Something of Interest
It used to be believed that sugar raised blood glucose levels more than did other carbohydrates because of its simpler chemical structure. However, it turned out that white bread or French fries have the same effect on blood sugar as pure glucose, while fructose, although a simple carbohydrate, has a minimal effect on blood sugar. As a result, as far as blood sugar is concerned, carbohydrates are classified according to their glycemic index, a system for measuring how quickly a food that is eaten raises blood sugar levels, and glycemic load, which takes into account both the glycemic index and the amount of carbohydrate in the food. This has led to carbohydrate counting, a method used by diabetics for planning their meals.
Studies on the link between sugars and diabetes are inconclusive, with some suggesting that eating excessive amounts of sugar does not increase the risk of diabetes, although the extra calories from consuming large amounts of sugar can lead to obesity, which may itself increase the risk of developing this disease. Other studies show correlation between refined sugar (free sugar) consumption and the onset of diabetes, and negative correlation with the consumption of fiber.
Sugar is the generalized name for a class of chemically-related sweet-flavored substances, most of which are used as food. They are carbohydrates, composed of carbon, hydrogen and oxygen. There are various types of sugar derived from different sources. Simple sugars are called monosaccharides and include glucose, fructose and galactose. The table or granulated sugar most customarily used as food is sucrose. Chemically-different substances may also have a sweet taste, but are not classified as sugars. Some are used as lower-calorie food substitutes for sugar described as artificial sweeteners.
Sugars are found in the tissues of most plants, but are only present in sufficient concentrations for efficient extraction in sugarcane and sugar beet. Sugarcane is a giant grass and has been cultivated in tropical climates in the Far East since ancient times. A great expansion in its production took place in the 18th century with the lay out of sugar plantations in the West Indies and Americas. This was the first time that sugar became available to the common people who previously had to rely on honey to sweeten foods. Sugar beet is a root crop, is cultivated in cooler climates, and became a major source of sugar in the 19th century when methods for extracting the sugar became available. Sugar production and trade have changed the course of human history in many ways. It influenced the formation of colonies, the perpetuation of slavery, the transition to indentured labour, the migration of peoples, wars between sugar trade-controlling nations in the 19th century, and the ethnic composition and political structure of the new world.
The world produced about 168 million tonnes of sugar in 2011. The average person consumes about 24 kilograms of sugar each year (33.1 kg in industrialised countries), equivalent to over 260 food calories per person, per day.
Since the latter part of the twentieth century, it has been questioned whether a diet high in sugars, especially refined sugars, is bad for human health. Sugar has been linked to obesity, and suspected of, or fully implicated as a cause in the occurrence of diabetes, cardiovascular disease, dementia, macular degeneration and tooth decay. Numerous studies have been undertaken to try to clarify the position, but with varying results, mainly because of the difficulty of finding populations for use as controls that do not consume, or are largely free of any sugar consumption.
The five largest producers of sugar in 2011 were Brazil, India, the European Union, China and Thailand. In the same year, the largest exporter of sugar was Brazil, distantly followed by Thailand, Australia and India. The largest importers were the European Union, United States and Indonesia. Currently, Brazil has the highest per capita consumption of sugar, followed by Australia, Thailand and the European Union.
History of Sugar
The history of sugar has five main phases:
Worldwide through the end of the medieval period, sugar was expensive and was considered a "fine spice", but from about 1500 onwards technological improvements and New World sources began turning it into a bulk commodity.
Types of sugar
Glucose, fructose and galactose are all simple sugars, monosaccharides, with the general formula C6H12O6.
Glucose, dextrose or grape sugar occurs naturally in fruits and plant juices and is the primary product of photosynthesis. Most ingested carbohydrates are converted into glucose during digestion and it is the form of sugar that is transported around the bodies of animals in the bloodstream. It can be manufactured from starch by the addition of enzymes or in the presence of acids. Glucose syrup is a liquid form of glucose that is widely used in the manufacture of foodstuffs. It can be manufactured from starch by enzymatic hydrolysis.
Fructose or fruit sugar occurs naturally in fruits, some root vegetables, cane sugar and honey and is the sweetest of the sugars. It is one of the components of sucrose or table sugar. It is used as a high fructose syrup which is manufactured from hydrolized corn starch which has been processed to yield corn syrup, with enzymes then added to convert part of the glucose into fructose.
Galactose does not generally occur in the free state but is a constituent with glucose of the disaccharide lactose or milk sugar. It is less sweet than glucose. It is a component of the antigens found on the surface of red blood cells that determine blood groups.
Sucrose, maltose and lactose are all compound sugars, disaccharides, with the general formula C12H22O11. They are formed by the combination of two monosaccharide molecules with the exclusion of a molecule of water.
Sucrose is found in the stems of sugar cane and roots of sugar beet. It also occurs naturally alongside fructose and glucose in other plants, particularly fruits and some roots such as carrots. The different proportions of sugars found in these foods determines the range of sweetness experienced when eating them. A molecule of sucrose is formed by the combination of a molecule of glucose with a molecule of fructose. After being eaten, sucrose is split into its constituent parts during digestion by a number of enzymes known as sucrases.
Maltose is formed during the germination of certain grains, most notably barley which is converted into malt, the source of the sugar's name. A molecule of maltose is formed by the combination of two molecules of glucose. It is less sweet than glucose, fructose or sucrose. It is formed in the body during the digestion of starch by the enzyme amylase and is itself broken down during digestion by the enzyme maltase.
Lactose is the naturally occurring sugar found in milk. A molecule of lactose is formed by the combination of a molecule of galactose with a molecule of glucose. It is broken down when consumed into its constituent parts by the enzyme lactase during digestion. Children have this enzyme but some adults no longer form it and they are unable to digest lactose.
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