The fructose found in fruit is not the same as that used in processed foods. Commercial fructose is not taken from fruit, but is made from corn starch and refined into a sugar known as high-fructose corn syrup (HFCS) a thick liquid containing two basic sugar building blocks, fructose and glucose, in roughly equal amounts. HFCS is a very popular sugar found in a vast number of processed products and under a variety of names.
Eating fresh, raw fruit containing fructose does not have the same effect on the body as does consuming processed foods containing fructose. This is because naturally-occurring fructose breaks down more slowly by an enzyme in the bowel and does not require insulin.
Fructose is three times sweeter than sucrose and accounts for about 10% of the daily calories of the average person. Alone, naturally-occurring fructose causes a much lower rise in blood sugar levels than does sucrose or glucose. Commercially prepared fructose acts more like a fat in the body and is stored in the same manner.
Diets high in commercially prepared fructose, especially those low in copper and magnesium, increase blood lipids leading to a higher risk of heart disease. Longterm consumption of commercial fructose is also associated with an increased risk of cataracts and kidney stones.
Fructose intolerance is a metabolic defect caused by a deficiency of the enzyme fructose-1-phosphoaldosase that results in hypoglycemia (low blood sugar) and hypophosphatemia (deficiency of blood phosphates). Longterm effects can lead to jaundice and enlargement of the liver.
Another disorder involves the enzyme, fructose1,6-diphosphatase, resulting in hypoglycemia, hyperventilation, shock, and convulsions. The essential treatment is the immediate and lifelong removal of all sources of fructose from the diet along with frequent meals and the avoidance of long fasts.
This page was updated in December 2005.
