Flash-04 wrote:в фруктах и ягодах разве не фруктоза? вроде бы для диабетиков она не так вредна как сахароза?
Sucrose is made from glucose and fructose units:
The glucose and fructose units are joined by an acetal oxygen bridge in the alpha orientation. The structure is easy to recognize because it contains the six member ring of glucose and the five member ring of fructose.
Sugar or more specifically sucrose is a carbohydrate that occurs naturally in every fruit and vegetable. It is the major product of photosynthesis, the process by which plants transform the sun's energy into food. Sugar occurs in greatest quantities in sugar cane and sugar beets from which it is separated for commercial use.
When sucrose is hydrolyzed it forms a 1:1 mixture of glucose and fructose. This mixture is the main ingredient in honey.
Carbohydrates are divided into two groups-simple carbohydrates and complex carbohydrates. Simple carbohydrates, sometimes called simple sugars, include fructose (fruit sugar), sucrose (table sugar), and lactose (milk sugar), as well as several other sugars. Fruits are one of the richest natural sources of simple carbohydrates. Complex carbohydrates are also made up of sugars, but the sugar molecules are strung together to form longer, more complex chains. Complex carbohydrates include fiber and starches. Foods rich in complex carbohydrates include vegetables, whole grains, peas, and beans.
Carbohydrates are the main source of blood glucose, which is a major fuel for all of the body's cells and the only source of energy for the brain and red blood cells. Except for fiber, which cannot be digested, both simple and complex carbohydrates are converted into glucose. The glucose is then either used directly to provide energy for the body, or stored in the liver for future use. When a person consumes more calories than the body is using, a portion of the carbohydrates consumed may also be stored in the body as fat.
Не уверена, какая доля сахара в фруктах представлена сахарозой, а какая фруктозой. Мне кажется, что сахарозы там больше.
Насколько я понимаю, фруктоза не вызывает таких колебаний в уровне инсулина, как сахароза, и в этом плане может быть лучше для диабетиков в качестве подсластителя. С другой стороны, из-за того, что фруктоза меньше влияет на sugar-sensing mechanisms (инсулин и др. гормоны), есть гипотеза, что она может скорее вызывать ожирение, чем сахароза (по крайней мере фруктоза в виде high fructose corn syrup).
Bantle JP.
Division of Endocrinology and Diabetes, Department of Medicine, University of Minnesota, MN, USA.
Fructose is a monosaccharide which is abundant in nature. It is the sweetest naturally occurring carbohydrate. The availability of fructose increased substantially when it became possible in the 1960s to economically produce high fructose syrups from corn starch and other starches. Such high fructose syrups are now used to sweeten soft drinks, fruit drinks, baked goods, jams, syrups and candies. The most recent data available suggest that fructose consumption is increasing worldwide. Fructose presently accounts for about 10% of average total energy intake in the United States. Studies in both healthy and diabetic subjects demonstrated that fructose produced a smaller postprandial rise in plasma glucose and serum insulin than other common carbohydrates. Substitution of dietary fructose for other carbohydrates produced a 13% reduction in mean plasma glucose in a study of type-1 and type-2 diabetic subjects. However, there is concern that fructose may aggravate lipemia, particularly in men. In one study, daylong plasma triglycerides (estimated by determining the area under response curves) in healthy men was 32% greater during a high fructose diet than during a high glucose diet. There is also concern that fructose may be a factor contributing to the growing worldwide prevalence of obesity. Increasing fructose consumption is temporally associated with the increase in obesity. Moreover, on theoretical grounds, dietary fructose might increase energy intake. Fructose stimulates insulin secretion less than does glucose and glucose-containing carbohydrates. Since insulin increases leptin release, lower circulating insulin and leptin after fructose ingestion might inhibit appetite less than consumption of other carbohydrates and lead to increased energy intake. However, there is not yet any convincing experimental evidence that dietary fructose does increase energy intake. Although evidence that fructose has adverse effects is limited, adding fructose in large amounts to the diet may be undesirable, particularly for men. Fructose that occurs naturally in fruits and vegetables is a modest component of energy intake and should not be of concern.
