Learn More About Sucrose

Table sugar is sucrose: one glucose molecule linked to one fructose molecule. Plants produce it naturally, and it also appears as an added ingredient in many everyday foods.

Sugarcane and sugar beet provide much of the sucrose used in food manufacturing. Fruit and vegetables contain varying amounts too, including mango, peaches, carrots and sweetcorn.

Which Foods contain Sucrose?

When reviewing sucrose intake, consider both naturally occurring sugars and sugar added during cooking or manufacture. The list below shows common sources; serving size and the overall meal remain important.

Sugarcane and Sugar Beets

Sugarcane and sugar beet are processed to extract the familiar sugar crystals used at home and in commercially prepared foods.

Fruits

Sucrose naturally occurs in many different types of fruit, including:

- Berries: strawberries, raspberries, and blackberries

- Citrus fruits: oranges, grapefruits, and lemons

- Tropical fruits: pineapple, mango, and papaya

- Stone fruits: peaches, plums, cherries, and nectarines

Vegetables

Some root vegetables and other vegetables also supply sucrose, although their overall sugar content varies:

- Parsnips and beets

- Carrots

- Corn

Processed foods

In processed foods, sucrose is often added for flavour and preservation.

- Processed snacks and desserts: biscuits, confectionery, and pastries

- Table sugar: commonly used in households to sweeten coffee, tea, baked goods, cakes, and other recipes

- Soft drinks and fruit juices: many sodas and juices contain added sucrose to enhance flavour

- Preserves and jams: sugar contributes sweetness and texture to jams, marmalades and fruit preserves; compare the ingredient list and serving size

- Sweetened dairy products: yoghurt, ice cream, and other sweetened dairy items

- Sauces: tomato sauce, barbecue sauce, and other condiments

How is Sucrose Digested?

Sucrase at the small-intestinal lining splits sucrose into glucose and fructose. The two sugars are then absorbed separately. This step is distinct from the digestion of starch.

Sucrose Digestion: in the Small Intestine

The sucrase component of the sucrase-isomaltase enzyme complex breaks the bond joining glucose and fructose. If this activity is reduced, the amount of sucrose comfortably tolerated may also be reduced.

- Fructose: Fructose is absorbed through a different transport process from glucose. Much of its subsequent metabolism takes place in the liver.

- Glucose: Glucose is absorbed into the circulation and can be used by body tissues for energy.

Sucrose Digestion: in the Large Intestine

Sucrose that escapes digestion can pass into the large bowel. There, bacterial fermentation produces gas, while poorly absorbed carbohydrate can increase water in the bowel. The resulting symptoms and their severity differ between people.

- Water Retention: Changes in bowel water can alter stool consistency and contribute to diarrhoea.

- Gas production: Bacterial fermentation can generate gas and distension. Bowel sensitivity influences whether this produces discomfort.

- Symptoms: Bloating, wind, discomfort and changes in bowel habit can follow, but these symptoms are not specific to sucrose malabsorption.

The enzyme invertase is used in some enzyme formulations intended to help break down sucrose. Suitability and directions depend on the product. It is not interchangeable with a prescribed treatment for sucrase-isomaltase deficiency.

What an go Wrong with Sucrose Digestion?

Problems can arise when sucrase activity is reduced or the intestinal lining is affected by another condition:

Enzyme Deficiency

A lack of the specific digestive enzyme sucrase (also known as invertase) can leave more sucrose undigested. Reduced activity may be inherited or may accompany intestinal injury, including untreated coeliac disease. A clinician can investigate the cause and advise on management.