From the chemical point of view carbohydrates are ternary organic compounds, formed by three elements: carbon, hydrogen and oxygen.

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1 Carbohydrates, or sugars, are key organic constituents of living matter; mainly represented by polymers synthesized in the plant world as "support material" (cellulose) or "spare" (starch), and in the animal world as a "reserve" material (glycogen). From the chemical point of view carbohydrates are ternary organic compounds, formed by three elements: carbon, hydrogen and oxygen. Carbohydrates are present only in foods of plant origin, with the exception of milk and its derivatives.

2 The production of carbohydrates in Nature takes place in green plants through the process of PHOTOSYNTHESIS which catalyzes the conversion of carbon dioxide and water in D (+) - glucose. This reaction is made thanks to the energy supplied by the sun in the form of light radiation.

3 can be differentiated from a CHEMICAL point of view as: simple sugars (monosaccharides), water soluble and with sweet taste; complex sugars (oligosaccharides and polysaccharides), insoluble and devoid of sweet taste. and from a NUTRITIONAL point of view, as: available carbohydrates, sugars and polysaccharides such as starch, with nutritional value as digestible, unavailable carbohydrate, such as certain oligosaccharides and non-digestible polysaccharides (cellulose, hemicellulose, pectin, etc..) and, finally, the socalled dietary fibers.

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5 Depending on the number of carbon atoms, we can distinguish among monosaccharides, trioses, tetroses, pentoses and hexoses. For instance, trioses have three carbon atoms, the hexoses have six. Simple glucose is found in fruits, vegetable extracts, honey and in the blood, where, in physiological conditions, is approximately g/l amounts (normal glycemic).

6 This concentration is kept constant by means of the INSULIN The lack of this hormone, as its insufficient production, determines an increase in blood glucose levels and the presence of glucose in the urine - DIABETES MELLITUS.

7 FRUCTOSE or fruit sugar is the sweetest monosaccharide, contained mainly in cherries, pears, strawberries and oranges. It is combined with the glucose in honey and ripe fruit to give sucrose. Fructose is levorotatory, it means that rotates polarized light to the left (experiment with a polarimeter). It is a glucose isomer. GALACTOSE does not exist free in Nature; it is produced by the hydrolysis of lactose and converted into glucose during its intestinal absorption. The genetic deficiency in infants of galactose-1-phosphate uridyl transferase, an enzyme that converts galactose into glucose, causes a metabolic disease known as galactosemia, which produces an abnormal increase of galactose in blood, responsible of a severe mental retardation.

8 OLIGOSACCHARIDES (disaccharides and trisaccharides) are obtained combining 2 or 3 molecules of monosaccharides, respectively. DISACCHARIDES The sugar commonly used at home as a sweetener is sucrose. Sucrose is naturally found in many plants, and it is industrially extracted from cane sugar or beet sugar (European areas). Other important disaccharides are maltose and lactose.

9 Lactose is found in mammal milk at varying rates: on average 4.5% in cow s milk; 4.9% in sheep s milk; 6.5% in that of woman. It has low sweetening power, so is used mainly for the production of reconstituted milk and some pharmaceutical preparations. It occurs in crystals, water soluble, and melting point at about 202 C. Maltose is composed by two glucose molecules, which can be released by acidic or enzymatic hydrolysis (maltase). It is produced in the process of germination of cereals, while in the human body is formed from starch, together with dextrin, by the action of diastase, a mixture of amylolytic enzymes derived from malted barley.

10 The natural product, which more than any other can be considered as a sweetener is the honey, consisting of a highly concentrated aqueous solution of simple sugars, with prevalence of fructose and sucrose, in addition small amounts of gummy substances, albuminoid and waxy, organic acids, ethers, minerals (iron, calcium and phosphorus) and vitamins B2, C and niacin.

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12 Complex carbohydrates or polysaccharides include starch and dietary fiber. Starch is the main source of available carbohydrates (to be used by the cell metabolism), in healthy adults.

13 The starch, the reserve carbohydrate of plants, is widespread in the plant kingdom. The pure compound is in the form of white amorphous powder, insoluble in cold water and alcohol. It consists of granules, structurally different depending on the plant material, (those of wheat starch are ovoid, while those of rice are smaller and prismatic); therefore, we can trace the origin of the flour by the morphological examination of the starch granules. WHEAT STARCH RICE STARCH POTATO STARCH

14 STARCH provides energy, readily usable, and is easily digested by humans, unlike cellulose. The starch, when ingested, is hydrolyzed and then cleaved into glucose units, which are carried by the blood and to the liver, where they recombine to form GLYCOGEN. It is the carbohydrate reserve material of animals and is found in the liver and musclesits structure is similar to amylopectin, with a greater degree of branching. CELLULOSE is the main constituent along with lignin of cell walls in plants. It is insoluble and very resistant to most chemical agents. Cellulose is not digested by human body for the lacking of the specific enzyme.

15 Bread and pasta are the strongly starchy foods. Bread is the first and most important food of man, is obtained from wheat flour for kneading with water, leavening and baking the dough.

16 As nutritional value, carbohydrates are the most important principles for the intake of energy, because, although having an energy value higher than that of proteins (4 kcal/g), they produce energy more readily, since their metabolism begins already in the mouth, thanks to the salivary enzyme, ptyalin. Classifiation of ENERGY FOODS (mainly because they provide energy): 1. CEREALS and their derivatives (bread, pasta, polenta, rice, etc.), mainly carbohydrate, because they provide quick energy use. For example, the common bread contains 61.3% carbohydrates and, then, develops 277 kcal/100 g; semolina pasta contains 74.6% carbohydrates and, then, develops 373 kcal/100 g. 2. FATS (including vegetable oils), because they provide a high input of energy (9 kcal / g).

17 Humans ingest more than 50% of the daily energy in the form of carbohydrates (mono, di and polysaccharides). The main function of carbohydrates is to provide energy to human body. Therefore, a part of glucose is used to meet immediate energy needs, a part is deposited in the form of glycogen in the liver and muscles, and the remaining portion is converted into fat and deposited in adipose tissue.

18 Carbohydrate amounts in human body stored as glycogen is very small (about 365 g: 110g in liver, 245 g in muscles, and 10 g in extracellular fluids). This reserve could ensure an amount of energy equal to about 1368 kcal, sufficient for up to 13 hours of moderate activity. Therefore, human body needs carbohydrates regularly to meet the constant demand of energy. Muscle glycogen is a source of energy only for processes occurring into muscle cells. In fact, muscle can not produce glucose directly, because this tissue does not possess the enzyme responsible for this conversion. Conversely, during muscle contractions glycogen is converted to lactic acid, which is then converted into glucose. Glucose derived from liver glycogen may be a source of energy for all the body's cells.

19 In addition to the crucial energetic action, carbohydrates perform specific regulatory functions: Regulation of lipid and protein metabolism Protection and detoxification of liver Energy reserve in the heart muscle Furthermore, the cellulose present in dietary fiber helps the bolus transit in the intestine and, therefore, facilitates digestion. Lactose facilitates the absorption of calcium. Ribose is one of the fundamental components of nucleic acids (DNA and RNA).

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21 The digestion of carbohydrates already starts in the mouth, thanks to the enzyme ptyalin present in the saliva and secreted by the parotid glands, which begins to hydrolyze the polysaccharides, into dextrins and, then, maltose and glucose. Digestion continues in the stomach due to gastric juice: the gastric peristaltic movements push starchy substances, become chime, toward the pylorus and, then, into the duodenum. Starch digestion is completed in the small intestine, thanks to several enzymes of pancreatic and enteric origin.

22 Dietary fiber is the set of complex carbohydrates (polysaccharides, cellulose, hemicellulose, lignin, inulin, oligosaccharides) and other substances not immediately digestible by humans and therefore not assimilated by the body. We often call "fiber" even non-fibrous food substances (eg pectin). Although it can not be considered a nutrient, dietary fiber exerts functional and metabolic effects that suggest an important component of the human diet. In addition to the increase in satiety and improving bowel function and disorders associated with it (constipation, diverticulosis), the introduction of fiber with foods has been linked to reduced risk for major chronic diseases, particularly colon and rectum cancers (partially explained by the dilution of potential carcinogens and the reduction of their contact time with the mucosa), diabetes and cardiovascular disease (for a reduction in blood cholesterol levels) (data from the National Research Council, 1989).

23 This classification arises from the consideration that not all carbohydrates present in food can be metabolized, as well as amidst the available carbohydrate can definitely include starch and simple sugars such as fructose, glucose and sucrose, while appearing definitely included among the unavailable carbohydrates, cellulose, hemicellulose, and more generally all those carbohydrates present in food and that can be included in what is defined as soluble dietary fiber.

24 Resistant starch is a type of starch that isn t fully broken down and absorbed, but rather turned into short-chain fatty acids by intestinal bacteria. This may lead to some unique health benefits. To get the most from resistant starch, choose whole, unprocessed sources of carbohydrate such as whole grains, fruits, vegetables, and beans/legumes. Thus, resistant starch is so named because it resists digestion. While most starches are broken down by enzymes in our small intestine into sugar, which is then absorbed into the blood, we can t fully absorb all kinds of starch. Some starch known as resistant starch (RS) isn t fully absorbed in the small intestine. Instead, RS makes its way to the large intestine (colon), where intestinal bacteria ferment it. RS is similar to fibre, although nutrition labels rarely take RS into account.

25 However, RS still plays an important role in our diets even though we don t necessarily absorb it. When RS is fermented in the large intestine, short chain fatty acids (SCFA) such as acetate, butyrate, and propionate, along with gases are produced. SCFAs can be absorbed into the body from the colon or be used by colonic bacteria for energy. Evidence suggests that SCFAs may benefit us in many ways. For instance, they: stimulate blood flow to the colon increase nutrient circulation inhibit the growth of pathogenic bacteria help us absorb minerals help prevent us from absorbing toxic/carcinogenic compounds The amount of SCFAs we have in our colon is related to the amount and type of carbohydrate we consume. And if we eat plenty of RS, we have plenty of SCFAs.

26 In a Research Review on processed vs. whole foods, researchers found that less-processed foods offered less energy than refined foods. In other words, although whole and processed foods may contain the same amount of calories, we absorb fewer calories of energy from whole foods. Since RS is incompletely digested, we only extract about 2 calories of energy per gram (versus about 4 calories per gram from other starches). That means 100 grams of resistant starch is actually only worth 200 calories, while 100 grams of other starch gives us 400 calories. The way we ve modified/processed grains and starchy vegetables in the modern food supply diminishes the amount of RS we consume (cereal bars instead of oats, burgers instead of beans, potato chips instead of boiled potatoes). Thus, to get the most benefits from RS, we need to consume it in whole food format. Most developed countries (including Europe, the United States, New Zealand, and Australia), which have a highly processed diet, consume about 3-9 g/day of RS. In developing countries, diets are often based around whole plant foods and the intake of RS tends to be around g/day.

27 RS is found in starchy plant foods such as: beans/legumes starchy fruits and vegetables (such as bananas) whole grains some types of cooked then cooled foods (such as potatoes and rice) The longer and hotter a starch is cooked, the less RS it tends to have.

28 IMPROVED BLOOD FATS RS may help to lower blood cholesterol and fats,. Also, since SCFAs can inhibit the breakdown of carbohydrates in the liver, RS can increase the amount of fat we utilize for energy. BETTER SATIETY RS can help us feel full. SCFAs can trigger the release of hormones that reduce the drive to eat (leptin, peptide YY, glucagon like peptide). RS slows the amount of nutrients released into the bloodstream, which keeps appetite stable. BETTER BODY COMPOSITION Since RS has less energy (calories) per gram than other starches, it can help us eat less. KEEPING US HYDRATED For those receiving treatment for cholera and/or diarrhea, RS can assist in the rehydration process (since it can normalize bowel function).

29 BETTER INSULIN SENSITIVITY RS doesn t digest into blood sugar, which means our bodies don t release much insulin in response. RS might also improve insulin sensitivity via alterations in fatty acid flux between muscle and fat cells. IMPROVED DIGESTION RS may help alleviate irritable bowel syndrome, diverticulitis, constipation, and ulcerative colitis. SCFAs can help to prevent the development of abnormal bacterial cells in the colon and enhance mineral absorption (especially calcium). IMPROVED IMMUNITY Consuming RS can influence the production of immune cells and inflammatory compounds in the gut.

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31 SUGAR SUBSTITUTES Sweet taste are also certain natural compounds belonging to the category of sugar alcohols such as sorbitol (found naturally in some fruits), xylitol and maltitol. These compounds, having a caloric value lower than that of fermentable sugars, are used in place of sugar to achieve some common low-calorie products (foods and drinks "light" or "sugar-free") and in order to prevent caries. Also various other compounds, artificially produced and with a strong sweetening power (30 to 500 times that of sugar), are used to sweeten light foods and drinks, since, at the used doses, are practically devoid of caloric power (cyclamates, aspartame, acesulfame, saccharin).

32 It should be emphasized that the consumption of sugar substitutes, although of current use, it is not indispensable, even in cases in which a low-calorie diet is followed for weight reduction. In fact, the use of these sweeteners not allows to reduce the body weight if the total amount of calories of the diet is not decreased and without an increasing of the physical activity. Anyway, even if substantially harmless in the doses permitted by law, the sweeteners may have restrictions on use, so the label must be carefully read for eventual contraindications. Their use is not recommended until 3 years of age and during pregnancy and lactation. Particular attention should be paid to children over the age of three years, to which any administration of products containing sweeteners should be made with caution.

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34 The polyalcohols sorbitol, mannitol, and xylitol are naturally produced by some plant species, such as fruits and berries. Commercially, these sweeteners are synthesized and not extracted from natural sources. All polyalcohols are slowly and not fully absorbed by passive diffusion in the bowel. Therefore, an excessive consumption (eg. greater than 50 g of sorbitol per day, greater than 20 g of mannitol per day) may be the cause of diarrheal phenomena. Sorbitol is the most common, naturally found, polyol that is higher in some types of fruit (apples and pears). It is obtained for reduction of glucose and is produced on an industrial scale by hydrogenation of this monosaccharide, using a catalyst. The sorbitol is usually used, in mixture with other polyalcohols, for sweetening chewing gum and confectionery.

35 Gums does not contain sugar as sucrose, brown sugar, honey, fructose, etc..., which are highly cariogenic, but sugar alcohols such as sorbitol (obtained from the berries of the rowan - Sorbus aucuparia), xylitol (extracted from trees) and mannitol. Such substances, despite having a sweet taste, similar to sucrose and to the natural sugars, "do not like" to the bacteria responsible of tooth decay, so the bacteria have less chance to reproduce and attack the teeth. Actually only xylitol is devoid of cariogenic power, sorbitol and mannitol have a little power instead. A Finnish study found a reduction of caries in children who chewed gum containing 100% xylitol (XyliFresh gum), compared to control groups that did not chew gum or chewing gum with sorbitol, in addition to the arrest or even regression of very small carious lesions. With the use of this sweetener, the bacterial plaque loses acidogenic power and its adhesiveness, characteristics cariogeniche which instead are strongly stimulated by the use of natural or refined sugars.

36 They are sweeteners to high sweetening power. The four intense sweeteners in current use in Italy are: acesulfame K, aspartame, cyclamate (acid cyclamic acid and its salts of sodium and calcium) and saccharin (and its sodium, potassium and calcium salts). Two other intense sweeteners are authorized in the EU countries but are not pretty much used in Italy: the neohesperidine DC and thaumatin. Intense sweeteners are present in so-called "Table-top sweeteners" (tablets, sachets, powder or drops) that in most of "sugar-free", "light" or diet products : chewing gum, candy, soft drinks, yogurt, jams, etc. Their sweetness varies from 30 to 500 times that of sucrose. Their calorific value is almost nil. Since you only need small amounts, replace sucrose with these substances can significantly reduce the contribution calorie of food.

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38 ARTIFICIAL SWEETENERS INDUCE GLUCOSE INTOLERANCE BY ALTERING THE GUT MICROBIOTA Non-caloric artificial sweeteners (NAS) are among the most widely used food additives worldwide, regularly consumed by lean and obese individuals alike. NAS consumption is considered safe and beneficial owing to their low caloric content, yet supporting scientific data remain sparse and controversial. In a recent paper (Nature Oct 9;514(7521): ), the study demonstrates that consumption of commonly used NAS formulations drives the development of glucose intolerance through induction of compositional and functional alterations to the intestinal microbiota. Collectively, their results link NAS consumption, dysbiosis and metabolic abnormalities, thereby calling for a reassessment of massive NAS usage. Take from

39 Thirty times sweeter than sugar and with no effect on blood sugar and little aftertaste. Stevia s history goes back to ancient times. Grown naturally in tropical climates, stevia is an herb in the chrysanthemum family that grows wild as a small shrub in Paraguay and Brazil, though it can easily be cultivated elsewhere. Paraguayans have used stevia as a food sweetener for centuries while other countries, including Brazil, Korea, Japan, China and much of South America, have a shorter record of stevia use.

40 Though widely available throughout the world, in 1991 stevia was banned in the U.S. due to early studies that suggested the sweetener may cause cancer. A follow-up study refuted the initial study and in 1995, the Food and Drug Administration (FDA) allowed stevia to be imported and sold as a food supplement, but not as a sweetener. In December 2008, the FDA declared stevia GRAS (Generally Recognized as Safe), and allowed its use in mainstream U.S. food production. Stevia is now present in a number of foods and beverages in the U.S., including Gatorade s G2, VitaminWater Zero, SoBe Lifewater Zero, Crystal Light and Sprite Green. Around the world it has been used in soft drinks, chewing gums, wines, yogurts, candies and many other products.

41 In its initial form, Stevia was sold as a ground-up powder of the stevia plant leaves. Though sweet, the powder also had a bitter aftertaste (mostly attributed to a compound found in the stevia plant called stevioside), which limited its acceptability as a sugar substitute. more than 100 species of stevia plant (rebaudiana) compound rebaudiosidea, the sweetest-flavored component of the stevia leaf Stevia is marketed under the trade names of Truvia (Coca-Cola and agricultural giant Cargill), PureVia (PepsiCo and Whole Earth Sweetener Company), and SweetLeaf (Wisdom Natural Brands). Despite the three different names, the sweetener is essentially the same product, each containing slightly different proportions of rebaudiosidea and stevioside.

42 After artificial sweeteners were banned in Japan more than 40 years ago, the Japanese began to sweeten their foods with stevia. And while they have conducted more than 40,000 clinical studies on stevia and concluded that it is safe for human use, there is a general lack of long-term studies on stevia s use and effects.

43 Stevia Sucrose aspartame acesulfame K Na ciclamate aspartame acesulfame K

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