Carbohydrate Guide

All sugars dissolve in water, some are sweeter than others, the taste can change during cooking, most sugars form colorless crystals when saturated in water, some may be brown. 

Monosaccharides provide 16kj (3.7kcal) per gram

Glucose~ occurs naturally in fruit, plant juice. Most carbohydrates in food are converted to glucose when digested. Glucose can also be manufactured from starch glucose syrups are usually from maize or wheat starch.

Fructose~ occurs naturally in some fruit and vegetables and honey, it is the sweetest form of sugar known. It is also a component of sucrose.

Sucrose~ occurs naturally in sugar cane, sugar beet, carrots. This is the stuff we normally sprinkle on our cornflakes.

Maltose~ this is formed by the break down of starch in digestion and during the brewing process of beer.

There are other substances that are also sweet~ sorbitol, mannitol, xylitol these are called polyols and are made from sugar. Sometimes they are used in diabetic foods because they are absorbed slowly, their energy value is 10kj (2.4 kcal) per gram. 

Other sweeteners are saccharin, aspartame, acesulfame K, these are classified as food additives as they have  no relationship to sugars. They are up to 500 times sweeter than sugar and used at very low levels, even aspartame the only one metabolized by the body provides us with no energy. Some sprinkle on sugar replacements are mixed with some carbohydrate therefore are energy giving, but much less than sugars.   

Starch

There are a number of starches, which are Polysaccharides composed of large numbers of glucose units linked together. They vary in shape on different plants, flour and potatoes contain large amounts and they can not be digested raw. Once cooked they can be digested. Starch provides 17.6 kj (4.2 kcal) per gram.

Glycogen is similar to starch but is made from animals not plants. Small amounts are stored in the liver and muscles as an energy reserve, it is not a significant food in our diet because it breaks down into glucose after the animals death.

Non-Starch Polysaccharides (Fibre or NSP)

Cellulose~ thousands of glucose units, can not be digested by humans, but because of its water binging ability assists in the passing of food through the intestines helping prevent constipation.

Pectin~ present in fruit, this is a fibrous substance , and is completely digested by us therefore has little effect on the faeces, however  it can help to reduce blood cholesterol.

Benifits of Fibre

• Obesity~ high fibre diets may be beneficial to those on weight loss diets by preventing constipation, improving blood sugar levels, and giving a feeling of fullness.

• Gallstones~ indigestion of wheat bran may alter bile salt composition so as to reduce likelihood of gallstone formation.

• Constipation~ fibre speeds up the passage of food through the intestine and bowel and forms a softer stool.

• Diverticulosis~ studies show suffers of this disease benefit from high fibre diets.

• Cancer of large bowel~ helps to prevent formation.

• Coronary heart disease~ there are studies to suggest that fibre may help prevent.

• Diabetes~ It appears that high fibre diet reduces swings in blood sugar levels.

Contra Indications of a High Fibre Diet

• Intestinal obstruction~ a high fibre diet should not be taken by anyone with colon cancer or bowel stricture

• Irritable bowel syndrome~ caused by wheat or other grain sensitivity

• Coeliac disease

• Osteomalacia or rickets caused by calcium 

• malabsorbtion~ pytates can inhibit calcium absorption.

• Iron deficiency~ pytates found in wheat fibre can reduce absorption of iron

• Zinc deficiency~ pytates can reduce absorption of zinc.