sugar (100g) = ½ banana = 1 glas of fruit-juice without sugar = ¼ fresh pineapple = 2 kiwis = 2 clementines = 1 peach = 3 apricots = 2 to 4 plums = ½ grape-fruit = 150g strawberry or banana = 10-15 cherries = 10-15 grapes = 200g melon or water-melon
Meats, fishes and eggs
100 g of meat	= 150 g fish = 100 g fowl = 2 eggs = 2 slices of ham, turkey or chicken = 180 g shell-fish = 18 oysters = 25-30 mussels
Starchy food
100 g of starchy food	= 100 g boiled potatoes =100 g boiled rice, pasta or semolina, or 25g uncooked = 100 g cooked dried vegetables (lentils, dried beans…) or 30-35 g uncooked = 40 g bread = 100 g cooked corn = 100 g peas = 25 g flour

Besides good nutrition, a holistic lifestyle including relaxation treatments can be helpful for your overall health. Acupuncture is one such treatment that can be beneficial to you. If you find yourself wondering “What are the benefits of acupuncture”, you can look into a variety of helpful resources online.