Sucrose is a disaccharide composed of one unit of glucose and one unit of fructose. It is digested by the enzyme sucrase, which is located on the absorptive surface of the small intestine. Sucrose is found in several fruits and vegetables and is present in large quantities in sugar beet and sugar cane – from which it is extracted and purified on a vast industrial scale. Sucrose is readily available in highly purified or partly purified forms (e.g. white sugar, brown sugar, treacle or syrup). It is also very widely used by food processors to sweeten, preserve and texturize a variety of foods. The terms ‘sucrose’ and ‘sugar’ are often used as if they are synonymous.
High sucrose consumption has frequently been blamed for many of the illnesses that afflict affluent populations. The poor health image of sucrose was encapsulated in the phrase ‘pure, white and deadly’. Its poor health image has led many food manufacturers to use other sugars, or sugar containing extracts, in their products so that they can imply in advertising claims that their product is ‘healthier’ because it has reduced levels of sucrose. The term extrinsic non-milk sugar has been used to cover all of the dietary sugars (still principally sucrose) that are not present as natural components of the fruits, vegetables and milk in the diet. Conversely, sugars that are naturally present within the cell walls of plants are termed intrinsic sugars (note that the sugars in fruit juice are classified as part of the extrinsic non-milk sugars).
Sucrose is a natural plant sugar. It happens to be present in large enough amounts in readily cultivatable plants to make it convenient for extraction in industrial quantities. It seems reasonable to suppose that, if sucrose is indeed innately harmful, as it is used in affluent countries, then other sugars used in the same ways and quantities are also likely to be harmful. Substitution of sucrose by other extracted sugars that have not yet acquired the poor health image of sucrose does not appear to offer a high probability of dietary ‘improvement’. Extrinsic non-milk sugars comprise roughly 10–20 percent of the total energy intake in most affluent populations.
Sucrose is chemically classified as a carbohydrate and a simple sugar, specifically a disaccharide composed of glucose and fructose. Its proper scientific name is -D-fructofuranosyl–D-glucopyranoside. The natural sweetness of fruit and honey comes from mixtures of sucrose, glucose, and fructose. The mild sweetness of milk comes from another disaccharide, lactose, composed of glucose and galactose.
Sugar cane and sugar beet have a naturally high content of sucrose and have been commercially exploited as concentrated sources of sucrose since 1600 AD. Sugar cane was first cultivated in Papua New Guinea 10 000 years ago, and the practice spread gradually to Egypt (2300 years ago), Arabia (1300 years ago), and Japan (1100 years ago). Sugar beet was first grown in Europe 500 years ago. Prior to this, refined sucrose was still a rare and expensive commodity and honey was much cheaper. When the industrial revolution began 200 years ago, sucrose consumption increased dramatically, replacing honey as the major source of concentrated sweetness. Intake of refined sucrose peaked in about 1900 and consumption has remained, with minor variations, much the same over the past century. Since 1970 high-fructose corn syrup solids (glucose–fructose syrups made from hydrolyzed corn starch) have partially replaced refined sucrose in manufactured products, particularly in the USA.
Food Sources of Sucrose
|Food name||Weight (g)||Sucrose (g)|
Health Effects of Sucrose
- Mood Swings
Sucrose has simple chemical composition due to which it is digested quickly. Foods rich in sucrose could cause an immediate increase in blood sugar which is followed by a sharp decrease. Sudden fall and rise in blood sugar affects mood resulting fatigue and irritability.
- Gain in weight
Balanced meal comprises of protein or complex carbohydrates which is slowly digested. Calories are burned at the same rate they are released into bloodstream as glucose. The simple molecular structure makes sucrose quickly digested releasing glucose into blood quickly than it is burned. Sucrose triggers sweet cravings causing more to eat.
- Insulin sensitivity
When blood sugar suddenly rises in the case of sucrose rich meal, high insulin is formed to shuttle glucose to muscle cells where it could be burned. Overtime, high insulin leads to wearing out of insulin receptors which causes in high blood glucose chronically.
- Tooth decay
If sucrose is allowed to remain on teeth, it provides bacteria an environment to grow. Bacteria feed on sugar and acid is formed as a waste. Eventually acid erodes tooth enamel resulting tooth loss or decay.
- Change in cholesterol
Besides high fat diet, large content of sucrose promotes triglyceride levels. These fats are present naturally in the blood. Too much could promote the chances of cardiovascular problems. Sucrose affects the level of cholesterol by lowering level of high density lipoproteins which is known to be good cholesterol.