Disorders of Carbohydrate Metabolism

Galactosemia is a disorder in which the body cannot break down the sugar called galactose. Galactose can be found in food, and the body can break down glucose: a simple sugar; the most com- lactose (milk sugar) to galactose and glucose. The body uses glucose for monly used fuel in cells energy. People with galactosemia lack the enzyme to break down galactose, so it builds up and becomes toxic. In reaction to this buildup of galactose the body makes some abnormal chemicals. The buildup of galactose and these chemicals can cause liver damage, kidney failure, stunted growth, men-cataract: clouding of the lens of the eye tal retardation, and cataracts in the eyes.

If not treated, galactosemia can cause death. Over time, children and young adults with galactosemia can have problems with speech, language, hearing, stunted growth, and certain learning disabilities. Children who do not follow a strict diet have an increased risk of having one or more of the problems listed above. Even when a strict diet is followed, some children do not do as well as others. Most girls with galactosemia have ovarian failure. The treatment for galactosemia is to restrict galactose and lactose from the diet for life. Since galactose is a part of lactose, all milk and all foods that contain milk must be eliminated from the diet, including foods that contain small amounts of milk products such as whey and casein. In addition, organ meats should not be eaten because they contain stored galactose.

Glycogen storage diseases require different treatments depending on the specific enzyme alteration. The most common type of glycogen storage disease is classified as type 1A. In this disorder the body is missing the enzyme that coverts the storage form of sugar (glycogen) into energy (glucose). If food is not eaten for two to four hours, blood glucose levels drop to a low level, leading to serious health problems such as seizures, poor growth, enlarged liver, high levels of some fats circulating in the blood, and high uric: from urine levels of uric and lactic acids in the blood. Dietary management of GSD-

1A eliminates table sugar (sucrose) and fruit sugar (fructose) and limits milk sugar (lactose), as the body cannot use some sugars in these foods. Frequent meals and snacks that are high in complex carbohydrates are recommended. In addition, often supplements of uncooked cornstarch are often eaten between meals to keep blood sugar levels stable. Eating a diet that prevents low blood sugar will promote normal growth, decrease liver enlargement, and the high blood levels of uric and lactic acids.

Disorders of fatty acid metabolism occur when the body is not able to break down fat to use as energy. The body's main source of energy is glucose, but when the body runs out of glucose, fats are used for energy. If untreated, these disorders can lead to serious complications affecting the liver, heart, eyes, and muscles. Treatment includes altering the kind and the amount of fat in the diet and frequent feedings of carbohydrate-containing foods.

Urea cycle disorders are inherited disorders of nitrogen metabolism. When protein is digested it breaks down into amino acids, and nitrogen is found in all the amino acids. Those who have these disorders cannot use nitrogen in a normal way. Dietary treatment for these disorders is to provide only the amount of protein that the body can safely use. The diet consists mostly of fruits, grains, and vegetables that contain low amounts of protein and, therefore, low amounts of nitrogen.

There are more than nineteen metabolic disorders that respond to nutrition therapy. The role of proper nutrition in the treatment of these disorders is crucial. Because these disorders are rare and require careful monitoring, affected individuals are best served by clinics specializing in metabolic disorders. see also Phenylketonuria (PKU).

Patricia D. Thomas


Acosta, P. B., and Yannicelli, S. (1993). "Energy and Protein Requirements of Infants and Children with Inherited Metabolic Disorders." Metabolic Currents 6:1-8.

Acosta, P. B., and Yannicelli, S. (2001). Ross Metabolic Formula System: Nutrition Support Protocols, 4th edition. Columbus, OH: Ross Laboratories.

Scriver, C. R.; Beaudet, A. L.; Sly, W. S.; and Valle, D., eds. (2001). The Metabolic and Molecular Bases of Inherited Disease, 8th edition. New York: McGraw-Hill.

fat: type of food molecule rich in carbon and hydrogen, with high energy content nitrogen: essential element for plant growth

Weight Loss All Star

Weight Loss All Star

Are you looking to lose weight or even just tone up? What is stopping you from having the body you want and help you feel great at the same time? I created Weight Loss All-Star for all those wanting to lose weight, and keep the weight off. I know how hard it is to do diets and stick with them, and get the motivation to get up and exercise.

Get My Free Ebook

Post a comment