Name: Yu-Rou Lin
Matriculation Number:260346
Course name: Biomedical Science
The "Sugar High": How Carbohydrates Power Life
Excessive glucose in the body is considered unhealthy and often leads to signs of diabetes. This
phenomenon is called “sugar high.” Sugar is a part of carbohydrates, and carbohydrates are
known to be the primary fuel sources due to their significant role in energy usage and storage.
The earliest discovery of carbohydrates as energy sources can be dated back to the early 19th
century, when the calorimetry method was first introduced. Scientists found that consuming
different foods can provide varying amounts of energy; subsequently, the energy value of
carbohydrates was measured as 4 kcal per gram.
By the late 19th century, Claude Bernard discovered glucose in the blood and therefore found
that the liver is an organ in the human body where glucose can be converted into glycogen to
maintain sugar homeostasis.
Moreover, in the 20th century, scientists uncovered how energy is used in the human body by
comparing the amount of glycogen before and after exercise. Soon after, glycolysis was
discovered, unveiling the core metabolic process of carbohydrate energy utilization.
Glucose is a type of carbohydrate and is the simplest and smallest form of saccharide. Aside
from glucose, galactose and fructose are also commonly seen monosaccharides. Galactose is
vital for building glycoproteins, glycolipids, and connective tissues. Galactose and glucose are
both brain sugars. Fructose is usually found in fruits, honey, and vegetables. It impacts blood
sugar less acutely but is primarily metabolized by the liver. It is also the sweetest sugar that can
be found in nature. With simple sugars, life can be powered.
By combining two specific monosaccharides, disaccharides such as maltose, lactose, and sucrose
can be formed. This process is called polymerization, or more specifically, condensation. In this
process, not only a disaccharide but also water is produced. Maltose consists of two glucose
molecules and usually appears in either a white crystalline solid or powder form. It is also an
essential component of starch. On the other hand, lactose is made up of a glucose molecule and a
galactose molecule. It can be found in dairy products such as cheese, yogurt, butter, and milk.
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However, lactose requires lactase to be broken down for digestion. When lactase is not
functioning properly, accumulated lactose leads to lactose intolerance. Sucrose is composed of a
fructose molecule and a glucose molecule. It is a primary transport sugar in plants.
Carbohydrates with larger molecular weights are called polysaccharides. They are essential and
can be found in almost every corner of living organisms. For energy storage, humans, fungi, and
bacteria mainly use glycogen, whereas plants use starch. In addition, many structural
components in organisms are made of polysaccharides. One well-known example is cellulose,
which forms the cell walls of plants and provides rigidity. Another example is chitin, which is
the main component of fungal cell walls and the exoskeletons of arthropods.
In conclusion, carbohydrates play an essential role in living organisms. From simple
monosaccharides such as glucose to complex polysaccharides like glycogen and cellulose,
carbohydrates not only support metabolic processes and energy storage but also biological
structures. However, excessive glucose intake can disrupt sugar homeostasis and lead to health
problems such as diabetes. Therefore, understanding how carbohydrates function in the body
highlights the importance of balanced energy intake for maintaining health.
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Reference
1. YOUNG FG. Claude Bernard and the discovery of glycogen; a century
of retrospect. Br Med J. 1957 Jun 22;1(5033):1431-7. doi:
10.1136/bmj.1.5033.1431. PMID: 13436813; PMCID: PMC1973429.
2.
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