Sugar is the
generalised 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 (also
known as dextrose), fructose and galactose. The table or granulated sugar most
customarily used as food is sucrose, a disaccharide (in the body, sucrose
hydrolyses into fructose and glucose). Other disaccharides include maltose and
lactose. 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 setting up of sugar plantations in the West Indies and
Americas. This was the first time that sugar became available to the common
people who had previously had to rely on honey to sweeten foods. Sugar beet is
a root crop and 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 has 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. Sugar provides energy
but no nutrients—empty calories.
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.
No comments:
Post a Comment