Carbohydrates provide the body mostly with energy, however, their components are anchored in every bodily cell. There are simple and complex carbohydrates. Simple carbohydrates include monosaccharides (glucose, fructose, mannose and galactose) and disaccharides (sucrose, lactose and maltose). The latter are quickly digested, provide a rapid source of energy and rapid secretion of insulin. Complex carbohydrates are polysaccharides (glycogen, starch and dietary fibre). The recommended intake of carbohydrates in the daily diet is more than 50% of the daily energy intake. Especially carbohydrate foods containing essential nutrients and dietary fibre are recommended. Simple sugars should not contribute more than 10% of the daily energy intake as they have a high glycaemic index (GI). The GI is a parameter that describes how fast the carbohydrates are absorbed into the blood after consumption elevating blood sugar levels, compared to pure glucose. The consumption of foods with a high GI (e.g. plain sugar, sweets, sweet drinks) results in more rapid and higher increases in blood glucose levels and causes an increased secretion of insulin. Strains on the pancreatic hormone system, which secretes insulin, can be seen in chronically increased blood glucose and insulin levels, which can lead to impaired glucose metabolism and insulin resistance. Studies have shown that high fructose (fruit sugar) intakes, especially in people with fructose intolerance, increase the risk of dyslipidemia, increase insulin resistance and visceral fat in overweight and obese people. There is however no evidence confirming that we should avoid the fructose that is naturally present in fruit, vegetables and other food. Fructose is not a recommended substitute for other sugars. It is estimated that it usually contributes 3 to 4 percent of our daily energy. The advantage of complex carbohydrates lies in the higher levels of dietary fibre, which is very important in a healthy and balanced diet as it reduces the GI value of food/meal and has a beneficial effect on digestion. In assessing the effect of carbohydrate foods/meals on the increase of blood glucose levels, glycaemic load was later introduced, which in addition to the GI value also includes the amount of carbohydrates per unit of food or meal. Studies have shown that meals with a low glycaemic load reduce the risk of metabolic diseases. Dietary fibre is a carbohydrate that usually has no utilisable energy value, but influences various important functions in the gastrointestinal tract. An orientation value for dietary fibre intake of adults is about 3.8 g/MJ or 16 g/1,000 kcal for women and 2.9 g/MJ or 12.5 g/1,000 kcal for men. However, excessive dietary fibre intake partly reduces the absorption of nutrients in the gastrointestinal tract, which should also be taken into account when planning diets, especially for children and the elderly. Dietary fibre can prevent many diseases and functional disorders. The most important are constipation, colon diverticulosis, colon cancer, gallstones, excessive weight, high blood cholesterol, diabetes and arteriosclerosis. There are soluble fibre, such as β-glucans, pectins, gums and partially hemicellulose, which are found in pome fruit, oranges, grapefruit, peas, lentils, soya beans, vegetables, and insoluble fibre, such as cellulose, hemicellulose and lignin, which are mainly found in wholegrain products.
Estimated carbohydrate intake (grams per day) calculated as 55 % of daily energy intake
|Adolescents and adults||Men||Women|
|15 to 19 years old||350||275|
|19 to 25 years old||350||260|
|25 to 51 years old||330||260|
|51 do manj kot 65 let||300||250|
|65 years old and older||275||220|