Medical Moment on the Acute Porphyrias
A proper diet is important to all individuals, regardless of health. Everyone should maintain a diet that provides all essential nutrients and should avoid being overweight or underweight. A desirable weight should be maintained by good dietary habits over a long period of time rather than by alternating periods of overeating and under eating.
Diet is important in the management of many diseases, diabetes mellitus for example. Also, many diseases can alter food intake. Therefore, attention to diet and nutrition is important in almost any disease.
Porphyrias are due to deficiencies in enzymes in the chemical pathway that makes heme from porphyrins and other precursor substances. This pathway of enzymes is called the heme biosynthetic pathway. Enzyme deficiencies in the Porphyrias are usually inherited. However, the enzyme deficiencies alone do not produce disease. Additional factors determine whether or not there will be disease manifestations. Diet is one of the additional factors that influences the manifestations of certain types of Porphyria.
The so-called acute Porphyrias, which are Acute Intermittent Porphyria, Hereditary Coproporphyria, Variegate Porphyria and ALAD Porphyria are characterized by acute attacks of abdominal pain and other symptoms. Attacks of these diseases can be brought on by reducing total caloric intake to starvation levels or following an unbalanced diet, such as the Atkin’s Diet, in which carbohydrate is reduced as low as possible. This does not mean that carbohydrates are particularly healthy in Porphyria, only that they should be represented in the diet and remain part of any regimen for weight loss. People who over-consume carbohydrates in hopes of preventing an acute attack are risking obesity with no proven benefit for their Porphyria. The acute Porphyrias are affected by diet because the chemical pathway in the liver that makes heme from porphyrins and other precursor substances registers changes between the fed and fasting states. The normal fast that occurs between meals and overnight is not a problem and, moreover, is generally healthy for body metabolism. A prolonged fast, however (greater than 24 hours) is risky. Some acute attacks have occurred for the first time in people who underwent surgery and were fasting for several days except for IV solution. When the patient is a known carrier of an acute Porphyria, a plan for supplying adequate calories must be part of the preparations for surgery.