Metabolic Syndrome Overview
The term metabolic syndrome is well recognized in the medical literature and in the lay press as well. Metabolic syndrome (also referred to as syndrome X or dysmetabolic syndrome) refers to an association between certain metabolic disorders and cardiovascular disease. While the criteria for the diagnosis vary, the concept of a clustering of risks factors that lead to cardiovascular disease is well accepted.
The main characteristics of metabolic syndrome include insulin resistance, hypertension (high blood pressure), abnormalities in cholesterol levels, and an increased risk for blood clotting. Most people with metabolic syndrome are overweight or obese.
Insulin resistance (IR) is a condition in which the cells of the body become resistant to the effects of insulin. Because of the central role that insulin resistance plays in metabolic syndrome, a separate article is devoted to insulin resistance.
The most widely accepted definition of metabolic syndrome is based on the guidelines from the 2001 National Cholesterol Education Program Adult Treatment Panel (ATP III).
Any three of the following traits in the same individual meet the criteria for the metabolic syndrome:
- Abdominal obesity: a waist circumference over 102 cm (40 in) in men and over 88 cm (35 inches) in women.
- Serum triglycerides 150 mg/dl or above.
- HDL cholesterol 40mg/dl or lower in men and 50mg/dl or lower in women.
- Blood pressure of 130/85 or more.
- Fasting blood glucose of 110 mg/dl or above. (Some groups say 100mg/dl)
Metabolic Syndrome Causes
Metabolic syndrome is unfortunately common. Approximately 20%-30% of the population in industrialized countries have metabolic syndrome. It is thought to affect approximately 50 million people in the US alone.
Weight is a significant influence on the development of metabolic syndrome. Metabolic syndrome is present in about 5% of people with normal body weight; it is present in about 22% of individuals who are overweight, and 60% of individuals considered obese. Adults who continue to gain five or more pounds per year raise their risk of developing metabolic syndrome by up to 45%.
As is true with many medical conditions,genetics and the environment both play important roles in the development of the metabolic syndrome. Genetic factors influence each individual component of the syndrome, and the syndrome itself. A family history that includes type 2 diabetes, hypertension, and early heart disease greatly increases the chance that an individual will develop the metabolic syndrome. Environmental issues such as low activity level, sedentary lifestyle, and progressive weight gain also contribute significantly to the risk of developing the metabolic syndrome.
Obesity is likely the greatest risk factor for metabolic syndrome; however other risk factors of concern include:
- women who are post-menopausal
- eating an excessively high carbohydrate diet
- lack of activity (even without weight change)
Metabolic Syndrome Symptoms
Symptoms depend on which components of the syndrome are present. Hypertension typically produces no symptoms but may present withblurred vision and headaches. Insulin resistance may be associated with difficulty losing weight and a sense of hypoglycemia(feeling of low blood sugar). In its extreme, metabolic syndrome can present with symptoms related to heart disease or stroke.
When to Seek Medical Care
If you have any of the risk factors associated with metabolic syndrome, or if you are at risk for any of the components of metabolic syndrome, you should discuss this with your health care practitioner. Similarly, if you have a strong family history of heart disease, stroke, early cardiac death, obesity and/or diabetes, you should seek medical advice.
Exams and Tests
A detailed history and physical examination should be performed. Each individual component of the syndrome should be evaluated distinctly. All of the following exams or tests may be warranted:
- blood pressure
- weight and body composition (if available)
- blood lipid levels
- diabetes assessment by fasting blood sugar, insulin level, hemoglobin A1c and oral glucose tolerance testing
Cardiac risk factors can be assessed to estimate cardiovascular risk. These may include blood tests for homocysteine and C-reactive protein (CRP) levels,electrocardiograms, angiograms, and more detailed assessments if necessary
Metabolic Syndrome Treatment
Self-Care at Home
Lifestyle modification is the preferred treatment of metabolic syndrome. Weight reduction usually requires a specifically tailored multifaceted program for the patient that includes diet and exercise. Medications may be useful in some instances. As noted above, most people who have metabolic syndrome are overweight and lead a sedentary lifestyle.
A detailed discussion of therapeutic diets and the pros and cons of each diet is beyond the scope of this article. However, one diet that is palatable and easily sustained and has shown benefit is the Mediterranean diet. The Mediterranean diet is rich in olive oil (a "good fat") and contains a reasonable and sustainable amount of protein and carbohydrates. Some studies have suggested that when compared to a low fat diet, people on the Mediterranean diet have had a greater decrease in body weight, greater improvements in lowering blood pressure and cholesterol levels, and improvement in other markers of heart disease; all of which are important in evaluating and treating metabolic syndrome.
A regular and consistent exercise program is also an important lifestyle modification that can be accomplished at home or a gym. Thirty minutes of exercise five days a week is a reasonable start, providing there are no medical contraindications to exercise. (It is prudent to consult your physician prior to starting any exercise program.) Lowering blood pressure and cholesterol levels, along with increasing insulin sensitivity, are beneficial effects of a regular consistent exercise program, regardless of whether weight loss is achieved. Thus, exercise in still a helpful tool in treating metabolic syndrome.
Medical management should be aimed at targeting the components of metabolic syndrome that are present.
If a patient with metabolic syndrome has already had a heart attack, their LDL ("bad") cholesterol should be reduced to a level below 70mg/dl. Lifestyle modifications and medications may both be necessary to achieve this desired reduction.
A person with diabetes has a heart attack risk equivalent to that of someone who has already a heart attack, and should be treated the same as a patient who has had a heart attack. What remains controversial is whether metabolic syndrome should be considered sufficient to raise the risk to this degree. If a patient has metabolic syndrome, a detailed discussion about therapy to reduce blood lipid levels is necessary between the patient and the doctor, as each individual case is unique.
Goals for lowering blood pressure are generally set lower than 130/80. In addition to lowering blood pressure, some blood pressure medications have other effects on the body. For example, ACE inhibitors (a class of blood pressure drugs) has been found to reduce the levels of insulin resistance and thus may slow the development of type 2 diabetes. This is an important consideration when discussing the choice of blood pressure drugs for a patient with metabolic syndrome.
While a healthy body weight should also be a goal of treatment, it is important to remember that a reduction in weight (as little as 5%-10%) can have a dramatic benefit on lowering blood pressure and cholesterol levels and increasing insulin sensitivity.
Medications should be tailored to target the specific components of the metabolic syndrome that are present in the patient.
Cholesterol-lowering drug classes include statins and fibrates. Blood pressure medications of various classes can be used, with consideration of coexisting diseases or conditions. Aspirin may be considered to reduce cardiac risk, along with supplements such as omega 3-fatty acids and fish oils.
Metformin (Glucophage), usually used to treat type 2 diabetes, also has been found to help prevent the onset of diabetes in people with metabolic syndrome. Many of my patients who have insulin resistance associated with metabolic syndrome opt for metformin therapy. However, there are currently no established guidelines on treating metabolic syndrome patients with metformin if they do not have overt diabetes.
Routine follow-up is recommended for patients with metabolic syndrome, both to address the treatment of the components present, as well as to monitor for the development of heart disease or associated problems.
Prevention of metabolic syndrome in its entirety may not be possible in all cases, given the genetic contribution. However, there are ways to prevent worsening of the individual components.
Prevention methods include:
- A consistent exercise routine: walking, bicycling, swimming, yoga, etc. Find an exercise buddy if you can't seem to be consistent with the routine.
- Take a walk during your work break, even if it is just around the building.
- Choose healthier foods and pass on the junk food.
- Evaluate what you feed your children. Are they eating healthy as well? Childhood obesity is rising dramatically in the United States.
- Urge children to go outside and play to get some exercise.
It all adds up. Preventing metabolic syndrome really means having a healthy sustainable lifestyle.
While these treatment options can be addressed at a doctor's office, implementation really has to occur in the real world. In addition to medications, an active attempt to choose healthier foods and exercising regularly is necessary. With sincere effort, we can alter the course of the syndrome in a positive way.
Synonyms and Keywords
metabolic syndrome x, metabolic syndrome diet, cardiovascular metabolic syndrome, dysmetabolic syndrome, syndrome x