While lactose intolerance has become widespread, it can be easily mistaken for the less common disease process of sucrose intolerance, for both present very similar symptoms. However, dairy products do not normally contain sucrose, but rather contain lactose. As both lactose and sucrose are disaccharides, these being sugars containing two monosaccharide, or simple sugar, components, the disease processes may mimic one another; however, the causes and treatments for each are quite different.
Composition of Cane Sugar
Cane sugar is virtually indistinguishable from beet sugar in molecular composition. Both are crystalline disaccharides and qualify as sucrose. The monosaccharides included in sucrose are glucose and fructose. Glucose is a type of sugar found in great quantity in grapes and honey. Cells convert starch into glucose through metabolism. Fructose is a monosaccharide found naturally in honey and many fruits.
Normal Digestion of Sucrose
A naturally occurring enzyme known as invertase (also called sucrase) splits sucrose into glucose and fructose in the body, allowing the intestinal tract to absorb both monosaccharides readily. The body normally produces this enzyme.
Definition of Sucrose Intolerance
Genetic abnormalities can produce a deficiency of invertase in the body, leading to sucrose intolerance because the intestines cannot easily take up complex disaccharides until split into monosaccharides. This closely mimics the more common lactose intolerance in how it originates and affects the body, which results from the body's inability to break down lactose into galactose and glucose due to the deficiency of the enzyme lactase. The deficiency of the enzyme invertase is most commonly a result of normal ageing.
Symptoms of Sucrose Intolerance
Some of the more common indications of sucrose intolerance are similar to those of lactose intolerance, in particular bloating, stomach cramps, diarrhoea and flatulence. When disaccharides such as sucrose or lactose pass into the digestive tract without first undergoing division---or absorbed into the bloodstream whole---they stimulate the rapid reproduction of gas-producing bacteria, resulting in excessive flatulence. Other symptoms include nervousness and anxiety, and sometimes heart palpitations that can lead to a cardiac arrhythmia (an irregular heart rhythm).
Those suffering from sucrose intolerance can take supplemental invertase orally. However, stomach acid destroys the enzyme before it can take effect. Supplemental invertase coated with a natural substance extracted from seaweed called sodium alginate can survive stomach acid and take effect in the intestines, though such supplements are very expensive and are not readily available. The best way to avoid sucrose intolerance is to avoid using table sugar completely and substitute it with a monosaccharide such as fructose or the less-sweet glucose.