Metabolic Disorders 101
Metabolic disorders come in several types. There are inherited metabolic disorders by the hundreds, which involve an individual lacking an enzyme that metabolizes a certain amino acid or other chemical substrate, resulting in a buildup of toxic chemicals in the system. These are relatively rare disorders affecting one out of every 1000 babies born. Some metabolic disorders are screened for in early infancy at the time the child is born. This is done so that treatment can begin early in life and complications do not develop.
Common Inherited Metabolic Disorders:
Inherited metabolic disorders are not that common but, because the treatment can be as simple as giving a child a certain enzyme or avoiding certain foods, they are screened for at the time of neonatal screening to give the child the best chance of survival without complications.
Some of these metabolic disorders include:
• Tay-Sachs disease
• Wilson’s disease
• Hurler syndrome
• Niemann-Pick disease
These metabolic disorders affect an individual from the time they are born. If treated early and for the rest of the person’s life, complications can be spared and the person can live a normal life.
Acquired Metabolic Disorders
Much more common are acquired metabolic disorders. Common metabolic disorders include diabetes mellitus type 2, hyperthyroidism, hypothyroidism, and metabolic syndrome. These usually affect adults and are either autoimmune diseases or diseases brought on by unhealthy lifestyles.
Let’s look at these more common diseases:
• Grave’s Disease. This is a disorder of elevated thyroid hormone production. It is an autoimmune disease in which an individual makes antibodies, which attack the thyroid gland, turning on thyroid function and resulting in the production of too much thyroxine (T4) and triiodothyronine (T3) hormones. People with Grave’s disease have an overactive metabolism and suffer from symptoms like rapid heart rate, elevated temperature, agitation, nervousness, weight loss, and tremor. A typical feature of Grave’s disease is exophthalmos, in which the eyeballs appear to bulge from the eye sockets. The treatment of this particular disorder is to give radioactive iodine to destroy the cells of the thyroid gland, creating a low thyroid condition, which is treated by giving back the right amount of thyroid hormone in pill form. If not treated, Grave’s disease can lead to a potentially life-threatening condition known as thyrotoxicosis in which there is a dangerously elevated metabolism.
• Hashimoto’s thyroiditis. This is a low thyroid condition in which autoantibodies attack the cells responsible for making thyroid hormones. The thyroid hormones T4 and T3 are responsible for the maximization of cellular metabolism. When the cells cannot metabolize well, they become sluggish and do not function well. Typical symptoms of Hashimoto’s thyroiditis include sluggish mood, depression, weight gain, constipation, dry skin, and dry hair. The cells cannot metabolize food well so that nutrients go to make fat while the cells themselves are starved of nutrition.
• Type 2 diabetes. This is an extremely common metabolic disorder caused by genetic factors as well as lifestyle factors. The exact role of each of these factors varies from person to person. Certainly, if you have a first degree relative who has diabetes (such as a sibling or parent); you have an elevated risk of developing this disorder. Eating too much, gaining weight, and exercising too little, also contribute to getting type 2 diabetes.
The main problem in type 2 diabetes is insulin resistance. For whatever reason, the cells do not respond to the amount of insulin in the system. In spite of elevated levels of insulin, the glucose does not enter the cells to be used as fuel for cellular metabolism. Elevated levels of glucose further raise the insulin, which is forced to put away the extra glucose levels as fat. Type 2 diabetics tend to be overweight, with an elevated fat to total body ratio. This means that all cellular processes tend to be less than adequate because the cells have to work harder to get all the fuel they need and, instead of providing the adequate nutrition for the cells, the glucose turns to fat.
There are often no real symptoms of type 2 diabetes unless it becomes severe. Things like the immune system are affected so that healing is poor, circulation can become compromised, and the type 2 diabetic is prone to typical diabetic complications, including diabetic neuropathy (damaged peripheral nerves), diabetic retinopathy (blindness secondary to vascular disease in the eyes), cardiovascular disease, and kidney failure. This is why screening for diabetes is so important. By the time symptoms are present, there is often end-organ damage, which cannot be reversed.
• Metabolic syndrome. This is a relatively common, yet serious metabolic disorder affecting men and women alike, and according to the American Heart Association, 47 million Americans have it and many don’t know they do. People with metabolic syndrome are suffering from insulin resistance so that most of them have elevated blood sugars and diabetes. They also tend to have truncal obesity with relatively thinner arms and legs and with most of the fat around the abdomen. The triglycerides can be dangerously high so the individual is at risk for pancreatitis secondary to hypertriglyceridemia. HDL cholesterol levels tend to be low, which means there is an increased risk of cardiovascular complications. High blood pressure is also a common feature of metabolic syndrome.
The increased risk of cardiovascular complications is what makes metabolic syndrome so dangerous. These people go on to develop a stroke, heart attack, or peripheral vascular disease. The diabetic component of the disease affects the nerves, eyes, and kidneys. The best treatment is to lose weight and to reduce the blood sugar, triglycerides, and blood pressure. Not much is yet known about metabolic syndrome in terms of why some people get it and others do not. Doctors are left with treating symptoms and lab values when the real problem of obesity is not easily addressed.
For those who are diagnosed with metabolic syndrome, reduction in weight through a low calorie diet and exercise is the best way to prevent the complications of the disorder. This takes a long-term commitment to better health and a healthier lifestyle. Metabolic disease may have a genetic component but most doctors feel that the bulk of the disorder is triggered by poor lifestyle choices, which is something that most people have some control over.