Galactitol

Galactitol is a type of sugar alcohol that is derived from the monosaccharide galactose. It is also known as dulcitol and is a naturally occurring product of plants and animals. Galactitol is used in the food industry as a low-calorie sweetener and in the pharmaceutical industry as a humectant.

Chemical Structure

Galactitol has the chemical formula C6H14O6. It is a six-carbon polyol (sugar alcohol) that is structurally similar to glucose. However, unlike glucose, galactitol does not contribute to the browning reaction that occurs during cooking, making it a suitable sweetener for heat-treated foods.

Metabolism

In the human body, galactitol is produced from galactose in a reaction catalyzed by the enzyme aldose reductase. This reaction is part of the polyol pathway, which also involves the conversion of glucose to sorbitol. Under normal conditions, the amount of galactitol produced is minimal. However, in individuals with galactosemia, a genetic disorder that impairs the body's ability to metabolize galactose, excessive amounts of galactitol can accumulate, leading to various health problems.

Health Effects

Excessive accumulation of galactitol in the body can lead to osmotic stress, which can damage cells and tissues. In individuals with galactosemia, this can result in symptoms such as cataracts, hepatomegaly (enlarged liver), failure to thrive, and developmental delay. Treatment for galactosemia involves a diet that is low in galactose.

Industrial Uses

In the food industry, galactitol is used as a low-calorie sweetener. It provides approximately 60% of the sweetness of sucrose (table sugar) and does not contribute to tooth decay. In the pharmaceutical industry, galactitol is used as a humectant, a substance that promotes the retention of moisture.

See Also

• Sugar alcohol
• Galactose
• Galactosemia
• Polyol pathway