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Sugars
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| Sugars, or glucides, are just sweet-tasting simple carbohydrates such as sucrose and lactose. They can be consumed in granular form, but they are also contained in large quantities in fruit and some complex carbohydrates such as starch. It is therefore necessary to dose them carefully, ensuring a moderate intake. |
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WHAT'S IN A GRAIN OF SUGAR? |
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Sugar, which is chemically defined as a glucide, is an organic substance that is part of the family of carbohydrates. Like these, it is composed of carbon, hydrogen and oxygen, but unlike complex carbohydrates (such as the starches in pasta, bread or potatoes), sugar is considered a simple carbohydrate. This is to be found in large quantities in fruit, milk or substances of vegetable origin which, following refinement are consumed in the form of cubes or white grains named sucrose more commonly known as sugar.
From a purely biochemical point of view, this substance is defined as a disaccharide because it is made up of two monosaccharides: fructose and glucose. But sugars can also appear in the form of oligosaccharides or polysaccharides, depending on the complexity of their chemical composition.
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Sugars can be subdivided depending on their origin (animal or vegetable), or according to the number of elements comprising their chemical composition.
Monosaccharides are generally white and sweet and dissolve in water. The main ones are glucose (found in fruit and vegetables, and which is the main quick-use nutrient for all the cells in the human body), fructose (mostly present in apples and pears, with sweetening power that is greater than all the other sugars) and galactose (present in milk).
Disaccharides are the most common and nutritious of sugars. In addition to sucrose, nature's most widespread disaccharide is lactose, contained in animal as well as human milk.
Last of all, the polysaccharides are considered to be complex carbohydrates; in addition to starch (which is of vegetable origin), they include animal substances such as glycogen, which provides the main energy reserve to the muscles.
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The main function of sugars is to supply energy, both of the type that is immediately available and that which is available in reserve form. Glucose, sucrose and fructose are ideal for topping up the body immediately, as they do not need to be digested to supply energy, whilst complex sugars such as starches must be subdivided into more simple elements during digestion. Nutritionally speaking, the latter are particularly important as they provide half of man's daily energy requirements in a healthy diet.
Sugars supply four calories per gram and are generally to be found in vegetable origin foods, such as cereals, fruit or honey, whilst they are virtually absent from animal origin ones, excepting milk which has a high sugar content.
In order to correctly calculate the right overall requirement it is necessary to remember that sugars are part of the same family as carbohydrates, and that it is therefore not advisable to exceed when combining sugary foods with other foods that are rich in starch.
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