Fructose vs Glucose

Diffen › Health

While fructose and glucose have the same calorific value, the two sugars are metabolized differently in the body. Fructose has a lower glycemic index than glucose but has a much higher glycemic load. Fructose causes seven times as much cell damage as does glucose, because it binds to cellular proteins seven times faster; and it releases 100 times the number of oxygen radicals (such as hydrogen peroxide, which kills everything in sight).^[1]

Fructose is a simple sugar commonly found in fruits and vegetables. Vast quantities are also manufactured in the lab. Glucose, also known as grape or blood sugar, is present in all major carbohydrates like starch and table sugar. While both are a good source of energy, excess of glucose can be fatal to diabetic patients, and excess of fructose can lead to health problems like insulin resistance and liver disease.

Comparison chart

Fructose versus Glucose comparison chart
	Fructose	Glucose
Other names	Fruit sugar, levulose, D-fructose	Blood sugar, dextrose, corn sugar, grape sugar
Kind of sugar	Simple sugar (monosaccharide)	Simple sugar (monosaccharide)
Molecular formula	C6H12O6	C6H12O6
functional group	ketone	aldehyde
Uses	Source of energy. Often added to food and drinks to improve taste.	Source of energy. Fuels cellular respiration.
Produced by	Photosynthesis, the breakdown of glycogen. Vast quantities produced artificially in the lab by the food industry.	Photosynthesis, the breakdown of glycogen.
Sources	Honey, flowers, berries, most root vegetables.	All major carbohydrates
Molar mass	180.16 g/mol	180.16 g/mol
Density	1.694 g/cm3	1.54 g/cm3
Melting point	103 °C	α-D-glucose: 146 °C, β-D-glucose: 150 °C
CAS number	57-48-7	50-99-7 Y

Fruits and vegetables are a natural source of fructose.

Calories

1 ounce of fructose contains 104 calories.

1 ounce of glucose contains 110 calories.

Effects on the Body

Excessive consumption of fructose has been linked to insulin resistance, obesity and non-alcoholic liver disease. Studies suggest that it leads to added fat in the belly, which is linked to an increased risk for heart disease and diabetes. Fructose also leads to higher cholesterol. Studies suggest that fructose lowers activity in the cortical control areas of the brain.

An excessive amount of glucose in the blood can be fatal. However, this only occurs in diabetic individuals when their pancreas does not release enough insulin into the bloodstream. Most fat gained from excessive intake of glucose is subcutaneous, or under the skin, which is not connected to heart disease or diabetes. Glucose is not linked to insulin resistance or higher cholesterol. Studies suggest that the consumption of glucose significantly raises the level of activity in the brain.

In a recent study conducted by Lane MD at Johns Hopkins University School of Medicine in Baltimore,US revealed that:

Fructose increases food intake whereas glucose decreases food intake. This is because glucose leads to an increase in hypothalamic ATP which gives rise to a suppression of food intake. Whereas fructose requires an enzyme that requires ATP, which causes ATP depletion thereby giving rise to an increase in food intake.
The rise in consumption of high-fructose sweeteners, soft drinks and corn syrup parallels the rise in the obesity epidemic.
High fructose diets promote insulin resistance and glucose intolerance which increases the rate of hepatic lipogenesis.
On a average Americans consume 140lbs of high fructose sweeteners per year, of which 77lbs is high fructose corn syrup.

Beneficial uses in the human body

Fructose is used in respiration to produce ATP and to build glycogen. It can also produce fat to store energy.

Cells also use glucose to fuel respiration. It is also used in Vitamin A production and for the synthesis of several substances, including starch and glycogen.

Sources of fructose and glucose

Fructose is naturally found in most fruits and vegetables (including sugar cane) and honey. Foods that contain table sugar, high-fructose corn syrup, agave nectar, maple syrup and fruit juice also contain fructose.

All major carbohydrates contain glucose. Examples include starch and table sugar.

Commercial use

Fructose is commercially added to many foods and beverages as a low cost sweetener. High fructose corn syrup is often added to processed food and drinks is the United States as a cheap sweetener, and has been the subject of many controversies, as it is allegedly associated with obesity, cardiovascular disease, diabetes and non-alcoholic fatty liver disease.

Glucose is also used as a sweetener in the form of corn syrup.

Relative sweetness of various sugars and sweeteners

Production

Fructose is produced by plants during photosynthesis.

Glucose is naturally produced during photosynthesis in plants or during the breakdown of glycogen. It is also produced commercially through the enzymatic hydrolysis of starch.