Nutrition in metabolic disease

Many inborn errors of metabolism are treated by dietary modification. There are three main strategies. 1. Some disorders lead to deficiency of a crucial product, which can be supplied by a special diet. This is illustrated by the need for a continuous enteral supply of glucose in hepatic glycogen storage diseases. 2. In other disorders, dietary restriction can prevent the accumulation of a substrate to toxic levels. Examples include the use of a low-phenylalanine diet in phenylketonuria and a minimal-galactose diet in galactosaemia. 3. In many disorders, catabolism during minor illnesses can lead to acute problems. These can usually be prevented by maintaining a high intake of glucose, either orally or intravenously. For inborn errors without specific dietary treatment, nutritional support is still important and may include tube feeding through a gastrostomy.