Carbohydrates.
Carbohydrates are chemical organic compounds that their molecules are consisted of oxygen, hydrogen and carbon atoms. Carbohydrates are  significant but not necessary dietary components in humans' diet, since they can occur as protein metabolism products. This is the reason, why many people, although do not eat many carbohydrates, are absolutely healthy. However, carbohydrates are important sources of stored energy. What is more, this category of foods does not burden the cardiovascular system as fats do. It is remarkable that health organizations, such as the Institute of Medicine, the Food and Agriculture Organization and the World Health Organization recommend that 40%-75% of the energy required for bodily function to be obtained from carbohydrates. This energy is released, as soon as carbohydrates are ingested and metabolized. At the latest stage, carbohydrates brake to glucose which is the basic element that provides energy. Since the energy derived from carbohydrates is mainly used in muscles and the nervous system, low-carbohydrates diets may result in impaired brain and muscle performance.
Insulin plays a key role in sugar metabolism and the control of blood glucose level. Carbohydrates include sugars, starches and fiber. Carbohydrates are more easily digested and absorbed than proteins or fats. Members of B complex vitamins, such as riboflavin, thiamine, niacin, pantothenic acid, pyridoxine and biotin, are very important for the metabolism of carbohydrates.
Carbohydrates are classified as monosaccharides, disaccharides, oligosaccharides and polysaccharides, depending on the structure of their chemical chain, since it may be consisted of one, two, more or many sugar units respectively. For instance, glucose and fructose are monosaccharides, sucrose, maltose and lactose are disaccharides, raffinose and stachyose are oligosaccharides, whereas starch, amylose, cellulose and glycogen are polysaccharides.
Food sources of carbohydrates.
Carbohydrates are contained in a huge range of foods either of animal or plant origin.
 Monosaccharides, such as fructose and galactose, are found in fruits and dairy products respectively. Simple carbohydrates are also  substances of processed and refined sugars such as candy, table sugar, brawn sugar, syrups and regular carbonated beverages.
Double sugars include lactose, sucrose and maltose. They can be found in dairy products, certain vegetables, beer, cereals, some baked goods and table sugar. Honey contains simple and double sugars, as well.
Complex carbohydrates often referred to as starchy sugars or polysaccharides. They are contained in numerous foods, such as whole grain breads and cereals, legumes, flour, rice, corn, oats, barley, wheat bran and pasta. Complex carbohydrates are also found in vegetables, such as cabbage, beets, potatoes, tomatoes, carrots, Brussels sprouts, turnips, cauliflowers and nearly in all rape fruits.
Recommendations about carbohydrates.
Although refined sugars provide calories, they are of low nutritional value, since they are deficient in vitamins, minerals and fiber. Refined sugary foods such as white flour, table sugar and polished rice, do not contain B complex vitamins or other important nutrients, unless they have been fortified. A diet that includes plenty of fruits can provide all the necessary carbohydrates, vitamins and other important nutrients, depending on the source. On the contrary, confectionery and fizzy drinks have no nutritional value and must be consumed in moderation, because they can result in dental problems and weight gain. Excessive amounts of carbohydrates will increase the total daily caloric intake and on a long term basis, they may lead to weight gain or obesity. On the other hand, prolonged low-carbohydrates diet may cause malnutrition, excessive unintentional weight loss or increased intake of fats for caloric supply which, in turn, can be a risk factor for atherosclerosis and other cardiovascular conditions. Dieticians suggest that 50% to 60% of total daily calories should be obtained from carbohydrates.
Complex carbohydrates, which are contained in vegetables, fruits and grains, are far more beneficial than the simple carbohydrates found in sugar, honey and confectionary. Complex carbohydrates provide fiber, vitamins and minerals, whereas refined sugars do not. In fact, foods high in complex carbohydrates are relatively low in calories and usually they are free of saturated fats and cholesterol. |
